new plumbing package (#118)

* plumbing: now core was renamed to core, and formats and clients moved inside

133 files changed, 2000 insertions, 1933 deletions

diff --git a/blame.go b/blame.go
index e698c78..f583299 100644
--- a/blame.go
+++ b/blame.go
@@ -8,13 +8,13 @@ import (
 	"strings"
 	"unicode/utf8"
 
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/diff"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 type Blame struct {
 	Path  string
-	Rev   core.Hash
+	Rev   plumbing.Hash
 	Lines []*line
 }
 
@@ -256,7 +256,7 @@ func prettyPrintAuthor(c *Commit) string {
 // utility function to calculate the number of runes needed
 // to print the longest author name in the blame of a file.
 func (b *blame) maxAuthorLength() int {
-	memo := make(map[core.Hash]struct{}, len(b.graph)-1)
+	memo := make(map[plumbing.Hash]struct{}, len(b.graph)-1)
 	fVs := b.graph[len(b.graph)-1]
 	m := 0
 	for ln := range fVs {
diff --git a/blame_test.go b/blame_test.go
index 2d9161c..53f2271 100644
--- a/blame_test.go
+++ b/blame_test.go
@@ -1,8 +1,8 @@
 package git
 
 import (
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/fixtures"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 
 	. "gopkg.in/check.v1"
 )
@@ -24,7 +24,7 @@ func (s *BlameSuite) mockBlame(t blameTest, c *C) (blame *Blame) {
 	r, ok := s.Repositories[t.repo]
 	c.Assert(ok, Equals, true)
 
-	commit, err := r.Commit(core.NewHash(t.rev))
+	commit, err := r.Commit(plumbing.NewHash(t.rev))
 	c.Assert(err, IsNil, Commentf("%v: repo=%s, rev=%s", err, r, t.rev))
 
 	f, err := commit.File(t.path)
@@ -36,7 +36,7 @@ func (s *BlameSuite) mockBlame(t blameTest, c *C) (blame *Blame) {
 
 	blamedLines := make([]*line, 0, len(t.blames))
 	for i := range t.blames {
-		commit, err := r.Commit(core.NewHash(t.blames[i]))
+		commit, err := r.Commit(plumbing.NewHash(t.blames[i]))
 		c.Assert(err, IsNil)
 		l := &line{
 			author: commit.Author.Email,
@@ -47,7 +47,7 @@ func (s *BlameSuite) mockBlame(t blameTest, c *C) (blame *Blame) {
 
 	return &Blame{
 		Path:  t.path,
-		Rev:   core.NewHash(t.rev),
+		Rev:   plumbing.NewHash(t.rev),
 		Lines: blamedLines,
 	}
 }
@@ -65,7 +65,7 @@ func (s *BlameSuite) TestBlame(c *C) {
 		r, ok := s.Repositories[t.repo]
 		c.Assert(ok, Equals, true)
 
-		commit, err := r.Commit(core.NewHash(t.rev))
+		commit, err := r.Commit(plumbing.NewHash(t.rev))
 		c.Assert(err, IsNil)
 
 		obt, err := commit.Blame(t.path)
diff --git a/blobs.go b/blobs.go
index 4ecd989..9585af8 100644
--- a/blobs.go
+++ b/blobs.go
@@ -3,35 +3,36 @@ package git
 import (
 	"io"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 )
 
 // Blob is used to store file data - it is generally a file.
 type Blob struct {
-	Hash core.Hash
+	Hash plumbing.Hash
 	Size int64
 
-	obj core.Object
+	obj plumbing.Object
 }
 
 // ID returns the object ID of the blob. The returned value will always match
 // the current value of Blob.Hash.
 //
 // ID is present to fulfill the Object interface.
-func (b *Blob) ID() core.Hash {
+func (b *Blob) ID() plumbing.Hash {
 	return b.Hash
 }
 
-// Type returns the type of object. It always returns core.BlobObject.
+// Type returns the type of object. It always returns plumbing.BlobObject.
 //
 // Type is present to fulfill the Object interface.
-func (b *Blob) Type() core.ObjectType {
-	return core.BlobObject
+func (b *Blob) Type() plumbing.ObjectType {
+	return plumbing.BlobObject
 }
 
-// Decode transforms a core.Object into a Blob struct.
-func (b *Blob) Decode(o core.Object) error {
-	if o.Type() != core.BlobObject {
+// Decode transforms a plumbing.Object into a Blob struct.
+func (b *Blob) Decode(o plumbing.Object) error {
+	if o.Type() != plumbing.BlobObject {
 		return ErrUnsupportedObject
 	}
 
@@ -42,8 +43,8 @@ func (b *Blob) Decode(o core.Object) error {
 	return nil
 }
 
-// Encode transforms a Blob into a core.Object.
-func (b *Blob) Encode(o core.Object) error {
+// Encode transforms a Blob into a plumbing.Object.
+func (b *Blob) Encode(o plumbing.Object) error {
 	w, err := o.Writer()
 	if err != nil {
 		return err
@@ -55,7 +56,7 @@ func (b *Blob) Encode(o core.Object) error {
 	}
 	defer checkClose(r, &err)
 	_, err = io.Copy(w, r)
-	o.SetType(core.BlobObject)
+	o.SetType(plumbing.BlobObject)
 	return err
 }
 
@@ -66,7 +67,7 @@ func (b *Blob) Reader() (io.ReadCloser, error) {
 
 // BlobIter provides an iterator for a set of blobs.
 type BlobIter struct {
-	core.ObjectIter
+	storer.ObjectIter
 	r *Repository
 }
 
@@ -74,7 +75,7 @@ type BlobIter struct {
 // object iterator.
 //
 // The returned BlobIter will automatically skip over non-blob objects.
-func NewBlobIter(r *Repository, iter core.ObjectIter) *BlobIter {
+func NewBlobIter(r *Repository, iter storer.ObjectIter) *BlobIter {
 	return &BlobIter{iter, r}
 }
 
@@ -87,7 +88,7 @@ func (iter *BlobIter) Next() (*Blob, error) {
 			return nil, err
 		}
 
-		if obj.Type() != core.BlobObject {
+		if obj.Type() != plumbing.BlobObject {
 			continue
 		}
 
@@ -100,8 +101,8 @@ func (iter *BlobIter) Next() (*Blob, error) {
 // an error happens or the end of the iter is reached. If ErrStop is sent
 // the iteration is stop but no error is returned. The iterator is closed.
 func (iter *BlobIter) ForEach(cb func(*Blob) error) error {
-	return iter.ObjectIter.ForEach(func(obj core.Object) error {
-		if obj.Type() != core.BlobObject {
+	return iter.ObjectIter.ForEach(func(obj plumbing.Object) error {
+		if obj.Type() != plumbing.BlobObject {
 			return nil
 		}
 
diff --git a/blobs_test.go b/blobs_test.go
index b667fa4..a323744 100644
--- a/blobs_test.go
+++ b/blobs_test.go
@@ -4,7 +4,7 @@ import (
 	"io"
 	"io/ioutil"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 
 	. "gopkg.in/check.v1"
 )
@@ -16,8 +16,8 @@ type BlobsSuite struct {
 var _ = Suite(&BlobsSuite{})
 
 func (s *BlobsSuite) TestBlobHash(c *C) {
-	o := &core.MemoryObject{}
-	o.SetType(core.BlobObject)
+	o := &plumbing.MemoryObject{}
+	o.SetType(plumbing.BlobObject)
 	o.SetSize(3)
 
 	writer, err := o.Writer()
@@ -42,11 +42,11 @@ func (s *BlobsSuite) TestBlobHash(c *C) {
 }
 
 func (s *BlobsSuite) TestBlobDecodeEncodeIdempotent(c *C) {
-	var objects []*core.MemoryObject
+	var objects []*plumbing.MemoryObject
 	for _, str := range []string{"foo", "foo\n"} {
-		obj := &core.MemoryObject{}
+		obj := &plumbing.MemoryObject{}
 		obj.Write([]byte(str))
-		obj.SetType(core.BlobObject)
+		obj.SetType(plumbing.BlobObject)
 		obj.Hash()
 		objects = append(objects, obj)
 	}
@@ -54,7 +54,7 @@ func (s *BlobsSuite) TestBlobDecodeEncodeIdempotent(c *C) {
 		blob := &Blob{}
 		err := blob.Decode(object)
 		c.Assert(err, IsNil)
-		newObject := &core.MemoryObject{}
+		newObject := &plumbing.MemoryObject{}
 		err = blob.Encode(newObject)
 		c.Assert(err, IsNil)
 		newObject.Hash() // Ensure Hash is pre-computed before deep comparison
diff --git a/commit.go b/commit.go
index c42236e..6f93832 100644
--- a/commit.go
+++ b/commit.go
@@ -8,11 +8,12 @@ import (
 	"sort"
 	"strings"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 )
 
 // Hash hash of an object
-type Hash core.Hash
+type Hash plumbing.Hash
 
 // Commit points to a single tree, marking it as what the project looked like
 // at a certain point in time. It contains meta-information about that point
@@ -20,13 +21,13 @@ type Hash core.Hash
 // commit, a pointer to the previous commit(s), etc.
 // http://schacon.github.io/gitbook/1_the_git_object_model.html
 type Commit struct {
-	Hash      core.Hash
+	Hash      plumbing.Hash
 	Author    Signature
 	Committer Signature
 	Message   string
 
-	tree    core.Hash
-	parents []core.Hash
+	tree    plumbing.Hash
+	parents []plumbing.Hash
 	r       *Repository
 }
 
@@ -38,7 +39,7 @@ func (c *Commit) Tree() (*Tree, error) {
 // Parents return a CommitIter to the parent Commits
 func (c *Commit) Parents() *CommitIter {
 	return NewCommitIter(c.r,
-		core.NewObjectLookupIter(c.r.s, core.CommitObject, c.parents),
+		storer.NewObjectLookupIter(c.r.s, plumbing.CommitObject, c.parents),
 	)
 }
 
@@ -73,20 +74,20 @@ func (c *Commit) Files() (*FileIter, error) {
 // the current value of Commit.Hash.
 //
 // ID is present to fulfill the Object interface.
-func (c *Commit) ID() core.Hash {
+func (c *Commit) ID() plumbing.Hash {
 	return c.Hash
 }
 
-// Type returns the type of object. It always returns core.CommitObject.
+// Type returns the type of object. It always returns plumbing.CommitObject.
 //
 // Type is present to fulfill the Object interface.
-func (c *Commit) Type() core.ObjectType {
-	return core.CommitObject
+func (c *Commit) Type() plumbing.ObjectType {
+	return plumbing.CommitObject
 }
 
-// Decode transforms a core.Object into a Commit struct.
-func (c *Commit) Decode(o core.Object) (err error) {
-	if o.Type() != core.CommitObject {
+// Decode transforms a plumbing.Object into a Commit struct.
+func (c *Commit) Decode(o plumbing.Object) (err error) {
+	if o.Type() != plumbing.CommitObject {
 		return ErrUnsupportedObject
 	}
 
@@ -117,9 +118,9 @@ func (c *Commit) Decode(o core.Object) (err error) {
 			split := bytes.SplitN(line, []byte{' '}, 2)
 			switch string(split[0]) {
 			case "tree":
-				c.tree = core.NewHash(string(split[1]))
+				c.tree = plumbing.NewHash(string(split[1]))
 			case "parent":
-				c.parents = append(c.parents, core.NewHash(string(split[1])))
+				c.parents = append(c.parents, plumbing.NewHash(string(split[1])))
 			case "author":
 				c.Author.Decode(split[1])
 			case "committer":
@@ -147,9 +148,9 @@ func (c *Commit) History() ([]*Commit, error) {
 	return commits, err
 }
 
-// Encode transforms a Commit into a core.Object.
-func (b *Commit) Encode(o core.Object) error {
-	o.SetType(core.CommitObject)
+// Encode transforms a Commit into a plumbing.Object.
+func (b *Commit) Encode(o plumbing.Object) error {
+	o.SetType(plumbing.CommitObject)
 	w, err := o.Writer()
 	if err != nil {
 		return err
@@ -184,7 +185,7 @@ func (b *Commit) Encode(o core.Object) error {
 func (c *Commit) String() string {
 	return fmt.Sprintf(
 		"%s %s\nAuthor: %s\nDate:   %s\n\n%s\n",
-		core.CommitObject, c.Hash, c.Author.String(),
+		plumbing.CommitObject, c.Hash, c.Author.String(),
 		c.Author.When.Format(DateFormat), indent(c.Message),
 	)
 }
@@ -204,7 +205,7 @@ func indent(t string) string {
 
 // CommitIter provides an iterator for a set of commits.
 type CommitIter struct {
-	core.ObjectIter
+	storer.ObjectIter
 	r *Repository
 }
 
@@ -212,7 +213,7 @@ type CommitIter struct {
 // object iterator.
 //
 // The returned CommitIter will automatically skip over non-commit objects.
-func NewCommitIter(r *Repository, iter core.ObjectIter) *CommitIter {
+func NewCommitIter(r *Repository, iter storer.ObjectIter) *CommitIter {
 	return &CommitIter{iter, r}
 }
 
@@ -232,7 +233,7 @@ func (iter *CommitIter) Next() (*Commit, error) {
 // an error happends or the end of the iter is reached. If ErrStop is sent
 // the iteration is stop but no error is returned. The iterator is closed.
 func (iter *CommitIter) ForEach(cb func(*Commit) error) error {
-	return iter.ObjectIter.ForEach(func(obj core.Object) error {
+	return iter.ObjectIter.ForEach(func(obj plumbing.Object) error {
 		commit := &Commit{r: iter.r}
 		if err := commit.Decode(obj); err != nil {
 			return err
diff --git a/commit_test.go b/commit_test.go
index 0020172..40e8973 100644
--- a/commit_test.go
+++ b/commit_test.go
@@ -4,8 +4,8 @@ import (
 	"io"
 	"time"
 
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/fixtures"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 
 	. "gopkg.in/check.v1"
 )
@@ -20,7 +20,7 @@ var _ = Suite(&SuiteCommit{})
 func (s *SuiteCommit) SetUpSuite(c *C) {
 	s.BaseSuite.SetUpSuite(c)
 
-	hash := core.NewHash("1669dce138d9b841a518c64b10914d88f5e488ea")
+	hash := plumbing.NewHash("1669dce138d9b841a518c64b10914d88f5e488ea")
 
 	var err error
 	s.Commit, err = s.Repository.Commit(hash)
@@ -28,8 +28,8 @@ func (s *SuiteCommit) SetUpSuite(c *C) {
 }
 
 func (s *SuiteCommit) TestDecodeNonCommit(c *C) {
-	hash := core.NewHash("9a48f23120e880dfbe41f7c9b7b708e9ee62a492")
-	blob, err := s.Repository.s.Object(core.AnyObject, hash)
+	hash := plumbing.NewHash("9a48f23120e880dfbe41f7c9b7b708e9ee62a492")
+	blob, err := s.Repository.s.Object(plumbing.AnyObject, hash)
 	c.Assert(err, IsNil)
 
 	commit := &Commit{}
@@ -38,7 +38,7 @@ func (s *SuiteCommit) TestDecodeNonCommit(c *C) {
 }
 
 func (s *SuiteCommit) TestType(c *C) {
-	c.Assert(s.Commit.Type(), Equals, core.CommitObject)
+	c.Assert(s.Commit.Type(), Equals, plumbing.CommitObject)
 }
 
 func (s *SuiteCommit) TestTree(c *C) {
@@ -72,24 +72,24 @@ func (s *SuiteCommit) TestCommitEncodeDecodeIdempotent(c *C) {
 			Author:    Signature{Name: "Foo", Email: "foo@example.local", When: ts},
 			Committer: Signature{Name: "Bar", Email: "bar@example.local", When: ts},
 			Message:   "Message\n\nFoo\nBar\nWith trailing blank lines\n\n",
-			tree:      core.NewHash("f000000000000000000000000000000000000001"),
-			parents:   []core.Hash{core.NewHash("f000000000000000000000000000000000000002")},
+			tree:      plumbing.NewHash("f000000000000000000000000000000000000001"),
+			parents:   []plumbing.Hash{plumbing.NewHash("f000000000000000000000000000000000000002")},
 		},
 		{
 			Author:    Signature{Name: "Foo", Email: "foo@example.local", When: ts},
 			Committer: Signature{Name: "Bar", Email: "bar@example.local", When: ts},
 			Message:   "Message\n\nFoo\nBar\nWith no trailing blank lines",
-			tree:      core.NewHash("0000000000000000000000000000000000000003"),
-			parents: []core.Hash{
-				core.NewHash("f000000000000000000000000000000000000004"),
-				core.NewHash("f000000000000000000000000000000000000005"),
-				core.NewHash("f000000000000000000000000000000000000006"),
-				core.NewHash("f000000000000000000000000000000000000007"),
+			tree:      plumbing.NewHash("0000000000000000000000000000000000000003"),
+			parents: []plumbing.Hash{
+				plumbing.NewHash("f000000000000000000000000000000000000004"),
+				plumbing.NewHash("f000000000000000000000000000000000000005"),
+				plumbing.NewHash("f000000000000000000000000000000000000006"),
+				plumbing.NewHash("f000000000000000000000000000000000000007"),
 			},
 		},
 	}
 	for _, commit := range commits {
-		obj := &core.MemoryObject{}
+		obj := &plumbing.MemoryObject{}
 		err = commit.Encode(obj)
 		c.Assert(err, IsNil)
 		newCommit := &Commit{}
@@ -130,7 +130,7 @@ func (s *SuiteCommit) TestString(c *C) {
 }
 
 func (s *SuiteCommit) TestStringMultiLine(c *C) {
-	hash := core.NewHash("e7d896db87294e33ca3202e536d4d9bb16023db3")
+	hash := plumbing.NewHash("e7d896db87294e33ca3202e536d4d9bb16023db3")
 
 	s.buildRepositories(c, fixtures.ByURL("https://github.com/src-d/go-git.git"))
 
diff --git a/commit_walker.go b/commit_walker.go
index e595a84..8685801 100644
--- a/commit_walker.go
+++ b/commit_walker.go
@@ -3,11 +3,11 @@ package git
 import (
 	"io"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 type commitWalker struct {
-	seen  map[core.Hash]bool
+	seen  map[plumbing.Hash]bool
 	stack []*CommitIter
 	start *Commit
 	cb    func(*Commit) error
@@ -16,7 +16,7 @@ type commitWalker struct {
 // WalkCommitHistory walks the commit history
 func WalkCommitHistory(c *Commit, cb func(*Commit) error) error {
 	w := &commitWalker{
-		seen:  make(map[core.Hash]bool),
+		seen:  make(map[plumbing.Hash]bool),
 		stack: make([]*CommitIter, 0),
 		start: c,
 		cb:    cb,
diff --git a/common.go b/common.go
index 2a55a37..aee932f 100644
--- a/common.go
+++ b/common.go
@@ -5,7 +5,7 @@ import (
 	"strings"
 
 	"gopkg.in/src-d/go-git.v4/config"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 )
 
 // Storer is a generic storage of objects, references and any information
@@ -13,8 +13,8 @@ import (
 // information in an system directory (such as `.git`) and others
 // implementations are in memmory being ephemeral
 type Storer interface {
-	core.ObjectStorer
-	core.ReferenceStorer
+	storer.ObjectStorer
+	storer.ReferenceStorer
 	config.ConfigStorer
 }
 
diff --git a/common_test.go b/common_test.go
index 672a157..95282ea 100644
--- a/common_test.go
+++ b/common_test.go
@@ -6,12 +6,12 @@ import (
 	"os"
 	"testing"
 
-	"gopkg.in/src-d/go-git.v4/clients"
-	"gopkg.in/src-d/go-git.v4/clients/common"
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/fixtures"
-	"gopkg.in/src-d/go-git.v4/formats/packfile"
-	"gopkg.in/src-d/go-git.v4/formats/packp"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/client"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/common"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packfile"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp"
 	"gopkg.in/src-d/go-git.v4/storage/filesystem"
 
 	. "gopkg.in/check.v1"
@@ -94,17 +94,17 @@ func (p *MockGitUploadPackService) Info() (*common.GitUploadPackInfo, error) {
 	c := packp.NewCapabilities()
 	c.Decode("6ecf0ef2c2dffb796033e5a02219af86ec6584e5 HEADmulti_ack thin-pack side-band side-band-64k ofs-delta shallow no-progress include-tag multi_ack_detailed no-done symref=HEAD:refs/heads/master agent=git/2:2.4.8~dbussink-fix-enterprise-tokens-compilation-1167-gc7006cf")
 
-	ref := core.ReferenceName("refs/heads/master")
-	branch := core.ReferenceName("refs/heads/branch")
-	tag := core.ReferenceName("refs/tags/v1.0.0")
+	ref := plumbing.ReferenceName("refs/heads/master")
+	branch := plumbing.ReferenceName("refs/heads/branch")
+	tag := plumbing.ReferenceName("refs/tags/v1.0.0")
 
 	return &common.GitUploadPackInfo{
 		Capabilities: c,
-		Refs: map[core.ReferenceName]*core.Reference{
-			core.HEAD: core.NewSymbolicReference(core.HEAD, ref),
-			ref:       core.NewHashReference(ref, h),
-			tag:       core.NewHashReference(tag, h),
-			branch:    core.NewHashReference(branch, core.NewHash("e8d3ffab552895c19b9fcf7aa264d277cde33881")),
+		Refs: map[plumbing.ReferenceName]*plumbing.Reference{
+			plumbing.HEAD: plumbing.NewSymbolicReference(plumbing.HEAD, ref),
+			ref:           plumbing.NewHashReference(ref, h),
+			tag:           plumbing.NewHashReference(tag, h),
+			branch:        plumbing.NewHashReference(branch, plumbing.NewHash("e8d3ffab552895c19b9fcf7aa264d277cde33881")),
 		},
 	}, nil
 }
diff --git a/config/refspec.go b/config/refspec.go
index 0f41c5a..fd0aa3d 100644
--- a/config/refspec.go
+++ b/config/refspec.go
@@ -3,7 +3,7 @@ package config
 import (
 	"strings"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 const (
@@ -57,8 +57,8 @@ func (s RefSpec) Src() string {
 	return spec[start:end]
 }
 
-// Match match the given core.ReferenceName against the source
-func (s RefSpec) Match(n core.ReferenceName) bool {
+// Match match the given plumbing.ReferenceName against the source
+func (s RefSpec) Match(n plumbing.ReferenceName) bool {
 	if !s.IsWildcard() {
 		return s.matchExact(n)
 	}
@@ -71,11 +71,11 @@ func (s RefSpec) IsWildcard() bool {
 	return strings.Index(string(s), refSpecWildcard) != -1
 }
 
-func (s RefSpec) matchExact(n core.ReferenceName) bool {
+func (s RefSpec) matchExact(n plumbing.ReferenceName) bool {
 	return s.Src() == n.String()
 }
 
-func (s RefSpec) matchGlob(n core.ReferenceName) bool {
+func (s RefSpec) matchGlob(n plumbing.ReferenceName) bool {
 	src := s.Src()
 	name := n.String()
 	wildcard := strings.Index(src, refSpecWildcard)
@@ -92,14 +92,14 @@ func (s RefSpec) matchGlob(n core.ReferenceName) bool {
 }
 
 // Dst returns the destination for the given remote reference
-func (s RefSpec) Dst(n core.ReferenceName) core.ReferenceName {
+func (s RefSpec) Dst(n plumbing.ReferenceName) plumbing.ReferenceName {
 	spec := string(s)
 	start := strings.Index(spec, refSpecSeparator) + 1
 	dst := spec[start:]
 	src := s.Src()
 
 	if !s.IsWildcard() {
-		return core.ReferenceName(dst)
+		return plumbing.ReferenceName(dst)
 	}
 
 	name := n.String()
@@ -107,7 +107,7 @@ func (s RefSpec) Dst(n core.ReferenceName) core.ReferenceName {
 	wd := strings.Index(dst, refSpecWildcard)
 	match := name[ws : len(name)-(len(src)-(ws+1))]
 
-	return core.ReferenceName(dst[0:wd] + match + dst[wd+1:])
+	return plumbing.ReferenceName(dst[0:wd] + match + dst[wd+1:])
 }
 
 func (s RefSpec) String() string {
@@ -115,7 +115,7 @@ func (s RefSpec) String() string {
 }
 
 // MatchAny returns true if any of the RefSpec match with the given ReferenceName
-func MatchAny(l []RefSpec, n core.ReferenceName) bool {
+func MatchAny(l []RefSpec, n plumbing.ReferenceName) bool {
 	for _, r := range l {
 		if r.Match(n) {
 			return true
diff --git a/config/refspec_test.go b/config/refspec_test.go
index 632f5a4..f0d1a0e 100644
--- a/config/refspec_test.go
+++ b/config/refspec_test.go
@@ -4,7 +4,7 @@ import (
 	"testing"
 
 	. "gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 type RefSpecSuite struct{}
@@ -42,20 +42,20 @@ func (s *RefSpecSuite) TestRefSpecSrc(c *C) {
 
 func (s *RefSpecSuite) TestRefSpecMatch(c *C) {
 	spec := RefSpec("refs/heads/master:refs/remotes/origin/master")
-	c.Assert(spec.Match(core.ReferenceName("refs/heads/foo")), Equals, false)
-	c.Assert(spec.Match(core.ReferenceName("refs/heads/master")), Equals, true)
+	c.Assert(spec.Match(plumbing.ReferenceName("refs/heads/foo")), Equals, false)
+	c.Assert(spec.Match(plumbing.ReferenceName("refs/heads/master")), Equals, true)
 }
 
 func (s *RefSpecSuite) TestRefSpecMatchBlob(c *C) {
 	spec := RefSpec("refs/heads/*:refs/remotes/origin/*")
-	c.Assert(spec.Match(core.ReferenceName("refs/tag/foo")), Equals, false)
-	c.Assert(spec.Match(core.ReferenceName("refs/heads/foo")), Equals, true)
+	c.Assert(spec.Match(plumbing.ReferenceName("refs/tag/foo")), Equals, false)
+	c.Assert(spec.Match(plumbing.ReferenceName("refs/heads/foo")), Equals, true)
 }
 
 func (s *RefSpecSuite) TestRefSpecDst(c *C) {
 	spec := RefSpec("refs/heads/master:refs/remotes/origin/master")
 	c.Assert(
-		spec.Dst(core.ReferenceName("refs/heads/master")).String(), Equals,
+		spec.Dst(plumbing.ReferenceName("refs/heads/master")).String(), Equals,
 		"refs/remotes/origin/master",
 	)
 }
@@ -63,7 +63,7 @@ func (s *RefSpecSuite) TestRefSpecDst(c *C) {
 func (s *RefSpecSuite) TestRefSpecDstBlob(c *C) {
 	spec := RefSpec("refs/heads/*:refs/remotes/origin/*")
 	c.Assert(
-		spec.Dst(core.ReferenceName("refs/heads/foo")).String(), Equals,
+		spec.Dst(plumbing.ReferenceName("refs/heads/foo")).String(), Equals,
 		"refs/remotes/origin/foo",
 	)
 }
@@ -73,7 +73,7 @@ func (s *RefSpecSuite) TestMatchAny(c *C) {
 		"refs/heads/foo:refs/remotes/origin/bar",
 	}
 
-	c.Assert(MatchAny(specs, core.ReferenceName("refs/heads/foo")), Equals, true)
-	c.Assert(MatchAny(specs, core.ReferenceName("refs/heads/bar")), Equals, true)
-	c.Assert(MatchAny(specs, core.ReferenceName("refs/heads/master")), Equals, false)
+	c.Assert(MatchAny(specs, plumbing.ReferenceName("refs/heads/foo")), Equals, true)
+	c.Assert(MatchAny(specs, plumbing.ReferenceName("refs/heads/bar")), Equals, true)
+	c.Assert(MatchAny(specs, plumbing.ReferenceName("refs/heads/master")), Equals, false)
 }
diff --git a/core/object_test.go b/core/object_test.go
deleted file mode 100644
index 5ebf26a..0000000
--- a/core/object_test.go
+++ /dev/null
@@ -1,176 +0,0 @@
-package core
-
-import (
-	"fmt"
-
-	. "gopkg.in/check.v1"
-)
-
-type ObjectSuite struct{}
-
-var _ = Suite(&ObjectSuite{})
-
-func (s *ObjectSuite) TestObjectTypeString(c *C) {
-	c.Assert(CommitObject.String(), Equals, "commit")
-	c.Assert(TreeObject.String(), Equals, "tree")
-	c.Assert(BlobObject.String(), Equals, "blob")
-	c.Assert(TagObject.String(), Equals, "tag")
-	c.Assert(REFDeltaObject.String(), Equals, "ref-delta")
-	c.Assert(OFSDeltaObject.String(), Equals, "ofs-delta")
-	c.Assert(AnyObject.String(), Equals, "any")
-	c.Assert(ObjectType(42).String(), Equals, "unknown")
-}
-
-func (s *ObjectSuite) TestObjectTypeBytes(c *C) {
-	c.Assert(CommitObject.Bytes(), DeepEquals, []byte("commit"))
-}
-
-func (s *ObjectSuite) TestObjectTypeValid(c *C) {
-	c.Assert(CommitObject.Valid(), Equals, true)
-	c.Assert(ObjectType(42).Valid(), Equals, false)
-}
-
-func (s *ObjectSuite) TestParseObjectType(c *C) {
-	for s, e := range map[string]ObjectType{
-		"commit":    CommitObject,
-		"tree":      TreeObject,
-		"blob":      BlobObject,
-		"tag":       TagObject,
-		"ref-delta": REFDeltaObject,
-		"ofs-delta": OFSDeltaObject,
-	} {
-		t, err := ParseObjectType(s)
-		c.Assert(err, IsNil)
-		c.Assert(e, Equals, t)
-	}
-
-	t, err := ParseObjectType("foo")
-	c.Assert(err, Equals, ErrInvalidType)
-	c.Assert(t, Equals, InvalidObject)
-}
-
-func (s *ObjectSuite) TestMultiObjectIterNext(c *C) {
-	expected := []Object{
-		&MemoryObject{},
-		&MemoryObject{},
-		&MemoryObject{},
-		&MemoryObject{},
-		&MemoryObject{},
-		&MemoryObject{},
-	}
-
-	iter := NewMultiObjectIter([]ObjectIter{
-		NewObjectSliceIter(expected[0:2]),
-		NewObjectSliceIter(expected[2:4]),
-		NewObjectSliceIter(expected[4:5]),
-	})
-
-	var i int
-	iter.ForEach(func(o Object) error {
-		c.Assert(o, Equals, expected[i])
-		i++
-		return nil
-	})
-
-	iter.Close()
-}
-
-func (s *ObjectSuite) TestObjectLookupIter(c *C) {
-	h := []Hash{
-		NewHash("0920f02906615b285040767a67c5cb30fe0f5e2c"),
-		NewHash("4921e391f1128010a2d957f8db15c5e729ccf94a"),
-	}
-
-	var count int
-
-	i := NewObjectLookupIter(&MockObjectStorage{}, CommitObject, h)
-	err := i.ForEach(func(o Object) error {
-		c.Assert(o, NotNil)
-		c.Assert(o.Hash().String(), Equals, h[count].String())
-		count++
-		return nil
-	})
-
-	c.Assert(err, IsNil)
-	i.Close()
-}
-
-func (s *ObjectSuite) TestObjectSliceIter(c *C) {
-	h := []Hash{
-		NewHash("0920f02906615b285040767a67c5cb30fe0f5e2c"),
-		NewHash("4921e391f1128010a2d957f8db15c5e729ccf94a"),
-	}
-
-	var count int
-
-	i := NewObjectSliceIter([]Object{
-		&MemoryObject{h: h[0]}, &MemoryObject{h: h[1]},
-	})
-
-	err := i.ForEach(func(o Object) error {
-		c.Assert(o, NotNil)
-		c.Assert(o.Hash().String(), Equals, h[count].String())
-		count++
-		return nil
-	})
-
-	c.Assert(count, Equals, 2)
-	c.Assert(err, IsNil)
-	c.Assert(i.series, HasLen, 0)
-}
-
-func (s *ObjectSuite) TestObjectSliceIterStop(c *C) {
-	h := []Hash{
-		NewHash("0920f02906615b285040767a67c5cb30fe0f5e2c"),
-		NewHash("4921e391f1128010a2d957f8db15c5e729ccf94a"),
-	}
-
-	i := NewObjectSliceIter([]Object{
-		&MemoryObject{h: h[0]}, &MemoryObject{h: h[1]},
-	})
-
-	var count = 0
-	err := i.ForEach(func(o Object) error {
-		c.Assert(o, NotNil)
-		c.Assert(o.Hash().String(), Equals, h[count].String())
-		count++
-		return ErrStop
-	})
-
-	c.Assert(count, Equals, 1)
-	c.Assert(err, IsNil)
-}
-
-func (s *ObjectSuite) TestObjectSliceIterError(c *C) {
-	i := NewObjectSliceIter([]Object{
-		&MemoryObject{h: NewHash("4921e391f1128010a2d957f8db15c5e729ccf94a")},
-	})
-
-	err := i.ForEach(func(Object) error {
-		return fmt.Errorf("a random error")
-	})
-
-	c.Assert(err, NotNil)
-}
-
-type MockObjectStorage struct{}
-
-func (o *MockObjectStorage) NewObject() Object {
-	return nil
-}
-
-func (o *MockObjectStorage) SetObject(obj Object) (Hash, error) {
-	return ZeroHash, nil
-}
-
-func (o *MockObjectStorage) Object(t ObjectType, h Hash) (Object, error) {
-	return &MemoryObject{h: h}, nil
-}
-
-func (o *MockObjectStorage) IterObjects(t ObjectType) (ObjectIter, error) {
-	return nil, nil
-}
-
-func (o *MockObjectStorage) Begin() Transaction {
-	return nil
-}
diff --git a/core/storage.go b/core/storage.go
deleted file mode 100644
index 101115b..0000000
--- a/core/storage.go
+++ /dev/null
@@ -1,83 +0,0 @@
-package core
-
-import (
-	"errors"
-	"io"
-)
-
-var (
-	//ErrStop is used to stop a ForEach function in an Iter
-	ErrStop = errors.New("stop iter")
-)
-
-// ObjectStorer generic storage of objects
-type ObjectStorer interface {
-	// NewObject returns a new Object, the real type of the object can be a
-	// custom implementation or the defaul one, MemoryObject
-	NewObject() Object
-	// SetObject save an object into the storage, the object shuld be create
-	// with the NewObject, method, and file if the type is not supported.
-	SetObject(Object) (Hash, error)
-	// Object an object by hash with the given ObjectType. Implementors
-	// should return (nil, ErrObjectNotFound) if an object doesn't exist with
-	// both the given hash and object type.
-	//
-	// Valid ObjectType values are CommitObject, BlobObject, TagObject,
-	// TreeObject and AnyObject. If AnyObject is given, the object must be
-	// looked up regardless of its type.
-	Object(ObjectType, Hash) (Object, error)
-	// IterObjects returns a custom ObjectIter over all the object on the
-	// storage.
-	//
-	// Valid ObjectType values are CommitObject, BlobObject, TagObject,
-	IterObjects(ObjectType) (ObjectIter, error)
-}
-
-// Transactioner is a optional method for ObjectStorer, it enable transaction
-// base write and read operations in the storage
-type Transactioner interface {
-	// Begin starts a transaction.
-	Begin() Transaction
-}
-
-// PackfileWriter is a optional method for ObjectStorer, it enable direct write
-// of packfile to the storage
-type PackfileWriter interface {
-	// PackfileWriter retuns a writer for writing a packfile to the Storage,
-	// this method is optional, if not implemented the ObjectStorer should
-	// return a ErrNotImplemented error.
-	//
-	// If the implementation not implements Writer the objects should be written
-	// using the Set method.
-	PackfileWriter() (io.WriteCloser, error)
-}
-
-// ObjectIter is a generic closable interface for iterating over objects.
-type ObjectIter interface {
-	Next() (Object, error)
-	ForEach(func(Object) error) error
-	Close()
-}
-
-// Transaction is an in-progress storage transaction. A transaction must end
-// with a call to Commit or Rollback.
-type Transaction interface {
-	SetObject(Object) (Hash, error)
-	Object(ObjectType, Hash) (Object, error)
-	Commit() error
-	Rollback() error
-}
-
-// ReferenceStorer generic storage of references
-type ReferenceStorer interface {
-	SetReference(*Reference) error
-	Reference(ReferenceName) (*Reference, error)
-	IterReferences() (ReferenceIter, error)
-}
-
-// ReferenceIter is a generic closable interface for iterating over references
-type ReferenceIter interface {
-	Next() (*Reference, error)
-	ForEach(func(*Reference) error) error
-	Close()
-}
diff --git a/cshared/auth_method_cshared.go b/cshared/auth_method_cshared.go
index 2219edb..9be3339 100644
--- a/cshared/auth_method_cshared.go
+++ b/cshared/auth_method_cshared.go
@@ -6,8 +6,8 @@ import (
 	"strings"
 
 	"golang.org/x/crypto/ssh"
-	"gopkg.in/src-d/go-git.v4/clients/http"
-	gssh "gopkg.in/src-d/go-git.v4/clients/ssh"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/http"
+	gssh "gopkg.in/src-d/go-git.v4/plumbing/client/ssh"
 )
 
 //export c_NewBasicAuth
diff --git a/cshared/commit_cshared.go b/cshared/commit_cshared.go
index 8cb91aa..756b0b2 100644
--- a/cshared/commit_cshared.go
+++ b/cshared/commit_cshared.go
@@ -8,8 +8,9 @@ import (
 	"unsafe"
 
 	"gopkg.in/src-d/go-git.v4"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
+import "gopkg.in/src-d/go-git.v4/plumbing/storer"
 
 //export c_Commit_get_Hash
 func c_Commit_get_Hash(c uint64) *C.char {
@@ -130,7 +131,7 @@ func c_Commit_Decode(o uint64) (uint64, int, *C.char) {
 	if !ok {
 		return IH, ErrorCodeNotFound, C.CString(MessageNotFound)
 	}
-	cobj := obj.(*core.Object)
+	cobj := obj.(*plumbing.Object)
 	err := commit.Decode(*cobj)
 	if err != nil {
 		return IH, ErrorCodeInternal, C.CString(err.Error())
@@ -196,7 +197,7 @@ func c_NewCommitIter(r uint64, iter uint64) uint64 {
 	if !ok {
 		return IH
 	}
-	obj_iter := obj.(*core.ObjectIter)
+	obj_iter := obj.(*storer.ObjectIter)
 	commit_iter := git.NewCommitIter(repo, *obj_iter)
 	handle := RegisterObject(commit_iter)
 	return uint64(handle)
diff --git a/cshared/file_cshared.go b/cshared/file_cshared.go
index 8191289..8ef6427 100644
--- a/cshared/file_cshared.go
+++ b/cshared/file_cshared.go
@@ -6,7 +6,7 @@ import (
 	"io/ioutil"
 
 	"gopkg.in/src-d/go-git.v4"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 //export c_File_get_Name
@@ -55,7 +55,7 @@ func c_File_Decode(o uint64) uint64 {
 	if !ok {
 		return IH
 	}
-	cobj := obj.(*core.Object)
+	cobj := obj.(*plumbing.Object)
 	file := git.File{}
 	file.Decode(*cobj)
 	return uint64(RegisterObject(&file))
diff --git a/cshared/objects_cshared.go b/cshared/objects_cshared.go
index 2600555..54b9426 100644
--- a/cshared/objects_cshared.go
+++ b/cshared/objects_cshared.go
@@ -7,7 +7,7 @@ import (
 	"time"
 
 	"gopkg.in/src-d/go-git.v4"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 //export c_Signature_Name
@@ -73,7 +73,7 @@ func c_Blob_Decode(o uint64) uint64 {
 	if !ok {
 		return IH
 	}
-	cobj := obj.(*core.Object)
+	cobj := obj.(*plumbing.Object)
 	blob := git.Blob{}
 	blob.Decode(*cobj)
 	return uint64(RegisterObject(&blob))
diff --git a/cshared/repository_cshared.go b/cshared/repository_cshared.go
index e11a6c0..76755bf 100644
--- a/cshared/repository_cshared.go
+++ b/cshared/repository_cshared.go
@@ -83,7 +83,7 @@ func c_Repository_set_Storage(r uint64, val uint64) {
 	if !ok {
 		return
 	}
-	repo.Storage = *obj.(*core.ObjectStorage)
+	repo.Storage = *obj.(*plumbing.ObjectStorage)
 }
 
 //export c_Repository_Pull
@@ -121,7 +121,7 @@ func c_Repository_Commit(r uint64, h []byte) (uint64, int, *C.char) {
 		return IH, ErrorCodeNotFound, C.CString(MessageNotFound)
 	}
 	repo := obj.(*git.Repository)
-	var hash core.Hash
+	var hash plumbing.Hash
 	copy(hash[:], h)
 	commit, err := repo.Commit(hash)
 	if err != nil {
@@ -153,7 +153,7 @@ func c_Repository_Tree(r uint64, h []byte) (uint64, int, *C.char) {
 		return IH, ErrorCodeNotFound, C.CString(MessageNotFound)
 	}
 	repo := obj.(*git.Repository)
-	var hash core.Hash
+	var hash plumbing.Hash
 	copy(hash[:], h)
 	tree, err := repo.Tree(hash)
 	if err != nil {
@@ -170,7 +170,7 @@ func c_Repository_Blob(r uint64, h []byte) (uint64, int, *C.char) {
 		return IH, ErrorCodeNotFound, C.CString(MessageNotFound)
 	}
 	repo := obj.(*git.Repository)
-	var hash core.Hash
+	var hash plumbing.Hash
 	copy(hash[:], h)
 	blob, err := repo.Blob(hash)
 	if err != nil {
@@ -187,7 +187,7 @@ func c_Repository_Tag(r uint64, h []byte) (uint64, int, *C.char) {
 		return IH, ErrorCodeNotFound, C.CString(MessageNotFound)
 	}
 	repo := obj.(*git.Repository)
-	var hash core.Hash
+	var hash plumbing.Hash
 	copy(hash[:], h)
 	tag, err := repo.Tag(hash)
 	if err != nil {
@@ -219,7 +219,7 @@ func c_Repository_Object(r uint64, h []byte) (uint64, int, *C.char) {
 		return IH, ErrorCodeNotFound, C.CString(MessageNotFound)
 	}
 	repo := obj.(*git.Repository)
-	var hash core.Hash
+	var hash plumbing.Hash
 	copy(hash[:], h)
 	robj, err := repo.Object(hash)
 	if err != nil {
diff --git a/cshared/tag_cshared.go b/cshared/tag_cshared.go
index 67c3ada..dd0814a 100644
--- a/cshared/tag_cshared.go
+++ b/cshared/tag_cshared.go
@@ -6,8 +6,9 @@ import (
 	"io"
 
 	"gopkg.in/src-d/go-git.v4"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
+import "gopkg.in/src-d/go-git.v4/plumbing/storer"
 
 func c_Tag_get_Hash(t uint64) *C.char {
 	obj, ok := GetObject(Handle(t))
@@ -79,7 +80,7 @@ func c_Tag_Decode(o uint64) (uint64, int, *C.char) {
 	if !ok {
 		return IH, ErrorCodeNotFound, C.CString(MessageNotFound)
 	}
-	cobj := obj.(*core.Object)
+	cobj := obj.(*plumbing.Object)
 	tag := git.Tag{}
 	err := tag.Decode(*cobj)
 	if err != nil {
@@ -165,7 +166,7 @@ func c_NewTagIter(r uint64, i uint64) uint64 {
 	if !ok {
 		return IH
 	}
-	iter := obj.(*core.ObjectIter)
+	iter := obj.(*storer.ObjectIter)
 	return uint64(RegisterObject(git.NewTagIter(repo, *iter)))
 }
 
diff --git a/cshared/tree_cshared.go b/cshared/tree_cshared.go
index 4974904..8533f60 100644
--- a/cshared/tree_cshared.go
+++ b/cshared/tree_cshared.go
@@ -10,7 +10,7 @@ package main
 import (
 //line /home/mcuadros/workspace/go/src/gopkg.in/src-d/go-git.v4/cshared/tree_cshared.go:7
 	"gopkg.in/src-d/go-git.v4"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 //line /home/mcuadros/workspace/go/src/gopkg.in/src-d/go-git.v4/cshared/tree_cshared.go:13
@@ -99,7 +99,7 @@ func c_Tree_Decode(o uint64) (uint64, int, *_Ctype_char) {
 	if !ok {
 		return IH, ErrorCodeNotFound, _Cfunc_CString(MessageNotFound)
 	}
-	cobj := obj.(*core.Object)
+	cobj := obj.(*plumbing.Object)
 	tree := git.Tree{}
 	err := tree.Decode(*cobj)
 	if err != nil {
diff --git a/examples/remotes/main.go b/examples/remotes/main.go
index 552d6a5..3ccecd7 100644
--- a/examples/remotes/main.go
+++ b/examples/remotes/main.go
@@ -7,7 +7,7 @@ import (
 
 	"gopkg.in/src-d/go-git.v4"
 	"gopkg.in/src-d/go-git.v4/config"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 func main() {
@@ -46,10 +46,10 @@ func main() {
 	color.Blue("git show-ref")
 
 	refs, _ := r.Refs()
-	refs.ForEach(func(ref *core.Reference) error {
+	refs.ForEach(func(ref *plumbing.Reference) error {
 		// The HEAD is ommitted in a `git show-ref` so we ignore the symbolic
 		// references, the HEAD
-		if ref.Type() == core.SymbolicReference {
+		if ref.Type() == plumbing.SymbolicReference {
 			return nil
 		}
 
diff --git a/examples/storage/aerospike/storage.go b/examples/storage/aerospike/storage.go
index 776fc33..a1d8c00 100644
--- a/examples/storage/aerospike/storage.go
+++ b/examples/storage/aerospike/storage.go
@@ -7,7 +7,8 @@ import (
 	"io/ioutil"
 
 	"gopkg.in/src-d/go-git.v4/config"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 
 	driver "github.com/aerospike/aerospike-client-go"
 )
@@ -32,11 +33,11 @@ func NewStorage(client *driver.Client, ns, url string) (*Storage, error) {
 	return &Storage{client: client, ns: ns, url: url}, nil
 }
 
-func (s *Storage) NewObject() core.Object {
-	return &core.MemoryObject{}
+func (s *Storage) NewObject() plumbing.Object {
+	return &plumbing.MemoryObject{}
 }
 
-func (s *Storage) SetObject(obj core.Object) (core.Hash, error) {
+func (s *Storage) SetObject(obj plumbing.Object) (plumbing.Hash, error) {
 	key, err := s.buildKey(obj.Hash(), obj.Type())
 	if err != nil {
 		return obj.Hash(), err
@@ -63,7 +64,7 @@ func (s *Storage) SetObject(obj core.Object) (core.Hash, error) {
 	return obj.Hash(), err
 }
 
-func (s *Storage) Object(t core.ObjectType, h core.Hash) (core.Object, error) {
+func (s *Storage) Object(t plumbing.ObjectType, h plumbing.Hash) (plumbing.Object, error) {
 	key, err := s.buildKey(h, t)
 	if err != nil {
 		return nil, err
@@ -75,13 +76,13 @@ func (s *Storage) Object(t core.ObjectType, h core.Hash) (core.Object, error) {
 	}
 
 	if rec == nil {
-		return nil, core.ErrObjectNotFound
+		return nil, plumbing.ErrObjectNotFound
 	}
 
 	return objectFromRecord(rec, t)
 }
 
-func (s *Storage) IterObjects(t core.ObjectType) (core.ObjectIter, error) {
+func (s *Storage) IterObjects(t plumbing.ObjectType) (storer.ObjectIter, error) {
 	stmnt := driver.NewStatement(s.ns, t.String())
 	err := stmnt.Addfilter(driver.NewEqualFilter(urlField, s.url))
 
@@ -93,16 +94,16 @@ func (s *Storage) IterObjects(t core.ObjectType) (core.ObjectIter, error) {
 	return &ObjectIter{t, rs.Records}, nil
 }
 
-func (s *Storage) buildKey(h core.Hash, t core.ObjectType) (*driver.Key, error) {
+func (s *Storage) buildKey(h plumbing.Hash, t plumbing.ObjectType) (*driver.Key, error) {
 	return driver.NewKey(s.ns, t.String(), fmt.Sprintf("%s|%s", s.url, h.String()))
 }
 
 type ObjectIter struct {
-	t  core.ObjectType
+	t  plumbing.ObjectType
 	ch chan *driver.Record
 }
 
-func (i *ObjectIter) Next() (core.Object, error) {
+func (i *ObjectIter) Next() (plumbing.Object, error) {
 	r := <-i.ch
 	if r == nil {
 		return nil, io.EOF
@@ -111,7 +112,7 @@ func (i *ObjectIter) Next() (core.Object, error) {
 	return objectFromRecord(r, i.t)
 }
 
-func (i *ObjectIter) ForEach(cb func(obj core.Object) error) error {
+func (i *ObjectIter) ForEach(cb func(obj plumbing.Object) error) error {
 	for {
 		obj, err := i.Next()
 		if err != nil {
@@ -123,7 +124,7 @@ func (i *ObjectIter) ForEach(cb func(obj core.Object) error) error {
 		}
 
 		if err := cb(obj); err != nil {
-			if err == core.ErrStop {
+			if err == storer.ErrStop {
 				return nil
 			}
 
@@ -134,10 +135,10 @@ func (i *ObjectIter) ForEach(cb func(obj core.Object) error) error {
 
 func (i *ObjectIter) Close() {}
 
-func objectFromRecord(r *driver.Record, t core.ObjectType) (core.Object, error) {
+func objectFromRecord(r *driver.Record, t plumbing.ObjectType) (plumbing.Object, error) {
 	content := r.Bins["blob"].([]byte)
 
-	o := &core.MemoryObject{}
+	o := &plumbing.MemoryObject{}
 	o.SetType(t)
 	o.SetSize(int64(len(content)))
 
@@ -149,7 +150,7 @@ func objectFromRecord(r *driver.Record, t core.ObjectType) (core.Object, error)
 	return o, nil
 }
 
-func (s *Storage) SetReference(ref *core.Reference) error {
+func (s *Storage) SetReference(ref *plumbing.Reference) error {
 	key, err := s.buildReferenceKey(ref.Name())
 	if err != nil {
 		return err
@@ -165,7 +166,7 @@ func (s *Storage) SetReference(ref *core.Reference) error {
 	return s.client.Put(nil, key, bins)
 }
 
-func (s *Storage) Reference(n core.ReferenceName) (*core.Reference, error) {
+func (s *Storage) Reference(n plumbing.ReferenceName) (*plumbing.Reference, error) {
 	key, err := s.buildReferenceKey(n)
 	if err != nil {
 		return nil, err
@@ -176,17 +177,17 @@ func (s *Storage) Reference(n core.ReferenceName) (*core.Reference, error) {
 		return nil, err
 	}
 
-	return core.NewReferenceFromStrings(
+	return plumbing.NewReferenceFromStrings(
 		rec.Bins["name"].(string),
 		rec.Bins["target"].(string),
 	), nil
 }
 
-func (s *Storage) buildReferenceKey(n core.ReferenceName) (*driver.Key, error) {
+func (s *Storage) buildReferenceKey(n plumbing.ReferenceName) (*driver.Key, error) {
 	return driver.NewKey(s.ns, referencesSet, fmt.Sprintf("%s|%s", s.url, n))
 }
 
-func (s *Storage) IterReferences() (core.ReferenceIter, error) {
+func (s *Storage) IterReferences() (storer.ReferenceIter, error) {
 	stmnt := driver.NewStatement(s.ns, referencesSet)
 	err := stmnt.Addfilter(driver.NewEqualFilter(urlField, s.url))
 	if err != nil {
@@ -198,15 +199,15 @@ func (s *Storage) IterReferences() (core.ReferenceIter, error) {
 		return nil, err
 	}
 
-	var refs []*core.Reference
+	var refs []*plumbing.Reference
 	for r := range rs.Records {
-		refs = append(refs, core.NewReferenceFromStrings(
+		refs = append(refs, plumbing.NewReferenceFromStrings(
 			r.Bins["name"].(string),
 			r.Bins["target"].(string),
 		))
 	}
 
-	return core.NewReferenceSliceIter(refs), nil
+	return storer.NewReferenceSliceIter(refs), nil
 }
 
 func (s *Storage) Config() (*config.Config, error) {
@@ -251,10 +252,10 @@ func createIndexes(c *driver.Client, ns string) error {
 	for _, set := range [...]string{
 		referencesSet,
 		configSet,
-		core.BlobObject.String(),
-		core.TagObject.String(),
-		core.TreeObject.String(),
-		core.CommitObject.String(),
+		plumbing.BlobObject.String(),
+		plumbing.TagObject.String(),
+		plumbing.TreeObject.String(),
+		plumbing.CommitObject.String(),
 	} {
 		if err := createIndex(c, ns, set); err != nil {
 			return err
diff --git a/file.go b/file.go
index 3278a8c..c5a6d42 100644
--- a/file.go
+++ b/file.go
@@ -6,7 +6,7 @@ import (
 	"os"
 	"strings"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 )
 
 // File represents git file objects.
@@ -83,7 +83,7 @@ func (iter *FileIter) Next() (*File, error) {
 }
 
 // ForEach call the cb function for each file contained on this iter until
-// an error happends or the end of the iter is reached. If core.ErrStop is sent
+// an error happends or the end of the iter is reached. If plumbing.ErrStop is sent
 // the iteration is stop but no error is returned. The iterator is closed.
 func (iter *FileIter) ForEach(cb func(*File) error) error {
 	defer iter.Close()
@@ -99,7 +99,7 @@ func (iter *FileIter) ForEach(cb func(*File) error) error {
 		}
 
 		if err := cb(f); err != nil {
-			if err == core.ErrStop {
+			if err == storer.ErrStop {
 				return nil
 			}
 
diff --git a/file_test.go b/file_test.go
index 01ad8ca..ca815c2 100644
--- a/file_test.go
+++ b/file_test.go
@@ -3,8 +3,9 @@ package git
 import (
 	"io"
 
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/fixtures"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 
 	. "gopkg.in/check.v1"
 )
@@ -42,7 +43,7 @@ var fileIterTests = []struct {
 func (s *FileSuite) TestIter(c *C) {
 	for i, t := range fileIterTests {
 		r := s.Repositories[t.repo]
-		commit, err := r.Commit(core.NewHash(t.commit))
+		commit, err := r.Commit(plumbing.NewHash(t.commit))
 		c.Assert(err, IsNil, Commentf("subtest %d: %v (%s)", i, err, t.commit))
 
 		tree, err := commit.Tree()
@@ -99,7 +100,7 @@ hs_err_pid*
 
 func (s *FileSuite) TestContents(c *C) {
 	for i, t := range contentsTests {
-		commit, err := s.Repositories[t.repo].Commit(core.NewHash(t.commit))
+		commit, err := s.Repositories[t.repo].Commit(plumbing.NewHash(t.commit))
 		c.Assert(err, IsNil, Commentf("subtest %d: %v (%s)", i, err, t.commit))
 
 		file, err := commit.File(t.path)
@@ -151,7 +152,7 @@ func (s *FileSuite) TestLines(c *C) {
 		r, ok := s.Repositories[t.repo]
 		c.Assert(ok, Equals, true, Commentf("cannot find repository %s", t.repo))
 
-		commit, err := r.Commit(core.NewHash(t.commit))
+		commit, err := r.Commit(plumbing.NewHash(t.commit))
 		c.Assert(err, IsNil, Commentf("subtest %d: %v (%s)", i, err, t.commit))
 
 		file, err := commit.File(t.path)
@@ -183,7 +184,7 @@ func (s *FileSuite) TestIgnoreEmptyDirEntries(c *C) {
 	s.buildRepositories(c, fixtures.ByTag("empty-folder"))
 
 	for i, t := range ignoreEmptyDirEntriesTests {
-		commit, err := s.Repositories[t.repo].Commit(core.NewHash(t.commit))
+		commit, err := s.Repositories[t.repo].Commit(plumbing.NewHash(t.commit))
 		c.Assert(err, IsNil, Commentf("subtest %d: %v (%s)", i, err, t.commit))
 
 		tree, err := commit.Tree()
@@ -199,7 +200,7 @@ func (s *FileSuite) TestIgnoreEmptyDirEntries(c *C) {
 }
 
 func (s *FileSuite) TestFileIter(c *C) {
-	hash := core.NewHash("1669dce138d9b841a518c64b10914d88f5e488ea")
+	hash := plumbing.NewHash("1669dce138d9b841a518c64b10914d88f5e488ea")
 
 	commit, err := s.Repository.Commit(hash)
 	c.Assert(err, IsNil)
@@ -227,7 +228,7 @@ func (s *FileSuite) TestFileIter(c *C) {
 	i = tree.Files()
 	i.ForEach(func(f *File) error {
 		count++
-		return core.ErrStop
+		return storer.ErrStop
 	})
 
 	c.Assert(count, Equals, 1)
diff --git a/fixtures/fixtures.go b/fixtures/fixtures.go
index 929fb5c..324f2da 100644
--- a/fixtures/fixtures.go
+++ b/fixtures/fixtures.go
@@ -9,7 +9,7 @@ import (
 	"github.com/alcortesm/tgz"
 
 	"gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 	"gopkg.in/src-d/go-git.v4/utils/fs"
 	osfs "gopkg.in/src-d/go-git.v4/utils/fs/os"
 )
@@ -23,98 +23,98 @@ var folders []string
 var fixtures = Fixtures{{
 	Tags:         []string{"packfile", "ofs-delta", ".git"},
 	URL:          "https://github.com/git-fixtures/basic.git",
-	Head:         core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"),
-	PackfileHash: core.NewHash("a3fed42da1e8189a077c0e6846c040dcf73fc9dd"),
-	DotGitHash:   core.NewHash("0a00a25543e6d732dbf4e8e9fec55c8e65fc4e8d"),
+	Head:         plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"),
+	PackfileHash: plumbing.NewHash("a3fed42da1e8189a077c0e6846c040dcf73fc9dd"),
+	DotGitHash:   plumbing.NewHash("0a00a25543e6d732dbf4e8e9fec55c8e65fc4e8d"),
 	ObjectsCount: 31,
 }, {
 	Tags:         []string{"packfile", "ref-delta", ".git"},
 	URL:          "https://github.com/git-fixtures/basic.git",
-	Head:         core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"),
-	PackfileHash: core.NewHash("c544593473465e6315ad4182d04d366c4592b829"),
-	DotGitHash:   core.NewHash("7cbde0ca02f13aedd5ec8b358ca17b1c0bf5ee64"),
+	Head:         plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"),
+	PackfileHash: plumbing.NewHash("c544593473465e6315ad4182d04d366c4592b829"),
+	DotGitHash:   plumbing.NewHash("7cbde0ca02f13aedd5ec8b358ca17b1c0bf5ee64"),
 	ObjectsCount: 31,
 }, {
 	Tags:         []string{"packfile", "ofs-delta", ".git", "single-branch"},
 	URL:          "https://github.com/git-fixtures/basic.git",
-	Head:         core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"),
-	PackfileHash: core.NewHash("61f0ee9c75af1f9678e6f76ff39fbe372b6f1c45"),
-	DotGitHash:   core.NewHash("21504f6d2cc2ef0c9d6ebb8802c7b49abae40c1a"),
+	Head:         plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"),
+	PackfileHash: plumbing.NewHash("61f0ee9c75af1f9678e6f76ff39fbe372b6f1c45"),
+	DotGitHash:   plumbing.NewHash("21504f6d2cc2ef0c9d6ebb8802c7b49abae40c1a"),
 	ObjectsCount: 28,
 }, {
 	Tags:       []string{".git", "merge-conflict"},
 	URL:        "https://github.com/git-fixtures/basic.git",
-	DotGitHash: core.NewHash("4870d54b5b04e43da8cf99ceec179d9675494af8"),
+	DotGitHash: plumbing.NewHash("4870d54b5b04e43da8cf99ceec179d9675494af8"),
 }, {
 	Tags:       []string{".git", "resolve-undo"},
 	URL:        "https://github.com/git-fixtures/basic.git",
-	DotGitHash: core.NewHash("df6781fd40b8f4911d70ce71f8387b991615cd6d"),
+	DotGitHash: plumbing.NewHash("df6781fd40b8f4911d70ce71f8387b991615cd6d"),
 }, {
 	Tags:       []string{".git", "intent-to-add"},
 	URL:        "https://github.com/git-fixtures/basic.git",
-	DotGitHash: core.NewHash("4e7600af05c3356e8b142263e127b76f010facfc"),
+	DotGitHash: plumbing.NewHash("4e7600af05c3356e8b142263e127b76f010facfc"),
 }, {
 	Tags:       []string{".git", "index-v4"},
 	URL:        "https://github.com/git-fixtures/basic.git",
-	DotGitHash: core.NewHash("935e5ac17c41c309c356639816ea0694a568c484"),
+	DotGitHash: plumbing.NewHash("935e5ac17c41c309c356639816ea0694a568c484"),
 }, {
 
 	Tags:         []string{"packfile", ".git", "unpacked", "multi-packfile"},
 	URL:          "https://github.com/src-d/go-git.git",
-	Head:         core.NewHash("e8788ad9165781196e917292d6055cba1d78664e"),
-	PackfileHash: core.NewHash("3559b3b47e695b33b0913237a4df3357e739831c"),
-	DotGitHash:   core.NewHash("174be6bd4292c18160542ae6dc6704b877b8a01a"),
+	Head:         plumbing.NewHash("e8788ad9165781196e917292d6055cba1d78664e"),
+	PackfileHash: plumbing.NewHash("3559b3b47e695b33b0913237a4df3357e739831c"),
+	DotGitHash:   plumbing.NewHash("174be6bd4292c18160542ae6dc6704b877b8a01a"),
 	ObjectsCount: 2133,
 }, {
 	Tags:         []string{"packfile", ".git", "tags"},
 	URL:          "https://github.com/git-fixtures/tags.git",
-	Head:         core.NewHash("f7b877701fbf855b44c0a9e86f3fdce2c298b07f"),
-	DotGitHash:   core.NewHash("c0c7c57ab1753ddbd26cc45322299ddd12842794"),
-	PackfileHash: core.NewHash("b68617dd8637fe6409d9842825a843a1d9a6e484"),
+	Head:         plumbing.NewHash("f7b877701fbf855b44c0a9e86f3fdce2c298b07f"),
+	DotGitHash:   plumbing.NewHash("c0c7c57ab1753ddbd26cc45322299ddd12842794"),
+	PackfileHash: plumbing.NewHash("b68617dd8637fe6409d9842825a843a1d9a6e484"),
 	ObjectsCount: 7,
 }, {
 	Tags:         []string{"packfile"},
 	URL:          "https://github.com/spinnaker/spinnaker.git",
-	Head:         core.NewHash("06ce06d0fc49646c4de733c45b7788aabad98a6f"),
-	PackfileHash: core.NewHash("f2e0a8889a746f7600e07d2246a2e29a72f696be"),
+	Head:         plumbing.NewHash("06ce06d0fc49646c4de733c45b7788aabad98a6f"),
+	PackfileHash: plumbing.NewHash("f2e0a8889a746f7600e07d2246a2e29a72f696be"),
 }, {
 	Tags:         []string{"packfile"},
 	URL:          "https://github.com/jamesob/desk.git",
-	Head:         core.NewHash("d2313db6e7ca7bac79b819d767b2a1449abb0a5d"),
-	PackfileHash: core.NewHash("4ec6344877f494690fc800aceaf2ca0e86786acb"),
+	Head:         plumbing.NewHash("d2313db6e7ca7bac79b819d767b2a1449abb0a5d"),
+	PackfileHash: plumbing.NewHash("4ec6344877f494690fc800aceaf2ca0e86786acb"),
 }, {
 	Tags:         []string{"packfile", "empty-folder"},
 	URL:          "https://github.com/cpcs499/Final_Pres_P.git",
-	Head:         core.NewHash("70bade703ce556c2c7391a8065c45c943e8b6bc3"),
-	PackfileHash: core.NewHash("29f304662fd64f102d94722cf5bd8802d9a9472c"),
+	Head:         plumbing.NewHash("70bade703ce556c2c7391a8065c45c943e8b6bc3"),
+	PackfileHash: plumbing.NewHash("29f304662fd64f102d94722cf5bd8802d9a9472c"),
 }, {
 	Tags:         []string{"packfile", "diff-tree"},
 	URL:          "https://github.com/github/gem-builder.git",
-	PackfileHash: core.NewHash("1ea0b3971fd64fdcdf3282bfb58e8cf10095e4e6"),
+	PackfileHash: plumbing.NewHash("1ea0b3971fd64fdcdf3282bfb58e8cf10095e4e6"),
 }, {
 	Tags:         []string{"packfile", "diff-tree"},
 	URL:          "https://github.com/githubtraining/example-branches.git",
-	PackfileHash: core.NewHash("bb8ee94710d3fa39379a630f76812c187217b312"),
+	PackfileHash: plumbing.NewHash("bb8ee94710d3fa39379a630f76812c187217b312"),
 }, {
 	Tags:         []string{"packfile", "diff-tree"},
 	URL:          "https://github.com/rumpkernel/rumprun-xen.git",
-	PackfileHash: core.NewHash("7861f2632868833a35fe5e4ab94f99638ec5129b"),
+	PackfileHash: plumbing.NewHash("7861f2632868833a35fe5e4ab94f99638ec5129b"),
 }, {
 	Tags:         []string{"packfile", "diff-tree"},
 	URL:          "https://github.com/mcuadros/skeetr.git",
-	PackfileHash: core.NewHash("36ef7a2296bfd526020340d27c5e1faa805d8d38"),
+	PackfileHash: plumbing.NewHash("36ef7a2296bfd526020340d27c5e1faa805d8d38"),
 }, {
 	Tags:         []string{"packfile", "diff-tree"},
 	URL:          "https://github.com/dezfowler/LiteMock.git",
-	PackfileHash: core.NewHash("0d9b6cfc261785837939aaede5986d7a7c212518"),
+	PackfileHash: plumbing.NewHash("0d9b6cfc261785837939aaede5986d7a7c212518"),
 }, {
 	Tags:         []string{"packfile", "diff-tree"},
 	URL:          "https://github.com/tyba/storable.git",
-	PackfileHash: core.NewHash("0d3d824fb5c930e7e7e1f0f399f2976847d31fd3"),
+	PackfileHash: plumbing.NewHash("0d3d824fb5c930e7e7e1f0f399f2976847d31fd3"),
 }, {
 	Tags:         []string{"packfile", "diff-tree"},
 	URL:          "https://github.com/toqueteos/ts3.git",
-	PackfileHash: core.NewHash("21b33a26eb7ffbd35261149fe5d886b9debab7cb"),
+	PackfileHash: plumbing.NewHash("21b33a26eb7ffbd35261149fe5d886b9debab7cb"),
 }}
 
 func All() Fixtures {
@@ -137,9 +137,9 @@ func ByTag(tag string) Fixtures {
 type Fixture struct {
 	URL          string
 	Tags         []string
-	Head         core.Hash
-	PackfileHash core.Hash
-	DotGitHash   core.Hash
+	Head         plumbing.Hash
+	PackfileHash plumbing.Hash
+	DotGitHash   plumbing.Hash
 	ObjectsCount int32
 }
 
diff --git a/formats/packfile/scanner_test.go b/formats/packfile/scanner_test.go
deleted file mode 100644
index 5f80da0..0000000
--- a/formats/packfile/scanner_test.go
+++ /dev/null
@@ -1,189 +0,0 @@
-package packfile
-
-import (
-	"bytes"
-	"io"
-
-	. "gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/fixtures"
-)
-
-type ScannerSuite struct {
-	fixtures.Suite
-}
-
-var _ = Suite(&ScannerSuite{})
-
-func (s *ScannerSuite) TestHeader(c *C) {
-	r := fixtures.Basic().One().Packfile()
-	p := NewScanner(r)
-
-	version, objects, err := p.Header()
-	c.Assert(err, IsNil)
-	c.Assert(version, Equals, VersionSupported)
-	c.Assert(objects, Equals, uint32(31))
-}
-
-func (s *ScannerSuite) TestNextObjectHeaderWithoutHeader(c *C) {
-	r := fixtures.Basic().One().Packfile()
-	p := NewScanner(r)
-
-	h, err := p.NextObjectHeader()
-	c.Assert(err, IsNil)
-	c.Assert(h, DeepEquals, &expectedHeadersOFS[0])
-
-	version, objects, err := p.Header()
-	c.Assert(err, IsNil)
-	c.Assert(version, Equals, VersionSupported)
-	c.Assert(objects, Equals, uint32(31))
-}
-
-func (s *ScannerSuite) TestNextObjectHeaderREFDelta(c *C) {
-	s.testNextObjectHeader(c, "ref-delta", expectedHeadersREF)
-}
-
-func (s *ScannerSuite) TestNextObjectHeaderOFSDelta(c *C) {
-	s.testNextObjectHeader(c, "ofs-delta", expectedHeadersOFS)
-}
-
-func (s *ScannerSuite) testNextObjectHeader(c *C, tag string, expected []ObjectHeader) {
-	r := fixtures.Basic().ByTag(tag).One().Packfile()
-	p := NewScanner(r)
-
-	_, objects, err := p.Header()
-	c.Assert(err, IsNil)
-
-	for i := 0; i < int(objects); i++ {
-		h, err := p.NextObjectHeader()
-		c.Assert(err, IsNil)
-		c.Assert(*h, DeepEquals, expected[i])
-
-		buf := bytes.NewBuffer(nil)
-		n, _, err := p.NextObject(buf)
-		c.Assert(err, IsNil)
-		c.Assert(n, Equals, h.Length)
-	}
-
-	n, err := p.Checksum()
-	c.Assert(err, IsNil)
-	c.Assert(n, HasLen, 20)
-}
-
-func (s *ScannerSuite) TestNextObjectHeaderWithOutReadObject(c *C) {
-	f := fixtures.Basic().ByTag("ref-delta").One()
-	r := f.Packfile()
-	p := NewScanner(r)
-
-	_, objects, err := p.Header()
-	c.Assert(err, IsNil)
-
-	for i := 0; i < int(objects); i++ {
-		h, _ := p.NextObjectHeader()
-		c.Assert(err, IsNil)
-		c.Assert(*h, DeepEquals, expectedHeadersREF[i])
-	}
-
-	err = p.discardObjectIfNeeded()
-	c.Assert(err, IsNil)
-
-	n, err := p.Checksum()
-	c.Assert(err, IsNil)
-	c.Assert(n, Equals, f.PackfileHash)
-}
-
-func (s *ScannerSuite) TestNextObjectHeaderWithOutReadObjectNonSeekable(c *C) {
-	f := fixtures.Basic().ByTag("ref-delta").One()
-	r := io.MultiReader(f.Packfile())
-	p := NewScanner(r)
-
-	_, objects, err := p.Header()
-	c.Assert(err, IsNil)
-
-	for i := 0; i < int(objects); i++ {
-		h, _ := p.NextObjectHeader()
-		c.Assert(err, IsNil)
-		c.Assert(*h, DeepEquals, expectedHeadersREF[i])
-	}
-
-	err = p.discardObjectIfNeeded()
-	c.Assert(err, IsNil)
-
-	n, err := p.Checksum()
-	c.Assert(err, IsNil)
-	c.Assert(n, Equals, f.PackfileHash)
-}
-
-var expectedHeadersOFS = []ObjectHeader{
-	{Type: core.CommitObject, Offset: 12, Length: 254},
-	{Type: core.OFSDeltaObject, Offset: 186, Length: 93, OffsetReference: 12},
-	{Type: core.CommitObject, Offset: 286, Length: 242},
-	{Type: core.CommitObject, Offset: 449, Length: 242},
-	{Type: core.CommitObject, Offset: 615, Length: 333},
-	{Type: core.CommitObject, Offset: 838, Length: 332},
-	{Type: core.CommitObject, Offset: 1063, Length: 244},
-	{Type: core.CommitObject, Offset: 1230, Length: 243},
-	{Type: core.CommitObject, Offset: 1392, Length: 187},
-	{Type: core.BlobObject, Offset: 1524, Length: 189},
-	{Type: core.BlobObject, Offset: 1685, Length: 18},
-	{Type: core.BlobObject, Offset: 1713, Length: 1072},
-	{Type: core.BlobObject, Offset: 2351, Length: 76110},
-	{Type: core.BlobObject, Offset: 78050, Length: 2780},
-	{Type: core.BlobObject, Offset: 78882, Length: 217848},
-	{Type: core.BlobObject, Offset: 80725, Length: 706},
-	{Type: core.BlobObject, Offset: 80998, Length: 11488},
-	{Type: core.BlobObject, Offset: 84032, Length: 78},
-	{Type: core.TreeObject, Offset: 84115, Length: 272},
-	{Type: core.OFSDeltaObject, Offset: 84375, Length: 43, OffsetReference: 84115},
-	{Type: core.TreeObject, Offset: 84430, Length: 38},
-	{Type: core.TreeObject, Offset: 84479, Length: 75},
-	{Type: core.TreeObject, Offset: 84559, Length: 38},
-	{Type: core.TreeObject, Offset: 84608, Length: 34},
-	{Type: core.BlobObject, Offset: 84653, Length: 9},
-	{Type: core.OFSDeltaObject, Offset: 84671, Length: 6, OffsetReference: 84375},
-	{Type: core.OFSDeltaObject, Offset: 84688, Length: 9, OffsetReference: 84375},
-	{Type: core.OFSDeltaObject, Offset: 84708, Length: 6, OffsetReference: 84375},
-	{Type: core.OFSDeltaObject, Offset: 84725, Length: 5, OffsetReference: 84115},
-	{Type: core.OFSDeltaObject, Offset: 84741, Length: 8, OffsetReference: 84375},
-	{Type: core.OFSDeltaObject, Offset: 84760, Length: 4, OffsetReference: 84741},
-}
-
-var expectedHeadersREF = []ObjectHeader{
-	{Type: core.CommitObject, Offset: 12, Length: 254},
-	{Type: core.REFDeltaObject, Offset: 186, Length: 93,
-		Reference: core.NewHash("e8d3ffab552895c19b9fcf7aa264d277cde33881")},
-	{Type: core.CommitObject, Offset: 304, Length: 242},
-	{Type: core.CommitObject, Offset: 467, Length: 242},
-	{Type: core.CommitObject, Offset: 633, Length: 333},
-	{Type: core.CommitObject, Offset: 856, Length: 332},
-	{Type: core.CommitObject, Offset: 1081, Length: 243},
-	{Type: core.CommitObject, Offset: 1243, Length: 244},
-	{Type: core.CommitObject, Offset: 1410, Length: 187},
-	{Type: core.BlobObject, Offset: 1542, Length: 189},
-	{Type: core.BlobObject, Offset: 1703, Length: 18},
-	{Type: core.BlobObject, Offset: 1731, Length: 1072},
-	{Type: core.BlobObject, Offset: 2369, Length: 76110},
-	{Type: core.TreeObject, Offset: 78068, Length: 38},
-	{Type: core.BlobObject, Offset: 78117, Length: 2780},
-	{Type: core.TreeObject, Offset: 79049, Length: 75},
-	{Type: core.BlobObject, Offset: 79129, Length: 217848},
-	{Type: core.BlobObject, Offset: 80972, Length: 706},
-	{Type: core.TreeObject, Offset: 81265, Length: 38},
-	{Type: core.BlobObject, Offset: 81314, Length: 11488},
-	{Type: core.TreeObject, Offset: 84752, Length: 34},
-	{Type: core.BlobObject, Offset: 84797, Length: 78},
-	{Type: core.TreeObject, Offset: 84880, Length: 271},
-	{Type: core.REFDeltaObject, Offset: 85141, Length: 6,
-		Reference: core.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c")},
-	{Type: core.REFDeltaObject, Offset: 85176, Length: 37,
-		Reference: core.NewHash("fb72698cab7617ac416264415f13224dfd7a165e")},
-	{Type: core.BlobObject, Offset: 85244, Length: 9},
-	{Type: core.REFDeltaObject, Offset: 85262, Length: 9,
-		Reference: core.NewHash("fb72698cab7617ac416264415f13224dfd7a165e")},
-	{Type: core.REFDeltaObject, Offset: 85300, Length: 6,
-		Reference: core.NewHash("fb72698cab7617ac416264415f13224dfd7a165e")},
-	{Type: core.TreeObject, Offset: 85335, Length: 110},
-	{Type: core.REFDeltaObject, Offset: 85448, Length: 8,
-		Reference: core.NewHash("eba74343e2f15d62adedfd8c883ee0262b5c8021")},
-	{Type: core.TreeObject, Offset: 85485, Length: 73},
-}
diff --git a/objects.go b/objects.go
index 9a0007d..d75d98a 100644
--- a/objects.go
+++ b/objects.go
@@ -8,7 +8,8 @@ import (
 	"strconv"
 	"time"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 )
 
 // ErrUnsupportedObject trigger when a non-supported object is being decoded.
@@ -34,13 +35,13 @@ var ErrUnsupportedObject = errors.New("unsupported object type")
 //   	}
 //   }
 //
-// This interface is intentionally different from core.Object, which is a lower
+// This interface is intentionally different from plumbing.Object, which is a lower
 // level interface used by storage implementations to read and write objects.
 type Object interface {
-	ID() core.Hash
-	Type() core.ObjectType
-	Decode(core.Object) error
-	Encode(core.Object) error
+	ID() plumbing.Hash
+	Type() plumbing.ObjectType
+	Decode(plumbing.Object) error
+	Encode(plumbing.Object) error
 }
 
 // Signature represents an action signed by a person
@@ -116,13 +117,13 @@ func (s *Signature) String() string {
 
 // ObjectIter provides an iterator for a set of objects.
 type ObjectIter struct {
-	core.ObjectIter
+	storer.ObjectIter
 	r *Repository
 }
 
 // NewObjectIter returns a ObjectIter for the given repository and underlying
 // object iterator.
-func NewObjectIter(r *Repository, iter core.ObjectIter) *ObjectIter {
+func NewObjectIter(r *Repository, iter storer.ObjectIter) *ObjectIter {
 	return &ObjectIter{iter, r}
 }
 
@@ -136,7 +137,7 @@ func (iter *ObjectIter) Next() (Object, error) {
 		}
 
 		o, err := iter.toObject(obj)
-		if err == core.ErrInvalidType {
+		if err == plumbing.ErrInvalidType {
 			continue
 		}
 
@@ -152,9 +153,9 @@ func (iter *ObjectIter) Next() (Object, error) {
 // an error happens or the end of the iter is reached. If ErrStop is sent
 // the iteration is stop but no error is returned. The iterator is closed.
 func (iter *ObjectIter) ForEach(cb func(Object) error) error {
-	return iter.ObjectIter.ForEach(func(obj core.Object) error {
+	return iter.ObjectIter.ForEach(func(obj plumbing.Object) error {
 		o, err := iter.toObject(obj)
-		if err == core.ErrInvalidType {
+		if err == plumbing.ErrInvalidType {
 			return nil
 		}
 
@@ -166,21 +167,21 @@ func (iter *ObjectIter) ForEach(cb func(Object) error) error {
 	})
 }
 
-func (iter *ObjectIter) toObject(obj core.Object) (Object, error) {
+func (iter *ObjectIter) toObject(obj plumbing.Object) (Object, error) {
 	switch obj.Type() {
-	case core.BlobObject:
+	case plumbing.BlobObject:
 		blob := &Blob{}
 		return blob, blob.Decode(obj)
-	case core.TreeObject:
+	case plumbing.TreeObject:
 		tree := &Tree{r: iter.r}
 		return tree, tree.Decode(obj)
-	case core.CommitObject:
+	case plumbing.CommitObject:
 		commit := &Commit{}
 		return commit, commit.Decode(obj)
-	case core.TagObject:
+	case plumbing.TagObject:
 		tag := &Tag{}
 		return tag, tag.Decode(obj)
 	default:
-		return nil, core.ErrInvalidType
+		return nil, plumbing.ErrInvalidType
 	}
 }
diff --git a/objects_test.go b/objects_test.go
index ee77869..78ebc6a 100644
--- a/objects_test.go
+++ b/objects_test.go
@@ -4,7 +4,7 @@ import (
 	"io/ioutil"
 	"time"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 
 	. "gopkg.in/check.v1"
 	"io"
@@ -17,7 +17,7 @@ type ObjectsSuite struct {
 var _ = Suite(&ObjectsSuite{})
 
 func (s *ObjectsSuite) TestNewCommit(c *C) {
-	hash := core.NewHash("a5b8b09e2f8fcb0bb99d3ccb0958157b40890d69")
+	hash := plumbing.NewHash("a5b8b09e2f8fcb0bb99d3ccb0958157b40890d69")
 	commit, err := s.Repository.Commit(hash)
 	c.Assert(err, IsNil)
 
@@ -45,7 +45,7 @@ func (s *ObjectsSuite) TestNewCommit(c *C) {
 }
 
 func (s *ObjectsSuite) TestParseTree(c *C) {
-	hash := core.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c")
+	hash := plumbing.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c")
 	tree, err := s.Repository.Tree(hash)
 	c.Assert(err, IsNil)
 
diff --git a/options.go b/options.go
index 4d289e9..edb908a 100644
--- a/options.go
+++ b/options.go
@@ -3,9 +3,9 @@ package git
 import (
 	"errors"
 
-	"gopkg.in/src-d/go-git.v4/clients/common"
 	"gopkg.in/src-d/go-git.v4/config"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/common"
 )
 
 const (
@@ -27,7 +27,7 @@ type CloneOptions struct {
 	// Name of the remote to be added, by default `origin`
 	RemoteName string
 	// Remote branch to clone
-	ReferenceName core.ReferenceName
+	ReferenceName plumbing.ReferenceName
 	// Fetch only ReferenceName if true
 	SingleBranch bool
 	// Limit fetching to the specified number of commits
@@ -45,7 +45,7 @@ func (o *CloneOptions) Validate() error {
 	}
 
 	if o.ReferenceName == "" {
-		o.ReferenceName = core.HEAD
+		o.ReferenceName = plumbing.HEAD
 	}
 
 	return nil
@@ -56,7 +56,7 @@ type PullOptions struct {
 	// Name of the remote to be pulled
 	RemoteName string
 	// Remote branch to clone
-	ReferenceName core.ReferenceName
+	ReferenceName plumbing.ReferenceName
 	// Fetch only ReferenceName if true
 	SingleBranch bool
 	// Limit fetching to the specified number of commits
@@ -70,7 +70,7 @@ func (o *PullOptions) Validate() error {
 	}
 
 	if o.ReferenceName == "" {
-		o.ReferenceName = core.HEAD
+		o.ReferenceName = plumbing.HEAD
 	}
 
 	return nil
diff --git a/clients/common.go b/plumbing/client/common.go
index c28c465..6a99339 100644
--- a/clients/common.go
+++ b/plumbing/client/common.go
@@ -16,9 +16,9 @@ package clients
 import (
 	"fmt"
 
-	"gopkg.in/src-d/go-git.v4/clients/common"
-	"gopkg.in/src-d/go-git.v4/clients/http"
-	"gopkg.in/src-d/go-git.v4/clients/ssh"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/common"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/http"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/ssh"
 )
 
 type GitUploadPackServiceFactory func(common.Endpoint) common.GitUploadPackService
diff --git a/clients/common/common.go b/plumbing/client/common/common.go
index c7cac00..97f78c4 100644
--- a/clients/common/common.go
+++ b/plumbing/client/common/common.go
@@ -11,10 +11,11 @@ import (
 	"regexp"
 	"strings"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp"
-	"gopkg.in/src-d/go-git.v4/formats/packp/advrefs"
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/advrefs"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 	"gopkg.in/src-d/go-git.v4/storage/memory"
 )
 
@@ -52,11 +53,11 @@ func NewEndpoint(endpoint string) (Endpoint, error) {
 
 	u, err := url.Parse(endpoint)
 	if err != nil {
-		return Endpoint{}, core.NewPermanentError(err)
+		return Endpoint{}, plumbing.NewPermanentError(err)
 	}
 
 	if !u.IsAbs() {
-		return Endpoint{}, core.NewPermanentError(fmt.Errorf(
+		return Endpoint{}, plumbing.NewPermanentError(fmt.Errorf(
 			"invalid endpoint: %s", endpoint,
 		))
 	}
@@ -95,15 +96,15 @@ func (i *GitUploadPackInfo) Decode(r io.Reader) error {
 	ar := advrefs.New()
 	if err := d.Decode(ar); err != nil {
 		if err == advrefs.ErrEmpty {
-			return core.NewPermanentError(err)
+			return plumbing.NewPermanentError(err)
 		}
-		return core.NewUnexpectedError(err)
+		return plumbing.NewUnexpectedError(err)
 	}
 
 	i.Capabilities = ar.Capabilities
 
 	if err := i.addRefs(ar); err != nil {
-		return core.NewUnexpectedError(err)
+		return plumbing.NewUnexpectedError(err)
 	}
 
 	return nil
@@ -111,7 +112,7 @@ func (i *GitUploadPackInfo) Decode(r io.Reader) error {
 
 func (i *GitUploadPackInfo) addRefs(ar *advrefs.AdvRefs) error {
 	for name, hash := range ar.References {
-		ref := core.NewReferenceFromStrings(name, hash.String())
+		ref := plumbing.NewReferenceFromStrings(name, hash.String())
 		i.Refs.SetReference(ref)
 	}
 
@@ -127,11 +128,11 @@ func (i *GitUploadPackInfo) addSymbolicRefs(ar *advrefs.AdvRefs) error {
 		chunks := strings.Split(symref, ":")
 		if len(chunks) != 2 {
 			err := fmt.Errorf("bad number of `:` in symref value (%q)", symref)
-			return core.NewUnexpectedError(err)
+			return plumbing.NewUnexpectedError(err)
 		}
-		name := core.ReferenceName(chunks[0])
-		target := core.ReferenceName(chunks[1])
-		ref := core.NewSymbolicReference(name, target)
+		name := plumbing.ReferenceName(chunks[0])
+		target := plumbing.ReferenceName(chunks[1])
+		ref := plumbing.NewSymbolicReference(name, target)
 		i.Refs.SetReference(ref)
 	}
 
@@ -142,8 +143,8 @@ func hasSymrefs(ar *advrefs.AdvRefs) bool {
 	return ar.Capabilities.Supports("symref")
 }
 
-func (i *GitUploadPackInfo) Head() *core.Reference {
-	ref, _ := core.ResolveReference(i.Refs, core.HEAD)
+func (i *GitUploadPackInfo) Head() *plumbing.Reference {
+	ref, _ := storer.ResolveReference(i.Refs, plumbing.HEAD)
 	return ref
 }
 
@@ -164,7 +165,7 @@ func (i *GitUploadPackInfo) Bytes() []byte {
 	_ = e.Encodef("%s HEAD\x00%s\n", i.Head().Hash(), i.Capabilities.String())
 
 	for _, ref := range i.Refs {
-		if ref.Type() != core.HashReference {
+		if ref.Type() != plumbing.HashReference {
 			continue
 		}
 
@@ -177,16 +178,16 @@ func (i *GitUploadPackInfo) Bytes() []byte {
 }
 
 type GitUploadPackRequest struct {
-	Wants []core.Hash
-	Haves []core.Hash
+	Wants []plumbing.Hash
+	Haves []plumbing.Hash
 	Depth int
 }
 
-func (r *GitUploadPackRequest) Want(h ...core.Hash) {
+func (r *GitUploadPackRequest) Want(h ...plumbing.Hash) {
 	r.Wants = append(r.Wants, h...)
 }
 
-func (r *GitUploadPackRequest) Have(h ...core.Hash) {
+func (r *GitUploadPackRequest) Have(h ...plumbing.Hash) {
 	r.Haves = append(r.Haves, h...)
 }
 
diff --git a/clients/common/common_test.go b/plumbing/client/common/common_test.go
index 5809584..cf4d871 100644
--- a/clients/common/common_test.go
+++ b/plumbing/client/common/common_test.go
@@ -5,8 +5,8 @@ import (
 	"encoding/base64"
 	"testing"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp"
 
 	. "gopkg.in/check.v1"
 )
@@ -56,13 +56,13 @@ func (s *SuiteCommon) TestGitUploadPackInfo(c *C) {
 	c.Assert(name, Equals, "refs/heads/master")
 	c.Assert(i.Refs, HasLen, 4)
 
-	ref := i.Refs[core.ReferenceName(name)]
+	ref := i.Refs[plumbing.ReferenceName(name)]
 	c.Assert(ref, NotNil)
 	c.Assert(ref.Hash().String(), Equals, "6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
 
-	ref = i.Refs[core.HEAD]
+	ref = i.Refs[plumbing.HEAD]
 	c.Assert(ref, NotNil)
-	c.Assert(ref.Target(), Equals, core.ReferenceName(name))
+	c.Assert(ref.Target(), Equals, plumbing.ReferenceName(name))
 }
 
 const GitUploadPackInfoNoHEADFixture = "MDAxZSMgc2VydmljZT1naXQtdXBsb2FkLXBhY2sKMDAwMDAwYmNkN2UxZmVlMjYxMjM0YmIzYTQzYzA5NmY1NTg3NDhhNTY5ZDc5ZWZmIHJlZnMvaGVhZHMvdjQAbXVsdGlfYWNrIHRoaW4tcGFjayBzaWRlLWJhbmQgc2lkZS1iYW5kLTY0ayBvZnMtZGVsdGEgc2hhbGxvdyBuby1wcm9ncmVzcyBpbmNsdWRlLXRhZyBtdWx0aV9hY2tfZGV0YWlsZWQgbm8tZG9uZSBhZ2VudD1naXQvMS45LjEKMDAwMA=="
@@ -95,11 +95,11 @@ func (s *SuiteCommon) TestGitUploadPackEncode(c *C) {
 	info := NewGitUploadPackInfo()
 	info.Capabilities.Add("symref", "HEAD:refs/heads/master")
 
-	ref := core.ReferenceName("refs/heads/master")
-	hash := core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
-	info.Refs = map[core.ReferenceName]*core.Reference{
-		core.HEAD: core.NewSymbolicReference(core.HEAD, ref),
-		ref:       core.NewHashReference(ref, hash),
+	ref := plumbing.ReferenceName("refs/heads/master")
+	hash := plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
+	info.Refs = map[plumbing.ReferenceName]*plumbing.Reference{
+		plumbing.HEAD: plumbing.NewSymbolicReference(plumbing.HEAD, ref),
+		ref:           plumbing.NewHashReference(ref, hash),
 	}
 
 	c.Assert(info.Head(), NotNil)
@@ -113,9 +113,9 @@ func (s *SuiteCommon) TestGitUploadPackEncode(c *C) {
 
 func (s *SuiteCommon) TestGitUploadPackRequest(c *C) {
 	r := &GitUploadPackRequest{}
-	r.Want(core.NewHash("d82f291cde9987322c8a0c81a325e1ba6159684c"))
-	r.Want(core.NewHash("2b41ef280fdb67a9b250678686a0c3e03b0a9989"))
-	r.Have(core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
+	r.Want(plumbing.NewHash("d82f291cde9987322c8a0c81a325e1ba6159684c"))
+	r.Want(plumbing.NewHash("2b41ef280fdb67a9b250678686a0c3e03b0a9989"))
+	r.Have(plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
 
 	c.Assert(r.String(), Equals,
 		"0032want d82f291cde9987322c8a0c81a325e1ba6159684c\n"+
diff --git a/clients/common_test.go b/plumbing/client/common_test.go
index 59fc300..058c4d3 100644
--- a/clients/common_test.go
+++ b/plumbing/client/common_test.go
@@ -5,7 +5,7 @@ import (
 	"io"
 	"testing"
 
-	"gopkg.in/src-d/go-git.v4/clients/common"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/common"
 
 	. "gopkg.in/check.v1"
 )
diff --git a/clients/http/common.go b/plumbing/client/http/common.go
index 483308a..4c07876 100644
--- a/clients/http/common.go
+++ b/plumbing/client/http/common.go
@@ -5,8 +5,8 @@ import (
 	"fmt"
 	"net/http"
 
-	"gopkg.in/src-d/go-git.v4/clients/common"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/common"
 )
 
 // HTTPAuthMethod concrete implementation of common.AuthMethod for HTTP services
@@ -62,7 +62,7 @@ func NewHTTPError(r *http.Response) error {
 	}
 
 	err := &HTTPError{r}
-	return core.NewUnexpectedError(err)
+	return plumbing.NewUnexpectedError(err)
 }
 
 // StatusCode returns the status code of the response
diff --git a/clients/http/common_test.go b/plumbing/client/http/common_test.go
index 287897d..287897d 100644
--- a/clients/http/common_test.go
+++ b/plumbing/client/http/common_test.go
diff --git a/clients/http/git_upload_pack.go b/plumbing/client/http/git_upload_pack.go
index f652150..c1f4a0b 100644
--- a/clients/http/git_upload_pack.go
+++ b/plumbing/client/http/git_upload_pack.go
@@ -8,9 +8,9 @@ import (
 	"net/http"
 	"strings"
 
-	"gopkg.in/src-d/go-git.v4/clients/common"
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/common"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
 )
 
 // GitUploadPackService git-upoad-pack service over HTTP
@@ -128,7 +128,7 @@ func (s *GitUploadPackService) doRequest(method, url string, content *strings.Re
 
 	req, err := http.NewRequest(method, url, body)
 	if err != nil {
-		return nil, core.NewPermanentError(err)
+		return nil, plumbing.NewPermanentError(err)
 	}
 
 	s.applyHeadersToRequest(req, content)
@@ -136,7 +136,7 @@ func (s *GitUploadPackService) doRequest(method, url string, content *strings.Re
 
 	res, err := s.client.Do(req)
 	if err != nil {
-		return nil, core.NewUnexpectedError(err)
+		return nil, plumbing.NewUnexpectedError(err)
 	}
 
 	if err := NewHTTPError(res); err != nil {
diff --git a/clients/http/git_upload_pack_test.go b/plumbing/client/http/git_upload_pack_test.go
index 579419f..a50dbdf 100644
--- a/clients/http/git_upload_pack_test.go
+++ b/plumbing/client/http/git_upload_pack_test.go
@@ -4,8 +4,8 @@ import (
 	"io/ioutil"
 
 	. "gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/clients/common"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/common"
 )
 
 type RemoteSuite struct {
@@ -95,7 +95,7 @@ func (s *RemoteSuite) TestFetch(c *C) {
 	c.Assert(r.Connect(), IsNil)
 
 	req := &common.GitUploadPackRequest{}
-	req.Want(core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
+	req.Want(plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
 
 	reader, err := r.Fetch(req)
 	c.Assert(err, IsNil)
@@ -110,8 +110,8 @@ func (s *RemoteSuite) TestFetchNoChanges(c *C) {
 	c.Assert(r.Connect(), IsNil)
 
 	req := &common.GitUploadPackRequest{}
-	req.Want(core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
-	req.Have(core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
+	req.Want(plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
+	req.Have(plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
 
 	reader, err := r.Fetch(req)
 	c.Assert(err, Equals, common.ErrEmptyGitUploadPack)
@@ -123,8 +123,8 @@ func (s *RemoteSuite) TestFetchMulti(c *C) {
 	c.Assert(r.Connect(), IsNil)
 
 	req := &common.GitUploadPackRequest{}
-	req.Want(core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
-	req.Want(core.NewHash("e8d3ffab552895c19b9fcf7aa264d277cde33881"))
+	req.Want(plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
+	req.Want(plumbing.NewHash("e8d3ffab552895c19b9fcf7aa264d277cde33881"))
 
 	reader, err := r.Fetch(req)
 	c.Assert(err, IsNil)
diff --git a/clients/ssh/auth_method.go b/plumbing/client/ssh/auth_method.go
index 1ce45ef..587f59a 100644
--- a/clients/ssh/auth_method.go
+++ b/plumbing/client/ssh/auth_method.go
@@ -7,7 +7,7 @@ import (
 
 	"golang.org/x/crypto/ssh"
 	"golang.org/x/crypto/ssh/agent"
-	"gopkg.in/src-d/go-git.v4/clients/common"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/common"
 )
 
 // AuthMethod is the interface all auth methods for the ssh client
diff --git a/clients/ssh/auth_method_test.go b/plumbing/client/ssh/auth_method_test.go
index a87c950..a87c950 100644
--- a/clients/ssh/auth_method_test.go
+++ b/plumbing/client/ssh/auth_method_test.go
diff --git a/clients/ssh/git_upload_pack.go b/plumbing/client/ssh/git_upload_pack.go
index d53dc63..e2b73fd 100644
--- a/clients/ssh/git_upload_pack.go
+++ b/plumbing/client/ssh/git_upload_pack.go
@@ -8,10 +8,10 @@ import (
 	"io"
 	"strings"
 
-	"gopkg.in/src-d/go-git.v4/clients/common"
-	"gopkg.in/src-d/go-git.v4/formats/packp/advrefs"
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
-	"gopkg.in/src-d/go-git.v4/formats/packp/ulreq"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/common"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/advrefs"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/ulreq"
 
 	"golang.org/x/crypto/ssh"
 )
diff --git a/clients/ssh/git_upload_pack_test.go b/plumbing/client/ssh/git_upload_pack_test.go
index d7160dc..4d5b2b1 100644
--- a/clients/ssh/git_upload_pack_test.go
+++ b/plumbing/client/ssh/git_upload_pack_test.go
@@ -5,8 +5,8 @@ import (
 	"os"
 
 	. "gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/clients/common"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/common"
 )
 
 type RemoteSuite struct {
@@ -106,7 +106,7 @@ func (s *RemoteSuite) TestCapabilities(c *C) {
 func (s *RemoteSuite) TestFetchNotConnected(c *C) {
 	r := NewGitUploadPackService(s.Endpoint)
 	pr := &common.GitUploadPackRequest{}
-	pr.Want(core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
+	pr.Want(plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
 	_, err := r.Fetch(pr)
 	c.Assert(err, Equals, ErrNotConnected)
 }
@@ -117,8 +117,8 @@ func (s *RemoteSuite) TestFetch(c *C) {
 	defer func() { c.Assert(r.Disconnect(), IsNil) }()
 
 	req := &common.GitUploadPackRequest{}
-	req.Want(core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
-	req.Want(core.NewHash("e8d3ffab552895c19b9fcf7aa264d277cde33881"))
+	req.Want(plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
+	req.Want(plumbing.NewHash("e8d3ffab552895c19b9fcf7aa264d277cde33881"))
 	reader, err := r.Fetch(req)
 	c.Assert(err, IsNil)
 	defer func() { c.Assert(reader.Close(), IsNil) }()
@@ -134,7 +134,7 @@ func (s *RemoteSuite) TestFetchError(c *C) {
 	defer func() { c.Assert(r.Disconnect(), IsNil) }()
 
 	req := &common.GitUploadPackRequest{}
-	req.Want(core.NewHash("1111111111111111111111111111111111111111"))
+	req.Want(plumbing.NewHash("1111111111111111111111111111111111111111"))
 
 	reader, err := r.Fetch(req)
 	c.Assert(err, IsNil)
diff --git a/core/errors.go b/plumbing/errors.go
index 50772b6..a3ebed3 100644
--- a/core/errors.go
+++ b/plumbing/errors.go
@@ -1,4 +1,4 @@
-package core
+package plumbing
 
 import "fmt"
 
diff --git a/formats/config/common.go b/plumbing/format/config/common.go
index d2f1e5c..d2f1e5c 100644
--- a/formats/config/common.go
+++ b/plumbing/format/config/common.go
diff --git a/formats/config/common_test.go b/plumbing/format/config/common_test.go
index 365b53f..365b53f 100644
--- a/formats/config/common_test.go
+++ b/plumbing/format/config/common_test.go
diff --git a/formats/config/decoder.go b/plumbing/format/config/decoder.go
index 0f02ce1..0f02ce1 100644
--- a/formats/config/decoder.go
+++ b/plumbing/format/config/decoder.go
diff --git a/formats/config/decoder_test.go b/plumbing/format/config/decoder_test.go
index 412549f..412549f 100644
--- a/formats/config/decoder_test.go
+++ b/plumbing/format/config/decoder_test.go
diff --git a/formats/config/doc.go b/plumbing/format/config/doc.go
index dd77fbc..dd77fbc 100644
--- a/formats/config/doc.go
+++ b/plumbing/format/config/doc.go
diff --git a/formats/config/encoder.go b/plumbing/format/config/encoder.go
index 88bdf65..88bdf65 100644
--- a/formats/config/encoder.go
+++ b/plumbing/format/config/encoder.go
diff --git a/formats/config/encoder_test.go b/plumbing/format/config/encoder_test.go
index 5335b83..5335b83 100644
--- a/formats/config/encoder_test.go
+++ b/plumbing/format/config/encoder_test.go
diff --git a/formats/config/fixtures_test.go b/plumbing/format/config/fixtures_test.go
index 12ff288..12ff288 100644
--- a/formats/config/fixtures_test.go
+++ b/plumbing/format/config/fixtures_test.go
diff --git a/formats/config/option.go b/plumbing/format/config/option.go
index dbb401c..dbb401c 100644
--- a/formats/config/option.go
+++ b/plumbing/format/config/option.go
diff --git a/formats/config/option_test.go b/plumbing/format/config/option_test.go
index 8588de1..8588de1 100644
--- a/formats/config/option_test.go
+++ b/plumbing/format/config/option_test.go
diff --git a/formats/config/section.go b/plumbing/format/config/section.go
index 1844913..1844913 100644
--- a/formats/config/section.go
+++ b/plumbing/format/config/section.go
diff --git a/formats/config/section_test.go b/plumbing/format/config/section_test.go
index cfd9f3f..cfd9f3f 100644
--- a/formats/config/section_test.go
+++ b/plumbing/format/config/section_test.go
diff --git a/formats/idxfile/decoder.go b/plumbing/format/idxfile/decoder.go
index 884d32b..e3ffc4b 100644
--- a/formats/idxfile/decoder.go
+++ b/plumbing/format/idxfile/decoder.go
@@ -5,7 +5,7 @@ import (
 	"errors"
 	"io"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 	"gopkg.in/src-d/go-git.v4/utils/binary"
 )
 
@@ -99,7 +99,7 @@ func readFanout(idx *Idxfile, r io.Reader) error {
 func readObjectNames(idx *Idxfile, r io.Reader) error {
 	c := int(idx.ObjectCount)
 	for i := 0; i < c; i++ {
-		var ref core.Hash
+		var ref plumbing.Hash
 		if _, err := r.Read(ref[:]); err != nil {
 			return err
 		}
diff --git a/formats/idxfile/decoder_test.go b/plumbing/format/idxfile/decoder_test.go
index 18546d2..5231e64 100644
--- a/formats/idxfile/decoder_test.go
+++ b/plumbing/format/idxfile/decoder_test.go
@@ -7,7 +7,7 @@ import (
 
 	. "gopkg.in/check.v1"
 	"gopkg.in/src-d/go-git.v4/fixtures"
-	"gopkg.in/src-d/go-git.v4/formats/packfile"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packfile"
 	"gopkg.in/src-d/go-git.v4/storage/memory"
 )
 
diff --git a/formats/idxfile/doc.go b/plumbing/format/idxfile/doc.go
index 8a76853..8a76853 100644
--- a/formats/idxfile/doc.go
+++ b/plumbing/format/idxfile/doc.go
diff --git a/formats/idxfile/encoder.go b/plumbing/format/idxfile/encoder.go
index 164414a..164414a 100644
--- a/formats/idxfile/encoder.go
+++ b/plumbing/format/idxfile/encoder.go
diff --git a/formats/idxfile/encoder_test.go b/plumbing/format/idxfile/encoder_test.go
index d9d83eb..9a53863 100644
--- a/formats/idxfile/encoder_test.go
+++ b/plumbing/format/idxfile/encoder_test.go
@@ -5,14 +5,14 @@ import (
 	"io/ioutil"
 
 	. "gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/fixtures"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 func (s *IdxfileSuite) TestEncode(c *C) {
 	expected := &Idxfile{}
-	expected.Add(core.NewHash("4bfc730165c370df4a012afbb45ba3f9c332c0d4"), 82, 82)
-	expected.Add(core.NewHash("8fa2238efdae08d83c12ee176fae65ff7c99af46"), 42, 42)
+	expected.Add(plumbing.NewHash("4bfc730165c370df4a012afbb45ba3f9c332c0d4"), 82, 82)
+	expected.Add(plumbing.NewHash("8fa2238efdae08d83c12ee176fae65ff7c99af46"), 42, 42)
 
 	buf := bytes.NewBuffer(nil)
 	e := NewEncoder(buf)
diff --git a/formats/idxfile/idxfile.go b/plumbing/format/idxfile/idxfile.go
index 8549d3f..8329c23 100644
--- a/formats/idxfile/idxfile.go
+++ b/plumbing/format/idxfile/idxfile.go
@@ -1,6 +1,6 @@
 package idxfile
 
-import "gopkg.in/src-d/go-git.v4/core"
+import "gopkg.in/src-d/go-git.v4/plumbing"
 
 const (
 	// VersionSupported is the only idx version supported.
@@ -24,12 +24,12 @@ type Idxfile struct {
 // An Entry represents data about an object in the packfile: its hash,
 // offset and CRC32 checksum.
 type Entry struct {
-	Hash   core.Hash
+	Hash   plumbing.Hash
 	CRC32  uint32
 	Offset uint64
 }
 
-func (idx *Idxfile) Add(h core.Hash, offset uint64, crc32 uint32) {
+func (idx *Idxfile) Add(h plumbing.Hash, offset uint64, crc32 uint32) {
 	idx.Entries = append(idx.Entries, Entry{
 		Hash:   h,
 		Offset: offset,
diff --git a/formats/index/decoder.go b/plumbing/format/index/decoder.go
index f3d4343..9069c9e 100644
--- a/formats/index/decoder.go
+++ b/plumbing/format/index/decoder.go
@@ -10,7 +10,7 @@ import (
 	"strconv"
 	"time"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 	"gopkg.in/src-d/go-git.v4/utils/binary"
 )
 
@@ -273,7 +273,7 @@ func (d *Decoder) getExtensionReader() (io.Reader, error) {
 }
 
 func (d *Decoder) readChecksum(expected []byte, alreadyRead [4]byte) error {
-	var h core.Hash
+	var h plumbing.Hash
 	copy(h[:4], alreadyRead[:])
 
 	if err := binary.Read(d.r, h[4:]); err != nil {
@@ -399,7 +399,7 @@ func (d *resolveUndoDecoder) Decode(ru *ResolveUndo) error {
 
 func (d *resolveUndoDecoder) readEntry() (*ResolveUndoEntry, error) {
 	e := &ResolveUndoEntry{
-		Stages: make(map[Stage]core.Hash, 0),
+		Stages: make(map[Stage]plumbing.Hash, 0),
 	}
 
 	path, err := binary.ReadUntil(d.r, '\x00')
@@ -416,7 +416,7 @@ func (d *resolveUndoDecoder) readEntry() (*ResolveUndoEntry, error) {
 	}
 
 	for s := range e.Stages {
-		var hash core.Hash
+		var hash plumbing.Hash
 		if err := binary.Read(d.r, hash[:]); err != nil {
 			return nil, err
 		}
@@ -439,7 +439,7 @@ func (d *resolveUndoDecoder) readStage(e *ResolveUndoEntry, s Stage) error {
 	}
 
 	if stage != 0 {
-		e.Stages[s] = core.ZeroHash
+		e.Stages[s] = plumbing.ZeroHash
 	}
 
 	return nil
diff --git a/formats/index/decoder_test.go b/plumbing/format/index/decoder_test.go
index a05417d..44ecb69 100644
--- a/formats/index/decoder_test.go
+++ b/plumbing/format/index/decoder_test.go
@@ -4,8 +4,8 @@ import (
 	"testing"
 
 	. "gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/fixtures"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 func Test(t *testing.T) { TestingT(t) }
@@ -80,11 +80,11 @@ func (s *IdxfileSuite) TestDecodeCacheTree(c *C) {
 }
 
 var expectedEntries = []TreeEntry{
-	{Path: "", Entries: 9, Trees: 4, Hash: core.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c")},
-	{Path: "go", Entries: 1, Trees: 0, Hash: core.NewHash("a39771a7651f97faf5c72e08224d857fc35133db")},
-	{Path: "php", Entries: 1, Trees: 0, Hash: core.NewHash("586af567d0bb5e771e49bdd9434f5e0fb76d25fa")},
-	{Path: "json", Entries: 2, Trees: 0, Hash: core.NewHash("5a877e6a906a2743ad6e45d99c1793642aaf8eda")},
-	{Path: "vendor", Entries: 1, Trees: 0, Hash: core.NewHash("cf4aa3b38974fb7d81f367c0830f7d78d65ab86b")},
+	{Path: "", Entries: 9, Trees: 4, Hash: plumbing.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c")},
+	{Path: "go", Entries: 1, Trees: 0, Hash: plumbing.NewHash("a39771a7651f97faf5c72e08224d857fc35133db")},
+	{Path: "php", Entries: 1, Trees: 0, Hash: plumbing.NewHash("586af567d0bb5e771e49bdd9434f5e0fb76d25fa")},
+	{Path: "json", Entries: 2, Trees: 0, Hash: plumbing.NewHash("5a877e6a906a2743ad6e45d99c1793642aaf8eda")},
+	{Path: "vendor", Entries: 1, Trees: 0, Hash: plumbing.NewHash("cf4aa3b38974fb7d81f367c0830f7d78d65ab86b")},
 }
 
 func (s *IdxfileSuite) TestDecodeMergeConflict(c *C) {
@@ -159,13 +159,13 @@ func (s *IdxfileSuite) TestDecodeResolveUndo(c *C) {
 	c.Assert(ru.Entries, HasLen, 2)
 	c.Assert(ru.Entries[0].Path, Equals, "go/example.go")
 	c.Assert(ru.Entries[0].Stages, HasLen, 3)
-	c.Assert(ru.Entries[0].Stages[AncestorMode], Not(Equals), core.ZeroHash)
-	c.Assert(ru.Entries[0].Stages[OurMode], Not(Equals), core.ZeroHash)
-	c.Assert(ru.Entries[0].Stages[TheirMode], Not(Equals), core.ZeroHash)
+	c.Assert(ru.Entries[0].Stages[AncestorMode], Not(Equals), plumbing.ZeroHash)
+	c.Assert(ru.Entries[0].Stages[OurMode], Not(Equals), plumbing.ZeroHash)
+	c.Assert(ru.Entries[0].Stages[TheirMode], Not(Equals), plumbing.ZeroHash)
 	c.Assert(ru.Entries[1].Path, Equals, "haskal/haskal.hs")
 	c.Assert(ru.Entries[1].Stages, HasLen, 2)
-	c.Assert(ru.Entries[1].Stages[OurMode], Not(Equals), core.ZeroHash)
-	c.Assert(ru.Entries[1].Stages[TheirMode], Not(Equals), core.ZeroHash)
+	c.Assert(ru.Entries[1].Stages[OurMode], Not(Equals), plumbing.ZeroHash)
+	c.Assert(ru.Entries[1].Stages[TheirMode], Not(Equals), plumbing.ZeroHash)
 }
 
 func (s *IdxfileSuite) TestDecodeV4(c *C) {
diff --git a/formats/index/doc.go b/plumbing/format/index/doc.go
index 00466af..3a72606 100644
--- a/formats/index/doc.go
+++ b/plumbing/format/index/doc.go
@@ -253,14 +253,14 @@ Git index format
   - Stat data of $GIT_DIR/info/exclude. See "Index entry" section from
     ctime field until "file size".
 
-  - Stat data of core.excludesfile
+  - Stat data of plumbing.excludesfile
 
   - 32-bit dir_flags (see struct dir_struct)
 
   - 160-bit SHA-1 of $GIT_DIR/info/exclude. Null SHA-1 means the file
     does not exist.
 
-  - 160-bit SHA-1 of core.excludesfile. Null SHA-1 means the file does
+  - 160-bit SHA-1 of plumbing.excludesfile. Null SHA-1 means the file does
     not exist.
 
   - NUL-terminated string of per-dir exclude file name. This usually
diff --git a/formats/index/encoder.go b/plumbing/format/index/encoder.go
index 94fbc68..94fbc68 100644
--- a/formats/index/encoder.go
+++ b/plumbing/format/index/encoder.go
diff --git a/formats/index/encoder_test.go b/plumbing/format/index/encoder_test.go
index 3085988..6770985 100644
--- a/formats/index/encoder_test.go
+++ b/plumbing/format/index/encoder_test.go
@@ -6,7 +6,7 @@ import (
 	"time"
 
 	. "gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 func (s *IdxfileSuite) TestEncode(c *C) {
@@ -21,7 +21,7 @@ func (s *IdxfileSuite) TestEncode(c *C) {
 			GID:        8484,
 			Size:       42,
 			Stage:      TheirMode,
-			Hash:       core.NewHash("e25b29c8946e0e192fae2edc1dabf7be71e8ecf3"),
+			Hash:       plumbing.NewHash("e25b29c8946e0e192fae2edc1dabf7be71e8ecf3"),
 			Name:       "foo",
 		}, {
 			CreatedAt:  time.Now(),
diff --git a/formats/index/index.go b/plumbing/format/index/index.go
index 35a5391..4a3c798 100644
--- a/formats/index/index.go
+++ b/plumbing/format/index/index.go
@@ -5,7 +5,7 @@ import (
 	"os"
 	"time"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 var (
@@ -47,7 +47,7 @@ type Index struct {
 // multiple Entry instances may appear for the same path name.
 type Entry struct {
 	// Hash is the SHA1 of the represented file
-	Hash core.Hash
+	Hash plumbing.Hash
 	// Name is the  Entry path name relative to top level directory
 	Name string
 	// CreatedAt time when the tracked path was created
@@ -90,7 +90,7 @@ type TreeEntry struct {
 	Trees int
 	// Hash object name for the object that would result from writing this span
 	// of index as a tree.
-	Hash core.Hash
+	Hash plumbing.Hash
 }
 
 // ResolveUndo when a conflict is resolved (e.g. with "git add path"), these
@@ -104,5 +104,5 @@ type ResolveUndo struct {
 // ResolveUndoEntry contains the information about a conflict when is resolved
 type ResolveUndoEntry struct {
 	Path   string
-	Stages map[Stage]core.Hash
+	Stages map[Stage]plumbing.Hash
 }
diff --git a/formats/objfile/common_test.go b/plumbing/format/objfile/common_test.go
index 682dfbb..7c8b75c 100644
--- a/formats/objfile/common_test.go
+++ b/plumbing/format/objfile/common_test.go
@@ -5,62 +5,62 @@ import (
 	"testing"
 
 	. "gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 type objfileFixture struct {
-	hash    string          // hash of data
-	t       core.ObjectType // object type
-	content string          // base64-encoded content
-	data    string          // base64-encoded objfile data
+	hash    string              // hash of data
+	t       plumbing.ObjectType // object type
+	content string              // base64-encoded content
+	data    string              // base64-encoded objfile data
 }
 
 var objfileFixtures = []objfileFixture{
 	{
 		"e69de29bb2d1d6434b8b29ae775ad8c2e48c5391",
-		core.BlobObject,
+		plumbing.BlobObject,
 		base64.StdEncoding.EncodeToString([]byte("")),
 		"eAFLyslPUjBgAAAJsAHw",
 	},
 	{
 		"a8a940627d132695a9769df883f85992f0ff4a43",
-		core.BlobObject,
+		plumbing.BlobObject,
 		base64.StdEncoding.EncodeToString([]byte("this is a test")),
 		"eAFLyslPUjA0YSjJyCxWAKJEhZLU4hIAUDYHOg==",
 	},
 	{
 		"4dc2174801ac4a3d36886210fd086fbe134cf7b2",
-		core.BlobObject,
+		plumbing.BlobObject,
 		base64.StdEncoding.EncodeToString([]byte("this\nis\n\n\na\nmultiline\n\ntest.\n")),
 		"eAFLyslPUjCyZCjJyCzmAiIurkSu3NKcksyczLxULq6S1OISPS4A1I8LMQ==",
 	},
 	{
 		"13e6f47dd57798bfdc728d91f5c6d7f40c5bb5fc",
-		core.BlobObject,
+		plumbing.BlobObject,
 		base64.StdEncoding.EncodeToString([]byte("this tests\r\nCRLF\r\nencoded files.\r\n")),
 		"eAFLyslPUjA2YSjJyCxWKEktLinm5XIO8nHj5UrNS85PSU1RSMvMSS3W4+UCABp3DNE=",
 	},
 	{
 		"72a7bc4667ab068e954172437b993d9fbaa137cb",
-		core.BlobObject,
+		plumbing.BlobObject,
 		base64.StdEncoding.EncodeToString([]byte("test@example.com")),
 		"eAFLyslPUjA0YyhJLS5xSK1IzC3ISdVLzs8FAGVtCIA=",
 	},
 	{
 		"bb2b40e85ec0455d1de72daff71583f0dd72a33f",
-		core.BlobObject,
+		plumbing.BlobObject,
 		base64.StdEncoding.EncodeToString([]byte("package main\r\n\r\nimport (\r\n\t\"fmt\"\r\n\t\"io\"\r\n\t\"os\"\r\n\r\n\t\"gopkg.in/src-d/go-git.v3\"\r\n)\r\n\r\nfunc main() {\r\n\tfmt.Printf(\"Retrieving %q ...\\n\", os.Args[2])\r\n\tr, err := git.NewRepository(os.Args[2], nil)\r\n\tif err != nil {\r\n\t\tpanic(err)\r\n\t}\r\n\r\n\tif err := r.Pull(\"origin\", \"refs/heads/master\"); err != nil {\r\n\t\tpanic(err)\r\n\t}\r\n\r\n\tdumpCommits(r)\r\n}\r\n\r\nfunc dumpCommits(r *git.Repository) {\r\n\titer := r.Commits()\r\n\tdefer iter.Close()\r\n\r\n\tfor {\r\n\t\tcommit, err := iter.Next()\r\n\t\tif err != nil {\r\n\t\t\tif err == io.EOF {\r\n\t\t\t\tbreak\r\n\t\t\t}\r\n\r\n\t\t\tpanic(err)\r\n\t\t}\r\n\r\n\t\tfmt.Println(commit)\r\n\t}\r\n}\r\n")),
 		"eAGNUU1LAzEU9JpC/0NcEFJps2ARQdmDFD3W0qt6SHez8dHdZH1JqyL+d/Oy/aDgQVh47LzJTGayatyKX99MzzpVrpXRvFVgh4PhANrOYeBiOGBZ3YaMJrg0nI+D/o3r1kaCzT2Wkyo3bmIgyO00rkfEqDe2TIJixL/jgagjFwg21CJb6oCgt2ANv3jnUsoXm4258/IejX++eo0CDMdcI/LbgpPuXH8sdec8BIdf4sgccwsN0aFO9POCgGTIOmWhFFGE9j/p1jtWFEW52DSNyByCAXLPUNc+f9Oq8nmrfNCYje7+o1lt2m7m2haCF2SVnFL6kw2/pBzHEH0rEH0oI8q9BF220nWEaSdnjfNaRDDCtcM+WZnsDgUl4lx/BuKxv6rYY0XBwcmHp8deh7EVarWmQ7uC2Glre/TweI0VvTk5xaTx+wWX66Gs",
 	},
 	{
 		"e94db0f9ffca44dc7bade6a3591f544183395a7c",
-		core.TreeObject,
+		plumbing.TreeObject,
 		"MTAwNjQ0IFRlc3QgMS50eHQAqKlAYn0TJpWpdp34g/hZkvD/SkMxMDA2NDQgVGVzdCAyLnR4dABNwhdIAaxKPTaIYhD9CG++E0z3sjEwMDY0NCBUZXN0IDMudHh0ABPm9H3Vd5i/3HKNkfXG1/QMW7X8MTAwNjQ0IFRlc3QgNC50eHQAcqe8RmerBo6VQXJDe5k9n7qhN8sxMDA2NDQgVGVzdCA1LnR4dAC7K0DoXsBFXR3nLa/3FYPw3XKjPw==",
 		"eAErKUpNVTC0NGAwNDAwMzFRCEktLlEw1CupKGFYsdIhqVZYberKsrk/mn9ETvrw38sZWZURWJXvIXEPxjVetmYdSQJ/OfL3Cft834SsyhisSvjZl9qr5TP23ynqnfj12PUvPNFb/yCrMgGrKlq+xy19NVvfVMci5+qZtvN3LTQ/jazKFKxqt7bDi7gDrrGyz3XXfxdt/nC3aLE9AA2STmk=",
 	},
 	{
 		"9d7f8a56eaf92469dee8a856e716a03387ddb076",
-		core.CommitObject,
+		plumbing.CommitObject,
 		"dHJlZSBlOTRkYjBmOWZmY2E0NGRjN2JhZGU2YTM1OTFmNTQ0MTgzMzk1YTdjCmF1dGhvciBKb3NodWEgU2pvZGluZyA8am9zaHVhLnNqb2RpbmdAc2NqYWxsaWFuY2UuY29tPiAxNDU2NTMxNTgzIC0wODAwCmNvbW1pdHRlciBKb3NodWEgU2pvZGluZyA8am9zaHVhLnNqb2RpbmdAc2NqYWxsaWFuY2UuY29tPiAxNDU2NTMxNTgzIC0wODAwCgpUZXN0IENvbW1pdAo=",
 		"eAGtjksOgjAUAF33FO8CktZ+aBNjTNy51Qs8Xl8FAjSh5f4SvILLmcVkKM/zUOEi3amuzMDBxE6mkBKhMZHaDiM71DaoZI1RXutgsSWBW+3zCs9c+g3hNeY4LB+4jgc35cf3QiNO04ALcUN5voEy1lmtrNdwll5Ksdt9oPIfUuLNpcLjCIov3ApFmQ==",
 	},
diff --git a/formats/objfile/reader.go b/plumbing/format/objfile/reader.go
index 5c319f6..e7e119c 100644
--- a/formats/objfile/reader.go
+++ b/plumbing/format/objfile/reader.go
@@ -6,8 +6,8 @@ import (
 	"io"
 	"strconv"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packfile"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packfile"
 )
 
 var (
@@ -22,7 +22,7 @@ var (
 type Reader struct {
 	multi  io.Reader
 	zlib   io.ReadCloser
-	hasher core.Hasher
+	hasher plumbing.Hasher
 }
 
 // NewReader returns a new Reader reading from r.
@@ -38,14 +38,14 @@ func NewReader(r io.Reader) (*Reader, error) {
 }
 
 // Header reads the type and the size of object, and prepares the reader for read
-func (r *Reader) Header() (t core.ObjectType, size int64, err error) {
+func (r *Reader) Header() (t plumbing.ObjectType, size int64, err error) {
 	var raw []byte
 	raw, err = r.readUntil(' ')
 	if err != nil {
 		return
 	}
 
-	t, err = core.ParseObjectType(string(raw))
+	t, err = plumbing.ParseObjectType(string(raw))
 	if err != nil {
 		return
 	}
@@ -86,8 +86,8 @@ func (r *Reader) readUntil(delim byte) ([]byte, error) {
 	}
 }
 
-func (r *Reader) prepareForRead(t core.ObjectType, size int64) {
-	r.hasher = core.NewHasher(t, size)
+func (r *Reader) prepareForRead(t plumbing.ObjectType, size int64) {
+	r.hasher = plumbing.NewHasher(t, size)
 	r.multi = io.TeeReader(r.zlib, r.hasher)
 }
 
@@ -103,7 +103,7 @@ func (r *Reader) Read(p []byte) (n int, err error) {
 }
 
 // Hash returns the hash of the object data stream that has been read so far.
-func (r *Reader) Hash() core.Hash {
+func (r *Reader) Hash() plumbing.Hash {
 	return r.hasher.Sum()
 }
 
diff --git a/formats/objfile/reader_test.go b/plumbing/format/objfile/reader_test.go
index a383fd2..715792d 100644
--- a/formats/objfile/reader_test.go
+++ b/plumbing/format/objfile/reader_test.go
@@ -8,7 +8,7 @@ import (
 	"io/ioutil"
 
 	. "gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 type SuiteReader struct{}
@@ -18,7 +18,7 @@ var _ = Suite(&SuiteReader{})
 func (s *SuiteReader) TestReadObjfile(c *C) {
 	for k, fixture := range objfileFixtures {
 		com := fmt.Sprintf("test %d: ", k)
-		hash := core.NewHash(fixture.hash)
+		hash := plumbing.NewHash(fixture.hash)
 		content, _ := base64.StdEncoding.DecodeString(fixture.content)
 		data, _ := base64.StdEncoding.DecodeString(fixture.data)
 
@@ -26,7 +26,7 @@ func (s *SuiteReader) TestReadObjfile(c *C) {
 	}
 }
 
-func testReader(c *C, source io.Reader, hash core.Hash, t core.ObjectType, content []byte, com string) {
+func testReader(c *C, source io.Reader, hash plumbing.Hash, t plumbing.ObjectType, content []byte, com string) {
 	r, err := NewReader(source)
 	c.Assert(err, IsNil)
 
diff --git a/formats/objfile/writer.go b/plumbing/format/objfile/writer.go
index d2f2314..44563d2 100644
--- a/formats/objfile/writer.go
+++ b/plumbing/format/objfile/writer.go
@@ -6,7 +6,7 @@ import (
 	"io"
 	"strconv"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 var (
@@ -19,7 +19,7 @@ var (
 type Writer struct {
 	raw    io.Writer
 	zlib   io.WriteCloser
-	hasher core.Hasher
+	hasher plumbing.Hasher
 	multi  io.Writer
 
 	closed  bool
@@ -38,11 +38,11 @@ func NewWriter(w io.Writer) *Writer {
 }
 
 // WriteHeader writes the type and the size and prepares to accept the object's
-// contents. If an invalid t is provided, core.ErrInvalidType is returned. If a
+// contents. If an invalid t is provided, plumbing.ErrInvalidType is returned. If a
 // negative size is provided, ErrNegativeSize is returned.
-func (w *Writer) WriteHeader(t core.ObjectType, size int64) error {
+func (w *Writer) WriteHeader(t plumbing.ObjectType, size int64) error {
 	if !t.Valid() {
-		return core.ErrInvalidType
+		return plumbing.ErrInvalidType
 	}
 	if size < 0 {
 		return ErrNegativeSize
@@ -59,10 +59,10 @@ func (w *Writer) WriteHeader(t core.ObjectType, size int64) error {
 	return err
 }
 
-func (w *Writer) prepareForWrite(t core.ObjectType, size int64) {
+func (w *Writer) prepareForWrite(t plumbing.ObjectType, size int64) {
 	w.pending = size
 
-	w.hasher = core.NewHasher(t, size)
+	w.hasher = plumbing.NewHasher(t, size)
 	w.multi = io.MultiWriter(w.zlib, w.hasher)
 }
 
@@ -91,7 +91,7 @@ func (w *Writer) Write(p []byte) (n int, err error) {
 
 // Hash returns the hash of the object data stream that has been written so far.
 // It can be called before or after Close.
-func (w *Writer) Hash() core.Hash {
+func (w *Writer) Hash() plumbing.Hash {
 	return w.hasher.Sum() // Not yet closed, return hash of data written so far
 }
 
diff --git a/formats/objfile/writer_test.go b/plumbing/format/objfile/writer_test.go
index 18bba79..46dbea6 100644
--- a/formats/objfile/writer_test.go
+++ b/plumbing/format/objfile/writer_test.go
@@ -7,7 +7,7 @@ import (
 	"io"
 
 	. "gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 type SuiteWriter struct{}
@@ -19,7 +19,7 @@ func (s *SuiteWriter) TestWriteObjfile(c *C) {
 		buffer := bytes.NewBuffer(nil)
 
 		com := fmt.Sprintf("test %d: ", k)
-		hash := core.NewHash(fixture.hash)
+		hash := plumbing.NewHash(fixture.hash)
 		content, _ := base64.StdEncoding.DecodeString(fixture.content)
 
 		// Write the data out to the buffer
@@ -30,7 +30,7 @@ func (s *SuiteWriter) TestWriteObjfile(c *C) {
 	}
 }
 
-func testWriter(c *C, dest io.Writer, hash core.Hash, t core.ObjectType, content []byte) {
+func testWriter(c *C, dest io.Writer, hash plumbing.Hash, t plumbing.ObjectType, content []byte) {
 	size := int64(len(content))
 	w := NewWriter(dest)
 
@@ -49,7 +49,7 @@ func (s *SuiteWriter) TestWriteOverflow(c *C) {
 	buf := bytes.NewBuffer(nil)
 	w := NewWriter(buf)
 
-	err := w.WriteHeader(core.BlobObject, 8)
+	err := w.WriteHeader(plumbing.BlobObject, 8)
 	c.Assert(err, IsNil)
 
 	n, err := w.Write([]byte("1234"))
@@ -65,16 +65,16 @@ func (s *SuiteWriter) TestNewWriterInvalidType(c *C) {
 	buf := bytes.NewBuffer(nil)
 	w := NewWriter(buf)
 
-	err := w.WriteHeader(core.InvalidObject, 8)
-	c.Assert(err, Equals, core.ErrInvalidType)
+	err := w.WriteHeader(plumbing.InvalidObject, 8)
+	c.Assert(err, Equals, plumbing.ErrInvalidType)
 }
 
 func (s *SuiteWriter) TestNewWriterInvalidSize(c *C) {
 	buf := bytes.NewBuffer(nil)
 	w := NewWriter(buf)
 
-	err := w.WriteHeader(core.BlobObject, -1)
+	err := w.WriteHeader(plumbing.BlobObject, -1)
 	c.Assert(err, Equals, ErrNegativeSize)
-	err = w.WriteHeader(core.BlobObject, -1651860)
+	err = w.WriteHeader(plumbing.BlobObject, -1651860)
 	c.Assert(err, Equals, ErrNegativeSize)
 }
diff --git a/formats/packfile/decoder.go b/plumbing/format/packfile/decoder.go
index e96980a..470e59b 100644
--- a/formats/packfile/decoder.go
+++ b/plumbing/format/packfile/decoder.go
@@ -3,7 +3,8 @@ package packfile
 import (
 	"bytes"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 )
 
 // Format specifies if the packfile uses ref-deltas or ofs-deltas.
@@ -34,7 +35,7 @@ var (
 	// to recall cannot be returned.
 	ErrCannotRecall = NewError("cannot recall object")
 	// ErrNonSeekable is returned if a NewDecoder is used with a non-seekable
-	// reader and without a core.ObjectStorage or ReadObjectAt method is called
+	// reader and without a plumbing.ObjectStorage or ReadObjectAt method is called
 	// without a seekable scanner
 	ErrNonSeekable = NewError("non-seekable scanner")
 	// ErrRollback error making Rollback over a transaction after an error
@@ -44,16 +45,16 @@ var (
 // Decoder reads and decodes packfiles from an input stream.
 type Decoder struct {
 	s  *Scanner
-	o  core.ObjectStorer
-	tx core.Transaction
+	o  storer.ObjectStorer
+	tx storer.Transaction
 
-	offsetToHash map[int64]core.Hash
-	hashToOffset map[core.Hash]int64
-	crcs         map[core.Hash]uint32
+	offsetToHash map[int64]plumbing.Hash
+	hashToOffset map[plumbing.Hash]int64
+	crcs         map[plumbing.Hash]uint32
 }
 
 // NewDecoder returns a new Decoder that reads from r.
-func NewDecoder(s *Scanner, o core.ObjectStorer) (*Decoder, error) {
+func NewDecoder(s *Scanner, o storer.ObjectStorer) (*Decoder, error) {
 	if !s.IsSeekable && o == nil {
 		return nil, ErrNonSeekable
 	}
@@ -62,16 +63,16 @@ func NewDecoder(s *Scanner, o core.ObjectStorer) (*Decoder, error) {
 		s: s,
 		o: o,
 
-		offsetToHash: make(map[int64]core.Hash, 0),
-		hashToOffset: make(map[core.Hash]int64, 0),
-		crcs:         make(map[core.Hash]uint32, 0),
+		offsetToHash: make(map[int64]plumbing.Hash, 0),
+		hashToOffset: make(map[plumbing.Hash]int64, 0),
+		crcs:         make(map[plumbing.Hash]uint32, 0),
 	}, nil
 }
 
 // Decode reads a packfile and stores it in the value pointed to by s.
-func (d *Decoder) Decode() (checksum core.Hash, err error) {
+func (d *Decoder) Decode() (checksum plumbing.Hash, err error) {
 	if err := d.doDecode(); err != nil {
-		return core.ZeroHash, err
+		return plumbing.ZeroHash, err
 	}
 
 	return d.s.Checksum()
@@ -83,7 +84,7 @@ func (d *Decoder) doDecode() error {
 		return err
 	}
 
-	_, isTxStorer := d.o.(core.Transactioner)
+	_, isTxStorer := d.o.(storer.Transactioner)
 	switch {
 	case d.o == nil:
 		return d.readObjects(int(count))
@@ -120,7 +121,7 @@ func (d *Decoder) readObjectsWithObjectStorer(count int) error {
 }
 
 func (d *Decoder) readObjectsWithObjectStorerTx(count int) error {
-	tx := d.o.(core.Transactioner).Begin()
+	tx := d.o.(storer.Transactioner).Begin()
 
 	for i := 0; i < count; i++ {
 		obj, err := d.ReadObject()
@@ -144,7 +145,7 @@ func (d *Decoder) readObjectsWithObjectStorerTx(count int) error {
 }
 
 // ReadObject reads a object from the stream and return it
-func (d *Decoder) ReadObject() (core.Object, error) {
+func (d *Decoder) ReadObject() (plumbing.Object, error) {
 	h, err := d.s.NextObjectHeader()
 	if err != nil {
 		return nil, err
@@ -155,11 +156,11 @@ func (d *Decoder) ReadObject() (core.Object, error) {
 	obj.SetType(h.Type)
 	var crc uint32
 	switch h.Type {
-	case core.CommitObject, core.TreeObject, core.BlobObject, core.TagObject:
+	case plumbing.CommitObject, plumbing.TreeObject, plumbing.BlobObject, plumbing.TagObject:
 		crc, err = d.fillRegularObjectContent(obj)
-	case core.REFDeltaObject:
+	case plumbing.REFDeltaObject:
 		crc, err = d.fillREFDeltaObjectContent(obj, h.Reference)
-	case core.OFSDeltaObject:
+	case plumbing.OFSDeltaObject:
 		crc, err = d.fillOFSDeltaObjectContent(obj, h.OffsetReference)
 	default:
 		err = ErrInvalidObject.AddDetails("type %q", h.Type)
@@ -176,16 +177,16 @@ func (d *Decoder) ReadObject() (core.Object, error) {
 	return obj, nil
 }
 
-func (d *Decoder) newObject() core.Object {
+func (d *Decoder) newObject() plumbing.Object {
 	if d.o == nil {
-		return &core.MemoryObject{}
+		return &plumbing.MemoryObject{}
 	}
 
 	return d.o.NewObject()
 }
 
 // ReadObjectAt reads an object at the given location
-func (d *Decoder) ReadObjectAt(offset int64) (core.Object, error) {
+func (d *Decoder) ReadObjectAt(offset int64) (plumbing.Object, error) {
 	if !d.s.IsSeekable {
 		return nil, ErrNonSeekable
 	}
@@ -205,7 +206,7 @@ func (d *Decoder) ReadObjectAt(offset int64) (core.Object, error) {
 	return d.ReadObject()
 }
 
-func (d *Decoder) fillRegularObjectContent(obj core.Object) (uint32, error) {
+func (d *Decoder) fillRegularObjectContent(obj plumbing.Object) (uint32, error) {
 	w, err := obj.Writer()
 	if err != nil {
 		return 0, err
@@ -215,7 +216,7 @@ func (d *Decoder) fillRegularObjectContent(obj core.Object) (uint32, error) {
 	return crc, err
 }
 
-func (d *Decoder) fillREFDeltaObjectContent(obj core.Object, ref core.Hash) (uint32, error) {
+func (d *Decoder) fillREFDeltaObjectContent(obj plumbing.Object, ref plumbing.Hash) (uint32, error) {
 	buf := bytes.NewBuffer(nil)
 	_, crc, err := d.s.NextObject(buf)
 	if err != nil {
@@ -231,7 +232,7 @@ func (d *Decoder) fillREFDeltaObjectContent(obj core.Object, ref core.Hash) (uin
 	return crc, ApplyDelta(obj, base, buf.Bytes())
 }
 
-func (d *Decoder) fillOFSDeltaObjectContent(obj core.Object, offset int64) (uint32, error) {
+func (d *Decoder) fillOFSDeltaObjectContent(obj plumbing.Object, offset int64) (uint32, error) {
 	buf := bytes.NewBuffer(nil)
 	_, crc, err := d.s.NextObject(buf)
 	if err != nil {
@@ -247,55 +248,55 @@ func (d *Decoder) fillOFSDeltaObjectContent(obj core.Object, offset int64) (uint
 	return crc, ApplyDelta(obj, base, buf.Bytes())
 }
 
-func (d *Decoder) setOffset(h core.Hash, offset int64) {
+func (d *Decoder) setOffset(h plumbing.Hash, offset int64) {
 	d.offsetToHash[offset] = h
 	d.hashToOffset[h] = offset
 }
 
-func (d *Decoder) setCRC(h core.Hash, crc uint32) {
+func (d *Decoder) setCRC(h plumbing.Hash, crc uint32) {
 	d.crcs[h] = crc
 }
 
-func (d *Decoder) recallByOffset(o int64) (core.Object, error) {
+func (d *Decoder) recallByOffset(o int64) (plumbing.Object, error) {
 	if d.s.IsSeekable {
 		return d.ReadObjectAt(o)
 	}
 
 	if h, ok := d.offsetToHash[o]; ok {
-		return d.tx.Object(core.AnyObject, h)
+		return d.tx.Object(plumbing.AnyObject, h)
 	}
 
-	return nil, core.ErrObjectNotFound
+	return nil, plumbing.ErrObjectNotFound
 }
 
-func (d *Decoder) recallByHash(h core.Hash) (core.Object, error) {
+func (d *Decoder) recallByHash(h plumbing.Hash) (plumbing.Object, error) {
 	if d.s.IsSeekable {
 		if o, ok := d.hashToOffset[h]; ok {
 			return d.ReadObjectAt(o)
 		}
 	}
 
-	obj, err := d.tx.Object(core.AnyObject, h)
-	if err != core.ErrObjectNotFound {
+	obj, err := d.tx.Object(plumbing.AnyObject, h)
+	if err != plumbing.ErrObjectNotFound {
 		return obj, err
 	}
 
-	return nil, core.ErrObjectNotFound
+	return nil, plumbing.ErrObjectNotFound
 }
 
 // SetOffsets sets the offsets, required when using the method ReadObjectAt,
 // without decoding the full packfile
-func (d *Decoder) SetOffsets(offsets map[core.Hash]int64) {
+func (d *Decoder) SetOffsets(offsets map[plumbing.Hash]int64) {
 	d.hashToOffset = offsets
 }
 
 // Offsets returns the objects read offset
-func (d *Decoder) Offsets() map[core.Hash]int64 {
+func (d *Decoder) Offsets() map[plumbing.Hash]int64 {
 	return d.hashToOffset
 }
 
 // CRCs returns the CRC-32 for each objected read
-func (d *Decoder) CRCs() map[core.Hash]uint32 {
+func (d *Decoder) CRCs() map[plumbing.Hash]uint32 {
 	return d.crcs
 }
 
diff --git a/formats/packfile/decoder_test.go b/plumbing/format/packfile/decoder_test.go
index aa178d7..e510cf2 100644
--- a/formats/packfile/decoder_test.go
+++ b/plumbing/format/packfile/decoder_test.go
@@ -4,9 +4,9 @@ import (
 	"io"
 	"testing"
 
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/fixtures"
-	"gopkg.in/src-d/go-git.v4/formats/idxfile"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/idxfile"
 	"gopkg.in/src-d/go-git.v4/storage/memory"
 
 	. "gopkg.in/check.v1"
@@ -149,8 +149,8 @@ func (s *ReaderSuite) TestSetOffsets(c *C) {
 	d, err := NewDecoder(scanner, nil)
 	c.Assert(err, IsNil)
 
-	h := core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
-	d.SetOffsets(map[core.Hash]int64{h: 42})
+	h := plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
+	d.SetOffsets(map[plumbing.Hash]int64{h: 42})
 
 	o := d.Offsets()
 	c.Assert(o, HasLen, 1)
@@ -160,20 +160,20 @@ func (s *ReaderSuite) TestSetOffsets(c *C) {
 func assertObjects(c *C, s *memory.Storage, expects []string) {
 	c.Assert(len(expects), Equals, len(s.Objects))
 	for _, exp := range expects {
-		obt, err := s.Object(core.AnyObject, core.NewHash(exp))
+		obt, err := s.Object(plumbing.AnyObject, plumbing.NewHash(exp))
 		c.Assert(err, IsNil)
 		c.Assert(obt.Hash().String(), Equals, exp)
 	}
 }
 
-func getOffsetsFromIdx(r io.Reader) map[core.Hash]int64 {
+func getOffsetsFromIdx(r io.Reader) map[plumbing.Hash]int64 {
 	idx := &idxfile.Idxfile{}
 	err := idxfile.NewDecoder(r).Decode(idx)
 	if err != nil {
 		panic(err)
 	}
 
-	offsets := make(map[core.Hash]int64)
+	offsets := make(map[plumbing.Hash]int64)
 	for _, e := range idx.Entries {
 		offsets[e.Hash] = int64(e.Offset)
 	}
diff --git a/formats/packfile/delta.go b/plumbing/format/packfile/delta.go
index d08f969..2493a39 100644
--- a/formats/packfile/delta.go
+++ b/plumbing/format/packfile/delta.go
@@ -3,7 +3,7 @@ package packfile
 import (
 	"io/ioutil"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 // See https://github.com/git/git/blob/49fa3dc76179e04b0833542fa52d0f287a4955ac/delta.h
@@ -14,7 +14,7 @@ import (
 const deltaSizeMin = 4
 
 // ApplyDelta writes to taget the result of applying the modification deltas in delta to base.
-func ApplyDelta(target, base core.Object, delta []byte) error {
+func ApplyDelta(target, base plumbing.Object, delta []byte) error {
 	r, err := base.Reader()
 	if err != nil {
 		return err
diff --git a/formats/packfile/doc.go b/plumbing/format/packfile/doc.go
index 0b173ca..0b173ca 100644
--- a/formats/packfile/doc.go
+++ b/plumbing/format/packfile/doc.go
diff --git a/formats/packfile/error.go b/plumbing/format/packfile/error.go
index c0b9163..c0b9163 100644
--- a/formats/packfile/error.go
+++ b/plumbing/format/packfile/error.go
diff --git a/formats/packfile/scanner.go b/plumbing/format/packfile/scanner.go
index 69cc7d0..130bb94 100644
--- a/formats/packfile/scanner.go
+++ b/plumbing/format/packfile/scanner.go
@@ -10,7 +10,7 @@ import (
 	"io"
 	"io/ioutil"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 	"gopkg.in/src-d/go-git.v4/utils/binary"
 )
 
@@ -34,10 +34,10 @@ const (
 // ObjectHeader contains the information related to the object, this information
 // is collected from the previous bytes to the content of the object.
 type ObjectHeader struct {
-	Type            core.ObjectType
+	Type            plumbing.ObjectType
 	Offset          int64
 	Length          int64
-	Reference       core.Hash
+	Reference       plumbing.Hash
 	OffsetReference int64
 }
 
@@ -166,14 +166,14 @@ func (s *Scanner) NextObjectHeader() (*ObjectHeader, error) {
 	}
 
 	switch h.Type {
-	case core.OFSDeltaObject:
+	case plumbing.OFSDeltaObject:
 		no, err := binary.ReadVariableWidthInt(s.r)
 		if err != nil {
 			return nil, err
 		}
 
 		h.OffsetReference = h.Offset - no
-	case core.REFDeltaObject:
+	case plumbing.REFDeltaObject:
 		var err error
 		h.Reference, err = binary.ReadHash(s.r)
 		if err != nil {
@@ -219,7 +219,7 @@ func (s *Scanner) discardObjectIfNeeded() error {
 
 // ReadObjectTypeAndLength reads and returns the object type and the
 // length field from an object entry in a packfile.
-func (s *Scanner) readObjectTypeAndLength() (core.ObjectType, int64, error) {
+func (s *Scanner) readObjectTypeAndLength() (plumbing.ObjectType, int64, error) {
 	t, c, err := s.readType()
 	if err != nil {
 		return t, 0, err
@@ -239,11 +239,11 @@ const (
 	lengthBits      = uint8(7)   // subsequent bytes has 7 bits to store the length
 )
 
-func (s *Scanner) readType() (core.ObjectType, byte, error) {
+func (s *Scanner) readType() (plumbing.ObjectType, byte, error) {
 	var c byte
 	var err error
 	if c, err = s.r.ReadByte(); err != nil {
-		return core.ObjectType(0), 0, err
+		return plumbing.ObjectType(0), 0, err
 	}
 
 	typ := parseType(c)
@@ -251,8 +251,8 @@ func (s *Scanner) readType() (core.ObjectType, byte, error) {
 	return typ, c, nil
 }
 
-func parseType(b byte) core.ObjectType {
-	return core.ObjectType((b & maskType) >> firstLengthBits)
+func parseType(b byte) plumbing.ObjectType {
+	return plumbing.ObjectType((b & maskType) >> firstLengthBits)
 }
 
 // the length is codified in the last 4 bits of the first byte and in
@@ -321,10 +321,10 @@ func (s *Scanner) Seek(offset int64) (previous int64, err error) {
 }
 
 // Checksum returns the checksum of the packfile
-func (s *Scanner) Checksum() (core.Hash, error) {
+func (s *Scanner) Checksum() (plumbing.Hash, error) {
 	err := s.discardObjectIfNeeded()
 	if err != nil {
-		return core.ZeroHash, err
+		return plumbing.ZeroHash, err
 	}
 
 	return binary.ReadHash(s.r)
diff --git a/plumbing/format/packfile/scanner_test.go b/plumbing/format/packfile/scanner_test.go
new file mode 100644
index 0000000..8e9a593
--- /dev/null
+++ b/plumbing/format/packfile/scanner_test.go
@@ -0,0 +1,189 @@
+package packfile
+
+import (
+	"bytes"
+	"io"
+
+	. "gopkg.in/check.v1"
+	"gopkg.in/src-d/go-git.v4/fixtures"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+)
+
+type ScannerSuite struct {
+	fixtures.Suite
+}
+
+var _ = Suite(&ScannerSuite{})
+
+func (s *ScannerSuite) TestHeader(c *C) {
+	r := fixtures.Basic().One().Packfile()
+	p := NewScanner(r)
+
+	version, objects, err := p.Header()
+	c.Assert(err, IsNil)
+	c.Assert(version, Equals, VersionSupported)
+	c.Assert(objects, Equals, uint32(31))
+}
+
+func (s *ScannerSuite) TestNextObjectHeaderWithoutHeader(c *C) {
+	r := fixtures.Basic().One().Packfile()
+	p := NewScanner(r)
+
+	h, err := p.NextObjectHeader()
+	c.Assert(err, IsNil)
+	c.Assert(h, DeepEquals, &expectedHeadersOFS[0])
+
+	version, objects, err := p.Header()
+	c.Assert(err, IsNil)
+	c.Assert(version, Equals, VersionSupported)
+	c.Assert(objects, Equals, uint32(31))
+}
+
+func (s *ScannerSuite) TestNextObjectHeaderREFDelta(c *C) {
+	s.testNextObjectHeader(c, "ref-delta", expectedHeadersREF)
+}
+
+func (s *ScannerSuite) TestNextObjectHeaderOFSDelta(c *C) {
+	s.testNextObjectHeader(c, "ofs-delta", expectedHeadersOFS)
+}
+
+func (s *ScannerSuite) testNextObjectHeader(c *C, tag string, expected []ObjectHeader) {
+	r := fixtures.Basic().ByTag(tag).One().Packfile()
+	p := NewScanner(r)
+
+	_, objects, err := p.Header()
+	c.Assert(err, IsNil)
+
+	for i := 0; i < int(objects); i++ {
+		h, err := p.NextObjectHeader()
+		c.Assert(err, IsNil)
+		c.Assert(*h, DeepEquals, expected[i])
+
+		buf := bytes.NewBuffer(nil)
+		n, _, err := p.NextObject(buf)
+		c.Assert(err, IsNil)
+		c.Assert(n, Equals, h.Length)
+	}
+
+	n, err := p.Checksum()
+	c.Assert(err, IsNil)
+	c.Assert(n, HasLen, 20)
+}
+
+func (s *ScannerSuite) TestNextObjectHeaderWithOutReadObject(c *C) {
+	f := fixtures.Basic().ByTag("ref-delta").One()
+	r := f.Packfile()
+	p := NewScanner(r)
+
+	_, objects, err := p.Header()
+	c.Assert(err, IsNil)
+
+	for i := 0; i < int(objects); i++ {
+		h, _ := p.NextObjectHeader()
+		c.Assert(err, IsNil)
+		c.Assert(*h, DeepEquals, expectedHeadersREF[i])
+	}
+
+	err = p.discardObjectIfNeeded()
+	c.Assert(err, IsNil)
+
+	n, err := p.Checksum()
+	c.Assert(err, IsNil)
+	c.Assert(n, Equals, f.PackfileHash)
+}
+
+func (s *ScannerSuite) TestNextObjectHeaderWithOutReadObjectNonSeekable(c *C) {
+	f := fixtures.Basic().ByTag("ref-delta").One()
+	r := io.MultiReader(f.Packfile())
+	p := NewScanner(r)
+
+	_, objects, err := p.Header()
+	c.Assert(err, IsNil)
+
+	for i := 0; i < int(objects); i++ {
+		h, _ := p.NextObjectHeader()
+		c.Assert(err, IsNil)
+		c.Assert(*h, DeepEquals, expectedHeadersREF[i])
+	}
+
+	err = p.discardObjectIfNeeded()
+	c.Assert(err, IsNil)
+
+	n, err := p.Checksum()
+	c.Assert(err, IsNil)
+	c.Assert(n, Equals, f.PackfileHash)
+}
+
+var expectedHeadersOFS = []ObjectHeader{
+	{Type: plumbing.CommitObject, Offset: 12, Length: 254},
+	{Type: plumbing.OFSDeltaObject, Offset: 186, Length: 93, OffsetReference: 12},
+	{Type: plumbing.CommitObject, Offset: 286, Length: 242},
+	{Type: plumbing.CommitObject, Offset: 449, Length: 242},
+	{Type: plumbing.CommitObject, Offset: 615, Length: 333},
+	{Type: plumbing.CommitObject, Offset: 838, Length: 332},
+	{Type: plumbing.CommitObject, Offset: 1063, Length: 244},
+	{Type: plumbing.CommitObject, Offset: 1230, Length: 243},
+	{Type: plumbing.CommitObject, Offset: 1392, Length: 187},
+	{Type: plumbing.BlobObject, Offset: 1524, Length: 189},
+	{Type: plumbing.BlobObject, Offset: 1685, Length: 18},
+	{Type: plumbing.BlobObject, Offset: 1713, Length: 1072},
+	{Type: plumbing.BlobObject, Offset: 2351, Length: 76110},
+	{Type: plumbing.BlobObject, Offset: 78050, Length: 2780},
+	{Type: plumbing.BlobObject, Offset: 78882, Length: 217848},
+	{Type: plumbing.BlobObject, Offset: 80725, Length: 706},
+	{Type: plumbing.BlobObject, Offset: 80998, Length: 11488},
+	{Type: plumbing.BlobObject, Offset: 84032, Length: 78},
+	{Type: plumbing.TreeObject, Offset: 84115, Length: 272},
+	{Type: plumbing.OFSDeltaObject, Offset: 84375, Length: 43, OffsetReference: 84115},
+	{Type: plumbing.TreeObject, Offset: 84430, Length: 38},
+	{Type: plumbing.TreeObject, Offset: 84479, Length: 75},
+	{Type: plumbing.TreeObject, Offset: 84559, Length: 38},
+	{Type: plumbing.TreeObject, Offset: 84608, Length: 34},
+	{Type: plumbing.BlobObject, Offset: 84653, Length: 9},
+	{Type: plumbing.OFSDeltaObject, Offset: 84671, Length: 6, OffsetReference: 84375},
+	{Type: plumbing.OFSDeltaObject, Offset: 84688, Length: 9, OffsetReference: 84375},
+	{Type: plumbing.OFSDeltaObject, Offset: 84708, Length: 6, OffsetReference: 84375},
+	{Type: plumbing.OFSDeltaObject, Offset: 84725, Length: 5, OffsetReference: 84115},
+	{Type: plumbing.OFSDeltaObject, Offset: 84741, Length: 8, OffsetReference: 84375},
+	{Type: plumbing.OFSDeltaObject, Offset: 84760, Length: 4, OffsetReference: 84741},
+}
+
+var expectedHeadersREF = []ObjectHeader{
+	{Type: plumbing.CommitObject, Offset: 12, Length: 254},
+	{Type: plumbing.REFDeltaObject, Offset: 186, Length: 93,
+		Reference: plumbing.NewHash("e8d3ffab552895c19b9fcf7aa264d277cde33881")},
+	{Type: plumbing.CommitObject, Offset: 304, Length: 242},
+	{Type: plumbing.CommitObject, Offset: 467, Length: 242},
+	{Type: plumbing.CommitObject, Offset: 633, Length: 333},
+	{Type: plumbing.CommitObject, Offset: 856, Length: 332},
+	{Type: plumbing.CommitObject, Offset: 1081, Length: 243},
+	{Type: plumbing.CommitObject, Offset: 1243, Length: 244},
+	{Type: plumbing.CommitObject, Offset: 1410, Length: 187},
+	{Type: plumbing.BlobObject, Offset: 1542, Length: 189},
+	{Type: plumbing.BlobObject, Offset: 1703, Length: 18},
+	{Type: plumbing.BlobObject, Offset: 1731, Length: 1072},
+	{Type: plumbing.BlobObject, Offset: 2369, Length: 76110},
+	{Type: plumbing.TreeObject, Offset: 78068, Length: 38},
+	{Type: plumbing.BlobObject, Offset: 78117, Length: 2780},
+	{Type: plumbing.TreeObject, Offset: 79049, Length: 75},
+	{Type: plumbing.BlobObject, Offset: 79129, Length: 217848},
+	{Type: plumbing.BlobObject, Offset: 80972, Length: 706},
+	{Type: plumbing.TreeObject, Offset: 81265, Length: 38},
+	{Type: plumbing.BlobObject, Offset: 81314, Length: 11488},
+	{Type: plumbing.TreeObject, Offset: 84752, Length: 34},
+	{Type: plumbing.BlobObject, Offset: 84797, Length: 78},
+	{Type: plumbing.TreeObject, Offset: 84880, Length: 271},
+	{Type: plumbing.REFDeltaObject, Offset: 85141, Length: 6,
+		Reference: plumbing.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c")},
+	{Type: plumbing.REFDeltaObject, Offset: 85176, Length: 37,
+		Reference: plumbing.NewHash("fb72698cab7617ac416264415f13224dfd7a165e")},
+	{Type: plumbing.BlobObject, Offset: 85244, Length: 9},
+	{Type: plumbing.REFDeltaObject, Offset: 85262, Length: 9,
+		Reference: plumbing.NewHash("fb72698cab7617ac416264415f13224dfd7a165e")},
+	{Type: plumbing.REFDeltaObject, Offset: 85300, Length: 6,
+		Reference: plumbing.NewHash("fb72698cab7617ac416264415f13224dfd7a165e")},
+	{Type: plumbing.TreeObject, Offset: 85335, Length: 110},
+	{Type: plumbing.REFDeltaObject, Offset: 85448, Length: 8,
+		Reference: plumbing.NewHash("eba74343e2f15d62adedfd8c883ee0262b5c8021")},
+	{Type: plumbing.TreeObject, Offset: 85485, Length: 73},
+}
diff --git a/formats/packp/advrefs/advrefs.go b/plumbing/format/packp/advrefs/advrefs.go
index ab4bcf5..4d7c897 100644
--- a/formats/packp/advrefs/advrefs.go
+++ b/plumbing/format/packp/advrefs/advrefs.go
@@ -3,8 +3,8 @@
 package advrefs
 
 import (
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp"
 )
 
 const (
@@ -39,11 +39,11 @@ var (
 // be filled up with whatever is found on the line.
 type AdvRefs struct {
 	Prefix       [][]byte // payloads of the prefix
-	Head         *core.Hash
+	Head         *plumbing.Hash
 	Capabilities *packp.Capabilities
-	References   map[string]core.Hash
-	Peeled       map[string]core.Hash
-	Shallows     []core.Hash
+	References   map[string]plumbing.Hash
+	Peeled       map[string]plumbing.Hash
+	Shallows     []plumbing.Hash
 }
 
 // New returns a pointer to a new AdvRefs value, ready to be used.
@@ -51,8 +51,8 @@ func New() *AdvRefs {
 	return &AdvRefs{
 		Prefix:       [][]byte{},
 		Capabilities: packp.NewCapabilities(),
-		References:   make(map[string]core.Hash),
-		Peeled:       make(map[string]core.Hash),
-		Shallows:     []core.Hash{},
+		References:   make(map[string]plumbing.Hash),
+		Peeled:       make(map[string]plumbing.Hash),
+		Shallows:     []plumbing.Hash{},
 	}
 }
diff --git a/formats/packp/advrefs/advrefs_test.go b/plumbing/format/packp/advrefs/advrefs_test.go
index 6950ba5..2639b6e 100644
--- a/formats/packp/advrefs/advrefs_test.go
+++ b/plumbing/format/packp/advrefs/advrefs_test.go
@@ -7,9 +7,9 @@ import (
 	"strings"
 	"testing"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp/advrefs"
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/advrefs"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
 
 	. "gopkg.in/check.v1"
 )
@@ -281,7 +281,7 @@ func ExampleEncoder_Encode() {
 	ar := advrefs.New()
 
 	// ...add a hash for the HEAD...
-	head := core.NewHash("1111111111111111111111111111111111111111")
+	head := plumbing.NewHash("1111111111111111111111111111111111111111")
 	ar.Head = &head
 
 	// ...add some server capabilities...
@@ -290,14 +290,14 @@ func ExampleEncoder_Encode() {
 	ar.Capabilities.Add("multi_ack")
 
 	// ...add a couple of references...
-	ar.References["refs/heads/master"] = core.NewHash("2222222222222222222222222222222222222222")
-	ar.References["refs/tags/v1"] = core.NewHash("3333333333333333333333333333333333333333")
+	ar.References["refs/heads/master"] = plumbing.NewHash("2222222222222222222222222222222222222222")
+	ar.References["refs/tags/v1"] = plumbing.NewHash("3333333333333333333333333333333333333333")
 
 	// ...including a peeled ref...
-	ar.Peeled["refs/tags/v1"] = core.NewHash("4444444444444444444444444444444444444444")
+	ar.Peeled["refs/tags/v1"] = plumbing.NewHash("4444444444444444444444444444444444444444")
 
 	// ...and finally add a shallow
-	ar.Shallows = append(ar.Shallows, core.NewHash("5555555555555555555555555555555555555555"))
+	ar.Shallows = append(ar.Shallows, plumbing.NewHash("5555555555555555555555555555555555555555"))
 
 	// Encode the advrefs.Contents to a bytes.Buffer.
 	// You can encode into stdout too, but you will not be able
diff --git a/formats/packp/advrefs/decoder.go b/plumbing/format/packp/advrefs/decoder.go
index a0cf5e6..b654882 100644
--- a/formats/packp/advrefs/decoder.go
+++ b/plumbing/format/packp/advrefs/decoder.go
@@ -7,8 +7,8 @@ import (
 	"fmt"
 	"io"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
 )
 
 // A Decoder reads and decodes AdvRef values from an input stream.
@@ -16,7 +16,7 @@ type Decoder struct {
 	s     *pktline.Scanner // a pkt-line scanner from the input stream
 	line  []byte           // current pkt-line contents, use parser.nextLine() to make it advance
 	nLine int              // current pkt-line number for debugging, begins at 1
-	hash  core.Hash        // last hash read
+	hash  plumbing.Hash    // last hash read
 	err   error            // sticky error, use the parser.error() method to fill this out
 	data  *AdvRefs         // parsed data is stored here
 }
@@ -240,15 +240,15 @@ func decodeOtherRefs(p *Decoder) decoderStateFn {
 }
 
 // Reads a ref-name
-func readRef(data []byte) (string, core.Hash, error) {
+func readRef(data []byte) (string, plumbing.Hash, error) {
 	chunks := bytes.Split(data, sp)
 	switch {
 	case len(chunks) == 1:
-		return "", core.ZeroHash, fmt.Errorf("malformed ref data: no space was found")
+		return "", plumbing.ZeroHash, fmt.Errorf("malformed ref data: no space was found")
 	case len(chunks) > 2:
-		return "", core.ZeroHash, fmt.Errorf("malformed ref data: more than one space found")
+		return "", plumbing.ZeroHash, fmt.Errorf("malformed ref data: more than one space found")
 	default:
-		return string(chunks[1]), core.NewHash(string(chunks[0])), nil
+		return string(chunks[1]), plumbing.NewHash(string(chunks[0])), nil
 	}
 }
 
@@ -268,7 +268,7 @@ func decodeShallow(p *Decoder) decoderStateFn {
 	}
 
 	text := p.line[:hashSize]
-	var h core.Hash
+	var h plumbing.Hash
 	if _, err := hex.Decode(h[:], text); err != nil {
 		p.error("invalid hash text: %s", err)
 		return nil
diff --git a/formats/packp/advrefs/decoder_test.go b/plumbing/format/packp/advrefs/decoder_test.go
index ee2f5ae..03867d3 100644
--- a/formats/packp/advrefs/decoder_test.go
+++ b/plumbing/format/packp/advrefs/decoder_test.go
@@ -5,10 +5,10 @@ import (
 	"io"
 	"strings"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp"
-	"gopkg.in/src-d/go-git.v4/formats/packp/advrefs"
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/advrefs"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
 
 	. "gopkg.in/check.v1"
 )
@@ -110,7 +110,7 @@ func (s *SuiteDecoder) TestHead(c *C) {
 	}
 	ar := testDecodeOK(c, payloads)
 	c.Assert(*ar.Head, Equals,
-		core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
+		plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
 }
 
 func (s *SuiteDecoder) TestFirstIsNotHead(c *C) {
@@ -121,7 +121,7 @@ func (s *SuiteDecoder) TestFirstIsNotHead(c *C) {
 	ar := testDecodeOK(c, payloads)
 	c.Assert(ar.Head, IsNil)
 	c.Assert(ar.References["refs/heads/master"], Equals,
-		core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
+		plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
 }
 
 func (s *SuiteDecoder) TestShortRef(c *C) {
@@ -269,36 +269,36 @@ func (s *SuiteDecoder) TestWithPrefixAndFlush(c *C) {
 func (s *SuiteDecoder) TestOtherRefs(c *C) {
 	for _, test := range [...]struct {
 		input      []string
-		references map[string]core.Hash
-		peeled     map[string]core.Hash
+		references map[string]plumbing.Hash
+		peeled     map[string]plumbing.Hash
 	}{
 		{
 			input: []string{
 				"6ecf0ef2c2dffb796033e5a02219af86ec6584e5 HEAD\x00ofs-delta symref=HEAD:/refs/heads/master\n",
 				pktline.FlushString,
 			},
-			references: make(map[string]core.Hash),
-			peeled:     make(map[string]core.Hash),
+			references: make(map[string]plumbing.Hash),
+			peeled:     make(map[string]plumbing.Hash),
 		}, {
 			input: []string{
 				"6ecf0ef2c2dffb796033e5a02219af86ec6584e5 HEAD\x00ofs-delta symref=HEAD:/refs/heads/master\n",
 				"1111111111111111111111111111111111111111 ref/foo",
 				pktline.FlushString,
 			},
-			references: map[string]core.Hash{
-				"ref/foo": core.NewHash("1111111111111111111111111111111111111111"),
+			references: map[string]plumbing.Hash{
+				"ref/foo": plumbing.NewHash("1111111111111111111111111111111111111111"),
 			},
-			peeled: make(map[string]core.Hash),
+			peeled: make(map[string]plumbing.Hash),
 		}, {
 			input: []string{
 				"6ecf0ef2c2dffb796033e5a02219af86ec6584e5 HEAD\x00ofs-delta symref=HEAD:/refs/heads/master\n",
 				"1111111111111111111111111111111111111111 ref/foo\n",
 				pktline.FlushString,
 			},
-			references: map[string]core.Hash{
-				"ref/foo": core.NewHash("1111111111111111111111111111111111111111"),
+			references: map[string]plumbing.Hash{
+				"ref/foo": plumbing.NewHash("1111111111111111111111111111111111111111"),
 			},
-			peeled: make(map[string]core.Hash),
+			peeled: make(map[string]plumbing.Hash),
 		}, {
 			input: []string{
 				"6ecf0ef2c2dffb796033e5a02219af86ec6584e5 HEAD\x00ofs-delta symref=HEAD:/refs/heads/master\n",
@@ -306,20 +306,20 @@ func (s *SuiteDecoder) TestOtherRefs(c *C) {
 				"2222222222222222222222222222222222222222 ref/bar",
 				pktline.FlushString,
 			},
-			references: map[string]core.Hash{
-				"ref/foo": core.NewHash("1111111111111111111111111111111111111111"),
-				"ref/bar": core.NewHash("2222222222222222222222222222222222222222"),
+			references: map[string]plumbing.Hash{
+				"ref/foo": plumbing.NewHash("1111111111111111111111111111111111111111"),
+				"ref/bar": plumbing.NewHash("2222222222222222222222222222222222222222"),
 			},
-			peeled: make(map[string]core.Hash),
+			peeled: make(map[string]plumbing.Hash),
 		}, {
 			input: []string{
 				"6ecf0ef2c2dffb796033e5a02219af86ec6584e5 HEAD\x00ofs-delta symref=HEAD:/refs/heads/master\n",
 				"1111111111111111111111111111111111111111 ref/foo^{}\n",
 				pktline.FlushString,
 			},
-			references: make(map[string]core.Hash),
-			peeled: map[string]core.Hash{
-				"ref/foo": core.NewHash("1111111111111111111111111111111111111111"),
+			references: make(map[string]plumbing.Hash),
+			peeled: map[string]plumbing.Hash{
+				"ref/foo": plumbing.NewHash("1111111111111111111111111111111111111111"),
 			},
 		}, {
 			input: []string{
@@ -328,11 +328,11 @@ func (s *SuiteDecoder) TestOtherRefs(c *C) {
 				"2222222222222222222222222222222222222222 ref/bar^{}",
 				pktline.FlushString,
 			},
-			references: map[string]core.Hash{
-				"ref/foo": core.NewHash("1111111111111111111111111111111111111111"),
+			references: map[string]plumbing.Hash{
+				"ref/foo": plumbing.NewHash("1111111111111111111111111111111111111111"),
 			},
-			peeled: map[string]core.Hash{
-				"ref/bar": core.NewHash("2222222222222222222222222222222222222222"),
+			peeled: map[string]plumbing.Hash{
+				"ref/bar": plumbing.NewHash("2222222222222222222222222222222222222222"),
 			},
 		}, {
 			input: []string{
@@ -348,18 +348,18 @@ func (s *SuiteDecoder) TestOtherRefs(c *C) {
 				"c39ae07f393806ccf406ef966e9a15afc43cc36a refs/tags/v2.6.11-tree^{}\n",
 				pktline.FlushString,
 			},
-			references: map[string]core.Hash{
-				"refs/heads/master":      core.NewHash("a6930aaee06755d1bdcfd943fbf614e4d92bb0c7"),
-				"refs/pull/10/head":      core.NewHash("51b8b4fb32271d39fbdd760397406177b2b0fd36"),
-				"refs/pull/100/head":     core.NewHash("02b5a6031ba7a8cbfde5d65ff9e13ecdbc4a92ca"),
-				"refs/pull/100/merge":    core.NewHash("c284c212704c43659bf5913656b8b28e32da1621"),
-				"refs/pull/101/merge":    core.NewHash("3d6537dce68c8b7874333a1720958bd8db3ae8ca"),
-				"refs/tags/v2.6.11":      core.NewHash("5dc01c595e6c6ec9ccda4f6f69c131c0dd945f8c"),
-				"refs/tags/v2.6.11-tree": core.NewHash("5dc01c595e6c6ec9ccda4f6f69c131c0dd945f8c"),
+			references: map[string]plumbing.Hash{
+				"refs/heads/master":      plumbing.NewHash("a6930aaee06755d1bdcfd943fbf614e4d92bb0c7"),
+				"refs/pull/10/head":      plumbing.NewHash("51b8b4fb32271d39fbdd760397406177b2b0fd36"),
+				"refs/pull/100/head":     plumbing.NewHash("02b5a6031ba7a8cbfde5d65ff9e13ecdbc4a92ca"),
+				"refs/pull/100/merge":    plumbing.NewHash("c284c212704c43659bf5913656b8b28e32da1621"),
+				"refs/pull/101/merge":    plumbing.NewHash("3d6537dce68c8b7874333a1720958bd8db3ae8ca"),
+				"refs/tags/v2.6.11":      plumbing.NewHash("5dc01c595e6c6ec9ccda4f6f69c131c0dd945f8c"),
+				"refs/tags/v2.6.11-tree": plumbing.NewHash("5dc01c595e6c6ec9ccda4f6f69c131c0dd945f8c"),
 			},
-			peeled: map[string]core.Hash{
-				"refs/tags/v2.6.11":      core.NewHash("c39ae07f393806ccf406ef966e9a15afc43cc36a"),
-				"refs/tags/v2.6.11-tree": core.NewHash("c39ae07f393806ccf406ef966e9a15afc43cc36a"),
+			peeled: map[string]plumbing.Hash{
+				"refs/tags/v2.6.11":      plumbing.NewHash("c39ae07f393806ccf406ef966e9a15afc43cc36a"),
+				"refs/tags/v2.6.11-tree": plumbing.NewHash("c39ae07f393806ccf406ef966e9a15afc43cc36a"),
 			},
 		},
 	} {
@@ -393,7 +393,7 @@ func (s *SuiteDecoder) TestMalformedOtherRefsMultipleSpaces(c *C) {
 func (s *SuiteDecoder) TestShallow(c *C) {
 	for _, test := range [...]struct {
 		input    []string
-		shallows []core.Hash
+		shallows []plumbing.Hash
 	}{
 		{
 			input: []string{
@@ -403,7 +403,7 @@ func (s *SuiteDecoder) TestShallow(c *C) {
 				"c39ae07f393806ccf406ef966e9a15afc43cc36a refs/tags/v2.6.11-tree^{}\n",
 				pktline.FlushString,
 			},
-			shallows: []core.Hash{},
+			shallows: []plumbing.Hash{},
 		}, {
 			input: []string{
 				"6ecf0ef2c2dffb796033e5a02219af86ec6584e5 HEAD\x00ofs-delta symref=HEAD:/refs/heads/master\n",
@@ -413,7 +413,7 @@ func (s *SuiteDecoder) TestShallow(c *C) {
 				"shallow 1111111111111111111111111111111111111111\n",
 				pktline.FlushString,
 			},
-			shallows: []core.Hash{core.NewHash("1111111111111111111111111111111111111111")},
+			shallows: []plumbing.Hash{plumbing.NewHash("1111111111111111111111111111111111111111")},
 		}, {
 			input: []string{
 				"6ecf0ef2c2dffb796033e5a02219af86ec6584e5 HEAD\x00ofs-delta symref=HEAD:/refs/heads/master\n",
@@ -424,9 +424,9 @@ func (s *SuiteDecoder) TestShallow(c *C) {
 				"shallow 2222222222222222222222222222222222222222\n",
 				pktline.FlushString,
 			},
-			shallows: []core.Hash{
-				core.NewHash("1111111111111111111111111111111111111111"),
-				core.NewHash("2222222222222222222222222222222222222222"),
+			shallows: []plumbing.Hash{
+				plumbing.NewHash("1111111111111111111111111111111111111111"),
+				plumbing.NewHash("2222222222222222222222222222222222222222"),
 			},
 		},
 	} {
diff --git a/formats/packp/advrefs/encoder.go b/plumbing/format/packp/advrefs/encoder.go
index 9874884..8c52f14 100644
--- a/formats/packp/advrefs/encoder.go
+++ b/plumbing/format/packp/advrefs/encoder.go
@@ -5,9 +5,9 @@ import (
 	"io"
 	"sort"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp"
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
 )
 
 // An Encoder writes AdvRefs values to an output stream.
@@ -71,15 +71,15 @@ func encodeFirstLine(e *Encoder) encoderStateFn {
 	return encodeRefs
 }
 
-func formatHead(h *core.Hash) string {
+func formatHead(h *plumbing.Hash) string {
 	if h == nil {
-		return core.ZeroHash.String()
+		return plumbing.ZeroHash.String()
 	}
 
 	return h.String()
 }
 
-func formatSeparator(h *core.Hash) string {
+func formatSeparator(h *plumbing.Hash) string {
 	if h == nil {
 		return noHead
 	}
@@ -117,7 +117,7 @@ func encodeRefs(e *Encoder) encoderStateFn {
 	return encodeShallow
 }
 
-func sortRefs(m map[string]core.Hash) []string {
+func sortRefs(m map[string]plumbing.Hash) []string {
 	ret := make([]string, 0, len(m))
 	for k := range m {
 		ret = append(ret, k)
@@ -139,7 +139,7 @@ func encodeShallow(e *Encoder) encoderStateFn {
 	return encodeFlush
 }
 
-func sortShallows(c []core.Hash) []string {
+func sortShallows(c []plumbing.Hash) []string {
 	ret := []string{}
 	for _, h := range c {
 		ret = append(ret, h.String())
diff --git a/formats/packp/advrefs/encoder_test.go b/plumbing/format/packp/advrefs/encoder_test.go
index 8fb475b..b4b085c 100644
--- a/formats/packp/advrefs/encoder_test.go
+++ b/plumbing/format/packp/advrefs/encoder_test.go
@@ -4,10 +4,10 @@ import (
 	"bytes"
 	"strings"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp"
-	"gopkg.in/src-d/go-git.v4/formats/packp/advrefs"
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/advrefs"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
 
 	. "gopkg.in/check.v1"
 )
@@ -50,7 +50,7 @@ func (s *SuiteEncoder) TestZeroValue(c *C) {
 }
 
 func (s *SuiteEncoder) TestHead(c *C) {
-	hash := core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
+	hash := plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
 	ar := &advrefs.AdvRefs{
 		Head: &hash,
 	}
@@ -81,7 +81,7 @@ func (s *SuiteEncoder) TestCapsNoHead(c *C) {
 }
 
 func (s *SuiteEncoder) TestCapsWithHead(c *C) {
-	hash := core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
+	hash := plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
 	capabilities := packp.NewCapabilities()
 	capabilities.Add("symref", "HEAD:/refs/heads/master")
 	capabilities.Add("ofs-delta")
@@ -100,12 +100,12 @@ func (s *SuiteEncoder) TestCapsWithHead(c *C) {
 }
 
 func (s *SuiteEncoder) TestRefs(c *C) {
-	references := map[string]core.Hash{
-		"refs/heads/master":      core.NewHash("a6930aaee06755d1bdcfd943fbf614e4d92bb0c7"),
-		"refs/tags/v2.6.12-tree": core.NewHash("1111111111111111111111111111111111111111"),
-		"refs/tags/v2.7.13-tree": core.NewHash("3333333333333333333333333333333333333333"),
-		"refs/tags/v2.6.13-tree": core.NewHash("2222222222222222222222222222222222222222"),
-		"refs/tags/v2.6.11-tree": core.NewHash("5dc01c595e6c6ec9ccda4f6f69c131c0dd945f8c"),
+	references := map[string]plumbing.Hash{
+		"refs/heads/master":      plumbing.NewHash("a6930aaee06755d1bdcfd943fbf614e4d92bb0c7"),
+		"refs/tags/v2.6.12-tree": plumbing.NewHash("1111111111111111111111111111111111111111"),
+		"refs/tags/v2.7.13-tree": plumbing.NewHash("3333333333333333333333333333333333333333"),
+		"refs/tags/v2.6.13-tree": plumbing.NewHash("2222222222222222222222222222222222222222"),
+		"refs/tags/v2.6.11-tree": plumbing.NewHash("5dc01c595e6c6ec9ccda4f6f69c131c0dd945f8c"),
 	}
 	ar := &advrefs.AdvRefs{
 		References: references,
@@ -125,16 +125,16 @@ func (s *SuiteEncoder) TestRefs(c *C) {
 }
 
 func (s *SuiteEncoder) TestPeeled(c *C) {
-	references := map[string]core.Hash{
-		"refs/heads/master":      core.NewHash("a6930aaee06755d1bdcfd943fbf614e4d92bb0c7"),
-		"refs/tags/v2.6.12-tree": core.NewHash("1111111111111111111111111111111111111111"),
-		"refs/tags/v2.7.13-tree": core.NewHash("3333333333333333333333333333333333333333"),
-		"refs/tags/v2.6.13-tree": core.NewHash("2222222222222222222222222222222222222222"),
-		"refs/tags/v2.6.11-tree": core.NewHash("5dc01c595e6c6ec9ccda4f6f69c131c0dd945f8c"),
+	references := map[string]plumbing.Hash{
+		"refs/heads/master":      plumbing.NewHash("a6930aaee06755d1bdcfd943fbf614e4d92bb0c7"),
+		"refs/tags/v2.6.12-tree": plumbing.NewHash("1111111111111111111111111111111111111111"),
+		"refs/tags/v2.7.13-tree": plumbing.NewHash("3333333333333333333333333333333333333333"),
+		"refs/tags/v2.6.13-tree": plumbing.NewHash("2222222222222222222222222222222222222222"),
+		"refs/tags/v2.6.11-tree": plumbing.NewHash("5dc01c595e6c6ec9ccda4f6f69c131c0dd945f8c"),
 	}
-	peeled := map[string]core.Hash{
-		"refs/tags/v2.7.13-tree": core.NewHash("4444444444444444444444444444444444444444"),
-		"refs/tags/v2.6.12-tree": core.NewHash("5555555555555555555555555555555555555555"),
+	peeled := map[string]plumbing.Hash{
+		"refs/tags/v2.7.13-tree": plumbing.NewHash("4444444444444444444444444444444444444444"),
+		"refs/tags/v2.6.12-tree": plumbing.NewHash("5555555555555555555555555555555555555555"),
 	}
 	ar := &advrefs.AdvRefs{
 		References: references,
@@ -157,11 +157,11 @@ func (s *SuiteEncoder) TestPeeled(c *C) {
 }
 
 func (s *SuiteEncoder) TestShallow(c *C) {
-	shallows := []core.Hash{
-		core.NewHash("1111111111111111111111111111111111111111"),
-		core.NewHash("4444444444444444444444444444444444444444"),
-		core.NewHash("3333333333333333333333333333333333333333"),
-		core.NewHash("2222222222222222222222222222222222222222"),
+	shallows := []plumbing.Hash{
+		plumbing.NewHash("1111111111111111111111111111111111111111"),
+		plumbing.NewHash("4444444444444444444444444444444444444444"),
+		plumbing.NewHash("3333333333333333333333333333333333333333"),
+		plumbing.NewHash("2222222222222222222222222222222222222222"),
 	}
 	ar := &advrefs.AdvRefs{
 		Shallows: shallows,
@@ -180,31 +180,31 @@ func (s *SuiteEncoder) TestShallow(c *C) {
 }
 
 func (s *SuiteEncoder) TestAll(c *C) {
-	hash := core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
+	hash := plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
 
 	capabilities := packp.NewCapabilities()
 	capabilities.Add("symref", "HEAD:/refs/heads/master")
 	capabilities.Add("ofs-delta")
 	capabilities.Add("multi_ack")
 
-	references := map[string]core.Hash{
-		"refs/heads/master":      core.NewHash("a6930aaee06755d1bdcfd943fbf614e4d92bb0c7"),
-		"refs/tags/v2.6.12-tree": core.NewHash("1111111111111111111111111111111111111111"),
-		"refs/tags/v2.7.13-tree": core.NewHash("3333333333333333333333333333333333333333"),
-		"refs/tags/v2.6.13-tree": core.NewHash("2222222222222222222222222222222222222222"),
-		"refs/tags/v2.6.11-tree": core.NewHash("5dc01c595e6c6ec9ccda4f6f69c131c0dd945f8c"),
+	references := map[string]plumbing.Hash{
+		"refs/heads/master":      plumbing.NewHash("a6930aaee06755d1bdcfd943fbf614e4d92bb0c7"),
+		"refs/tags/v2.6.12-tree": plumbing.NewHash("1111111111111111111111111111111111111111"),
+		"refs/tags/v2.7.13-tree": plumbing.NewHash("3333333333333333333333333333333333333333"),
+		"refs/tags/v2.6.13-tree": plumbing.NewHash("2222222222222222222222222222222222222222"),
+		"refs/tags/v2.6.11-tree": plumbing.NewHash("5dc01c595e6c6ec9ccda4f6f69c131c0dd945f8c"),
 	}
 
-	peeled := map[string]core.Hash{
-		"refs/tags/v2.7.13-tree": core.NewHash("4444444444444444444444444444444444444444"),
-		"refs/tags/v2.6.12-tree": core.NewHash("5555555555555555555555555555555555555555"),
+	peeled := map[string]plumbing.Hash{
+		"refs/tags/v2.7.13-tree": plumbing.NewHash("4444444444444444444444444444444444444444"),
+		"refs/tags/v2.6.12-tree": plumbing.NewHash("5555555555555555555555555555555555555555"),
 	}
 
-	shallows := []core.Hash{
-		core.NewHash("1111111111111111111111111111111111111111"),
-		core.NewHash("4444444444444444444444444444444444444444"),
-		core.NewHash("3333333333333333333333333333333333333333"),
-		core.NewHash("2222222222222222222222222222222222222222"),
+	shallows := []plumbing.Hash{
+		plumbing.NewHash("1111111111111111111111111111111111111111"),
+		plumbing.NewHash("4444444444444444444444444444444444444444"),
+		plumbing.NewHash("3333333333333333333333333333333333333333"),
+		plumbing.NewHash("2222222222222222222222222222222222222222"),
 	}
 
 	ar := &advrefs.AdvRefs{
@@ -235,8 +235,8 @@ func (s *SuiteEncoder) TestAll(c *C) {
 }
 
 func (s *SuiteEncoder) TestErrorTooLong(c *C) {
-	references := map[string]core.Hash{
-		strings.Repeat("a", pktline.MaxPayloadSize): core.NewHash("a6930aaee06755d1bdcfd943fbf614e4d92bb0c7"),
+	references := map[string]plumbing.Hash{
+		strings.Repeat("a", pktline.MaxPayloadSize): plumbing.NewHash("a6930aaee06755d1bdcfd943fbf614e4d92bb0c7"),
 	}
 	ar := &advrefs.AdvRefs{
 		References: references,
diff --git a/formats/packp/capabilities.go b/plumbing/format/packp/capabilities.go
index d77c2fa..d77c2fa 100644
--- a/formats/packp/capabilities.go
+++ b/plumbing/format/packp/capabilities.go
diff --git a/formats/packp/capabilities_test.go b/plumbing/format/packp/capabilities_test.go
index e42a0c7..e42a0c7 100644
--- a/formats/packp/capabilities_test.go
+++ b/plumbing/format/packp/capabilities_test.go
diff --git a/formats/packp/doc.go b/plumbing/format/packp/doc.go
index 4950d1d..4950d1d 100644
--- a/formats/packp/doc.go
+++ b/plumbing/format/packp/doc.go
diff --git a/formats/packp/pktline/encoder.go b/plumbing/format/packp/pktline/encoder.go
index 0a88a9b..0a88a9b 100644
--- a/formats/packp/pktline/encoder.go
+++ b/plumbing/format/packp/pktline/encoder.go
diff --git a/formats/packp/pktline/encoder_test.go b/plumbing/format/packp/pktline/encoder_test.go
index 618002d..cd97593 100644
--- a/formats/packp/pktline/encoder_test.go
+++ b/plumbing/format/packp/pktline/encoder_test.go
@@ -6,7 +6,7 @@ import (
 	"strings"
 	"testing"
 
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
 
 	. "gopkg.in/check.v1"
 )
diff --git a/formats/packp/pktline/scanner.go b/plumbing/format/packp/pktline/scanner.go
index 3ce2adf..3ce2adf 100644
--- a/formats/packp/pktline/scanner.go
+++ b/plumbing/format/packp/pktline/scanner.go
diff --git a/formats/packp/pktline/scanner_test.go b/plumbing/format/packp/pktline/scanner_test.go
index b5a3c7d..c5395cf 100644
--- a/formats/packp/pktline/scanner_test.go
+++ b/plumbing/format/packp/pktline/scanner_test.go
@@ -6,7 +6,7 @@ import (
 	"io"
 	"strings"
 
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
 
 	. "gopkg.in/check.v1"
 )
diff --git a/formats/packp/ulreq/decoder.go b/plumbing/format/packp/ulreq/decoder.go
index 63ccd4d..9083e04 100644
--- a/formats/packp/ulreq/decoder.go
+++ b/plumbing/format/packp/ulreq/decoder.go
@@ -8,8 +8,8 @@ import (
 	"strconv"
 	"time"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
 )
 
 const (
@@ -108,16 +108,16 @@ func decodeFirstWant(d *Decoder) decoderStateFn {
 	return decodeCaps
 }
 
-func (d *Decoder) readHash() (core.Hash, bool) {
+func (d *Decoder) readHash() (plumbing.Hash, bool) {
 	if len(d.line) < hashSize {
 		d.err = fmt.Errorf("malformed hash: %v", d.line)
-		return core.ZeroHash, false
+		return plumbing.ZeroHash, false
 	}
 
-	var hash core.Hash
+	var hash plumbing.Hash
 	if _, err := hex.Decode(hash[:], d.line[:hashSize]); err != nil {
 		d.error("invalid hash text: %s", err)
-		return core.ZeroHash, false
+		return plumbing.ZeroHash, false
 	}
 	d.line = d.line[hashSize:]
 
diff --git a/formats/packp/ulreq/decoder_test.go b/plumbing/format/packp/ulreq/decoder_test.go
index b313395..01e4f90 100644
--- a/formats/packp/ulreq/decoder_test.go
+++ b/plumbing/format/packp/ulreq/decoder_test.go
@@ -6,8 +6,8 @@ import (
 	"sort"
 	"time"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
 
 	. "gopkg.in/check.v1"
 )
@@ -67,8 +67,8 @@ func (s *SuiteDecoder) TestWantOK(c *C) {
 	}
 	ur := testDecodeOK(c, payloads)
 
-	c.Assert(ur.Wants, DeepEquals, []core.Hash{
-		core.NewHash("1111111111111111111111111111111111111111"),
+	c.Assert(ur.Wants, DeepEquals, []plumbing.Hash{
+		plumbing.NewHash("1111111111111111111111111111111111111111"),
 	})
 }
 
@@ -93,8 +93,8 @@ func (s *SuiteDecoder) TestWantWithCapabilities(c *C) {
 		pktline.FlushString,
 	}
 	ur := testDecodeOK(c, payloads)
-	c.Assert(ur.Wants, DeepEquals, []core.Hash{
-		core.NewHash("1111111111111111111111111111111111111111")})
+	c.Assert(ur.Wants, DeepEquals, []plumbing.Hash{
+		plumbing.NewHash("1111111111111111111111111111111111111111")})
 
 	c.Assert(ur.Capabilities.Supports("ofs-delta"), Equals, true)
 	c.Assert(ur.Capabilities.Supports("multi_ack"), Equals, true)
@@ -110,11 +110,11 @@ func (s *SuiteDecoder) TestManyWantsNoCapabilities(c *C) {
 	}
 	ur := testDecodeOK(c, payloads)
 
-	expected := []core.Hash{
-		core.NewHash("1111111111111111111111111111111111111111"),
-		core.NewHash("2222222222222222222222222222222222222222"),
-		core.NewHash("3333333333333333333333333333333333333333"),
-		core.NewHash("4444444444444444444444444444444444444444"),
+	expected := []plumbing.Hash{
+		plumbing.NewHash("1111111111111111111111111111111111111111"),
+		plumbing.NewHash("2222222222222222222222222222222222222222"),
+		plumbing.NewHash("3333333333333333333333333333333333333333"),
+		plumbing.NewHash("4444444444444444444444444444444444444444"),
 	}
 
 	sort.Sort(byHash(ur.Wants))
@@ -122,7 +122,7 @@ func (s *SuiteDecoder) TestManyWantsNoCapabilities(c *C) {
 	c.Assert(ur.Wants, DeepEquals, expected)
 }
 
-type byHash []core.Hash
+type byHash []plumbing.Hash
 
 func (a byHash) Len() int      { return len(a) }
 func (a byHash) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
@@ -166,11 +166,11 @@ func (s *SuiteDecoder) TestManyWantsWithCapabilities(c *C) {
 	}
 	ur := testDecodeOK(c, payloads)
 
-	expected := []core.Hash{
-		core.NewHash("1111111111111111111111111111111111111111"),
-		core.NewHash("2222222222222222222222222222222222222222"),
-		core.NewHash("3333333333333333333333333333333333333333"),
-		core.NewHash("4444444444444444444444444444444444444444"),
+	expected := []plumbing.Hash{
+		plumbing.NewHash("1111111111111111111111111111111111111111"),
+		plumbing.NewHash("2222222222222222222222222222222222222222"),
+		plumbing.NewHash("3333333333333333333333333333333333333333"),
+		plumbing.NewHash("4444444444444444444444444444444444444444"),
 	}
 
 	sort.Sort(byHash(ur.Wants))
@@ -189,12 +189,12 @@ func (s *SuiteDecoder) TestSingleShallowSingleWant(c *C) {
 	}
 	ur := testDecodeOK(c, payloads)
 
-	expectedWants := []core.Hash{
-		core.NewHash("3333333333333333333333333333333333333333"),
+	expectedWants := []plumbing.Hash{
+		plumbing.NewHash("3333333333333333333333333333333333333333"),
 	}
 
-	expectedShallows := []core.Hash{
-		core.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+	expectedShallows := []plumbing.Hash{
+		plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
 	}
 
 	c.Assert(ur.Wants, DeepEquals, expectedWants)
@@ -215,16 +215,16 @@ func (s *SuiteDecoder) TestSingleShallowManyWants(c *C) {
 	}
 	ur := testDecodeOK(c, payloads)
 
-	expectedWants := []core.Hash{
-		core.NewHash("1111111111111111111111111111111111111111"),
-		core.NewHash("2222222222222222222222222222222222222222"),
-		core.NewHash("3333333333333333333333333333333333333333"),
-		core.NewHash("4444444444444444444444444444444444444444"),
+	expectedWants := []plumbing.Hash{
+		plumbing.NewHash("1111111111111111111111111111111111111111"),
+		plumbing.NewHash("2222222222222222222222222222222222222222"),
+		plumbing.NewHash("3333333333333333333333333333333333333333"),
+		plumbing.NewHash("4444444444444444444444444444444444444444"),
 	}
 	sort.Sort(byHash(expectedWants))
 
-	expectedShallows := []core.Hash{
-		core.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+	expectedShallows := []plumbing.Hash{
+		plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
 	}
 
 	sort.Sort(byHash(ur.Wants))
@@ -246,15 +246,15 @@ func (s *SuiteDecoder) TestManyShallowSingleWant(c *C) {
 	}
 	ur := testDecodeOK(c, payloads)
 
-	expectedWants := []core.Hash{
-		core.NewHash("3333333333333333333333333333333333333333"),
+	expectedWants := []plumbing.Hash{
+		plumbing.NewHash("3333333333333333333333333333333333333333"),
 	}
 
-	expectedShallows := []core.Hash{
-		core.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
-		core.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
-		core.NewHash("cccccccccccccccccccccccccccccccccccccccc"),
-		core.NewHash("dddddddddddddddddddddddddddddddddddddddd"),
+	expectedShallows := []plumbing.Hash{
+		plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+		plumbing.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
+		plumbing.NewHash("cccccccccccccccccccccccccccccccccccccccc"),
+		plumbing.NewHash("dddddddddddddddddddddddddddddddddddddddd"),
 	}
 	sort.Sort(byHash(expectedShallows))
 
@@ -280,19 +280,19 @@ func (s *SuiteDecoder) TestManyShallowManyWants(c *C) {
 	}
 	ur := testDecodeOK(c, payloads)
 
-	expectedWants := []core.Hash{
-		core.NewHash("1111111111111111111111111111111111111111"),
-		core.NewHash("2222222222222222222222222222222222222222"),
-		core.NewHash("3333333333333333333333333333333333333333"),
-		core.NewHash("4444444444444444444444444444444444444444"),
+	expectedWants := []plumbing.Hash{
+		plumbing.NewHash("1111111111111111111111111111111111111111"),
+		plumbing.NewHash("2222222222222222222222222222222222222222"),
+		plumbing.NewHash("3333333333333333333333333333333333333333"),
+		plumbing.NewHash("4444444444444444444444444444444444444444"),
 	}
 	sort.Sort(byHash(expectedWants))
 
-	expectedShallows := []core.Hash{
-		core.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
-		core.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
-		core.NewHash("cccccccccccccccccccccccccccccccccccccccc"),
-		core.NewHash("dddddddddddddddddddddddddddddddddddddddd"),
+	expectedShallows := []plumbing.Hash{
+		plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+		plumbing.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
+		plumbing.NewHash("cccccccccccccccccccccccccccccccccccccccc"),
+		plumbing.NewHash("dddddddddddddddddddddddddddddddddddddddd"),
 	}
 	sort.Sort(byHash(expectedShallows))
 
@@ -500,11 +500,11 @@ func (s *SuiteDecoder) TestAll(c *C) {
 	}
 	ur := testDecodeOK(c, payloads)
 
-	expectedWants := []core.Hash{
-		core.NewHash("1111111111111111111111111111111111111111"),
-		core.NewHash("2222222222222222222222222222222222222222"),
-		core.NewHash("3333333333333333333333333333333333333333"),
-		core.NewHash("4444444444444444444444444444444444444444"),
+	expectedWants := []plumbing.Hash{
+		plumbing.NewHash("1111111111111111111111111111111111111111"),
+		plumbing.NewHash("2222222222222222222222222222222222222222"),
+		plumbing.NewHash("3333333333333333333333333333333333333333"),
+		plumbing.NewHash("4444444444444444444444444444444444444444"),
 	}
 	sort.Sort(byHash(expectedWants))
 	sort.Sort(byHash(ur.Wants))
@@ -513,11 +513,11 @@ func (s *SuiteDecoder) TestAll(c *C) {
 	c.Assert(ur.Capabilities.Supports("ofs-delta"), Equals, true)
 	c.Assert(ur.Capabilities.Supports("multi_ack"), Equals, true)
 
-	expectedShallows := []core.Hash{
-		core.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
-		core.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
-		core.NewHash("cccccccccccccccccccccccccccccccccccccccc"),
-		core.NewHash("dddddddddddddddddddddddddddddddddddddddd"),
+	expectedShallows := []plumbing.Hash{
+		plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"),
+		plumbing.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"),
+		plumbing.NewHash("cccccccccccccccccccccccccccccccccccccccc"),
+		plumbing.NewHash("dddddddddddddddddddddddddddddddddddddddd"),
 	}
 	sort.Sort(byHash(expectedShallows))
 	sort.Sort(byHash(ur.Shallows))
diff --git a/formats/packp/ulreq/encoder.go b/plumbing/format/packp/ulreq/encoder.go
index 1e40b63..1264e0e 100644
--- a/formats/packp/ulreq/encoder.go
+++ b/plumbing/format/packp/ulreq/encoder.go
@@ -6,8 +6,8 @@ import (
 	"sort"
 	"time"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
 )
 
 // An Encoder writes UlReq values to an output stream.
@@ -47,7 +47,7 @@ func (e *Encoder) Encode(v *UlReq) error {
 
 type encoderStateFn func(*Encoder) encoderStateFn
 
-func sortHashes(list []core.Hash) []string {
+func sortHashes(list []plumbing.Hash) []string {
 	sorted := make([]string, len(list))
 	for i, hash := range list {
 		sorted[i] = hash.String()
diff --git a/formats/packp/ulreq/encoder_test.go b/plumbing/format/packp/ulreq/encoder_test.go
index 56a8c2a..44c6d26 100644
--- a/formats/packp/ulreq/encoder_test.go
+++ b/plumbing/format/packp/ulreq/encoder_test.go
@@ -4,8 +4,8 @@ import (
 	"bytes"
 	"time"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
 
 	. "gopkg.in/check.v1"
 )
@@ -57,7 +57,7 @@ func (s *SuiteEncoder) TestZeroValue(c *C) {
 
 func (s *SuiteEncoder) TestOneWant(c *C) {
 	ur := New()
-	ur.Wants = append(ur.Wants, core.NewHash("1111111111111111111111111111111111111111"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("1111111111111111111111111111111111111111"))
 
 	expected := []string{
 		"want 1111111111111111111111111111111111111111\n",
@@ -69,7 +69,7 @@ func (s *SuiteEncoder) TestOneWant(c *C) {
 
 func (s *SuiteEncoder) TestOneWantWithCapabilities(c *C) {
 	ur := New()
-	ur.Wants = append(ur.Wants, core.NewHash("1111111111111111111111111111111111111111"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("1111111111111111111111111111111111111111"))
 	ur.Capabilities.Add("sysref", "HEAD:/refs/heads/master")
 	ur.Capabilities.Add("multi_ack")
 	ur.Capabilities.Add("thin-pack")
@@ -86,11 +86,11 @@ func (s *SuiteEncoder) TestOneWantWithCapabilities(c *C) {
 
 func (s *SuiteEncoder) TestWants(c *C) {
 	ur := New()
-	ur.Wants = append(ur.Wants, core.NewHash("4444444444444444444444444444444444444444"))
-	ur.Wants = append(ur.Wants, core.NewHash("1111111111111111111111111111111111111111"))
-	ur.Wants = append(ur.Wants, core.NewHash("3333333333333333333333333333333333333333"))
-	ur.Wants = append(ur.Wants, core.NewHash("2222222222222222222222222222222222222222"))
-	ur.Wants = append(ur.Wants, core.NewHash("5555555555555555555555555555555555555555"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("4444444444444444444444444444444444444444"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("1111111111111111111111111111111111111111"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("3333333333333333333333333333333333333333"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("2222222222222222222222222222222222222222"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("5555555555555555555555555555555555555555"))
 
 	expected := []string{
 		"want 1111111111111111111111111111111111111111\n",
@@ -106,11 +106,11 @@ func (s *SuiteEncoder) TestWants(c *C) {
 
 func (s *SuiteEncoder) TestWantsWithCapabilities(c *C) {
 	ur := New()
-	ur.Wants = append(ur.Wants, core.NewHash("4444444444444444444444444444444444444444"))
-	ur.Wants = append(ur.Wants, core.NewHash("1111111111111111111111111111111111111111"))
-	ur.Wants = append(ur.Wants, core.NewHash("3333333333333333333333333333333333333333"))
-	ur.Wants = append(ur.Wants, core.NewHash("2222222222222222222222222222222222222222"))
-	ur.Wants = append(ur.Wants, core.NewHash("5555555555555555555555555555555555555555"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("4444444444444444444444444444444444444444"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("1111111111111111111111111111111111111111"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("3333333333333333333333333333333333333333"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("2222222222222222222222222222222222222222"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("5555555555555555555555555555555555555555"))
 
 	ur.Capabilities.Add("sysref", "HEAD:/refs/heads/master")
 	ur.Capabilities.Add("multi_ack")
@@ -132,9 +132,9 @@ func (s *SuiteEncoder) TestWantsWithCapabilities(c *C) {
 
 func (s *SuiteEncoder) TestShallow(c *C) {
 	ur := New()
-	ur.Wants = append(ur.Wants, core.NewHash("1111111111111111111111111111111111111111"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("1111111111111111111111111111111111111111"))
 	ur.Capabilities.Add("multi_ack")
-	ur.Shallows = append(ur.Shallows, core.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"))
+	ur.Shallows = append(ur.Shallows, plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"))
 
 	expected := []string{
 		"want 1111111111111111111111111111111111111111 multi_ack\n",
@@ -147,12 +147,12 @@ func (s *SuiteEncoder) TestShallow(c *C) {
 
 func (s *SuiteEncoder) TestManyShallows(c *C) {
 	ur := New()
-	ur.Wants = append(ur.Wants, core.NewHash("1111111111111111111111111111111111111111"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("1111111111111111111111111111111111111111"))
 	ur.Capabilities.Add("multi_ack")
-	ur.Shallows = append(ur.Shallows, core.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"))
-	ur.Shallows = append(ur.Shallows, core.NewHash("dddddddddddddddddddddddddddddddddddddddd"))
-	ur.Shallows = append(ur.Shallows, core.NewHash("cccccccccccccccccccccccccccccccccccccccc"))
-	ur.Shallows = append(ur.Shallows, core.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"))
+	ur.Shallows = append(ur.Shallows, plumbing.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"))
+	ur.Shallows = append(ur.Shallows, plumbing.NewHash("dddddddddddddddddddddddddddddddddddddddd"))
+	ur.Shallows = append(ur.Shallows, plumbing.NewHash("cccccccccccccccccccccccccccccccccccccccc"))
+	ur.Shallows = append(ur.Shallows, plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"))
 
 	expected := []string{
 		"want 1111111111111111111111111111111111111111 multi_ack\n",
@@ -168,7 +168,7 @@ func (s *SuiteEncoder) TestManyShallows(c *C) {
 
 func (s *SuiteEncoder) TestDepthCommits(c *C) {
 	ur := New()
-	ur.Wants = append(ur.Wants, core.NewHash("1111111111111111111111111111111111111111"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("1111111111111111111111111111111111111111"))
 	ur.Depth = DepthCommits(1234)
 
 	expected := []string{
@@ -182,7 +182,7 @@ func (s *SuiteEncoder) TestDepthCommits(c *C) {
 
 func (s *SuiteEncoder) TestDepthSinceUTC(c *C) {
 	ur := New()
-	ur.Wants = append(ur.Wants, core.NewHash("1111111111111111111111111111111111111111"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("1111111111111111111111111111111111111111"))
 	since := time.Date(2015, time.January, 2, 3, 4, 5, 0, time.UTC)
 	ur.Depth = DepthSince(since)
 
@@ -197,7 +197,7 @@ func (s *SuiteEncoder) TestDepthSinceUTC(c *C) {
 
 func (s *SuiteEncoder) TestDepthSinceNonUTC(c *C) {
 	ur := New()
-	ur.Wants = append(ur.Wants, core.NewHash("1111111111111111111111111111111111111111"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("1111111111111111111111111111111111111111"))
 	berlin, err := time.LoadLocation("Europe/Berlin")
 	c.Assert(err, IsNil)
 	since := time.Date(2015, time.January, 2, 3, 4, 5, 0, berlin)
@@ -216,7 +216,7 @@ func (s *SuiteEncoder) TestDepthSinceNonUTC(c *C) {
 
 func (s *SuiteEncoder) TestDepthReference(c *C) {
 	ur := New()
-	ur.Wants = append(ur.Wants, core.NewHash("1111111111111111111111111111111111111111"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("1111111111111111111111111111111111111111"))
 	ur.Depth = DepthReference("refs/heads/feature-foo")
 
 	expected := []string{
@@ -230,11 +230,11 @@ func (s *SuiteEncoder) TestDepthReference(c *C) {
 
 func (s *SuiteEncoder) TestAll(c *C) {
 	ur := New()
-	ur.Wants = append(ur.Wants, core.NewHash("4444444444444444444444444444444444444444"))
-	ur.Wants = append(ur.Wants, core.NewHash("1111111111111111111111111111111111111111"))
-	ur.Wants = append(ur.Wants, core.NewHash("3333333333333333333333333333333333333333"))
-	ur.Wants = append(ur.Wants, core.NewHash("2222222222222222222222222222222222222222"))
-	ur.Wants = append(ur.Wants, core.NewHash("5555555555555555555555555555555555555555"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("4444444444444444444444444444444444444444"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("1111111111111111111111111111111111111111"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("3333333333333333333333333333333333333333"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("2222222222222222222222222222222222222222"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("5555555555555555555555555555555555555555"))
 
 	ur.Capabilities.Add("sysref", "HEAD:/refs/heads/master")
 	ur.Capabilities.Add("multi_ack")
@@ -242,10 +242,10 @@ func (s *SuiteEncoder) TestAll(c *C) {
 	ur.Capabilities.Add("side-band")
 	ur.Capabilities.Add("ofs-delta")
 
-	ur.Shallows = append(ur.Shallows, core.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"))
-	ur.Shallows = append(ur.Shallows, core.NewHash("dddddddddddddddddddddddddddddddddddddddd"))
-	ur.Shallows = append(ur.Shallows, core.NewHash("cccccccccccccccccccccccccccccccccccccccc"))
-	ur.Shallows = append(ur.Shallows, core.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"))
+	ur.Shallows = append(ur.Shallows, plumbing.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"))
+	ur.Shallows = append(ur.Shallows, plumbing.NewHash("dddddddddddddddddddddddddddddddddddddddd"))
+	ur.Shallows = append(ur.Shallows, plumbing.NewHash("cccccccccccccccccccccccccccccccccccccccc"))
+	ur.Shallows = append(ur.Shallows, plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"))
 
 	since := time.Date(2015, time.January, 2, 3, 4, 5, 0, time.UTC)
 	ur.Depth = DepthSince(since)
diff --git a/formats/packp/ulreq/ulreq.go b/plumbing/format/packp/ulreq/ulreq.go
index e47450a..d2cc7c0 100644
--- a/formats/packp/ulreq/ulreq.go
+++ b/plumbing/format/packp/ulreq/ulreq.go
@@ -5,8 +5,8 @@ package ulreq
 import (
 	"time"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp"
 )
 
 // UlReq values represent the information transmitted on a
@@ -14,8 +14,8 @@ import (
 // safe, use the New function instead.
 type UlReq struct {
 	Capabilities *packp.Capabilities
-	Wants        []core.Hash
-	Shallows     []core.Hash
+	Wants        []plumbing.Hash
+	Shallows     []plumbing.Hash
 	Depth        Depth
 }
 
@@ -49,8 +49,8 @@ func (d DepthReference) isDepth() {}
 func New() *UlReq {
 	return &UlReq{
 		Capabilities: packp.NewCapabilities(),
-		Wants:        []core.Hash{},
-		Shallows:     []core.Hash{},
+		Wants:        []plumbing.Hash{},
+		Shallows:     []plumbing.Hash{},
 		Depth:        DepthCommits(0),
 	}
 }
diff --git a/formats/packp/ulreq/ulreq_test.go b/plumbing/format/packp/ulreq/ulreq_test.go
index 2c5e85a..06963ff 100644
--- a/formats/packp/ulreq/ulreq_test.go
+++ b/plumbing/format/packp/ulreq/ulreq_test.go
@@ -7,8 +7,8 @@ import (
 	"testing"
 	"time"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packp/pktline"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp/pktline"
 
 	. "gopkg.in/check.v1"
 )
@@ -20,17 +20,17 @@ func ExampleEncoder_Encode() {
 	ur := New()
 
 	// Add a couple of wants
-	ur.Wants = append(ur.Wants, core.NewHash("3333333333333333333333333333333333333333"))
-	ur.Wants = append(ur.Wants, core.NewHash("1111111111111111111111111111111111111111"))
-	ur.Wants = append(ur.Wants, core.NewHash("2222222222222222222222222222222222222222"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("3333333333333333333333333333333333333333"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("1111111111111111111111111111111111111111"))
+	ur.Wants = append(ur.Wants, plumbing.NewHash("2222222222222222222222222222222222222222"))
 
 	// And some capabilities you will like the server to use
 	ur.Capabilities.Add("sysref", "HEAD:/refs/heads/master")
 	ur.Capabilities.Add("ofs-delta")
 
 	// Add a couple of shallows
-	ur.Shallows = append(ur.Shallows, core.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"))
-	ur.Shallows = append(ur.Shallows, core.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"))
+	ur.Shallows = append(ur.Shallows, plumbing.NewHash("bbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbbb"))
+	ur.Shallows = append(ur.Shallows, plumbing.NewHash("aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"))
 
 	// And retrict the answer of the server to commits newer than "2015-01-02 03:04:05 UTC"
 	since := time.Date(2015, time.January, 2, 3, 4, 5, 0, time.UTC)
diff --git a/core/hash.go b/plumbing/hash.go
index c50ffb2..7fa953d 100644
--- a/core/hash.go
+++ b/plumbing/hash.go
@@ -1,4 +1,4 @@
-package core
+package plumbing
 
 import (
 	"crypto/sha1"
diff --git a/core/hash_test.go b/plumbing/hash_test.go
index 782777e..370811e 100644
--- a/core/hash_test.go
+++ b/plumbing/hash_test.go
@@ -1,4 +1,4 @@
-package core
+package plumbing
 
 import (
 	"testing"
diff --git a/core/memory.go b/plumbing/memory.go
index dabee3a..c65ce1f 100644
--- a/core/memory.go
+++ b/plumbing/memory.go
@@ -1,4 +1,4 @@
-package core
+package plumbing
 
 import (
 	"bytes"
diff --git a/core/memory_test.go b/plumbing/memory_test.go
index f1c3f64..879ed37 100644
--- a/core/memory_test.go
+++ b/plumbing/memory_test.go
@@ -1,4 +1,4 @@
-package core
+package plumbing
 
 import (
 	"io/ioutil"
diff --git a/plumbing/object.go b/plumbing/object.go
new file mode 100644
index 0000000..23abd4f
--- /dev/null
+++ b/plumbing/object.go
@@ -0,0 +1,94 @@
+// package plumbing implement the core interfaces and structs used by go-git
+package plumbing
+
+import (
+	"errors"
+	"io"
+)
+
+var (
+	ErrObjectNotFound = errors.New("object not found")
+	// ErrInvalidType is returned when an invalid object type is provided.
+	ErrInvalidType = errors.New("invalid object type")
+)
+
+// Object is a generic representation of any git object
+type Object interface {
+	Hash() Hash
+	Type() ObjectType
+	SetType(ObjectType)
+	Size() int64
+	SetSize(int64)
+	Reader() (io.ReadCloser, error)
+	Writer() (io.WriteCloser, error)
+}
+
+// ObjectType internal object type
+// Integer values from 0 to 7 map to those exposed by git.
+// AnyObject is used to represent any from 0 to 7.
+type ObjectType int8
+
+const (
+	InvalidObject ObjectType = 0
+	CommitObject  ObjectType = 1
+	TreeObject    ObjectType = 2
+	BlobObject    ObjectType = 3
+	TagObject     ObjectType = 4
+	// 5 reserved for future expansion
+	OFSDeltaObject ObjectType = 6
+	REFDeltaObject ObjectType = 7
+
+	AnyObject ObjectType = -127
+)
+
+func (t ObjectType) String() string {
+	switch t {
+	case CommitObject:
+		return "commit"
+	case TreeObject:
+		return "tree"
+	case BlobObject:
+		return "blob"
+	case TagObject:
+		return "tag"
+	case OFSDeltaObject:
+		return "ofs-delta"
+	case REFDeltaObject:
+		return "ref-delta"
+	case AnyObject:
+		return "any"
+	default:
+		return "unknown"
+	}
+}
+
+func (t ObjectType) Bytes() []byte {
+	return []byte(t.String())
+}
+
+// Valid returns true if t is a valid ObjectType.
+func (t ObjectType) Valid() bool {
+	return t >= CommitObject && t <= REFDeltaObject
+}
+
+// ParseObjectType parses a string representation of ObjectType. It returns an
+// error on parse failure.
+func ParseObjectType(value string) (typ ObjectType, err error) {
+	switch value {
+	case "commit":
+		typ = CommitObject
+	case "tree":
+		typ = TreeObject
+	case "blob":
+		typ = BlobObject
+	case "tag":
+		typ = TagObject
+	case "ofs-delta":
+		typ = OFSDeltaObject
+	case "ref-delta":
+		typ = REFDeltaObject
+	default:
+		err = ErrInvalidType
+	}
+	return
+}
diff --git a/plumbing/object_test.go b/plumbing/object_test.go
new file mode 100644
index 0000000..4d2dbe2
--- /dev/null
+++ b/plumbing/object_test.go
@@ -0,0 +1,46 @@
+package plumbing
+
+import . "gopkg.in/check.v1"
+
+type ObjectSuite struct{}
+
+var _ = Suite(&ObjectSuite{})
+
+func (s *ObjectSuite) TestObjectTypeString(c *C) {
+	c.Assert(CommitObject.String(), Equals, "commit")
+	c.Assert(TreeObject.String(), Equals, "tree")
+	c.Assert(BlobObject.String(), Equals, "blob")
+	c.Assert(TagObject.String(), Equals, "tag")
+	c.Assert(REFDeltaObject.String(), Equals, "ref-delta")
+	c.Assert(OFSDeltaObject.String(), Equals, "ofs-delta")
+	c.Assert(AnyObject.String(), Equals, "any")
+	c.Assert(ObjectType(42).String(), Equals, "unknown")
+}
+
+func (s *ObjectSuite) TestObjectTypeBytes(c *C) {
+	c.Assert(CommitObject.Bytes(), DeepEquals, []byte("commit"))
+}
+
+func (s *ObjectSuite) TestObjectTypeValid(c *C) {
+	c.Assert(CommitObject.Valid(), Equals, true)
+	c.Assert(ObjectType(42).Valid(), Equals, false)
+}
+
+func (s *ObjectSuite) TestParseObjectType(c *C) {
+	for s, e := range map[string]ObjectType{
+		"commit":    CommitObject,
+		"tree":      TreeObject,
+		"blob":      BlobObject,
+		"tag":       TagObject,
+		"ref-delta": REFDeltaObject,
+		"ofs-delta": OFSDeltaObject,
+	} {
+		t, err := ParseObjectType(s)
+		c.Assert(err, IsNil)
+		c.Assert(e, Equals, t)
+	}
+
+	t, err := ParseObjectType("foo")
+	c.Assert(err, Equals, ErrInvalidType)
+	c.Assert(t, Equals, InvalidObject)
+}
diff --git a/core/reference.go b/plumbing/reference.go
index ee55a6a..98516c7 100644
--- a/core/reference.go
+++ b/plumbing/reference.go
@@ -1,9 +1,8 @@
-package core
+package plumbing
 
 import (
 	"errors"
 	"fmt"
-	"io"
 	"strings"
 )
 
@@ -14,13 +13,10 @@ const (
 	refRemotePrefix = refPrefix + "remotes/"
 	refNotePrefix   = refPrefix + "notes/"
 	symrefPrefix    = "ref: "
-
-	maxResolveRecursion = 1024
 )
 
 var (
-	ErrMaxResolveRecursion = errors.New("max. recursion level reached")
-	ErrReferenceNotFound   = errors.New("reference not found")
+	ErrReferenceNotFound = errors.New("reference not found")
 )
 
 // ReferenceType reference type's
@@ -148,83 +144,3 @@ func (r *Reference) String() string {
 	s := r.Strings()
 	return fmt.Sprintf("%s %s", s[1], s[0])
 }
-
-// ReferenceSliceIter implements ReferenceIter. It iterates over a series of
-// references stored in a slice and yields each one in turn when Next() is
-// called.
-//
-// The ReferenceSliceIter must be closed with a call to Close() when it is no
-// longer needed.
-type ReferenceSliceIter struct {
-	series []*Reference
-	pos    int
-}
-
-// NewReferenceSliceIter returns a reference iterator for the given slice of
-// objects.
-func NewReferenceSliceIter(series []*Reference) *ReferenceSliceIter {
-	return &ReferenceSliceIter{
-		series: series,
-	}
-}
-
-// Next returns the next reference from the iterator. If the iterator has
-// reached the end it will return io.EOF as an error.
-func (iter *ReferenceSliceIter) Next() (*Reference, error) {
-	if iter.pos >= len(iter.series) {
-		return nil, io.EOF
-	}
-
-	obj := iter.series[iter.pos]
-	iter.pos++
-	return obj, nil
-}
-
-// ForEach call the cb function for each reference contained on this iter until
-// an error happends or the end of the iter is reached. If ErrStop is sent
-// the iteration is stop but no error is returned. The iterator is closed.
-func (iter *ReferenceSliceIter) ForEach(cb func(*Reference) error) error {
-	defer iter.Close()
-	for _, r := range iter.series {
-		if err := cb(r); err != nil {
-			if err == ErrStop {
-				return nil
-			}
-
-			return nil
-		}
-	}
-
-	return nil
-}
-
-// Close releases any resources used by the iterator.
-func (iter *ReferenceSliceIter) Close() {
-	iter.pos = len(iter.series)
-}
-
-func ResolveReference(s ReferenceStorer, n ReferenceName) (*Reference, error) {
-	r, err := s.Reference(n)
-	if err != nil || r == nil {
-		return r, err
-	}
-	return resolveReference(s, r, 0)
-}
-
-func resolveReference(s ReferenceStorer, r *Reference, recursion int) (*Reference, error) {
-	if r.Type() != SymbolicReference {
-		return r, nil
-	}
-
-	if recursion > maxResolveRecursion {
-		return nil, ErrMaxResolveRecursion
-	}
-
-	t, err := s.Reference(r.Target())
-	if err != nil {
-		return nil, err
-	}
-
-	recursion++
-	return resolveReference(s, t, recursion)
-}
diff --git a/core/reference_test.go b/plumbing/reference_test.go
index b14f24c..4d9b393 100644
--- a/core/reference_test.go
+++ b/plumbing/reference_test.go
@@ -1,10 +1,6 @@
-package core
+package plumbing
 
-import (
-	"io"
-
-	. "gopkg.in/check.v1"
-)
+import . "gopkg.in/check.v1"
 
 type ReferenceSuite struct{}
 
@@ -63,58 +59,3 @@ func (s *ReferenceSuite) TestIsTag(c *C) {
 	r := NewHashReference(ReferenceName("refs/tags/v3.1."), ZeroHash)
 	c.Assert(r.IsTag(), Equals, true)
 }
-
-func (s *ReferenceSuite) TestReferenceSliceIterNext(c *C) {
-	slice := []*Reference{
-		NewReferenceFromStrings("foo", "foo"),
-		NewReferenceFromStrings("bar", "bar"),
-	}
-
-	i := NewReferenceSliceIter(slice)
-	foo, err := i.Next()
-	c.Assert(err, IsNil)
-	c.Assert(foo == slice[0], Equals, true)
-
-	bar, err := i.Next()
-	c.Assert(err, IsNil)
-	c.Assert(bar == slice[1], Equals, true)
-
-	empty, err := i.Next()
-	c.Assert(err, Equals, io.EOF)
-	c.Assert(empty, IsNil)
-}
-
-func (s *ReferenceSuite) TestReferenceSliceIterForEach(c *C) {
-	slice := []*Reference{
-		NewReferenceFromStrings("foo", "foo"),
-		NewReferenceFromStrings("bar", "bar"),
-	}
-
-	i := NewReferenceSliceIter(slice)
-	var count int
-	i.ForEach(func(r *Reference) error {
-		c.Assert(r == slice[count], Equals, true)
-		count++
-		return nil
-	})
-
-	c.Assert(count, Equals, 2)
-}
-
-func (s *ReferenceSuite) TestReferenceSliceIterForEachStop(c *C) {
-	slice := []*Reference{
-		NewReferenceFromStrings("foo", "foo"),
-		NewReferenceFromStrings("bar", "bar"),
-	}
-
-	i := NewReferenceSliceIter(slice)
-
-	var count int
-	i.ForEach(func(r *Reference) error {
-		c.Assert(r == slice[count], Equals, true)
-		count++
-		return ErrStop
-	})
-
-	c.Assert(count, Equals, 1)
-}
diff --git a/plumbing/storer/index.go b/plumbing/storer/index.go
new file mode 100644
index 0000000..e087296
--- /dev/null
+++ b/plumbing/storer/index.go
@@ -0,0 +1,9 @@
+package storer
+
+import "gopkg.in/src-d/go-git.v4/plumbing/format/index"
+
+// IndexStorer generic storage of index.Index
+type IndexStorer interface {
+	SetIndex(*index.Index) error
+	Index() (*index.Index, error)
+}
diff --git a/core/object.go b/plumbing/storer/object.go
index 8125465..c7841b6 100644
--- a/core/object.go
+++ b/plumbing/storer/object.go
@@ -1,96 +1,71 @@
-// Package core implement the core interfaces and structs used by go-git
-package core
+package storer
 
 import (
 	"errors"
 	"io"
-)
 
-var (
-	ErrObjectNotFound = errors.New("object not found")
-	// ErrInvalidType is returned when an invalid object type is provided.
-	ErrInvalidType = errors.New("invalid object type")
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
-// Object is a generic representation of any git object
-type Object interface {
-	Hash() Hash
-	Type() ObjectType
-	SetType(ObjectType)
-	Size() int64
-	SetSize(int64)
-	Reader() (io.ReadCloser, error)
-	Writer() (io.WriteCloser, error)
-}
-
-// ObjectType internal object type
-// Integer values from 0 to 7 map to those exposed by git.
-// AnyObject is used to represent any from 0 to 7.
-type ObjectType int8
-
-const (
-	InvalidObject ObjectType = 0
-	CommitObject  ObjectType = 1
-	TreeObject    ObjectType = 2
-	BlobObject    ObjectType = 3
-	TagObject     ObjectType = 4
-	// 5 reserved for future expansion
-	OFSDeltaObject ObjectType = 6
-	REFDeltaObject ObjectType = 7
-
-	AnyObject ObjectType = -127
+var (
+	//ErrStop is used to stop a ForEach function in an Iter
+	ErrStop = errors.New("stop iter")
 )
 
-func (t ObjectType) String() string {
-	switch t {
-	case CommitObject:
-		return "commit"
-	case TreeObject:
-		return "tree"
-	case BlobObject:
-		return "blob"
-	case TagObject:
-		return "tag"
-	case OFSDeltaObject:
-		return "ofs-delta"
-	case REFDeltaObject:
-		return "ref-delta"
-	case AnyObject:
-		return "any"
-	default:
-		return "unknown"
-	}
-}
-
-func (t ObjectType) Bytes() []byte {
-	return []byte(t.String())
-}
-
-// Valid returns true if t is a valid ObjectType.
-func (t ObjectType) Valid() bool {
-	return t >= CommitObject && t <= REFDeltaObject
+// ObjectStorer generic storage of objects
+type ObjectStorer interface {
+	// NewObject returns a new plumbing.Object, the real type of the object can
+	// be a custom implementation or the defaul one, plumbing.MemoryObject
+	NewObject() plumbing.Object
+	// SetObject save an object into the storage, the object shuld be create
+	// with the NewObject, method, and file if the type is not supported.
+	SetObject(plumbing.Object) (plumbing.Hash, error)
+	// Object get an object by hash with the given plumbing.ObjectType.
+	// Implementors should return (nil, plumbing.ErrObjectNotFound) if an object
+	// doesn't exist with both the given hash and object type.
+	//
+	// Valid plumbing.ObjectType values are CommitObject, BlobObject, TagObject,
+	// TreeObject and AnyObject. If plumbing.AnyObject is given, the object must
+	// be looked up regardless of its type.
+	Object(plumbing.ObjectType, plumbing.Hash) (plumbing.Object, error)
+	// IterObjects returns a custom ObjectIter over all the object on the
+	// storage.
+	//
+	// Valid plumbing.ObjectType values are CommitObject, BlobObject, TagObject,
+	IterObjects(plumbing.ObjectType) (ObjectIter, error)
+}
+
+// Transactioner is a optional method for ObjectStorer, it enable transaction
+// base write and read operations in the storage
+type Transactioner interface {
+	// Begin starts a transaction.
+	Begin() Transaction
+}
+
+// PackfileWriter is a optional method for ObjectStorer, it enable direct write
+// of packfile to the storage
+type PackfileWriter interface {
+	// PackfileWriter retuns a writer for writing a packfile to the storage
+	//
+	// If the Storer not implements PackfileWriter the objects should be written
+	// using the Set method.
+	PackfileWriter() (io.WriteCloser, error)
+}
+
+// ObjectIter is a generic closable interface for iterating over objects.
+type ObjectIter interface {
+	Next() (plumbing.Object, error)
+	ForEach(func(plumbing.Object) error) error
+	Close()
 }
 
-// ParseObjectType parses a string representation of ObjectType. It returns an
-// error on parse failure.
-func ParseObjectType(value string) (typ ObjectType, err error) {
-	switch value {
-	case "commit":
-		typ = CommitObject
-	case "tree":
-		typ = TreeObject
-	case "blob":
-		typ = BlobObject
-	case "tag":
-		typ = TagObject
-	case "ofs-delta":
-		typ = OFSDeltaObject
-	case "ref-delta":
-		typ = REFDeltaObject
-	default:
-		err = ErrInvalidType
-	}
-	return
+// Transaction is an in-progress storage transaction. A transaction must end
+// with a call to Commit or Rollback.
+type Transaction interface {
+	SetObject(plumbing.Object) (plumbing.Hash, error)
+	Object(plumbing.ObjectType, plumbing.Hash) (plumbing.Object, error)
+	Commit() error
+	Rollback() error
 }
 
 // ObjectLookupIter implements ObjectIter. It iterates over a series of object
@@ -102,14 +77,15 @@ func ParseObjectType(value string) (typ ObjectType, err error) {
 // longer needed.
 type ObjectLookupIter struct {
 	storage ObjectStorer
-	series  []Hash
-	t       ObjectType
+	series  []plumbing.Hash
+	t       plumbing.ObjectType
 	pos     int
 }
 
 // NewObjectLookupIter returns an object iterator given an object storage and
 // a slice of object hashes.
-func NewObjectLookupIter(storage ObjectStorer, t ObjectType, series []Hash) *ObjectLookupIter {
+func NewObjectLookupIter(
+	storage ObjectStorer, t plumbing.ObjectType, series []plumbing.Hash) *ObjectLookupIter {
 	return &ObjectLookupIter{
 		storage: storage,
 		series:  series,
@@ -119,9 +95,9 @@ func NewObjectLookupIter(storage ObjectStorer, t ObjectType, series []Hash) *Obj
 
 // Next returns the next object from the iterator. If the iterator has reached
 // the end it will return io.EOF as an error. If the object can't be found in
-// the object storage, it will return ErrObjectNotFound as an error. If the
-// object is retreieved successfully error will be nil.
-func (iter *ObjectLookupIter) Next() (Object, error) {
+// the object storage, it will return plumbing.ErrObjectNotFound as an error.
+// If the object is retreieved successfully error will be nil.
+func (iter *ObjectLookupIter) Next() (plumbing.Object, error) {
 	if iter.pos >= len(iter.series) {
 		return nil, io.EOF
 	}
@@ -138,7 +114,7 @@ func (iter *ObjectLookupIter) Next() (Object, error) {
 // ForEach call the cb function for each object contained on this iter until
 // an error happends or the end of the iter is reached. If ErrStop is sent
 // the iteration is stop but no error is returned. The iterator is closed.
-func (iter *ObjectLookupIter) ForEach(cb func(Object) error) error {
+func (iter *ObjectLookupIter) ForEach(cb func(plumbing.Object) error) error {
 	return ForEachIterator(iter, cb)
 }
 
@@ -153,12 +129,12 @@ func (iter *ObjectLookupIter) Close() {
 // The ObjectSliceIter must be closed with a call to Close() when it is no
 // longer needed.
 type ObjectSliceIter struct {
-	series []Object
+	series []plumbing.Object
 	pos    int
 }
 
 // NewObjectSliceIter returns an object iterator for the given slice of objects.
-func NewObjectSliceIter(series []Object) *ObjectSliceIter {
+func NewObjectSliceIter(series []plumbing.Object) *ObjectSliceIter {
 	return &ObjectSliceIter{
 		series: series,
 	}
@@ -167,7 +143,7 @@ func NewObjectSliceIter(series []Object) *ObjectSliceIter {
 // Next returns the next object from the iterator. If the iterator has reached
 // the end it will return io.EOF as an error. If the object is retreieved
 // successfully error will be nil.
-func (iter *ObjectSliceIter) Next() (Object, error) {
+func (iter *ObjectSliceIter) Next() (plumbing.Object, error) {
 	if len(iter.series) == 0 {
 		return nil, io.EOF
 	}
@@ -181,13 +157,13 @@ func (iter *ObjectSliceIter) Next() (Object, error) {
 // ForEach call the cb function for each object contained on this iter until
 // an error happends or the end of the iter is reached. If ErrStop is sent
 // the iteration is stop but no error is returned. The iterator is closed.
-func (iter *ObjectSliceIter) ForEach(cb func(Object) error) error {
+func (iter *ObjectSliceIter) ForEach(cb func(plumbing.Object) error) error {
 	return ForEachIterator(iter, cb)
 }
 
 // Close releases any resources used by the iterator.
 func (iter *ObjectSliceIter) Close() {
-	iter.series = []Object{}
+	iter.series = []plumbing.Object{}
 }
 
 // MultiObjectIter implements ObjectIter. It iterates over several ObjectIter,
@@ -206,7 +182,7 @@ func NewMultiObjectIter(iters []ObjectIter) ObjectIter {
 
 // Next returns the next object from the iterator, if one iterator reach io.EOF
 // is removed and the next one is used.
-func (iter *MultiObjectIter) Next() (Object, error) {
+func (iter *MultiObjectIter) Next() (plumbing.Object, error) {
 	if len(iter.iters) == 0 {
 		return nil, io.EOF
 	}
@@ -224,7 +200,7 @@ func (iter *MultiObjectIter) Next() (Object, error) {
 // ForEach call the cb function for each object contained on this iter until
 // an error happends or the end of the iter is reached. If ErrStop is sent
 // the iteration is stop but no error is returned. The iterator is closed.
-func (iter *MultiObjectIter) ForEach(cb func(Object) error) error {
+func (iter *MultiObjectIter) ForEach(cb func(plumbing.Object) error) error {
 	return ForEachIterator(iter, cb)
 }
 
@@ -236,13 +212,13 @@ func (iter *MultiObjectIter) Close() {
 }
 
 type bareIterator interface {
-	Next() (Object, error)
+	Next() (plumbing.Object, error)
 	Close()
 }
 
 // ForEachIterator is a helper function to build iterators without need to
 // rewrite the same ForEach function each time.
-func ForEachIterator(iter bareIterator, cb func(Object) error) error {
+func ForEachIterator(iter bareIterator, cb func(plumbing.Object) error) error {
 	defer iter.Close()
 	for {
 		obj, err := iter.Next()
diff --git a/plumbing/storer/object_test.go b/plumbing/storer/object_test.go
new file mode 100644
index 0000000..a0a7755
--- /dev/null
+++ b/plumbing/storer/object_test.go
@@ -0,0 +1,150 @@
+package storer
+
+import (
+	"fmt"
+	"testing"
+
+	. "gopkg.in/check.v1"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+)
+
+func Test(t *testing.T) { TestingT(t) }
+
+type ObjectSuite struct {
+	Objects []plumbing.Object
+	Hash    []plumbing.Hash
+}
+
+var _ = Suite(&ObjectSuite{})
+
+func (s *ObjectSuite) SetUpSuite(c *C) {
+	s.Objects = []plumbing.Object{
+		s.buildObject([]byte("foo")),
+		s.buildObject([]byte("bar")),
+	}
+
+	for _, o := range s.Objects {
+		s.Hash = append(s.Hash, o.Hash())
+	}
+}
+
+func (s *ObjectSuite) TestMultiObjectIterNext(c *C) {
+	expected := []plumbing.Object{
+		&plumbing.MemoryObject{},
+		&plumbing.MemoryObject{},
+		&plumbing.MemoryObject{},
+		&plumbing.MemoryObject{},
+		&plumbing.MemoryObject{},
+		&plumbing.MemoryObject{},
+	}
+
+	iter := NewMultiObjectIter([]ObjectIter{
+		NewObjectSliceIter(expected[0:2]),
+		NewObjectSliceIter(expected[2:4]),
+		NewObjectSliceIter(expected[4:5]),
+	})
+
+	var i int
+	iter.ForEach(func(o plumbing.Object) error {
+		c.Assert(o, Equals, expected[i])
+		i++
+		return nil
+	})
+
+	iter.Close()
+}
+
+func (s *ObjectSuite) buildObject(content []byte) plumbing.Object {
+	o := &plumbing.MemoryObject{}
+	o.Write(content)
+
+	return o
+}
+
+func (s *ObjectSuite) TestObjectLookupIter(c *C) {
+	var count int
+
+	storage := &MockObjectStorage{s.Objects}
+	i := NewObjectLookupIter(storage, plumbing.CommitObject, s.Hash)
+	err := i.ForEach(func(o plumbing.Object) error {
+		c.Assert(o, NotNil)
+		c.Assert(o.Hash().String(), Equals, s.Hash[count].String())
+		count++
+		return nil
+	})
+
+	c.Assert(err, IsNil)
+	i.Close()
+}
+
+func (s *ObjectSuite) TestObjectSliceIter(c *C) {
+	var count int
+
+	i := NewObjectSliceIter(s.Objects)
+	err := i.ForEach(func(o plumbing.Object) error {
+		c.Assert(o, NotNil)
+		c.Assert(o.Hash().String(), Equals, s.Hash[count].String())
+		count++
+		return nil
+	})
+
+	c.Assert(count, Equals, 2)
+	c.Assert(err, IsNil)
+	c.Assert(i.series, HasLen, 0)
+}
+
+func (s *ObjectSuite) TestObjectSliceIterStop(c *C) {
+	i := NewObjectSliceIter(s.Objects)
+
+	var count = 0
+	err := i.ForEach(func(o plumbing.Object) error {
+		c.Assert(o, NotNil)
+		c.Assert(o.Hash().String(), Equals, s.Hash[count].String())
+		count++
+		return ErrStop
+	})
+
+	c.Assert(count, Equals, 1)
+	c.Assert(err, IsNil)
+}
+
+func (s *ObjectSuite) TestObjectSliceIterError(c *C) {
+	i := NewObjectSliceIter([]plumbing.Object{
+		s.buildObject([]byte("foo")),
+	})
+
+	err := i.ForEach(func(plumbing.Object) error {
+		return fmt.Errorf("a random error")
+	})
+
+	c.Assert(err, NotNil)
+}
+
+type MockObjectStorage struct {
+	db []plumbing.Object
+}
+
+func (o *MockObjectStorage) NewObject() plumbing.Object {
+	return nil
+}
+
+func (o *MockObjectStorage) SetObject(obj plumbing.Object) (plumbing.Hash, error) {
+	return plumbing.ZeroHash, nil
+}
+
+func (o *MockObjectStorage) Object(t plumbing.ObjectType, h plumbing.Hash) (plumbing.Object, error) {
+	for _, o := range o.db {
+		if o.Hash() == h {
+			return o, nil
+		}
+	}
+	return nil, plumbing.ErrObjectNotFound
+}
+
+func (o *MockObjectStorage) IterObjects(t plumbing.ObjectType) (ObjectIter, error) {
+	return nil, nil
+}
+
+func (o *MockObjectStorage) Begin() Transaction {
+	return nil
+}
diff --git a/plumbing/storer/reference.go b/plumbing/storer/reference.go
new file mode 100644
index 0000000..5e818c6
--- /dev/null
+++ b/plumbing/storer/reference.go
@@ -0,0 +1,109 @@
+package storer
+
+import (
+	"errors"
+	"io"
+
+	"gopkg.in/src-d/go-git.v4/plumbing"
+)
+
+const MaxResolveRecursion = 1024
+
+// ErrMaxResolveRecursion is returned by ResolveReference is MaxResolveRecursion
+// is exceeded
+var ErrMaxResolveRecursion = errors.New("max. recursion level reached")
+
+// ReferenceStorer generic storage of references
+type ReferenceStorer interface {
+	SetReference(*plumbing.Reference) error
+	Reference(plumbing.ReferenceName) (*plumbing.Reference, error)
+	IterReferences() (ReferenceIter, error)
+}
+
+// ReferenceIter is a generic closable interface for iterating over references
+type ReferenceIter interface {
+	Next() (*plumbing.Reference, error)
+	ForEach(func(*plumbing.Reference) error) error
+	Close()
+}
+
+// ReferenceSliceIter implements ReferenceIter. It iterates over a series of
+// references stored in a slice and yields each one in turn when Next() is
+// called.
+//
+// The ReferenceSliceIter must be closed with a call to Close() when it is no
+// longer needed.
+type ReferenceSliceIter struct {
+	series []*plumbing.Reference
+	pos    int
+}
+
+// NewReferenceSliceIter returns a reference iterator for the given slice of
+// objects.
+func NewReferenceSliceIter(series []*plumbing.Reference) *ReferenceSliceIter {
+	return &ReferenceSliceIter{
+		series: series,
+	}
+}
+
+// Next returns the next reference from the iterator. If the iterator has
+// reached the end it will return io.EOF as an error.
+func (iter *ReferenceSliceIter) Next() (*plumbing.Reference, error) {
+	if iter.pos >= len(iter.series) {
+		return nil, io.EOF
+	}
+
+	obj := iter.series[iter.pos]
+	iter.pos++
+	return obj, nil
+}
+
+// ForEach call the cb function for each reference contained on this iter until
+// an error happends or the end of the iter is reached. If ErrStop is sent
+// the iteration is stop but no error is returned. The iterator is closed.
+func (iter *ReferenceSliceIter) ForEach(cb func(*plumbing.Reference) error) error {
+	defer iter.Close()
+	for _, r := range iter.series {
+		if err := cb(r); err != nil {
+			if err == ErrStop {
+				return nil
+			}
+
+			return nil
+		}
+	}
+
+	return nil
+}
+
+// Close releases any resources used by the iterator.
+func (iter *ReferenceSliceIter) Close() {
+	iter.pos = len(iter.series)
+}
+
+// ResolveReference resolve a SymbolicReference to a HashReference
+func ResolveReference(s ReferenceStorer, n plumbing.ReferenceName) (*plumbing.Reference, error) {
+	r, err := s.Reference(n)
+	if err != nil || r == nil {
+		return r, err
+	}
+	return resolveReference(s, r, 0)
+}
+
+func resolveReference(s ReferenceStorer, r *plumbing.Reference, recursion int) (*plumbing.Reference, error) {
+	if r.Type() != plumbing.SymbolicReference {
+		return r, nil
+	}
+
+	if recursion > MaxResolveRecursion {
+		return nil, ErrMaxResolveRecursion
+	}
+
+	t, err := s.Reference(r.Target())
+	if err != nil {
+		return nil, err
+	}
+
+	recursion++
+	return resolveReference(s, t, recursion)
+}
diff --git a/plumbing/storer/reference_test.go b/plumbing/storer/reference_test.go
new file mode 100644
index 0000000..3014df5
--- /dev/null
+++ b/plumbing/storer/reference_test.go
@@ -0,0 +1,67 @@
+package storer
+
+import (
+	"io"
+
+	. "gopkg.in/check.v1"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+)
+
+type ReferenceSuite struct{}
+
+var _ = Suite(&ReferenceSuite{})
+
+func (s *ReferenceSuite) TestReferenceSliceIterNext(c *C) {
+	slice := []*plumbing.Reference{
+		plumbing.NewReferenceFromStrings("foo", "foo"),
+		plumbing.NewReferenceFromStrings("bar", "bar"),
+	}
+
+	i := NewReferenceSliceIter(slice)
+	foo, err := i.Next()
+	c.Assert(err, IsNil)
+	c.Assert(foo == slice[0], Equals, true)
+
+	bar, err := i.Next()
+	c.Assert(err, IsNil)
+	c.Assert(bar == slice[1], Equals, true)
+
+	empty, err := i.Next()
+	c.Assert(err, Equals, io.EOF)
+	c.Assert(empty, IsNil)
+}
+
+func (s *ReferenceSuite) TestReferenceSliceIterForEach(c *C) {
+	slice := []*plumbing.Reference{
+		plumbing.NewReferenceFromStrings("foo", "foo"),
+		plumbing.NewReferenceFromStrings("bar", "bar"),
+	}
+
+	i := NewReferenceSliceIter(slice)
+	var count int
+	i.ForEach(func(r *plumbing.Reference) error {
+		c.Assert(r == slice[count], Equals, true)
+		count++
+		return nil
+	})
+
+	c.Assert(count, Equals, 2)
+}
+
+func (s *ReferenceSuite) TestReferenceSliceIterForEachStop(c *C) {
+	slice := []*plumbing.Reference{
+		plumbing.NewReferenceFromStrings("foo", "foo"),
+		plumbing.NewReferenceFromStrings("bar", "bar"),
+	}
+
+	i := NewReferenceSliceIter(slice)
+
+	var count int
+	i.ForEach(func(r *plumbing.Reference) error {
+		c.Assert(r == slice[count], Equals, true)
+		count++
+		return ErrStop
+	})
+
+	c.Assert(count, Equals, 1)
+}
diff --git a/references.go b/references.go
index 7590560..0ce7ea6 100644
--- a/references.go
+++ b/references.go
@@ -3,8 +3,8 @@ package git
 import (
 	"io"
 
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/diff"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 
 	"github.com/sergi/go-diff/diffmatchpatch"
 )
@@ -20,7 +20,7 @@ import (
 //   (see git path-id for hints on how to fix this).
 func (c *Commit) References(path string) ([]*Commit, error) {
 	var result []*Commit
-	seen := make(map[core.Hash]struct{}, 0)
+	seen := make(map[plumbing.Hash]struct{}, 0)
 	if err := walkGraph(&result, &seen, c.r, c, path); err != nil {
 		return nil, err
 	}
@@ -33,7 +33,7 @@ func (c *Commit) References(path string) ([]*Commit, error) {
 
 // Recursive traversal of the commit graph, generating a linear history
 // of the path.
-func walkGraph(result *[]*Commit, seen *map[core.Hash]struct{}, repo *Repository, current *Commit, path string) error {
+func walkGraph(result *[]*Commit, seen *map[plumbing.Hash]struct{}, repo *Repository, current *Commit, path string) error {
 	// check and update seen
 	if _, ok := (*seen)[current.Hash]; ok {
 		return nil
@@ -117,10 +117,10 @@ func differentContents(path string, c *Commit, cs []*Commit) ([]*Commit, error)
 }
 
 // blobHash returns the hash of a path in a commit
-func blobHash(path string, commit *Commit) (hash core.Hash, found bool) {
+func blobHash(path string, commit *Commit) (hash plumbing.Hash, found bool) {
 	file, err := commit.File(path)
 	if err != nil {
-		var empty core.Hash
+		var empty plumbing.Hash
 		return empty, found
 	}
 	return file.Hash, true
diff --git a/references_test.go b/references_test.go
index 112fe3a..f5a2fdc 100644
--- a/references_test.go
+++ b/references_test.go
@@ -4,8 +4,8 @@ import (
 	"bytes"
 	"fmt"
 
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/fixtures"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 
 	. "gopkg.in/check.v1"
 )
@@ -296,7 +296,7 @@ func (s *ReferencesSuite) TestRevList(c *C) {
 		repo, ok := s.Repositories[t.repo]
 		c.Assert(ok, Equals, true)
 
-		commit, err := repo.Commit(core.NewHash(t.commit))
+		commit, err := repo.Commit(plumbing.NewHash(t.commit))
 		c.Assert(err, IsNil)
 
 		revs, err := commit.References(t.path)
@@ -305,7 +305,7 @@ func (s *ReferencesSuite) TestRevList(c *C) {
 
 		for i := range revs {
 			if revs[i].Hash.String() != t.revs[i] {
-				commit, err := repo.Commit(core.NewHash(t.revs[i]))
+				commit, err := repo.Commit(plumbing.NewHash(t.revs[i]))
 				c.Assert(err, IsNil)
 				equiv, err := equivalent(t.path, revs[i], commit)
 				c.Assert(err, IsNil)
@@ -363,7 +363,7 @@ func (s *ReferencesSuite) commits(cc *C, repo string, hs ...string) []*Commit {
 	cc.Assert(ok, Equals, true)
 	result := make([]*Commit, 0, len(hs))
 	for _, h := range hs {
-		c, err := r.Commit(core.NewHash(h))
+		c, err := r.Commit(plumbing.NewHash(h))
 		cc.Assert(err, IsNil)
 		result = append(result, c)
 	}
diff --git a/remote.go b/remote.go
index 518a2b1..f5cc7f7 100644
--- a/remote.go
+++ b/remote.go
@@ -5,12 +5,13 @@ import (
 	"fmt"
 	"io"
 
-	"gopkg.in/src-d/go-git.v4/clients"
-	"gopkg.in/src-d/go-git.v4/clients/common"
 	"gopkg.in/src-d/go-git.v4/config"
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/packfile"
-	"gopkg.in/src-d/go-git.v4/formats/packp"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/client"
+	"gopkg.in/src-d/go-git.v4/plumbing/client/common"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packfile"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packp"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 )
 
 var NoErrAlreadyUpToDate = errors.New("already up-to-date")
@@ -113,8 +114,8 @@ func (r *Remote) Fetch(o *FetchOptions) (err error) {
 	return r.updateLocalReferenceStorage(o.RefSpecs, refs)
 }
 
-func (r *Remote) getWantedReferences(spec []config.RefSpec) ([]*core.Reference, error) {
-	var refs []*core.Reference
+func (r *Remote) getWantedReferences(spec []config.RefSpec) ([]*plumbing.Reference, error) {
+	var refs []*plumbing.Reference
 	iter, err := r.Refs()
 	if err != nil {
 		return refs, err
@@ -128,8 +129,8 @@ func (r *Remote) getWantedReferences(spec []config.RefSpec) ([]*core.Reference,
 		}
 	}
 
-	return refs, iter.ForEach(func(ref *core.Reference) error {
-		if ref.Type() != core.HashReference {
+	return refs, iter.ForEach(func(ref *plumbing.Reference) error {
+		if ref.Type() != plumbing.HashReference {
 			return nil
 		}
 
@@ -139,8 +140,8 @@ func (r *Remote) getWantedReferences(spec []config.RefSpec) ([]*core.Reference,
 			}
 		}
 
-		_, err := r.s.Object(core.CommitObject, ref.Hash())
-		if err == core.ErrObjectNotFound {
+		_, err := r.s.Object(plumbing.CommitObject, ref.Hash())
+		if err == plumbing.ErrObjectNotFound {
 			refs = append(refs, ref)
 			return nil
 		}
@@ -150,7 +151,7 @@ func (r *Remote) getWantedReferences(spec []config.RefSpec) ([]*core.Reference,
 }
 
 func (r *Remote) buildRequest(
-	s core.ReferenceStorer, o *FetchOptions, refs []*core.Reference,
+	s storer.ReferenceStorer, o *FetchOptions, refs []*plumbing.Reference,
 ) (*common.GitUploadPackRequest, error) {
 	req := &common.GitUploadPackRequest{}
 	req.Depth = o.Depth
@@ -164,8 +165,8 @@ func (r *Remote) buildRequest(
 		return nil, err
 	}
 
-	err = i.ForEach(func(ref *core.Reference) error {
-		if ref.Type() != core.HashReference {
+	err = i.ForEach(func(ref *plumbing.Reference) error {
+		if ref.Type() != plumbing.HashReference {
 			return nil
 		}
 
@@ -177,7 +178,7 @@ func (r *Remote) buildRequest(
 }
 
 func (r *Remote) updateObjectStorage(reader io.Reader) error {
-	if sw, ok := r.s.(core.PackfileWriter); ok {
+	if sw, ok := r.s.(storer.PackfileWriter); ok {
 		w, err := sw.PackfileWriter()
 		if err != nil {
 			return err
@@ -198,19 +199,19 @@ func (r *Remote) updateObjectStorage(reader io.Reader) error {
 	return err
 }
 
-func (r *Remote) updateLocalReferenceStorage(specs []config.RefSpec, refs []*core.Reference) error {
+func (r *Remote) updateLocalReferenceStorage(specs []config.RefSpec, refs []*plumbing.Reference) error {
 	for _, spec := range specs {
 		for _, ref := range refs {
 			if !spec.Match(ref.Name()) {
 				continue
 			}
 
-			if ref.Type() != core.HashReference {
+			if ref.Type() != plumbing.HashReference {
 				continue
 			}
 
 			name := spec.Dst(ref.Name())
-			n := core.NewHashReference(name, ref.Hash())
+			n := plumbing.NewHashReference(name, ref.Hash())
 			if err := r.s.SetReference(n); err != nil {
 				return err
 			}
@@ -226,13 +227,13 @@ func (r *Remote) buildFetchedTags() error {
 		return err
 	}
 
-	return iter.ForEach(func(ref *core.Reference) error {
+	return iter.ForEach(func(ref *plumbing.Reference) error {
 		if !ref.IsTag() {
 			return nil
 		}
 
-		_, err := r.s.Object(core.AnyObject, ref.Hash())
-		if err == core.ErrObjectNotFound {
+		_, err := r.s.Object(plumbing.AnyObject, ref.Hash())
+		if err == plumbing.ErrObjectNotFound {
 			return nil
 		}
 
@@ -245,21 +246,21 @@ func (r *Remote) buildFetchedTags() error {
 }
 
 // Head returns the Reference of the HEAD
-func (r *Remote) Head() *core.Reference {
+func (r *Remote) Head() *plumbing.Reference {
 	return r.upInfo.Head()
 }
 
 // Ref returns the Hash pointing the given refName
-func (r *Remote) Ref(name core.ReferenceName, resolved bool) (*core.Reference, error) {
+func (r *Remote) Ref(name plumbing.ReferenceName, resolved bool) (*plumbing.Reference, error) {
 	if resolved {
-		return core.ResolveReference(r.upInfo.Refs, name)
+		return storer.ResolveReference(r.upInfo.Refs, name)
 	}
 
 	return r.upInfo.Refs.Reference(name)
 }
 
 // Refs returns a map with all the References
-func (r *Remote) Refs() (core.ReferenceIter, error) {
+func (r *Remote) Refs() (storer.ReferenceIter, error) {
 	return r.upInfo.Refs.IterReferences()
 }
 
diff --git a/remote_test.go b/remote_test.go
index 04167cd..f129c68 100644
--- a/remote_test.go
+++ b/remote_test.go
@@ -6,7 +6,8 @@ import (
 	"os"
 
 	"gopkg.in/src-d/go-git.v4/config"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 	"gopkg.in/src-d/go-git.v4/storage/filesystem"
 	"gopkg.in/src-d/go-git.v4/storage/memory"
 	osfs "gopkg.in/src-d/go-git.v4/utils/fs/os"
@@ -58,7 +59,7 @@ func (s *RemoteSuite) TestDefaultBranch(c *C) {
 	r.upSrv = &MockGitUploadPackService{}
 
 	c.Assert(r.Connect(), IsNil)
-	c.Assert(r.Head().Name(), Equals, core.ReferenceName("refs/heads/master"))
+	c.Assert(r.Head().Name(), Equals, plumbing.ReferenceName("refs/heads/master"))
 }
 
 func (s *RemoteSuite) TestCapabilities(c *C) {
@@ -83,10 +84,10 @@ func (s *RemoteSuite) TestFetch(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(sto.Objects, HasLen, 31)
 
-	expectedRefs := []*core.Reference{
-		core.NewReferenceFromStrings("refs/remotes/origin/master", "6ecf0ef2c2dffb796033e5a02219af86ec6584e5"),
-		core.NewReferenceFromStrings("refs/remotes/origin/branch", "e8d3ffab552895c19b9fcf7aa264d277cde33881"),
-		core.NewReferenceFromStrings("refs/tags/v1.0.0", "6ecf0ef2c2dffb796033e5a02219af86ec6584e5"),
+	expectedRefs := []*plumbing.Reference{
+		plumbing.NewReferenceFromStrings("refs/remotes/origin/master", "6ecf0ef2c2dffb796033e5a02219af86ec6584e5"),
+		plumbing.NewReferenceFromStrings("refs/remotes/origin/branch", "e8d3ffab552895c19b9fcf7aa264d277cde33881"),
+		plumbing.NewReferenceFromStrings("refs/tags/v1.0.0", "6ecf0ef2c2dffb796033e5a02219af86ec6584e5"),
 	}
 
 	for _, exp := range expectedRefs {
@@ -102,7 +103,7 @@ type mockPackfileWriter struct {
 
 func (m *mockPackfileWriter) PackfileWriter() (io.WriteCloser, error) {
 	m.PackfileWriterCalled = true
-	return m.Storer.(core.PackfileWriter).PackfileWriter()
+	return m.Storer.(storer.PackfileWriter).PackfileWriter()
 }
 
 func (s *RemoteSuite) TestFetchWithPackfileWriter(c *C) {
@@ -128,10 +129,10 @@ func (s *RemoteSuite) TestFetchWithPackfileWriter(c *C) {
 	c.Assert(err, IsNil)
 
 	var count int
-	iter, err := mock.IterObjects(core.AnyObject)
+	iter, err := mock.IterObjects(plumbing.AnyObject)
 	c.Assert(err, IsNil)
 
-	iter.ForEach(func(core.Object) error {
+	iter.ForEach(func(plumbing.Object) error {
 		count++
 		return nil
 	})
@@ -163,7 +164,7 @@ func (s *RemoteSuite) TestHead(c *C) {
 
 	err := r.Connect()
 	c.Assert(err, IsNil)
-	c.Assert(r.Head().Hash(), Equals, core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
+	c.Assert(r.Head().Hash(), Equals, plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
 }
 
 func (s *RemoteSuite) TestRef(c *C) {
@@ -173,13 +174,13 @@ func (s *RemoteSuite) TestRef(c *C) {
 	err := r.Connect()
 	c.Assert(err, IsNil)
 
-	ref, err := r.Ref(core.HEAD, false)
+	ref, err := r.Ref(plumbing.HEAD, false)
 	c.Assert(err, IsNil)
-	c.Assert(ref.Name(), Equals, core.HEAD)
+	c.Assert(ref.Name(), Equals, plumbing.HEAD)
 
-	ref, err = r.Ref(core.HEAD, true)
+	ref, err = r.Ref(plumbing.HEAD, true)
 	c.Assert(err, IsNil)
-	c.Assert(ref.Name(), Equals, core.ReferenceName("refs/heads/master"))
+	c.Assert(ref.Name(), Equals, plumbing.ReferenceName("refs/heads/master"))
 }
 
 func (s *RemoteSuite) TestRefs(c *C) {
diff --git a/repository.go b/repository.go
index 899127b..ec3a1f9 100644
--- a/repository.go
+++ b/repository.go
@@ -5,7 +5,8 @@ import (
 	"fmt"
 
 	"gopkg.in/src-d/go-git.v4/config"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 	"gopkg.in/src-d/go-git.v4/storage/filesystem"
 	"gopkg.in/src-d/go-git.v4/storage/memory"
 	osfs "gopkg.in/src-d/go-git.v4/utils/fs/os"
@@ -176,7 +177,7 @@ func (r *Repository) updateRemoteConfig(
 		return nil
 	}
 
-	head, err := core.ResolveReference(remote.Info().Refs, o.ReferenceName)
+	head, err := storer.ResolveReference(remote.Info().Refs, o.ReferenceName)
 	if err != nil {
 		return err
 	}
@@ -195,10 +196,10 @@ func (r *Repository) updateRemoteConfig(
 
 }
 
-func (r *Repository) createReferences(ref *core.Reference) error {
+func (r *Repository) createReferences(ref *plumbing.Reference) error {
 	if !ref.IsBranch() {
 		// detached HEAD mode
-		head := core.NewHashReference(core.HEAD, ref.Hash())
+		head := plumbing.NewHashReference(plumbing.HEAD, ref.Hash())
 		return r.s.SetReference(head)
 	}
 
@@ -206,7 +207,7 @@ func (r *Repository) createReferences(ref *core.Reference) error {
 		return err
 	}
 
-	head := core.NewSymbolicReference(core.HEAD, ref.Name())
+	head := plumbing.NewSymbolicReference(plumbing.HEAD, ref.Name())
 	return r.s.SetReference(head)
 }
 
@@ -218,7 +219,7 @@ func (r *Repository) IsEmpty() (bool, error) {
 	}
 
 	var count int
-	return count == 0, iter.ForEach(func(r *core.Reference) error {
+	return count == 0, iter.ForEach(func(r *plumbing.Reference) error {
 		count++
 		return nil
 	})
@@ -264,8 +265,8 @@ func (r *Repository) Pull(o *PullOptions) error {
 }
 
 // Commit return the commit with the given hash
-func (r *Repository) Commit(h core.Hash) (*Commit, error) {
-	commit, err := r.Object(core.CommitObject, h)
+func (r *Repository) Commit(h plumbing.Hash) (*Commit, error) {
+	commit, err := r.Object(plumbing.CommitObject, h)
 	if err != nil {
 		return nil, err
 	}
@@ -275,7 +276,7 @@ func (r *Repository) Commit(h core.Hash) (*Commit, error) {
 
 // Commits decode the objects into commits
 func (r *Repository) Commits() (*CommitIter, error) {
-	iter, err := r.s.IterObjects(core.CommitObject)
+	iter, err := r.s.IterObjects(plumbing.CommitObject)
 	if err != nil {
 		return nil, err
 	}
@@ -284,8 +285,8 @@ func (r *Repository) Commits() (*CommitIter, error) {
 }
 
 // Tree return the tree with the given hash
-func (r *Repository) Tree(h core.Hash) (*Tree, error) {
-	tree, err := r.Object(core.TreeObject, h)
+func (r *Repository) Tree(h plumbing.Hash) (*Tree, error) {
+	tree, err := r.Object(plumbing.TreeObject, h)
 	if err != nil {
 		return nil, err
 	}
@@ -295,7 +296,7 @@ func (r *Repository) Tree(h core.Hash) (*Tree, error) {
 
 // Trees decodes the objects into trees
 func (r *Repository) Trees() (*TreeIter, error) {
-	iter, err := r.s.IterObjects(core.TreeObject)
+	iter, err := r.s.IterObjects(plumbing.TreeObject)
 	if err != nil {
 		return nil, err
 	}
@@ -304,8 +305,8 @@ func (r *Repository) Trees() (*TreeIter, error) {
 }
 
 // Blob returns the blob with the given hash
-func (r *Repository) Blob(h core.Hash) (*Blob, error) {
-	blob, err := r.Object(core.BlobObject, h)
+func (r *Repository) Blob(h plumbing.Hash) (*Blob, error) {
+	blob, err := r.Object(plumbing.BlobObject, h)
 	if err != nil {
 		return nil, err
 	}
@@ -315,7 +316,7 @@ func (r *Repository) Blob(h core.Hash) (*Blob, error) {
 
 // Blobs decodes the objects into blobs
 func (r *Repository) Blobs() (*BlobIter, error) {
-	iter, err := r.s.IterObjects(core.BlobObject)
+	iter, err := r.s.IterObjects(plumbing.BlobObject)
 	if err != nil {
 		return nil, err
 	}
@@ -324,8 +325,8 @@ func (r *Repository) Blobs() (*BlobIter, error) {
 }
 
 // Tag returns a tag with the given hash.
-func (r *Repository) Tag(h core.Hash) (*Tag, error) {
-	tag, err := r.Object(core.TagObject, h)
+func (r *Repository) Tag(h plumbing.Hash) (*Tag, error) {
+	tag, err := r.Object(plumbing.TagObject, h)
 	if err != nil {
 		return nil, err
 	}
@@ -336,7 +337,7 @@ func (r *Repository) Tag(h core.Hash) (*Tag, error) {
 // Tags returns a TagIter that can step through all of the annotated tags
 // in the repository.
 func (r *Repository) Tags() (*TagIter, error) {
-	iter, err := r.s.IterObjects(core.TagObject)
+	iter, err := r.s.IterObjects(plumbing.TagObject)
 	if err != nil {
 		return nil, err
 	}
@@ -345,37 +346,37 @@ func (r *Repository) Tags() (*TagIter, error) {
 }
 
 // Object returns an object with the given hash.
-func (r *Repository) Object(t core.ObjectType, h core.Hash) (Object, error) {
+func (r *Repository) Object(t plumbing.ObjectType, h plumbing.Hash) (Object, error) {
 	obj, err := r.s.Object(t, h)
 	if err != nil {
-		if err == core.ErrObjectNotFound {
+		if err == plumbing.ErrObjectNotFound {
 			return nil, ErrObjectNotFound
 		}
 		return nil, err
 	}
 
 	switch obj.Type() {
-	case core.CommitObject:
+	case plumbing.CommitObject:
 		commit := &Commit{r: r}
 		return commit, commit.Decode(obj)
-	case core.TreeObject:
+	case plumbing.TreeObject:
 		tree := &Tree{r: r}
 		return tree, tree.Decode(obj)
-	case core.BlobObject:
+	case plumbing.BlobObject:
 		blob := &Blob{}
 		return blob, blob.Decode(obj)
-	case core.TagObject:
+	case plumbing.TagObject:
 		tag := &Tag{r: r}
 		return tag, tag.Decode(obj)
 	default:
-		return nil, core.ErrInvalidType
+		return nil, plumbing.ErrInvalidType
 	}
 }
 
 // Objects returns an ObjectIter that can step through all of the annotated tags
 // in the repository.
 func (r *Repository) Objects() (*ObjectIter, error) {
-	iter, err := r.s.IterObjects(core.AnyObject)
+	iter, err := r.s.IterObjects(plumbing.AnyObject)
 	if err != nil {
 		return nil, err
 	}
@@ -384,20 +385,20 @@ func (r *Repository) Objects() (*ObjectIter, error) {
 }
 
 // Head returns the reference where HEAD is pointing
-func (r *Repository) Head() (*core.Reference, error) {
-	return core.ResolveReference(r.s, core.HEAD)
+func (r *Repository) Head() (*plumbing.Reference, error) {
+	return storer.ResolveReference(r.s, plumbing.HEAD)
 }
 
 // Ref returns the Hash pointing the given refName
-func (r *Repository) Ref(name core.ReferenceName, resolved bool) (*core.Reference, error) {
+func (r *Repository) Ref(name plumbing.ReferenceName, resolved bool) (*plumbing.Reference, error) {
 	if resolved {
-		return core.ResolveReference(r.s, name)
+		return storer.ResolveReference(r.s, name)
 	}
 
 	return r.s.Reference(name)
 }
 
 // Refs returns a map with all the References
-func (r *Repository) Refs() (core.ReferenceIter, error) {
+func (r *Repository) Refs() (storer.ReferenceIter, error) {
 	return r.s.IterReferences()
 }
diff --git a/repository_test.go b/repository_test.go
index 6c7fe4f..dbcc232 100644
--- a/repository_test.go
+++ b/repository_test.go
@@ -2,7 +2,7 @@ package git
 
 import (
 	"gopkg.in/src-d/go-git.v4/config"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 	"gopkg.in/src-d/go-git.v4/storage/memory"
 
 	. "gopkg.in/check.v1"
@@ -64,7 +64,7 @@ func (s *RepositorySuite) TestClone(c *C) {
 	r := NewMemoryRepository()
 
 	head, err := r.Head()
-	c.Assert(err, Equals, core.ErrReferenceNotFound)
+	c.Assert(err, Equals, plumbing.ErrReferenceNotFound)
 	c.Assert(head, IsNil)
 
 	err = r.Clone(&CloneOptions{
@@ -77,10 +77,10 @@ func (s *RepositorySuite) TestClone(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(remotes, HasLen, 1)
 
-	head, err = r.Ref(core.HEAD, false)
+	head, err = r.Ref(plumbing.HEAD, false)
 	c.Assert(err, IsNil)
 	c.Assert(head, NotNil)
-	c.Assert(head.Type(), Equals, core.SymbolicReference)
+	c.Assert(head.Type(), Equals, plumbing.SymbolicReference)
 	c.Assert(head.Target().String(), Equals, "refs/heads/master")
 
 	branch, err := r.Ref(head.Target(), false)
@@ -91,13 +91,13 @@ func (s *RepositorySuite) TestClone(c *C) {
 	branch, err = r.Ref("refs/remotes/origin/master", false)
 	c.Assert(err, IsNil)
 	c.Assert(branch, NotNil)
-	c.Assert(branch.Type(), Equals, core.HashReference)
+	c.Assert(branch.Type(), Equals, plumbing.HashReference)
 	c.Assert(branch.Hash().String(), Equals, "6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
 
 	branch, err = r.Ref("refs/remotes/origin/branch", false)
 	c.Assert(err, IsNil)
 	c.Assert(branch, NotNil)
-	c.Assert(branch.Type(), Equals, core.HashReference)
+	c.Assert(branch.Type(), Equals, plumbing.HashReference)
 	c.Assert(branch.Hash().String(), Equals, "e8d3ffab552895c19b9fcf7aa264d277cde33881")
 }
 
@@ -105,7 +105,7 @@ func (s *RepositorySuite) TestCloneNonEmpty(c *C) {
 	r := NewMemoryRepository()
 
 	head, err := r.Head()
-	c.Assert(err, Equals, core.ErrReferenceNotFound)
+	c.Assert(err, Equals, plumbing.ErrReferenceNotFound)
 	c.Assert(head, IsNil)
 
 	o := &CloneOptions{URL: RepositoryFixture}
@@ -120,12 +120,12 @@ func (s *RepositorySuite) TestCloneSingleBranchAndNonHEAD(c *C) {
 	r := NewMemoryRepository()
 
 	head, err := r.Head()
-	c.Assert(err, Equals, core.ErrReferenceNotFound)
+	c.Assert(err, Equals, plumbing.ErrReferenceNotFound)
 	c.Assert(head, IsNil)
 
 	err = r.Clone(&CloneOptions{
 		URL:           RepositoryFixture,
-		ReferenceName: core.ReferenceName("refs/heads/branch"),
+		ReferenceName: plumbing.ReferenceName("refs/heads/branch"),
 		SingleBranch:  true,
 	})
 
@@ -135,10 +135,10 @@ func (s *RepositorySuite) TestCloneSingleBranchAndNonHEAD(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(remotes, HasLen, 1)
 
-	head, err = r.Ref(core.HEAD, false)
+	head, err = r.Ref(plumbing.HEAD, false)
 	c.Assert(err, IsNil)
 	c.Assert(head, NotNil)
-	c.Assert(head.Type(), Equals, core.SymbolicReference)
+	c.Assert(head.Type(), Equals, plumbing.SymbolicReference)
 	c.Assert(head.Target().String(), Equals, "refs/heads/branch")
 
 	branch, err := r.Ref(head.Target(), false)
@@ -149,7 +149,7 @@ func (s *RepositorySuite) TestCloneSingleBranchAndNonHEAD(c *C) {
 	branch, err = r.Ref("refs/remotes/origin/branch", false)
 	c.Assert(err, IsNil)
 	c.Assert(branch, NotNil)
-	c.Assert(branch.Type(), Equals, core.HashReference)
+	c.Assert(branch.Type(), Equals, plumbing.HashReference)
 	c.Assert(branch.Hash().String(), Equals, "e8d3ffab552895c19b9fcf7aa264d277cde33881")
 }
 
@@ -157,7 +157,7 @@ func (s *RepositorySuite) TestCloneSingleBranch(c *C) {
 	r := NewMemoryRepository()
 
 	head, err := r.Head()
-	c.Assert(err, Equals, core.ErrReferenceNotFound)
+	c.Assert(err, Equals, plumbing.ErrReferenceNotFound)
 	c.Assert(head, IsNil)
 
 	err = r.Clone(&CloneOptions{
@@ -171,10 +171,10 @@ func (s *RepositorySuite) TestCloneSingleBranch(c *C) {
 	c.Assert(err, IsNil)
 	c.Assert(remotes, HasLen, 1)
 
-	head, err = r.Ref(core.HEAD, false)
+	head, err = r.Ref(plumbing.HEAD, false)
 	c.Assert(err, IsNil)
 	c.Assert(head, NotNil)
-	c.Assert(head.Type(), Equals, core.SymbolicReference)
+	c.Assert(head.Type(), Equals, plumbing.SymbolicReference)
 	c.Assert(head.Target().String(), Equals, "refs/heads/master")
 
 	branch, err := r.Ref(head.Target(), false)
@@ -185,7 +185,7 @@ func (s *RepositorySuite) TestCloneSingleBranch(c *C) {
 	branch, err = r.Ref("refs/remotes/origin/master", false)
 	c.Assert(err, IsNil)
 	c.Assert(branch, NotNil)
-	c.Assert(branch.Type(), Equals, core.HashReference)
+	c.Assert(branch.Type(), Equals, plumbing.HashReference)
 	c.Assert(branch.Hash().String(), Equals, "6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
 }
 
@@ -193,13 +193,13 @@ func (s *RepositorySuite) TestCloneDetachedHEAD(c *C) {
 	r := NewMemoryRepository()
 	err := r.Clone(&CloneOptions{
 		URL:           RepositoryFixture,
-		ReferenceName: core.ReferenceName("refs/tags/v1.0.0"),
+		ReferenceName: plumbing.ReferenceName("refs/tags/v1.0.0"),
 	})
 
-	head, err := r.Ref(core.HEAD, false)
+	head, err := r.Ref(plumbing.HEAD, false)
 	c.Assert(err, IsNil)
 	c.Assert(head, NotNil)
-	c.Assert(head.Type(), Equals, core.HashReference)
+	c.Assert(head.Type(), Equals, plumbing.HashReference)
 	c.Assert(head.Hash().String(), Equals, "6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
 }
 
@@ -259,14 +259,14 @@ func (s *RepositorySuite) TestCommit(c *C) {
 
 	c.Assert(err, IsNil)
 
-	hash := core.NewHash("b8e471f58bcbca63b07bda20e428190409c2db47")
+	hash := plumbing.NewHash("b8e471f58bcbca63b07bda20e428190409c2db47")
 	commit, err := r.Commit(hash)
 	c.Assert(err, IsNil)
 
 	c.Assert(commit.Hash.IsZero(), Equals, false)
 	c.Assert(commit.Hash, Equals, commit.ID())
 	c.Assert(commit.Hash, Equals, hash)
-	c.Assert(commit.Type(), Equals, core.CommitObject)
+	c.Assert(commit.Type(), Equals, plumbing.CommitObject)
 
 	tree, err := commit.Tree()
 	c.Assert(err, IsNil)
@@ -292,7 +292,7 @@ func (s *RepositorySuite) TestCommits(c *C) {
 		count++
 		c.Assert(commit.Hash.IsZero(), Equals, false)
 		c.Assert(commit.Hash, Equals, commit.ID())
-		c.Assert(commit.Type(), Equals, core.CommitObject)
+		c.Assert(commit.Type(), Equals, plumbing.CommitObject)
 	}
 
 	c.Assert(count, Equals, 9)
@@ -303,13 +303,13 @@ func (s *RepositorySuite) TestTag(c *C) {
 	err := r.Clone(&CloneOptions{URL: "https://github.com/spinnaker/spinnaker.git"})
 	c.Assert(err, IsNil)
 
-	hash := core.NewHash("0a3fb06ff80156fb153bcdcc58b5e16c2d27625c")
+	hash := plumbing.NewHash("0a3fb06ff80156fb153bcdcc58b5e16c2d27625c")
 	tag, err := r.Tag(hash)
 	c.Assert(err, IsNil)
 
 	c.Assert(tag.Hash.IsZero(), Equals, false)
 	c.Assert(tag.Hash, Equals, hash)
-	c.Assert(tag.Type(), Equals, core.TagObject)
+	c.Assert(tag.Type(), Equals, plumbing.TagObject)
 }
 
 func (s *RepositorySuite) TestTags(c *C) {
@@ -324,13 +324,13 @@ func (s *RepositorySuite) TestTags(c *C) {
 	tags.ForEach(func(tag *Tag) error {
 		count++
 		c.Assert(tag.Hash.IsZero(), Equals, false)
-		c.Assert(tag.Type(), Equals, core.TagObject)
+		c.Assert(tag.Type(), Equals, plumbing.TagObject)
 
 		return nil
 	})
 
 	refs, _ := r.Refs()
-	refs.ForEach(func(ref *core.Reference) error {
+	refs.ForEach(func(ref *plumbing.Reference) error {
 		return nil
 	})
 
@@ -352,13 +352,13 @@ func (s *RepositorySuite) TestRef(c *C) {
 	err := r.Clone(&CloneOptions{URL: RepositoryFixture})
 	c.Assert(err, IsNil)
 
-	ref, err := r.Ref(core.HEAD, false)
+	ref, err := r.Ref(plumbing.HEAD, false)
 	c.Assert(err, IsNil)
-	c.Assert(ref.Name(), Equals, core.HEAD)
+	c.Assert(ref.Name(), Equals, plumbing.HEAD)
 
-	ref, err = r.Ref(core.HEAD, true)
+	ref, err = r.Ref(plumbing.HEAD, true)
 	c.Assert(err, IsNil)
-	c.Assert(ref.Name(), Equals, core.ReferenceName("refs/heads/master"))
+	c.Assert(ref.Name(), Equals, plumbing.ReferenceName("refs/heads/master"))
 }
 
 func (s *RepositorySuite) TestRefs(c *C) {
@@ -378,13 +378,13 @@ func (s *RepositorySuite) TestObject(c *C) {
 	err := r.Clone(&CloneOptions{URL: "https://github.com/spinnaker/spinnaker.git"})
 	c.Assert(err, IsNil)
 
-	hash := core.NewHash("0a3fb06ff80156fb153bcdcc58b5e16c2d27625c")
+	hash := plumbing.NewHash("0a3fb06ff80156fb153bcdcc58b5e16c2d27625c")
 	tag, err := r.Tag(hash)
 	c.Assert(err, IsNil)
 
 	c.Assert(tag.Hash.IsZero(), Equals, false)
 	c.Assert(tag.Hash, Equals, hash)
-	c.Assert(tag.Type(), Equals, core.TagObject)
+	c.Assert(tag.Type(), Equals, plumbing.TagObject)
 }
 
 func (s *RepositorySuite) TestObjectNotFound(c *C) {
@@ -392,8 +392,8 @@ func (s *RepositorySuite) TestObjectNotFound(c *C) {
 	err := r.Clone(&CloneOptions{URL: "https://github.com/git-fixtures/basic.git"})
 	c.Assert(err, IsNil)
 
-	hash := core.NewHash("0a3fb06ff80156fb153bcdcc58b5e16c2d27625c")
-	tag, err := r.Object(core.TagObject, hash)
-	c.Assert(err, DeepEquals, core.ErrObjectNotFound)
+	hash := plumbing.NewHash("0a3fb06ff80156fb153bcdcc58b5e16c2d27625c")
+	tag, err := r.Object(plumbing.TagObject, hash)
+	c.Assert(err, DeepEquals, plumbing.ErrObjectNotFound)
 	c.Assert(tag, IsNil)
 }
diff --git a/storage/filesystem/config.go b/storage/filesystem/config.go
index 4b47937..510f51c 100644
--- a/storage/filesystem/config.go
+++ b/storage/filesystem/config.go
@@ -4,7 +4,7 @@ import (
 	"os"
 
 	"gopkg.in/src-d/go-git.v4/config"
-	gitconfig "gopkg.in/src-d/go-git.v4/formats/config"
+	gitconfig "gopkg.in/src-d/go-git.v4/plumbing/format/config"
 	"gopkg.in/src-d/go-git.v4/storage/filesystem/internal/dotgit"
 )
 
diff --git a/storage/filesystem/internal/dotgit/dotgit.go b/storage/filesystem/internal/dotgit/dotgit.go
index 6606153..3a6227e 100644
--- a/storage/filesystem/internal/dotgit/dotgit.go
+++ b/storage/filesystem/internal/dotgit/dotgit.go
@@ -9,7 +9,7 @@ import (
 	"os"
 	"strings"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 	"gopkg.in/src-d/go-git.v4/utils/fs"
 )
 
@@ -76,7 +76,7 @@ func (d *DotGit) NewObjectPack() (*PackWriter, error) {
 }
 
 // ObjectPacks returns the list of availables packfiles
-func (d *DotGit) ObjectPacks() ([]core.Hash, error) {
+func (d *DotGit) ObjectPacks() ([]plumbing.Hash, error) {
 	packDir := d.fs.Join(objectsPath, packPath)
 	files, err := d.fs.ReadDir(packDir)
 	if err != nil {
@@ -87,14 +87,14 @@ func (d *DotGit) ObjectPacks() ([]core.Hash, error) {
 		return nil, err
 	}
 
-	var packs []core.Hash
+	var packs []plumbing.Hash
 	for _, f := range files {
 		if !strings.HasSuffix(f.Name(), packExt) {
 			continue
 		}
 
 		n := f.Name()
-		h := core.NewHash(n[5 : len(n)-5]) //pack-(hash).pack
+		h := plumbing.NewHash(n[5 : len(n)-5]) //pack-(hash).pack
 		packs = append(packs, h)
 
 	}
@@ -103,7 +103,7 @@ func (d *DotGit) ObjectPacks() ([]core.Hash, error) {
 }
 
 // ObjectPack returns a fs.File of the given packfile
-func (d *DotGit) ObjectPack(hash core.Hash) (fs.File, error) {
+func (d *DotGit) ObjectPack(hash plumbing.Hash) (fs.File, error) {
 	file := d.fs.Join(objectsPath, packPath, fmt.Sprintf("pack-%s.pack", hash.String()))
 
 	pack, err := d.fs.Open(file)
@@ -119,7 +119,7 @@ func (d *DotGit) ObjectPack(hash core.Hash) (fs.File, error) {
 }
 
 // ObjectPackIdx returns a fs.File of the index file for a given packfile
-func (d *DotGit) ObjectPackIdx(hash core.Hash) (fs.File, error) {
+func (d *DotGit) ObjectPackIdx(hash plumbing.Hash) (fs.File, error) {
 	file := d.fs.Join(objectsPath, packPath, fmt.Sprintf("pack-%s.idx", hash.String()))
 	idx, err := d.fs.Open(file)
 	if err != nil {
@@ -140,7 +140,7 @@ func (d *DotGit) NewObject() (*ObjectWriter, error) {
 
 // Objects returns a slice with the hashes of objects found under the
 // .git/objects/ directory.
-func (d *DotGit) Objects() ([]core.Hash, error) {
+func (d *DotGit) Objects() ([]plumbing.Hash, error) {
 	files, err := d.fs.ReadDir(objectsPath)
 	if err != nil {
 		if os.IsNotExist(err) {
@@ -150,7 +150,7 @@ func (d *DotGit) Objects() ([]core.Hash, error) {
 		return nil, err
 	}
 
-	var objects []core.Hash
+	var objects []plumbing.Hash
 	for _, f := range files {
 		if f.IsDir() && len(f.Name()) == 2 && isHex(f.Name()) {
 			base := f.Name()
@@ -160,7 +160,7 @@ func (d *DotGit) Objects() ([]core.Hash, error) {
 			}
 
 			for _, o := range d {
-				objects = append(objects, core.NewHash(base+o.Name()))
+				objects = append(objects, plumbing.NewHash(base+o.Name()))
 			}
 		}
 	}
@@ -169,19 +169,19 @@ func (d *DotGit) Objects() ([]core.Hash, error) {
 }
 
 // Object return a fs.File poiting the object file, if exists
-func (d *DotGit) Object(h core.Hash) (fs.File, error) {
+func (d *DotGit) Object(h plumbing.Hash) (fs.File, error) {
 	hash := h.String()
 	file := d.fs.Join(objectsPath, hash[0:2], hash[2:40])
 
 	return d.fs.Open(file)
 }
 
-func (d *DotGit) SetRef(r *core.Reference) error {
+func (d *DotGit) SetRef(r *plumbing.Reference) error {
 	var content string
 	switch r.Type() {
-	case core.SymbolicReference:
+	case plumbing.SymbolicReference:
 		content = fmt.Sprintf("ref: %s\n", r.Target())
-	case core.HashReference:
+	case plumbing.HashReference:
 		content = fmt.Sprintln(r.Hash().String())
 	}
 
@@ -198,8 +198,8 @@ func (d *DotGit) SetRef(r *core.Reference) error {
 
 // Refs scans the git directory collecting references, which it returns.
 // Symbolic references are resolved and included in the output.
-func (d *DotGit) Refs() ([]*core.Reference, error) {
-	var refs []*core.Reference
+func (d *DotGit) Refs() ([]*plumbing.Reference, error) {
+	var refs []*plumbing.Reference
 	if err := d.addRefsFromPackedRefs(&refs); err != nil {
 		return nil, err
 	}
@@ -216,7 +216,7 @@ func (d *DotGit) Refs() ([]*core.Reference, error) {
 }
 
 // Ref returns the reference for a given reference name.
-func (d *DotGit) Ref(name core.ReferenceName) (*core.Reference, error) {
+func (d *DotGit) Ref(name plumbing.ReferenceName) (*plumbing.Reference, error) {
 	ref, err := d.readReferenceFile(".", name.String())
 	if err == nil {
 		return ref, nil
@@ -233,10 +233,10 @@ func (d *DotGit) Ref(name core.ReferenceName) (*core.Reference, error) {
 		}
 	}
 
-	return nil, core.ErrReferenceNotFound
+	return nil, plumbing.ErrReferenceNotFound
 }
 
-func (d *DotGit) addRefsFromPackedRefs(refs *[]*core.Reference) (err error) {
+func (d *DotGit) addRefsFromPackedRefs(refs *[]*plumbing.Reference) (err error) {
 	f, err := d.fs.Open(packedRefsPath)
 	if err != nil {
 		if os.IsNotExist(err) {
@@ -267,7 +267,7 @@ func (d *DotGit) addRefsFromPackedRefs(refs *[]*core.Reference) (err error) {
 }
 
 // process lines from a packed-refs file
-func (d *DotGit) processLine(line string) (*core.Reference, error) {
+func (d *DotGit) processLine(line string) (*plumbing.Reference, error) {
 	switch line[0] {
 	case '#': // comment - ignore
 		return nil, nil
@@ -279,15 +279,15 @@ func (d *DotGit) processLine(line string) (*core.Reference, error) {
 			return nil, ErrPackedRefsBadFormat
 		}
 
-		return core.NewReferenceFromStrings(ws[1], ws[0]), nil
+		return plumbing.NewReferenceFromStrings(ws[1], ws[0]), nil
 	}
 }
 
-func (d *DotGit) addRefsFromRefDir(refs *[]*core.Reference) error {
+func (d *DotGit) addRefsFromRefDir(refs *[]*plumbing.Reference) error {
 	return d.walkReferencesTree(refs, refsPath)
 }
 
-func (d *DotGit) walkReferencesTree(refs *[]*core.Reference, relPath string) error {
+func (d *DotGit) walkReferencesTree(refs *[]*plumbing.Reference, relPath string) error {
 	files, err := d.fs.ReadDir(relPath)
 	if err != nil {
 		if os.IsNotExist(err) {
@@ -320,7 +320,7 @@ func (d *DotGit) walkReferencesTree(refs *[]*core.Reference, relPath string) err
 	return nil
 }
 
-func (d *DotGit) addRefFromHEAD(refs *[]*core.Reference) error {
+func (d *DotGit) addRefFromHEAD(refs *[]*plumbing.Reference) error {
 	ref, err := d.readReferenceFile(".", "HEAD")
 	if err != nil {
 		if os.IsNotExist(err) {
@@ -334,7 +334,7 @@ func (d *DotGit) addRefFromHEAD(refs *[]*core.Reference) error {
 	return nil
 }
 
-func (d *DotGit) readReferenceFile(refsPath, refFile string) (ref *core.Reference, err error) {
+func (d *DotGit) readReferenceFile(refsPath, refFile string) (ref *plumbing.Reference, err error) {
 	path := d.fs.Join(refsPath, refFile)
 
 	f, err := d.fs.Open(path)
@@ -354,7 +354,7 @@ func (d *DotGit) readReferenceFile(refsPath, refFile string) (ref *core.Referenc
 	}
 
 	line := strings.TrimSpace(string(b))
-	return core.NewReferenceFromStrings(refFile, line), nil
+	return plumbing.NewReferenceFromStrings(refFile, line), nil
 }
 
 func isHex(s string) bool {
diff --git a/storage/filesystem/internal/dotgit/dotgit_test.go b/storage/filesystem/internal/dotgit/dotgit_test.go
index a5d25e3..bcd8d96 100644
--- a/storage/filesystem/internal/dotgit/dotgit_test.go
+++ b/storage/filesystem/internal/dotgit/dotgit_test.go
@@ -7,8 +7,8 @@ import (
 	"strings"
 	"testing"
 
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/fixtures"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 	osfs "gopkg.in/src-d/go-git.v4/utils/fs/os"
 
 	. "gopkg.in/check.v1"
@@ -30,21 +30,21 @@ func (s *SuiteDotGit) TestSetRefs(c *C) {
 	fs := osfs.New(tmp)
 	dir := New(fs)
 
-	err = dir.SetRef(core.NewReferenceFromStrings(
+	err = dir.SetRef(plumbing.NewReferenceFromStrings(
 		"refs/heads/foo",
 		"e8d3ffab552895c19b9fcf7aa264d277cde33881",
 	))
 
 	c.Assert(err, IsNil)
 
-	err = dir.SetRef(core.NewReferenceFromStrings(
+	err = dir.SetRef(plumbing.NewReferenceFromStrings(
 		"refs/heads/symbolic",
 		"ref: refs/heads/foo",
 	))
 
 	c.Assert(err, IsNil)
 
-	err = dir.SetRef(core.NewReferenceFromStrings(
+	err = dir.SetRef(plumbing.NewReferenceFromStrings(
 		"bar",
 		"e8d3ffab552895c19b9fcf7aa264d277cde33881",
 	))
@@ -103,7 +103,7 @@ func (s *SuiteDotGit) TestRefsFromReferenceFile(c *C) {
 
 	ref := findReference(refs, "refs/remotes/origin/HEAD")
 	c.Assert(ref, NotNil)
-	c.Assert(ref.Type(), Equals, core.SymbolicReference)
+	c.Assert(ref.Type(), Equals, plumbing.SymbolicReference)
 	c.Assert(string(ref.Target()), Equals, "refs/remotes/origin/master")
 
 }
@@ -117,7 +117,7 @@ func (s *SuiteDotGit) TestRefsFromHEADFile(c *C) {
 
 	ref := findReference(refs, "HEAD")
 	c.Assert(ref, NotNil)
-	c.Assert(ref.Type(), Equals, core.SymbolicReference)
+	c.Assert(ref.Type(), Equals, plumbing.SymbolicReference)
 	c.Assert(string(ref.Target()), Equals, "refs/heads/master")
 }
 
@@ -130,8 +130,8 @@ func (s *SuiteDotGit) TestConfig(c *C) {
 	c.Assert(filepath.Base(file.Filename()), Equals, "config")
 }
 
-func findReference(refs []*core.Reference, name string) *core.Reference {
-	n := core.ReferenceName(name)
+func findReference(refs []*plumbing.Reference, name string) *plumbing.Reference {
+	n := plumbing.ReferenceName(name)
 	for _, ref := range refs {
 		if ref.Name() == n {
 			return ref
@@ -176,11 +176,11 @@ func (s *SuiteDotGit) TestObjectPackNotFound(c *C) {
 	fs := fixtures.Basic().ByTag(".git").One().DotGit()
 	dir := New(fs)
 
-	pack, err := dir.ObjectPack(core.ZeroHash)
+	pack, err := dir.ObjectPack(plumbing.ZeroHash)
 	c.Assert(err, Equals, ErrPackfileNotFound)
 	c.Assert(pack, IsNil)
 
-	idx, err := dir.ObjectPackIdx(core.ZeroHash)
+	idx, err := dir.ObjectPackIdx(plumbing.ZeroHash)
 	c.Assert(idx, IsNil)
 }
 
@@ -194,7 +194,7 @@ func (s *SuiteDotGit) TestNewObject(c *C) {
 	w, err := dir.NewObject()
 	c.Assert(err, IsNil)
 
-	err = w.WriteHeader(core.BlobObject, 14)
+	err = w.WriteHeader(plumbing.BlobObject, 14)
 	n, err := w.Write([]byte("this is a test"))
 	c.Assert(err, IsNil)
 	c.Assert(n, Equals, 14)
@@ -225,7 +225,7 @@ func (s *SuiteDotGit) TestObject(c *C) {
 	fs := fixtures.ByTag(".git").ByTag("unpacked").One().DotGit()
 	dir := New(fs)
 
-	hash := core.NewHash("03db8e1fbe133a480f2867aac478fd866686d69e")
+	hash := plumbing.NewHash("03db8e1fbe133a480f2867aac478fd866686d69e")
 	file, err := dir.Object(hash)
 	c.Assert(err, IsNil)
 	c.Assert(strings.HasSuffix(
@@ -238,7 +238,7 @@ func (s *SuiteDotGit) TestObjectNotFound(c *C) {
 	fs := fixtures.ByTag(".git").ByTag("unpacked").One().DotGit()
 	dir := New(fs)
 
-	hash := core.NewHash("not-found-object")
+	hash := plumbing.NewHash("not-found-object")
 	file, err := dir.Object(hash)
 	c.Assert(err, NotNil)
 	c.Assert(file, IsNil)
diff --git a/storage/filesystem/internal/dotgit/writers.go b/storage/filesystem/internal/dotgit/writers.go
index 4641572..d3d3b43 100644
--- a/storage/filesystem/internal/dotgit/writers.go
+++ b/storage/filesystem/internal/dotgit/writers.go
@@ -5,20 +5,20 @@ import (
 	"io"
 	"sync/atomic"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/idxfile"
-	"gopkg.in/src-d/go-git.v4/formats/objfile"
-	"gopkg.in/src-d/go-git.v4/formats/packfile"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/idxfile"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/objfile"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packfile"
 	"gopkg.in/src-d/go-git.v4/utils/fs"
 )
 
 type PackWriter struct {
-	Notify func(h core.Hash, i idxfile.Idxfile)
+	Notify func(h plumbing.Hash, i idxfile.Idxfile)
 
 	fs       fs.Filesystem
 	fr, fw   fs.File
 	synced   *syncedReader
-	checksum core.Hash
+	checksum plumbing.Hash
 	index    idxfile.Idxfile
 	result   chan error
 }
diff --git a/storage/filesystem/object.go b/storage/filesystem/object.go
index f780183..5868748 100644
--- a/storage/filesystem/object.go
+++ b/storage/filesystem/object.go
@@ -4,10 +4,11 @@ import (
 	"io"
 	"os"
 
-	"gopkg.in/src-d/go-git.v4/core"
-	"gopkg.in/src-d/go-git.v4/formats/idxfile"
-	"gopkg.in/src-d/go-git.v4/formats/objfile"
-	"gopkg.in/src-d/go-git.v4/formats/packfile"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/idxfile"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/objfile"
+	"gopkg.in/src-d/go-git.v4/plumbing/format/packfile"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 	"gopkg.in/src-d/go-git.v4/storage/filesystem/internal/dotgit"
 	"gopkg.in/src-d/go-git.v4/storage/memory"
 	"gopkg.in/src-d/go-git.v4/utils/fs"
@@ -15,13 +16,13 @@ import (
 
 type ObjectStorage struct {
 	dir   *dotgit.DotGit
-	index map[core.Hash]index
+	index map[plumbing.Hash]index
 }
 
 func newObjectStorage(dir *dotgit.DotGit) (ObjectStorage, error) {
 	s := ObjectStorage{
 		dir:   dir,
-		index: make(map[core.Hash]index, 0),
+		index: make(map[plumbing.Hash]index, 0),
 	}
 
 	return s, s.loadIdxFiles()
@@ -42,7 +43,7 @@ func (s *ObjectStorage) loadIdxFiles() error {
 	return nil
 }
 
-func (s *ObjectStorage) loadIdxFile(h core.Hash) error {
+func (s *ObjectStorage) loadIdxFile(h plumbing.Hash) error {
 	idx, err := s.dir.ObjectPackIdx(h)
 	if err != nil {
 		return err
@@ -52,8 +53,8 @@ func (s *ObjectStorage) loadIdxFile(h core.Hash) error {
 	return s.index[h].Decode(idx)
 }
 
-func (s *ObjectStorage) NewObject() core.Object {
-	return &core.MemoryObject{}
+func (s *ObjectStorage) NewObject() plumbing.Object {
+	return &plumbing.MemoryObject{}
 }
 
 func (s *ObjectStorage) PackfileWriter() (io.WriteCloser, error) {
@@ -62,7 +63,7 @@ func (s *ObjectStorage) PackfileWriter() (io.WriteCloser, error) {
 		return nil, err
 	}
 
-	w.Notify = func(h core.Hash, idx idxfile.Idxfile) {
+	w.Notify = func(h plumbing.Hash, idx idxfile.Idxfile) {
 		s.index[h] = make(index)
 		for _, e := range idx.Entries {
 			s.index[h][e.Hash] = int64(e.Offset)
@@ -73,31 +74,31 @@ func (s *ObjectStorage) PackfileWriter() (io.WriteCloser, error) {
 }
 
 // Set adds a new object to the storage.
-func (s *ObjectStorage) SetObject(o core.Object) (core.Hash, error) {
-	if o.Type() == core.OFSDeltaObject || o.Type() == core.REFDeltaObject {
-		return core.ZeroHash, core.ErrInvalidType
+func (s *ObjectStorage) SetObject(o plumbing.Object) (plumbing.Hash, error) {
+	if o.Type() == plumbing.OFSDeltaObject || o.Type() == plumbing.REFDeltaObject {
+		return plumbing.ZeroHash, plumbing.ErrInvalidType
 	}
 
 	ow, err := s.dir.NewObject()
 	if err != nil {
-		return core.ZeroHash, err
+		return plumbing.ZeroHash, err
 	}
 
 	defer ow.Close()
 
 	or, err := o.Reader()
 	if err != nil {
-		return core.ZeroHash, err
+		return plumbing.ZeroHash, err
 	}
 
 	defer or.Close()
 
 	if err := ow.WriteHeader(o.Type(), o.Size()); err != nil {
-		return core.ZeroHash, err
+		return plumbing.ZeroHash, err
 	}
 
 	if _, err := io.Copy(ow, or); err != nil {
-		return core.ZeroHash, err
+		return plumbing.ZeroHash, err
 	}
 
 	return o.Hash(), nil
@@ -105,9 +106,9 @@ func (s *ObjectStorage) SetObject(o core.Object) (core.Hash, error) {
 
 // Get returns the object with the given hash, by searching for it in
 // the packfile and the git object directories.
-func (s *ObjectStorage) Object(t core.ObjectType, h core.Hash) (core.Object, error) {
+func (s *ObjectStorage) Object(t plumbing.ObjectType, h plumbing.Hash) (plumbing.Object, error) {
 	obj, err := s.getFromUnpacked(h)
-	if err == core.ErrObjectNotFound {
+	if err == plumbing.ErrObjectNotFound {
 		obj, err = s.getFromPackfile(h)
 	}
 
@@ -115,18 +116,18 @@ func (s *ObjectStorage) Object(t core.ObjectType, h core.Hash) (core.Object, err
 		return nil, err
 	}
 
-	if core.AnyObject != t && obj.Type() != t {
-		return nil, core.ErrObjectNotFound
+	if plumbing.AnyObject != t && obj.Type() != t {
+		return nil, plumbing.ErrObjectNotFound
 	}
 
 	return obj, nil
 }
 
-func (s *ObjectStorage) getFromUnpacked(h core.Hash) (obj core.Object, err error) {
+func (s *ObjectStorage) getFromUnpacked(h plumbing.Hash) (obj plumbing.Object, err error) {
 	f, err := s.dir.Object(h)
 	if err != nil {
 		if os.IsNotExist(err) {
-			return nil, core.ErrObjectNotFound
+			return nil, plumbing.ErrObjectNotFound
 		}
 
 		return nil, err
@@ -160,10 +161,10 @@ func (s *ObjectStorage) getFromUnpacked(h core.Hash) (obj core.Object, err error
 
 // Get returns the object with the given hash, by searching for it in
 // the packfile.
-func (s *ObjectStorage) getFromPackfile(h core.Hash) (core.Object, error) {
+func (s *ObjectStorage) getFromPackfile(h plumbing.Hash) (plumbing.Object, error) {
 	pack, offset := s.findObjectInPackfile(h)
 	if offset == -1 {
-		return nil, core.ErrObjectNotFound
+		return nil, plumbing.ErrObjectNotFound
 	}
 
 	f, err := s.dir.ObjectPack(pack)
@@ -183,26 +184,26 @@ func (s *ObjectStorage) getFromPackfile(h core.Hash) (core.Object, error) {
 	return d.ReadObjectAt(offset)
 }
 
-func (s *ObjectStorage) findObjectInPackfile(h core.Hash) (core.Hash, int64) {
+func (s *ObjectStorage) findObjectInPackfile(h plumbing.Hash) (plumbing.Hash, int64) {
 	for packfile, index := range s.index {
 		if offset, ok := index[h]; ok {
 			return packfile, offset
 		}
 	}
 
-	return core.ZeroHash, -1
+	return plumbing.ZeroHash, -1
 }
 
 // Iter returns an iterator for all the objects in the packfile with the
 // given type.
-func (s *ObjectStorage) IterObjects(t core.ObjectType) (core.ObjectIter, error) {
+func (s *ObjectStorage) IterObjects(t plumbing.ObjectType) (storer.ObjectIter, error) {
 	objects, err := s.dir.Objects()
 	if err != nil {
 		return nil, err
 	}
 
-	seen := make(map[core.Hash]bool, 0)
-	var iters []core.ObjectIter
+	seen := make(map[plumbing.Hash]bool, 0)
+	var iters []storer.ObjectIter
 	if len(objects) != 0 {
 		iters = append(iters, &objectsIter{s: s, t: t, h: objects})
 		seen = hashListAsMap(objects)
@@ -214,17 +215,17 @@ func (s *ObjectStorage) IterObjects(t core.ObjectType) (core.ObjectIter, error)
 	}
 
 	iters = append(iters, packi...)
-	return core.NewMultiObjectIter(iters), nil
+	return storer.NewMultiObjectIter(iters), nil
 }
 
 func (s *ObjectStorage) buildPackfileIters(
-	t core.ObjectType, seen map[core.Hash]bool) ([]core.ObjectIter, error) {
+	t plumbing.ObjectType, seen map[plumbing.Hash]bool) ([]storer.ObjectIter, error) {
 	packs, err := s.dir.ObjectPacks()
 	if err != nil {
 		return nil, err
 	}
 
-	var iters []core.ObjectIter
+	var iters []storer.ObjectIter
 	for _, h := range packs {
 		pack, err := s.dir.ObjectPack(h)
 		if err != nil {
@@ -242,7 +243,7 @@ func (s *ObjectStorage) buildPackfileIters(
 	return iters, nil
 }
 
-type index map[core.Hash]int64
+type index map[plumbing.Hash]int64
 
 func (i index) Decode(r io.Reader) error {
 	idx := &idxfile.Idxfile{}
@@ -262,14 +263,14 @@ func (i index) Decode(r io.Reader) error {
 type packfileIter struct {
 	f fs.File
 	d *packfile.Decoder
-	t core.ObjectType
+	t plumbing.ObjectType
 
-	seen     map[core.Hash]bool
+	seen     map[plumbing.Hash]bool
 	position uint32
 	total    uint32
 }
 
-func newPackfileIter(f fs.File, t core.ObjectType, seen map[core.Hash]bool) (core.ObjectIter, error) {
+func newPackfileIter(f fs.File, t plumbing.ObjectType, seen map[plumbing.Hash]bool) (storer.ObjectIter, error) {
 	s := packfile.NewScanner(f)
 	_, total, err := s.Header()
 	if err != nil {
@@ -291,7 +292,7 @@ func newPackfileIter(f fs.File, t core.ObjectType, seen map[core.Hash]bool) (cor
 	}, nil
 }
 
-func (iter *packfileIter) Next() (core.Object, error) {
+func (iter *packfileIter) Next() (plumbing.Object, error) {
 	if iter.position >= iter.total {
 		return nil, io.EOF
 	}
@@ -306,7 +307,7 @@ func (iter *packfileIter) Next() (core.Object, error) {
 		return iter.Next()
 	}
 
-	if iter.t != core.AnyObject && iter.t != obj.Type() {
+	if iter.t != plumbing.AnyObject && iter.t != obj.Type() {
 		return iter.Next()
 	}
 
@@ -314,7 +315,7 @@ func (iter *packfileIter) Next() (core.Object, error) {
 }
 
 // ForEach is never called since is used inside of a MultiObjectIterator
-func (iter *packfileIter) ForEach(cb func(core.Object) error) error {
+func (iter *packfileIter) ForEach(cb func(plumbing.Object) error) error {
 	return nil
 }
 
@@ -325,11 +326,11 @@ func (iter *packfileIter) Close() {
 
 type objectsIter struct {
 	s *ObjectStorage
-	t core.ObjectType
-	h []core.Hash
+	t plumbing.ObjectType
+	h []plumbing.Hash
 }
 
-func (iter *objectsIter) Next() (core.Object, error) {
+func (iter *objectsIter) Next() (plumbing.Object, error) {
 	if len(iter.h) == 0 {
 		return nil, io.EOF
 	}
@@ -341,7 +342,7 @@ func (iter *objectsIter) Next() (core.Object, error) {
 		return nil, err
 	}
 
-	if iter.t != core.AnyObject && iter.t != obj.Type() {
+	if iter.t != plumbing.AnyObject && iter.t != obj.Type() {
 		return iter.Next()
 	}
 
@@ -349,16 +350,16 @@ func (iter *objectsIter) Next() (core.Object, error) {
 }
 
 // ForEach is never called since is used inside of a MultiObjectIterator
-func (iter *objectsIter) ForEach(cb func(core.Object) error) error {
+func (iter *objectsIter) ForEach(cb func(plumbing.Object) error) error {
 	return nil
 }
 
 func (iter *objectsIter) Close() {
-	iter.h = []core.Hash{}
+	iter.h = []plumbing.Hash{}
 }
 
-func hashListAsMap(l []core.Hash) map[core.Hash]bool {
-	m := make(map[core.Hash]bool, len(l))
+func hashListAsMap(l []plumbing.Hash) map[plumbing.Hash]bool {
+	m := make(map[plumbing.Hash]bool, len(l))
 	for _, h := range l {
 		m[h] = true
 	}
diff --git a/storage/filesystem/object_test.go b/storage/filesystem/object_test.go
index 38e4b6d..f839420 100644
--- a/storage/filesystem/object_test.go
+++ b/storage/filesystem/object_test.go
@@ -1,8 +1,8 @@
 package filesystem
 
 import (
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/fixtures"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 	"gopkg.in/src-d/go-git.v4/storage/filesystem/internal/dotgit"
 
 	. "gopkg.in/check.v1"
@@ -19,8 +19,8 @@ func (s *FsSuite) TestGetFromObjectFile(c *C) {
 	o, err := newObjectStorage(dotgit.New(fs))
 	c.Assert(err, IsNil)
 
-	expected := core.NewHash("f3dfe29d268303fc6e1bbce268605fc99573406e")
-	obj, err := o.Object(core.AnyObject, expected)
+	expected := plumbing.NewHash("f3dfe29d268303fc6e1bbce268605fc99573406e")
+	obj, err := o.Object(plumbing.AnyObject, expected)
 	c.Assert(err, IsNil)
 	c.Assert(obj.Hash(), Equals, expected)
 }
@@ -31,8 +31,8 @@ func (s *FsSuite) TestGetFromPackfile(c *C) {
 		o, err := newObjectStorage(dotgit.New(fs))
 		c.Assert(err, IsNil)
 
-		expected := core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
-		obj, err := o.Object(core.AnyObject, expected)
+		expected := plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5")
+		obj, err := o.Object(plumbing.AnyObject, expected)
 		c.Assert(err, IsNil)
 		c.Assert(obj.Hash(), Equals, expected)
 	})
@@ -43,12 +43,12 @@ func (s *FsSuite) TestGetFromPackfileMultiplePackfiles(c *C) {
 	o, err := newObjectStorage(dotgit.New(fs))
 	c.Assert(err, IsNil)
 
-	expected := core.NewHash("8d45a34641d73851e01d3754320b33bb5be3c4d3")
+	expected := plumbing.NewHash("8d45a34641d73851e01d3754320b33bb5be3c4d3")
 	obj, err := o.getFromPackfile(expected)
 	c.Assert(err, IsNil)
 	c.Assert(obj.Hash(), Equals, expected)
 
-	expected = core.NewHash("e9cfa4c9ca160546efd7e8582ec77952a27b17db")
+	expected = plumbing.NewHash("e9cfa4c9ca160546efd7e8582ec77952a27b17db")
 	obj, err = o.getFromPackfile(expected)
 	c.Assert(err, IsNil)
 	c.Assert(obj.Hash(), Equals, expected)
@@ -60,11 +60,11 @@ func (s *FsSuite) TestIter(c *C) {
 		o, err := newObjectStorage(dotgit.New(fs))
 		c.Assert(err, IsNil)
 
-		iter, err := o.IterObjects(core.AnyObject)
+		iter, err := o.IterObjects(plumbing.AnyObject)
 		c.Assert(err, IsNil)
 
 		var count int32
-		err = iter.ForEach(func(o core.Object) error {
+		err = iter.ForEach(func(o plumbing.Object) error {
 			count++
 			return nil
 		})
@@ -80,11 +80,11 @@ func (s *FsSuite) TestIterWithType(c *C) {
 		o, err := newObjectStorage(dotgit.New(fs))
 		c.Assert(err, IsNil)
 
-		iter, err := o.IterObjects(core.CommitObject)
+		iter, err := o.IterObjects(plumbing.CommitObject)
 		c.Assert(err, IsNil)
 
-		err = iter.ForEach(func(o core.Object) error {
-			c.Assert(o.Type(), Equals, core.CommitObject)
+		err = iter.ForEach(func(o plumbing.Object) error {
+			c.Assert(o.Type(), Equals, plumbing.CommitObject)
 			return nil
 		})
 
diff --git a/storage/filesystem/reference.go b/storage/filesystem/reference.go
index 0015859..93da68c 100644
--- a/storage/filesystem/reference.go
+++ b/storage/filesystem/reference.go
@@ -1,7 +1,8 @@
 package filesystem
 
 import (
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 	"gopkg.in/src-d/go-git.v4/storage/filesystem/internal/dotgit"
 )
 
@@ -9,19 +10,19 @@ type ReferenceStorage struct {
 	dir *dotgit.DotGit
 }
 
-func (r *ReferenceStorage) SetReference(ref *core.Reference) error {
+func (r *ReferenceStorage) SetReference(ref *plumbing.Reference) error {
 	return r.dir.SetRef(ref)
 }
 
-func (r *ReferenceStorage) Reference(n core.ReferenceName) (*core.Reference, error) {
+func (r *ReferenceStorage) Reference(n plumbing.ReferenceName) (*plumbing.Reference, error) {
 	return r.dir.Ref(n)
 }
 
-func (r *ReferenceStorage) IterReferences() (core.ReferenceIter, error) {
+func (r *ReferenceStorage) IterReferences() (storer.ReferenceIter, error) {
 	refs, err := r.dir.Refs()
 	if err != nil {
 		return nil, err
 	}
 
-	return core.NewReferenceSliceIter(refs), nil
+	return storer.NewReferenceSliceIter(refs), nil
 }
diff --git a/storage/memory/storage.go b/storage/memory/storage.go
index 8141cfc..a7a2150 100644
--- a/storage/memory/storage.go
+++ b/storage/memory/storage.go
@@ -5,7 +5,8 @@ import (
 	"fmt"
 
 	"gopkg.in/src-d/go-git.v4/config"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 )
 
 var ErrUnsupportedObjectType = fmt.Errorf("unsupported object type")
@@ -26,11 +27,11 @@ func NewStorage() *Storage {
 		ReferenceStorage: make(ReferenceStorage, 0),
 		ConfigStorage:    ConfigStorage{},
 		ObjectStorage: ObjectStorage{
-			Objects: make(map[core.Hash]core.Object, 0),
-			Commits: make(map[core.Hash]core.Object, 0),
-			Trees:   make(map[core.Hash]core.Object, 0),
-			Blobs:   make(map[core.Hash]core.Object, 0),
-			Tags:    make(map[core.Hash]core.Object, 0),
+			Objects: make(map[plumbing.Hash]plumbing.Object, 0),
+			Commits: make(map[plumbing.Hash]plumbing.Object, 0),
+			Trees:   make(map[plumbing.Hash]plumbing.Object, 0),
+			Blobs:   make(map[plumbing.Hash]plumbing.Object, 0),
+			Tags:    make(map[plumbing.Hash]plumbing.Object, 0),
 		},
 	}
 }
@@ -57,29 +58,29 @@ func (c *ConfigStorage) Config() (*config.Config, error) {
 }
 
 type ObjectStorage struct {
-	Objects map[core.Hash]core.Object
-	Commits map[core.Hash]core.Object
-	Trees   map[core.Hash]core.Object
-	Blobs   map[core.Hash]core.Object
-	Tags    map[core.Hash]core.Object
+	Objects map[plumbing.Hash]plumbing.Object
+	Commits map[plumbing.Hash]plumbing.Object
+	Trees   map[plumbing.Hash]plumbing.Object
+	Blobs   map[plumbing.Hash]plumbing.Object
+	Tags    map[plumbing.Hash]plumbing.Object
 }
 
-func (o *ObjectStorage) NewObject() core.Object {
-	return &core.MemoryObject{}
+func (o *ObjectStorage) NewObject() plumbing.Object {
+	return &plumbing.MemoryObject{}
 }
 
-func (o *ObjectStorage) SetObject(obj core.Object) (core.Hash, error) {
+func (o *ObjectStorage) SetObject(obj plumbing.Object) (plumbing.Hash, error) {
 	h := obj.Hash()
 	o.Objects[h] = obj
 
 	switch obj.Type() {
-	case core.CommitObject:
+	case plumbing.CommitObject:
 		o.Commits[h] = o.Objects[h]
-	case core.TreeObject:
+	case plumbing.TreeObject:
 		o.Trees[h] = o.Objects[h]
-	case core.BlobObject:
+	case plumbing.BlobObject:
 		o.Blobs[h] = o.Objects[h]
-	case core.TagObject:
+	case plumbing.TagObject:
 		o.Tags[h] = o.Objects[h]
 	default:
 		return h, ErrUnsupportedObjectType
@@ -88,64 +89,64 @@ func (o *ObjectStorage) SetObject(obj core.Object) (core.Hash, error) {
 	return h, nil
 }
 
-func (o *ObjectStorage) Object(t core.ObjectType, h core.Hash) (core.Object, error) {
+func (o *ObjectStorage) Object(t plumbing.ObjectType, h plumbing.Hash) (plumbing.Object, error) {
 	obj, ok := o.Objects[h]
-	if !ok || (core.AnyObject != t && obj.Type() != t) {
-		return nil, core.ErrObjectNotFound
+	if !ok || (plumbing.AnyObject != t && obj.Type() != t) {
+		return nil, plumbing.ErrObjectNotFound
 	}
 
 	return obj, nil
 }
 
-func (o *ObjectStorage) IterObjects(t core.ObjectType) (core.ObjectIter, error) {
-	var series []core.Object
+func (o *ObjectStorage) IterObjects(t plumbing.ObjectType) (storer.ObjectIter, error) {
+	var series []plumbing.Object
 	switch t {
-	case core.AnyObject:
+	case plumbing.AnyObject:
 		series = flattenObjectMap(o.Objects)
-	case core.CommitObject:
+	case plumbing.CommitObject:
 		series = flattenObjectMap(o.Commits)
-	case core.TreeObject:
+	case plumbing.TreeObject:
 		series = flattenObjectMap(o.Trees)
-	case core.BlobObject:
+	case plumbing.BlobObject:
 		series = flattenObjectMap(o.Blobs)
-	case core.TagObject:
+	case plumbing.TagObject:
 		series = flattenObjectMap(o.Tags)
 	}
 
-	return core.NewObjectSliceIter(series), nil
+	return storer.NewObjectSliceIter(series), nil
 }
 
-func flattenObjectMap(m map[core.Hash]core.Object) []core.Object {
-	objects := make([]core.Object, 0, len(m))
+func flattenObjectMap(m map[plumbing.Hash]plumbing.Object) []plumbing.Object {
+	objects := make([]plumbing.Object, 0, len(m))
 	for _, obj := range m {
 		objects = append(objects, obj)
 	}
 	return objects
 }
 
-func (o *ObjectStorage) Begin() core.Transaction {
+func (o *ObjectStorage) Begin() storer.Transaction {
 	return &TxObjectStorage{
 		Storage: o,
-		Objects: make(map[core.Hash]core.Object, 0),
+		Objects: make(map[plumbing.Hash]plumbing.Object, 0),
 	}
 }
 
 type TxObjectStorage struct {
 	Storage *ObjectStorage
-	Objects map[core.Hash]core.Object
+	Objects map[plumbing.Hash]plumbing.Object
 }
 
-func (tx *TxObjectStorage) SetObject(obj core.Object) (core.Hash, error) {
+func (tx *TxObjectStorage) SetObject(obj plumbing.Object) (plumbing.Hash, error) {
 	h := obj.Hash()
 	tx.Objects[h] = obj
 
 	return h, nil
 }
 
-func (tx *TxObjectStorage) Object(t core.ObjectType, h core.Hash) (core.Object, error) {
+func (tx *TxObjectStorage) Object(t plumbing.ObjectType, h plumbing.Hash) (plumbing.Object, error) {
 	obj, ok := tx.Objects[h]
-	if !ok || (core.AnyObject != t && obj.Type() != t) {
-		return nil, core.ErrObjectNotFound
+	if !ok || (plumbing.AnyObject != t && obj.Type() != t) {
+		return nil, plumbing.ErrObjectNotFound
 	}
 
 	return obj, nil
@@ -163,13 +164,13 @@ func (tx *TxObjectStorage) Commit() error {
 }
 
 func (tx *TxObjectStorage) Rollback() error {
-	tx.Objects = make(map[core.Hash]core.Object, 0)
+	tx.Objects = make(map[plumbing.Hash]plumbing.Object, 0)
 	return nil
 }
 
-type ReferenceStorage map[core.ReferenceName]*core.Reference
+type ReferenceStorage map[plumbing.ReferenceName]*plumbing.Reference
 
-func (r ReferenceStorage) SetReference(ref *core.Reference) error {
+func (r ReferenceStorage) SetReference(ref *plumbing.Reference) error {
 	if ref != nil {
 		r[ref.Name()] = ref
 	}
@@ -177,20 +178,20 @@ func (r ReferenceStorage) SetReference(ref *core.Reference) error {
 	return nil
 }
 
-func (r ReferenceStorage) Reference(n core.ReferenceName) (*core.Reference, error) {
+func (r ReferenceStorage) Reference(n plumbing.ReferenceName) (*plumbing.Reference, error) {
 	ref, ok := r[n]
 	if !ok {
-		return nil, core.ErrReferenceNotFound
+		return nil, plumbing.ErrReferenceNotFound
 	}
 
 	return ref, nil
 }
 
-func (r ReferenceStorage) IterReferences() (core.ReferenceIter, error) {
-	var refs []*core.Reference
+func (r ReferenceStorage) IterReferences() (storer.ReferenceIter, error) {
+	var refs []*plumbing.Reference
 	for _, ref := range r {
 		refs = append(refs, ref)
 	}
 
-	return core.NewReferenceSliceIter(refs), nil
+	return storer.NewReferenceSliceIter(refs), nil
 }
diff --git a/storage/test/storage_suite.go b/storage/test/storage_suite.go
index 451528f..d5e1464 100644
--- a/storage/test/storage_suite.go
+++ b/storage/test/storage_suite.go
@@ -8,53 +8,54 @@ import (
 	"io/ioutil"
 
 	"gopkg.in/src-d/go-git.v4/config"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 
 	. "gopkg.in/check.v1"
 )
 
-type storer interface {
-	core.ObjectStorer
-	core.ReferenceStorer
+type Storer interface {
+	storer.ObjectStorer
+	storer.ReferenceStorer
 	config.ConfigStorer
 }
 
 type TestObject struct {
-	Object core.Object
+	Object plumbing.Object
 	Hash   string
-	Type   core.ObjectType
+	Type   plumbing.ObjectType
 }
 
 type BaseStorageSuite struct {
-	Storer storer
+	Storer Storer
 
-	validTypes  []core.ObjectType
-	testObjects map[core.ObjectType]TestObject
+	validTypes  []plumbing.ObjectType
+	testObjects map[plumbing.ObjectType]TestObject
 }
 
-func NewBaseStorageSuite(s storer) BaseStorageSuite {
-	commit := &core.MemoryObject{}
-	commit.SetType(core.CommitObject)
-	tree := &core.MemoryObject{}
-	tree.SetType(core.TreeObject)
-	blob := &core.MemoryObject{}
-	blob.SetType(core.BlobObject)
-	tag := &core.MemoryObject{}
-	tag.SetType(core.TagObject)
+func NewBaseStorageSuite(s Storer) BaseStorageSuite {
+	commit := &plumbing.MemoryObject{}
+	commit.SetType(plumbing.CommitObject)
+	tree := &plumbing.MemoryObject{}
+	tree.SetType(plumbing.TreeObject)
+	blob := &plumbing.MemoryObject{}
+	blob.SetType(plumbing.BlobObject)
+	tag := &plumbing.MemoryObject{}
+	tag.SetType(plumbing.TagObject)
 
 	return BaseStorageSuite{
 		Storer: s,
-		validTypes: []core.ObjectType{
-			core.CommitObject,
-			core.BlobObject,
-			core.TagObject,
-			core.TreeObject,
+		validTypes: []plumbing.ObjectType{
+			plumbing.CommitObject,
+			plumbing.BlobObject,
+			plumbing.TagObject,
+			plumbing.TreeObject,
 		},
-		testObjects: map[core.ObjectType]TestObject{
-			core.CommitObject: {commit, "dcf5b16e76cce7425d0beaef62d79a7d10fce1f5", core.CommitObject},
-			core.TreeObject:   {tree, "4b825dc642cb6eb9a060e54bf8d69288fbee4904", core.TreeObject},
-			core.BlobObject:   {blob, "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391", core.BlobObject},
-			core.TagObject:    {tag, "d994c6bb648123a17e8f70a966857c546b2a6f94", core.TagObject},
+		testObjects: map[plumbing.ObjectType]TestObject{
+			plumbing.CommitObject: {commit, "dcf5b16e76cce7425d0beaef62d79a7d10fce1f5", plumbing.CommitObject},
+			plumbing.TreeObject:   {tree, "4b825dc642cb6eb9a060e54bf8d69288fbee4904", plumbing.TreeObject},
+			plumbing.BlobObject:   {blob, "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391", plumbing.BlobObject},
+			plumbing.TagObject:    {tag, "d994c6bb648123a17e8f70a966857c546b2a6f94", plumbing.TagObject},
 		}}
 }
 
@@ -70,7 +71,7 @@ func (s *BaseStorageSuite) TestSetObjectAndGetObject(c *C) {
 		c.Assert(err, IsNil)
 		c.Assert(objectEquals(o, to.Object), IsNil)
 
-		o, err = s.Storer.Object(core.AnyObject, h)
+		o, err = s.Storer.Object(plumbing.AnyObject, h)
 		c.Assert(err, IsNil)
 		c.Assert(objectEquals(o, to.Object), IsNil)
 
@@ -81,14 +82,14 @@ func (s *BaseStorageSuite) TestSetObjectAndGetObject(c *C) {
 
 			o, err = s.Storer.Object(t, h)
 			c.Assert(o, IsNil)
-			c.Assert(err, Equals, core.ErrObjectNotFound)
+			c.Assert(err, Equals, plumbing.ErrObjectNotFound)
 		}
 	}
 }
 
 func (s *BaseStorageSuite) TestSetObjectInvalid(c *C) {
 	o := s.Storer.NewObject()
-	o.SetType(core.REFDeltaObject)
+	o.SetType(plumbing.REFDeltaObject)
 
 	_, err := s.Storer.SetObject(o)
 	c.Assert(err, NotNil)
@@ -115,11 +116,11 @@ func (s *BaseStorageSuite) TestStorerIter(c *C) {
 		c.Assert(err, Equals, io.EOF, comment)
 	}
 
-	i, err := s.Storer.IterObjects(core.AnyObject)
+	i, err := s.Storer.IterObjects(plumbing.AnyObject)
 	c.Assert(err, IsNil)
 
-	foundObjects := []core.Object{}
-	i.ForEach(func(o core.Object) error {
+	foundObjects := []plumbing.Object{}
+	i.ForEach(func(o plumbing.Object) error {
 		foundObjects = append(foundObjects, o)
 		return nil
 	})
@@ -138,9 +139,9 @@ func (s *BaseStorageSuite) TestStorerIter(c *C) {
 }
 
 func (s *BaseStorageSuite) TestObjectStorerTxSetObjectAndCommit(c *C) {
-	storer, ok := s.Storer.(core.Transactioner)
+	storer, ok := s.Storer.(storer.Transactioner)
 	if !ok {
-		c.Skip("not a core.ObjectStorerTx")
+		c.Skip("not a plumbing.ObjectStorerTx")
 	}
 
 	tx := storer.Begin()
@@ -150,7 +151,7 @@ func (s *BaseStorageSuite) TestObjectStorerTxSetObjectAndCommit(c *C) {
 		c.Assert(h.String(), Equals, o.Hash)
 	}
 
-	iter, err := s.Storer.IterObjects(core.AnyObject)
+	iter, err := s.Storer.IterObjects(plumbing.AnyObject)
 	c.Assert(err, IsNil)
 	_, err = iter.Next()
 	c.Assert(err, Equals, io.EOF)
@@ -158,11 +159,11 @@ func (s *BaseStorageSuite) TestObjectStorerTxSetObjectAndCommit(c *C) {
 	err = tx.Commit()
 	c.Assert(err, IsNil)
 
-	iter, err = s.Storer.IterObjects(core.AnyObject)
+	iter, err = s.Storer.IterObjects(plumbing.AnyObject)
 	c.Assert(err, IsNil)
 
 	var count int
-	iter.ForEach(func(o core.Object) error {
+	iter.ForEach(func(o plumbing.Object) error {
 		count++
 		return nil
 	})
@@ -171,9 +172,9 @@ func (s *BaseStorageSuite) TestObjectStorerTxSetObjectAndCommit(c *C) {
 }
 
 func (s *BaseStorageSuite) TestObjectStorerTxSetObjectAndGetObject(c *C) {
-	storer, ok := s.Storer.(core.Transactioner)
+	storer, ok := s.Storer.(storer.Transactioner)
 	if !ok {
-		c.Skip("not a core.ObjectStorerTx")
+		c.Skip("not a plumbing.ObjectStorerTx")
 	}
 
 	tx := storer.Begin()
@@ -182,27 +183,27 @@ func (s *BaseStorageSuite) TestObjectStorerTxSetObjectAndGetObject(c *C) {
 		c.Assert(err, IsNil)
 		c.Assert(h.String(), Equals, expected.Hash)
 
-		o, err := tx.Object(expected.Type, core.NewHash(expected.Hash))
+		o, err := tx.Object(expected.Type, plumbing.NewHash(expected.Hash))
 		c.Assert(o.Hash().String(), DeepEquals, expected.Hash)
 	}
 }
 
 func (s *BaseStorageSuite) TestObjectStorerTxGetObjectNotFound(c *C) {
-	storer, ok := s.Storer.(core.Transactioner)
+	storer, ok := s.Storer.(storer.Transactioner)
 	if !ok {
-		c.Skip("not a core.ObjectStorerTx")
+		c.Skip("not a plumbing.ObjectStorerTx")
 	}
 
 	tx := storer.Begin()
-	o, err := tx.Object(core.AnyObject, core.ZeroHash)
+	o, err := tx.Object(plumbing.AnyObject, plumbing.ZeroHash)
 	c.Assert(o, IsNil)
-	c.Assert(err, Equals, core.ErrObjectNotFound)
+	c.Assert(err, Equals, plumbing.ErrObjectNotFound)
 }
 
 func (s *BaseStorageSuite) TestObjectStorerTxSetObjectAndRollback(c *C) {
-	storer, ok := s.Storer.(core.Transactioner)
+	storer, ok := s.Storer.(storer.Transactioner)
 	if !ok {
-		c.Skip("not a core.ObjectStorerTx")
+		c.Skip("not a plumbing.ObjectStorerTx")
 	}
 
 	tx := storer.Begin()
@@ -215,7 +216,7 @@ func (s *BaseStorageSuite) TestObjectStorerTxSetObjectAndRollback(c *C) {
 	err := tx.Rollback()
 	c.Assert(err, IsNil)
 
-	iter, err := s.Storer.IterObjects(core.AnyObject)
+	iter, err := s.Storer.IterObjects(plumbing.AnyObject)
 	c.Assert(err, IsNil)
 	_, err = iter.Next()
 	c.Assert(err, Equals, io.EOF)
@@ -223,29 +224,29 @@ func (s *BaseStorageSuite) TestObjectStorerTxSetObjectAndRollback(c *C) {
 
 func (s *BaseStorageSuite) TestSetReferenceAndGetReference(c *C) {
 	err := s.Storer.SetReference(
-		core.NewReferenceFromStrings("foo", "bc9968d75e48de59f0870ffb71f5e160bbbdcf52"),
+		plumbing.NewReferenceFromStrings("foo", "bc9968d75e48de59f0870ffb71f5e160bbbdcf52"),
 	)
 	c.Assert(err, IsNil)
 
 	err = s.Storer.SetReference(
-		core.NewReferenceFromStrings("bar", "482e0eada5de4039e6f216b45b3c9b683b83bfa"),
+		plumbing.NewReferenceFromStrings("bar", "482e0eada5de4039e6f216b45b3c9b683b83bfa"),
 	)
 	c.Assert(err, IsNil)
 
-	e, err := s.Storer.Reference(core.ReferenceName("foo"))
+	e, err := s.Storer.Reference(plumbing.ReferenceName("foo"))
 	c.Assert(err, IsNil)
 	c.Assert(e.Hash().String(), Equals, "bc9968d75e48de59f0870ffb71f5e160bbbdcf52")
 }
 
 func (s *BaseStorageSuite) TestGetReferenceNotFound(c *C) {
-	r, err := s.Storer.Reference(core.ReferenceName("bar"))
-	c.Assert(err, Equals, core.ErrReferenceNotFound)
+	r, err := s.Storer.Reference(plumbing.ReferenceName("bar"))
+	c.Assert(err, Equals, plumbing.ErrReferenceNotFound)
 	c.Assert(r, IsNil)
 }
 
 func (s *BaseStorageSuite) TestIterReferences(c *C) {
 	err := s.Storer.SetReference(
-		core.NewReferenceFromStrings("refs/foo", "bc9968d75e48de59f0870ffb71f5e160bbbdcf52"),
+		plumbing.NewReferenceFromStrings("refs/foo", "bc9968d75e48de59f0870ffb71f5e160bbbdcf52"),
 	)
 	c.Assert(err, IsNil)
 
@@ -284,7 +285,7 @@ func (s *BaseStorageSuite) TestSetConfigInvalid(c *C) {
 	c.Assert(err, NotNil)
 }
 
-func objectEquals(a core.Object, b core.Object) error {
+func objectEquals(a plumbing.Object, b plumbing.Object) error {
 	ha := a.Hash()
 	hb := b.Hash()
 	if ha != hb {
diff --git a/tag.go b/tag.go
index 0a8014b..7ab3689 100644
--- a/tag.go
+++ b/tag.go
@@ -7,7 +7,8 @@ import (
 	"io"
 	"io/ioutil"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 )
 
 // Tag represents an annotated tag object. It points to a single git object of
@@ -18,12 +19,12 @@ import (
 //
 // https://git-scm.com/book/en/v2/Git-Internals-Git-References#Tags
 type Tag struct {
-	Hash       core.Hash
+	Hash       plumbing.Hash
 	Name       string
 	Tagger     Signature
 	Message    string
-	TargetType core.ObjectType
-	Target     core.Hash
+	TargetType plumbing.ObjectType
+	Target     plumbing.Hash
 
 	r *Repository
 }
@@ -32,20 +33,20 @@ type Tag struct {
 // The returned value will always match the current value of Tag.Hash.
 //
 // ID is present to fulfill the Object interface.
-func (t *Tag) ID() core.Hash {
+func (t *Tag) ID() plumbing.Hash {
 	return t.Hash
 }
 
-// Type returns the type of object. It always returns core.TagObject.
+// Type returns the type of object. It always returns plumbing.TagObject.
 //
 // Type is present to fulfill the Object interface.
-func (t *Tag) Type() core.ObjectType {
-	return core.TagObject
+func (t *Tag) Type() plumbing.ObjectType {
+	return plumbing.TagObject
 }
 
-// Decode transforms a core.Object into a Tag struct.
-func (t *Tag) Decode(o core.Object) (err error) {
-	if o.Type() != core.TagObject {
+// Decode transforms a plumbing.Object into a Tag struct.
+func (t *Tag) Decode(o plumbing.Object) (err error) {
+	if o.Type() != plumbing.TagObject {
 		return ErrUnsupportedObject
 	}
 
@@ -72,9 +73,9 @@ func (t *Tag) Decode(o core.Object) (err error) {
 		split := bytes.SplitN(line, []byte{' '}, 2)
 		switch string(split[0]) {
 		case "object":
-			t.Target = core.NewHash(string(split[1]))
+			t.Target = plumbing.NewHash(string(split[1]))
 		case "type":
-			t.TargetType, err = core.ParseObjectType(string(split[1]))
+			t.TargetType, err = plumbing.ParseObjectType(string(split[1]))
 			if err != nil {
 				return err
 			}
@@ -98,9 +99,9 @@ func (t *Tag) Decode(o core.Object) (err error) {
 	return nil
 }
 
-// Encode transforms a Tag into a core.Object.
-func (t *Tag) Encode(o core.Object) error {
-	o.SetType(core.TagObject)
+// Encode transforms a Tag into a plumbing.Object.
+func (t *Tag) Encode(o plumbing.Object) error {
+	o.SetType(plumbing.TagObject)
 	w, err := o.Writer()
 	if err != nil {
 		return err
@@ -131,7 +132,7 @@ func (t *Tag) Encode(o core.Object) error {
 // Commit returns the commit pointed to by the tag. If the tag points to a
 // different type of object ErrUnsupportedObject will be returned.
 func (t *Tag) Commit() (*Commit, error) {
-	if t.TargetType != core.CommitObject {
+	if t.TargetType != plumbing.CommitObject {
 		return nil, ErrUnsupportedObject
 	}
 	return t.r.Commit(t.Target)
@@ -142,13 +143,13 @@ func (t *Tag) Commit() (*Commit, error) {
 // to a commit or tree object ErrUnsupportedObject will be returned.
 func (t *Tag) Tree() (*Tree, error) {
 	switch t.TargetType {
-	case core.CommitObject:
+	case plumbing.CommitObject:
 		commit, err := t.r.Commit(t.Target)
 		if err != nil {
 			return nil, err
 		}
 		return commit.Tree()
-	case core.TreeObject:
+	case plumbing.TreeObject:
 		return t.r.Tree(t.Target)
 	default:
 		return nil, ErrUnsupportedObject
@@ -158,7 +159,7 @@ func (t *Tag) Tree() (*Tree, error) {
 // Blob returns the blob pointed to by the tag. If the tag points to a
 // different type of object ErrUnsupportedObject will be returned.
 func (t *Tag) Blob() (*Blob, error) {
-	if t.TargetType != core.BlobObject {
+	if t.TargetType != plumbing.BlobObject {
 		return nil, ErrUnsupportedObject
 	}
 	return t.r.Blob(t.Target)
@@ -176,14 +177,14 @@ func (t *Tag) String() string {
 
 	return fmt.Sprintf(
 		"%s %s\nTagger: %s\nDate:   %s\n\n%s\n%s",
-		core.TagObject, t.Name, t.Tagger.String(), t.Tagger.When.Format(DateFormat),
+		plumbing.TagObject, t.Name, t.Tagger.String(), t.Tagger.When.Format(DateFormat),
 		t.Message, objectAsString(obj),
 	)
 }
 
 // TagIter provides an iterator for a set of tags.
 type TagIter struct {
-	core.ObjectIter
+	storer.ObjectIter
 	r *Repository
 }
 
@@ -191,7 +192,7 @@ type TagIter struct {
 // object iterator.
 //
 // The returned TagIter will automatically skip over non-tag objects.
-func NewTagIter(r *Repository, iter core.ObjectIter) *TagIter {
+func NewTagIter(r *Repository, iter storer.ObjectIter) *TagIter {
 	return &TagIter{iter, r}
 }
 
@@ -211,7 +212,7 @@ func (iter *TagIter) Next() (*Tag, error) {
 // an error happends or the end of the iter is reached. If ErrStop is sent
 // the iteration is stop but no error is returned. The iterator is closed.
 func (iter *TagIter) ForEach(cb func(*Tag) error) error {
-	return iter.ObjectIter.ForEach(func(obj core.Object) error {
+	return iter.ObjectIter.ForEach(func(obj plumbing.Object) error {
 		tag := &Tag{r: iter.r}
 		if err := tag.Decode(obj); err != nil {
 			return err
diff --git a/tag_test.go b/tag_test.go
index aaedebe..652577b 100644
--- a/tag_test.go
+++ b/tag_test.go
@@ -5,8 +5,8 @@ import (
 	"time"
 
 	. "gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/fixtures"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 type TagSuite struct {
@@ -23,7 +23,7 @@ func (s *TagSuite) SetUpSuite(c *C) {
 func (s *TagSuite) TestName(c *C) {
 	r := s.Repositories["https://github.com/git-fixtures/tags.git"]
 
-	tag, err := r.Tag(core.NewHash("b742a2a9fa0afcfa9a6fad080980fbc26b007c69"))
+	tag, err := r.Tag(plumbing.NewHash("b742a2a9fa0afcfa9a6fad080980fbc26b007c69"))
 	c.Assert(err, IsNil)
 	c.Assert(tag.Name, Equals, "annotated-tag")
 }
@@ -31,7 +31,7 @@ func (s *TagSuite) TestName(c *C) {
 func (s *TagSuite) TestTagger(c *C) {
 	r := s.Repositories["https://github.com/git-fixtures/tags.git"]
 
-	tag, err := r.Tag(core.NewHash("b742a2a9fa0afcfa9a6fad080980fbc26b007c69"))
+	tag, err := r.Tag(plumbing.NewHash("b742a2a9fa0afcfa9a6fad080980fbc26b007c69"))
 	c.Assert(err, IsNil)
 	c.Assert(tag.Tagger.String(), Equals, "Máximo Cuadros <mcuadros@gmail.com>")
 }
@@ -39,83 +39,83 @@ func (s *TagSuite) TestTagger(c *C) {
 func (s *TagSuite) TestAnnotated(c *C) {
 	r := s.Repositories["https://github.com/git-fixtures/tags.git"]
 
-	tag, err := r.Tag(core.NewHash("b742a2a9fa0afcfa9a6fad080980fbc26b007c69"))
+	tag, err := r.Tag(plumbing.NewHash("b742a2a9fa0afcfa9a6fad080980fbc26b007c69"))
 	c.Assert(err, IsNil)
 	c.Assert(tag.Message, Equals, "example annotated tag\n")
 
 	commit, err := tag.Commit()
 	c.Assert(err, IsNil)
-	c.Assert(commit.Type(), Equals, core.CommitObject)
+	c.Assert(commit.Type(), Equals, plumbing.CommitObject)
 	c.Assert(commit.ID().String(), Equals, "f7b877701fbf855b44c0a9e86f3fdce2c298b07f")
 }
 
 func (s *TagSuite) TestCommit(c *C) {
 	r := s.Repositories["https://github.com/git-fixtures/tags.git"]
 
-	tag, err := r.Tag(core.NewHash("ad7897c0fb8e7d9a9ba41fa66072cf06095a6cfc"))
+	tag, err := r.Tag(plumbing.NewHash("ad7897c0fb8e7d9a9ba41fa66072cf06095a6cfc"))
 	c.Assert(err, IsNil)
 	c.Assert(tag.Message, Equals, "a tagged commit\n")
 
 	commit, err := tag.Commit()
 	c.Assert(err, IsNil)
-	c.Assert(commit.Type(), Equals, core.CommitObject)
+	c.Assert(commit.Type(), Equals, plumbing.CommitObject)
 	c.Assert(commit.ID().String(), Equals, "f7b877701fbf855b44c0a9e86f3fdce2c298b07f")
 }
 
 func (s *TagSuite) TestBlob(c *C) {
 	r := s.Repositories["https://github.com/git-fixtures/tags.git"]
 
-	tag, err := r.Tag(core.NewHash("fe6cb94756faa81e5ed9240f9191b833db5f40ae"))
+	tag, err := r.Tag(plumbing.NewHash("fe6cb94756faa81e5ed9240f9191b833db5f40ae"))
 	c.Assert(err, IsNil)
 	c.Assert(tag.Message, Equals, "a tagged blob\n")
 
 	blob, err := tag.Blob()
 	c.Assert(err, IsNil)
-	c.Assert(blob.Type(), Equals, core.BlobObject)
+	c.Assert(blob.Type(), Equals, plumbing.BlobObject)
 	c.Assert(blob.ID().String(), Equals, "e69de29bb2d1d6434b8b29ae775ad8c2e48c5391")
 }
 
 func (s *TagSuite) TestTree(c *C) {
 	r := s.Repositories["https://github.com/git-fixtures/tags.git"]
 
-	tag, err := r.Tag(core.NewHash("152175bf7e5580299fa1f0ba41ef6474cc043b70"))
+	tag, err := r.Tag(plumbing.NewHash("152175bf7e5580299fa1f0ba41ef6474cc043b70"))
 	c.Assert(err, IsNil)
 	c.Assert(tag.Message, Equals, "a tagged tree\n")
 
 	tree, err := tag.Tree()
 	c.Assert(err, IsNil)
-	c.Assert(tree.Type(), Equals, core.TreeObject)
+	c.Assert(tree.Type(), Equals, plumbing.TreeObject)
 	c.Assert(tree.ID().String(), Equals, "70846e9a10ef7b41064b40f07713d5b8b9a8fc73")
 }
 
 func (s *TagSuite) TestTreeFromCommit(c *C) {
 	r := s.Repositories["https://github.com/git-fixtures/tags.git"]
 
-	tag, err := r.Tag(core.NewHash("ad7897c0fb8e7d9a9ba41fa66072cf06095a6cfc"))
+	tag, err := r.Tag(plumbing.NewHash("ad7897c0fb8e7d9a9ba41fa66072cf06095a6cfc"))
 	c.Assert(err, IsNil)
 	c.Assert(tag.Message, Equals, "a tagged commit\n")
 
 	tree, err := tag.Tree()
 	c.Assert(err, IsNil)
-	c.Assert(tree.Type(), Equals, core.TreeObject)
+	c.Assert(tree.Type(), Equals, plumbing.TreeObject)
 	c.Assert(tree.ID().String(), Equals, "70846e9a10ef7b41064b40f07713d5b8b9a8fc73")
 }
 
 func (s *TagSuite) TestObject(c *C) {
 	r := s.Repositories["https://github.com/git-fixtures/tags.git"]
 
-	tag, err := r.Tag(core.NewHash("ad7897c0fb8e7d9a9ba41fa66072cf06095a6cfc"))
+	tag, err := r.Tag(plumbing.NewHash("ad7897c0fb8e7d9a9ba41fa66072cf06095a6cfc"))
 	c.Assert(err, IsNil)
 
 	obj, err := tag.Object()
 	c.Assert(err, IsNil)
-	c.Assert(obj.Type(), Equals, core.CommitObject)
+	c.Assert(obj.Type(), Equals, plumbing.CommitObject)
 	c.Assert(obj.ID().String(), Equals, "f7b877701fbf855b44c0a9e86f3fdce2c298b07f")
 }
 
 func (s *TagSuite) TestTagItter(c *C) {
 	r := s.Repositories["https://github.com/git-fixtures/tags.git"]
-	iter, err := r.s.IterObjects(core.TagObject)
+	iter, err := r.s.IterObjects(plumbing.TagObject)
 	c.Assert(err, IsNil)
 
 	var count int
@@ -131,7 +131,7 @@ func (s *TagSuite) TestTagItter(c *C) {
 
 func (s *TagSuite) TestTagIterError(c *C) {
 	r := s.Repositories["https://github.com/git-fixtures/tags.git"]
-	iter, err := r.s.IterObjects(core.TagObject)
+	iter, err := r.s.IterObjects(plumbing.TagObject)
 	c.Assert(err, IsNil)
 
 	i := NewTagIter(r, iter)
@@ -150,18 +150,18 @@ func (s *TagSuite) TestTagEncodeDecodeIdempotent(c *C) {
 			Name:       "foo",
 			Tagger:     Signature{Name: "Foo", Email: "foo@example.local", When: ts},
 			Message:    "Message\n\nFoo\nBar\nBaz\n\n",
-			TargetType: core.BlobObject,
-			Target:     core.NewHash("b029517f6300c2da0f4b651b8642506cd6aaf45d"),
+			TargetType: plumbing.BlobObject,
+			Target:     plumbing.NewHash("b029517f6300c2da0f4b651b8642506cd6aaf45d"),
 		},
 		{
 			Name:       "foo",
 			Tagger:     Signature{Name: "Foo", Email: "foo@example.local", When: ts},
-			TargetType: core.BlobObject,
-			Target:     core.NewHash("b029517f6300c2da0f4b651b8642506cd6aaf45d"),
+			TargetType: plumbing.BlobObject,
+			Target:     plumbing.NewHash("b029517f6300c2da0f4b651b8642506cd6aaf45d"),
 		},
 	}
 	for _, tag := range tags {
-		obj := &core.MemoryObject{}
+		obj := &plumbing.MemoryObject{}
 		err = tag.Encode(obj)
 		c.Assert(err, IsNil)
 		newTag := &Tag{}
@@ -175,7 +175,7 @@ func (s *TagSuite) TestTagEncodeDecodeIdempotent(c *C) {
 func (s *TagSuite) TestString(c *C) {
 	r := s.Repositories["https://github.com/git-fixtures/tags.git"]
 
-	tag, err := r.Tag(core.NewHash("b742a2a9fa0afcfa9a6fad080980fbc26b007c69"))
+	tag, err := r.Tag(plumbing.NewHash("b742a2a9fa0afcfa9a6fad080980fbc26b007c69"))
 	c.Assert(err, IsNil)
 	c.Assert(tag.String(), Equals, ""+
 		"tag annotated-tag\n"+
diff --git a/tree.go b/tree.go
index 4d08396..753ed0c 100644
--- a/tree.go
+++ b/tree.go
@@ -10,7 +10,8 @@ import (
 	"strconv"
 	"strings"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 )
 
 const (
@@ -30,7 +31,7 @@ var (
 // and/or blobs (i.e. files and sub-directories)
 type Tree struct {
 	Entries []TreeEntry
-	Hash    core.Hash
+	Hash    plumbing.Hash
 
 	r *Repository
 	m map[string]*TreeEntry
@@ -40,7 +41,7 @@ type Tree struct {
 type TreeEntry struct {
 	Name string
 	Mode os.FileMode
-	Hash core.Hash
+	Hash plumbing.Hash
 }
 
 // File returns the hash of the file identified by the `path` argument.
@@ -51,7 +52,7 @@ func (t *Tree) File(path string) (*File, error) {
 		return nil, ErrFileNotFound
 	}
 
-	obj, err := t.r.s.Object(core.BlobObject, e.Hash)
+	obj, err := t.r.s.Object(plumbing.BlobObject, e.Hash)
 	if err != nil {
 		return nil, err
 	}
@@ -84,7 +85,7 @@ func (t *Tree) dir(baseName string) (*Tree, error) {
 		return nil, errDirNotFound
 	}
 
-	obj, err := t.r.s.Object(core.TreeObject, entry.Hash)
+	obj, err := t.r.s.Object(plumbing.TreeObject, entry.Hash)
 	if err != nil {
 		return nil, err
 	}
@@ -118,18 +119,18 @@ func (t *Tree) Files() *FileIter {
 // the current value of Tree.Hash.
 //
 // ID is present to fulfill the Object interface.
-func (t *Tree) ID() core.Hash {
+func (t *Tree) ID() plumbing.Hash {
 	return t.Hash
 }
 
-// Type returns the type of object. It always returns core.TreeObject.
-func (t *Tree) Type() core.ObjectType {
-	return core.TreeObject
+// Type returns the type of object. It always returns plumbing.TreeObject.
+func (t *Tree) Type() plumbing.ObjectType {
+	return plumbing.TreeObject
 }
 
-// Decode transform an core.Object into a Tree struct
-func (t *Tree) Decode(o core.Object) (err error) {
-	if o.Type() != core.TreeObject {
+// Decode transform an plumbing.Object into a Tree struct
+func (t *Tree) Decode(o plumbing.Object) (err error) {
+	if o.Type() != plumbing.TreeObject {
 		return ErrUnsupportedObject
 	}
 
@@ -168,7 +169,7 @@ func (t *Tree) Decode(o core.Object) (err error) {
 			return err
 		}
 
-		var hash core.Hash
+		var hash plumbing.Hash
 		if _, err = io.ReadFull(r, hash[:]); err != nil {
 			return err
 		}
@@ -201,9 +202,9 @@ func (t *Tree) decodeFileMode(mode string) (os.FileMode, error) {
 	return m, nil
 }
 
-// Encode transforms a Tree into a core.Object.
-func (t *Tree) Encode(o core.Object) error {
-	o.SetType(core.TreeObject)
+// Encode transforms a Tree into a plumbing.Object.
+func (t *Tree) Encode(o plumbing.Object) error {
+	o.SetType(plumbing.TreeObject)
 	w, err := o.Writer()
 	if err != nil {
 		return err
@@ -371,7 +372,7 @@ func (w *TreeWalker) Close() {
 
 // TreeIter provides an iterator for a set of trees.
 type TreeIter struct {
-	core.ObjectIter
+	storer.ObjectIter
 	r *Repository
 }
 
@@ -379,7 +380,7 @@ type TreeIter struct {
 // object iterator.
 //
 // The returned TreeIter will automatically skip over non-tree objects.
-func NewTreeIter(r *Repository, iter core.ObjectIter) *TreeIter {
+func NewTreeIter(r *Repository, iter storer.ObjectIter) *TreeIter {
 	return &TreeIter{iter, r}
 }
 
@@ -392,7 +393,7 @@ func (iter *TreeIter) Next() (*Tree, error) {
 			return nil, err
 		}
 
-		if obj.Type() != core.TreeObject {
+		if obj.Type() != plumbing.TreeObject {
 			continue
 		}
 
@@ -405,8 +406,8 @@ func (iter *TreeIter) Next() (*Tree, error) {
 // an error happens or the end of the iter is reached. If ErrStop is sent
 // the iteration is stop but no error is returned. The iterator is closed.
 func (iter *TreeIter) ForEach(cb func(*Tree) error) error {
-	return iter.ObjectIter.ForEach(func(obj core.Object) error {
-		if obj.Type() != core.TreeObject {
+	return iter.ObjectIter.ForEach(func(obj plumbing.Object) error {
+		if obj.Type() != plumbing.TreeObject {
 			return nil
 		}
 
diff --git a/tree_diff.go b/tree_diff.go
index 1f5f076..d5f0377 100644
--- a/tree_diff.go
+++ b/tree_diff.go
@@ -7,7 +7,7 @@ import (
 	"sort"
 	"strings"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 type Action int
@@ -250,10 +250,10 @@ func hasChange(a, b *Tree, path string) (bool, error) {
 	return ha != hb, nil
 }
 
-func hash(tree *Tree, path string) (core.Hash, error) {
+func hash(tree *Tree, path string) (plumbing.Hash, error) {
 	file, err := tree.File(path)
 	if err != nil {
-		var empty core.Hash
+		var empty plumbing.Hash
 		return empty, fmt.Errorf("cannot find file %s in tree: %s", path, err)
 	}
 
diff --git a/tree_diff_test.go b/tree_diff_test.go
index 58f0a29..81fee5d 100644
--- a/tree_diff_test.go
+++ b/tree_diff_test.go
@@ -3,8 +3,8 @@ package git
 import (
 	"sort"
 
-	"gopkg.in/src-d/go-git.v4/core"
 	"gopkg.in/src-d/go-git.v4/fixtures"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 
 	. "gopkg.in/check.v1"
 )
@@ -42,13 +42,13 @@ func (s *DiffTreeSuite) TestActionString(c *C) {
 }
 
 func (s *DiffTreeSuite) TestChangeFilesInsert(c *C) {
-	tree, err := s.Repository.Tree(core.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c"))
+	tree, err := s.Repository.Tree(plumbing.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c"))
 	c.Assert(err, IsNil)
 
 	change := &Change{Action: Insert}
 	change.To.Name = "json/long.json"
 	change.To.Tree = tree
-	change.To.TreeEntry.Hash = core.NewHash("49c6bb89b17060d7b4deacb7b338fcc6ea2352a9")
+	change.To.TreeEntry.Hash = plumbing.NewHash("49c6bb89b17060d7b4deacb7b338fcc6ea2352a9")
 
 	from, to, err := change.Files()
 	c.Assert(err, IsNil)
@@ -57,13 +57,13 @@ func (s *DiffTreeSuite) TestChangeFilesInsert(c *C) {
 }
 
 func (s *DiffTreeSuite) TestChangeFilesDelete(c *C) {
-	tree, err := s.Repository.Tree(core.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c"))
+	tree, err := s.Repository.Tree(plumbing.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c"))
 	c.Assert(err, IsNil)
 
 	change := &Change{Action: Delete}
 	change.From.Name = "json/long.json"
 	change.From.Tree = tree
-	change.From.TreeEntry.Hash = core.NewHash("49c6bb89b17060d7b4deacb7b338fcc6ea2352a9")
+	change.From.TreeEntry.Hash = plumbing.NewHash("49c6bb89b17060d7b4deacb7b338fcc6ea2352a9")
 
 	from, to, err := change.Files()
 	c.Assert(err, IsNil)
@@ -72,16 +72,16 @@ func (s *DiffTreeSuite) TestChangeFilesDelete(c *C) {
 }
 
 func (s *DiffTreeSuite) TestChangeFilesModify(c *C) {
-	tree, err := s.Repository.Tree(core.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c"))
+	tree, err := s.Repository.Tree(plumbing.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c"))
 	c.Assert(err, IsNil)
 
 	change := &Change{Action: Modify}
 	change.To.Name = "json/long.json"
 	change.To.Tree = tree
-	change.To.TreeEntry.Hash = core.NewHash("49c6bb89b17060d7b4deacb7b338fcc6ea2352a9")
+	change.To.TreeEntry.Hash = plumbing.NewHash("49c6bb89b17060d7b4deacb7b338fcc6ea2352a9")
 	change.From.Name = "json/long.json"
 	change.From.Tree = tree
-	change.From.TreeEntry.Hash = core.NewHash("9a48f23120e880dfbe41f7c9b7b708e9ee62a492")
+	change.From.TreeEntry.Hash = plumbing.NewHash("9a48f23120e880dfbe41f7c9b7b708e9ee62a492")
 
 	from, to, err := change.Files()
 	c.Assert(err, IsNil)
@@ -410,7 +410,7 @@ func tree(repo *Repository, commitHashStr string) (*Tree, error) {
 		return nil, nil
 	}
 
-	commit, err := repo.Commit(core.NewHash(commitHashStr))
+	commit, err := repo.Commit(plumbing.NewHash(commitHashStr))
 	if err != nil {
 		return nil, err
 	}
diff --git a/tree_test.go b/tree_test.go
index 237363d..6e12ceb 100644
--- a/tree_test.go
+++ b/tree_test.go
@@ -4,7 +4,7 @@ import (
 	"io"
 	"os"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 
 	. "gopkg.in/check.v1"
 )
@@ -18,7 +18,7 @@ var _ = Suite(&TreeSuite{})
 
 func (s *TreeSuite) SetUpSuite(c *C) {
 	s.BaseSuite.SetUpSuite(c)
-	hash := core.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c")
+	hash := plumbing.NewHash("a8d315b2b1c615d43042c3a62402b8a54288cf5c")
 
 	var err error
 	s.Tree, err = s.Repository.Tree(hash)
@@ -36,8 +36,8 @@ func (s *TreeSuite) TestDecode(c *C) {
 }
 
 func (s *TreeSuite) TestDecodeNonTree(c *C) {
-	hash := core.NewHash("9a48f23120e880dfbe41f7c9b7b708e9ee62a492")
-	blob, err := s.Repository.s.Object(core.BlobObject, hash)
+	hash := plumbing.NewHash("9a48f23120e880dfbe41f7c9b7b708e9ee62a492")
+	blob, err := s.Repository.s.Object(plumbing.BlobObject, hash)
 	c.Assert(err, IsNil)
 
 	tree := &Tree{}
@@ -46,7 +46,7 @@ func (s *TreeSuite) TestDecodeNonTree(c *C) {
 }
 
 func (s *TreeSuite) TestType(c *C) {
-	c.Assert(s.Tree.Type(), Equals, core.TreeObject)
+	c.Assert(s.Tree.Type(), Equals, plumbing.TreeObject)
 }
 
 func (s *TreeSuite) TestFile(c *C) {
@@ -72,23 +72,23 @@ func (s *TreeSuite) TestFiles(c *C) {
 	c.Assert(count, Equals, 9)
 }
 
-// This core.Object implementation has a reader that only returns 6
+// This plumbing.Object implementation has a reader that only returns 6
 // bytes at a time, this should simulate the conditions when a read
 // returns less bytes than asked, for example when reading a hash which
 // is bigger than 6 bytes.
 type SortReadObject struct {
-	t    core.ObjectType
-	h    core.Hash
+	t    plumbing.ObjectType
+	h    plumbing.Hash
 	cont []byte
 	sz   int64
 }
 
-func (o *SortReadObject) Hash() core.Hash           { return o.h }
-func (o *SortReadObject) Type() core.ObjectType     { return o.t }
-func (o *SortReadObject) SetType(t core.ObjectType) { o.t = t }
-func (o *SortReadObject) Size() int64               { return o.sz }
-func (o *SortReadObject) SetSize(s int64)           { o.sz = s }
-func (o *SortReadObject) Content() []byte           { return o.cont }
+func (o *SortReadObject) Hash() plumbing.Hash           { return o.h }
+func (o *SortReadObject) Type() plumbing.ObjectType     { return o.t }
+func (o *SortReadObject) SetType(t plumbing.ObjectType) { o.t = t }
+func (o *SortReadObject) Size() int64                   { return o.sz }
+func (o *SortReadObject) SetSize(s int64)               { o.sz = s }
+func (o *SortReadObject) Content() []byte               { return o.cont }
 func (o *SortReadObject) Reader() (io.ReadCloser, error) {
 	return &SortReadCloser{pos: 0, data: o.cont}, nil
 }
@@ -128,14 +128,14 @@ func (s *TreeSuite) TestTreeDecodeEncodeIdempotent(c *C) {
 	trees := []*Tree{
 		{
 			Entries: []TreeEntry{
-				{"foo", os.FileMode(0), core.NewHash("b029517f6300c2da0f4b651b8642506cd6aaf45d")},
-				{"bar", os.FileMode(0), core.NewHash("c029517f6300c2da0f4b651b8642506cd6aaf45d")},
-				{"baz", os.FileMode(0), core.NewHash("d029517f6300c2da0f4b651b8642506cd6aaf45d")},
+				{"foo", os.FileMode(0), plumbing.NewHash("b029517f6300c2da0f4b651b8642506cd6aaf45d")},
+				{"bar", os.FileMode(0), plumbing.NewHash("c029517f6300c2da0f4b651b8642506cd6aaf45d")},
+				{"baz", os.FileMode(0), plumbing.NewHash("d029517f6300c2da0f4b651b8642506cd6aaf45d")},
 			},
 		},
 	}
 	for _, tree := range trees {
-		obj := &core.MemoryObject{}
+		obj := &plumbing.MemoryObject{}
 		err := tree.Encode(obj)
 		c.Assert(err, IsNil)
 		newTree := &Tree{}
@@ -181,7 +181,7 @@ func (s *TreeSuite) TestTreeIter(c *C) {
 
 func (s *TreeSuite) TestTreeWalkerNext(c *C) {
 	r := s.Repository
-	commit, err := r.Commit(core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
+	commit, err := r.Commit(plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
 	c.Assert(err, IsNil)
 
 	tree, err := commit.Tree()
@@ -206,7 +206,7 @@ func (s *TreeSuite) TestTreeWalkerNext(c *C) {
 
 func (s *TreeSuite) TestTreeWalkerNextNonRecursive(c *C) {
 	r := s.Repository
-	commit, err := r.Commit(core.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
+	commit, err := r.Commit(plumbing.NewHash("6ecf0ef2c2dffb796033e5a02219af86ec6584e5"))
 	c.Assert(err, IsNil)
 
 	tree, err := commit.Tree()
@@ -844,8 +844,8 @@ func (s *TreeSuite) TestTreeDecodeReadBug(c *C) {
 		0xf0, 0xd2, 0x87,
 	}
 	obj := &SortReadObject{
-		t:    core.TreeObject,
-		h:    core.ZeroHash,
+		t:    plumbing.TreeObject,
+		h:    plumbing.ZeroHash,
 		cont: cont,
 		sz:   5313,
 	}
@@ -854,570 +854,570 @@ func (s *TreeSuite) TestTreeDecodeReadBug(c *C) {
 		Entries: []TreeEntry{
 			{
 				Name: "alter.c", Mode: 0x81a4,
-				Hash: core.Hash{0xa4, 0x9d, 0x33, 0x49, 0xd7, 0xe2, 0x3f, 0xb5, 0x81, 0x19, 0x4f, 0x4c, 0xb5, 0x9a, 0xc0, 0xd5, 0x1b, 0x2, 0x1f, 0x78},
+				Hash: plumbing.Hash{0xa4, 0x9d, 0x33, 0x49, 0xd7, 0xe2, 0x3f, 0xb5, 0x81, 0x19, 0x4f, 0x4c, 0xb5, 0x9a, 0xc0, 0xd5, 0x1b, 0x2, 0x1f, 0x78},
 			},
 			{
 				Name: "analyze.c", Mode: 0x81a4,
-				Hash: core.Hash{0x9a, 0x3e, 0x95, 0x97, 0xdb, 0xb, 0x3, 0x20, 0x77, 0xc9, 0x1d, 0x96, 0x9d, 0x22, 0xc6, 0x27, 0x3f, 0x70, 0x2a, 0xc},
+				Hash: plumbing.Hash{0x9a, 0x3e, 0x95, 0x97, 0xdb, 0xb, 0x3, 0x20, 0x77, 0xc9, 0x1d, 0x96, 0x9d, 0x22, 0xc6, 0x27, 0x3f, 0x70, 0x2a, 0xc},
 			},
 			{
 				Name: "attach.c", Mode: 0x81a4,
-				Hash: core.Hash{0xb8, 0xe1, 0x21, 0x99, 0xb5, 0x7d, 0xe8, 0x11, 0xea, 0xe0, 0xd0, 0x61, 0x42, 0xd5, 0xac, 0x4f, 0xd4, 0x30, 0xb1, 0xd8},
+				Hash: plumbing.Hash{0xb8, 0xe1, 0x21, 0x99, 0xb5, 0x7d, 0xe8, 0x11, 0xea, 0xe0, 0xd0, 0x61, 0x42, 0xd5, 0xac, 0x4f, 0xd4, 0x30, 0xb1, 0xd8},
 			},
 			{
 				Name: "auth.c", Mode: 0x81a4,
-				Hash: core.Hash{0xd3, 0x8b, 0xb8, 0x36, 0xa7, 0x84, 0xfb, 0xfa, 0xb6, 0xab, 0x7b, 0x3, 0xd4, 0xe6, 0xdd, 0x43, 0xed, 0xc4, 0x1f, 0xa7},
+				Hash: plumbing.Hash{0xd3, 0x8b, 0xb8, 0x36, 0xa7, 0x84, 0xfb, 0xfa, 0xb6, 0xab, 0x7b, 0x3, 0xd4, 0xe6, 0xdd, 0x43, 0xed, 0xc4, 0x1f, 0xa7},
 			},
 			{
 				Name: "backup.c", Mode: 0x81a4,
-				Hash: core.Hash{0x25, 0x2f, 0x61, 0xcf, 0xca, 0xa8, 0xfc, 0xf3, 0x13, 0x7e, 0x8, 0xed, 0x68, 0x47, 0xdc, 0xfe, 0x1d, 0xc1, 0xde, 0x54},
+				Hash: plumbing.Hash{0x25, 0x2f, 0x61, 0xcf, 0xca, 0xa8, 0xfc, 0xf3, 0x13, 0x7e, 0x8, 0xed, 0x68, 0x47, 0xdc, 0xfe, 0x1d, 0xc1, 0xde, 0x54},
 			},
 			{
 				Name: "bitvec.c", Mode: 0x81a4,
-				Hash: core.Hash{0x52, 0x18, 0x4a, 0xa9, 0x64, 0xce, 0x18, 0x98, 0xf3, 0x5d, 0x1b, 0x3d, 0x87, 0x87, 0x1c, 0x2d, 0xe, 0xf4, 0xc5, 0x3d},
+				Hash: plumbing.Hash{0x52, 0x18, 0x4a, 0xa9, 0x64, 0xce, 0x18, 0x98, 0xf3, 0x5d, 0x1b, 0x3d, 0x87, 0x87, 0x1c, 0x2d, 0xe, 0xf4, 0xc5, 0x3d},
 			},
 			{
 				Name: "btmutex.c", Mode: 0x81a4,
-				Hash: core.Hash{0xd8, 0x7d, 0x4d, 0x5f, 0xee, 0xb6, 0x30, 0x7a, 0xec, 0xdc, 0x9a, 0x83, 0x11, 0x14, 0x89, 0xab, 0x30, 0xc6, 0x78, 0xc3},
+				Hash: plumbing.Hash{0xd8, 0x7d, 0x4d, 0x5f, 0xee, 0xb6, 0x30, 0x7a, 0xec, 0xdc, 0x9a, 0x83, 0x11, 0x14, 0x89, 0xab, 0x30, 0xc6, 0x78, 0xc3},
 			},
 			{
 				Name: "btree.c", Mode: 0x81a4,
-				Hash: core.Hash{0x3c, 0xa6, 0x5, 0x83, 0xe3, 0xc8, 0xe3, 0x12, 0x0, 0xf9, 0x73, 0xe0, 0xe9, 0xc4, 0x53, 0x62, 0x58, 0xb2, 0x64, 0x39},
+				Hash: plumbing.Hash{0x3c, 0xa6, 0x5, 0x83, 0xe3, 0xc8, 0xe3, 0x12, 0x0, 0xf9, 0x73, 0xe0, 0xe9, 0xc4, 0x53, 0x62, 0x58, 0xb2, 0x64, 0x39},
 			},
 			{
 				Name: "btree.h", Mode: 0x81a4,
-				Hash: core.Hash{0xac, 0xe0, 0xf8, 0xcd, 0x21, 0x77, 0x70, 0xa2, 0xf6, 0x6b, 0x2e, 0xb8, 0x71, 0xbb, 0xc5, 0xfd, 0xc6, 0xfc, 0x2b, 0x68},
+				Hash: plumbing.Hash{0xac, 0xe0, 0xf8, 0xcd, 0x21, 0x77, 0x70, 0xa2, 0xf6, 0x6b, 0x2e, 0xb8, 0x71, 0xbb, 0xc5, 0xfd, 0xc6, 0xfc, 0x2b, 0x68},
 			},
 			{
 				Name: "btreeInt.h", Mode: 0x81a4,
-				Hash: core.Hash{0xce, 0x3c, 0x54, 0x93, 0xf8, 0xca, 0xd0, 0xbc, 0x54, 0x8a, 0xe8, 0xe4, 0x4e, 0x51, 0x28, 0x31, 0xd8, 0xfa, 0xc4, 0x31},
+				Hash: plumbing.Hash{0xce, 0x3c, 0x54, 0x93, 0xf8, 0xca, 0xd0, 0xbc, 0x54, 0x8a, 0xe8, 0xe4, 0x4e, 0x51, 0x28, 0x31, 0xd8, 0xfa, 0xc4, 0x31},
 			},
 			{
 				Name: "build.c", Mode: 0x81a4,
-				Hash: core.Hash{0x3c, 0x91, 0xcd, 0xcf, 0xdb, 0x7b, 0x1, 0x7c, 0xbc, 0x2d, 0x5c, 0x29, 0x57, 0x1a, 0x98, 0x27, 0xd, 0xe0, 0x71, 0xe6},
+				Hash: plumbing.Hash{0x3c, 0x91, 0xcd, 0xcf, 0xdb, 0x7b, 0x1, 0x7c, 0xbc, 0x2d, 0x5c, 0x29, 0x57, 0x1a, 0x98, 0x27, 0xd, 0xe0, 0x71, 0xe6},
 			},
 			{
 				Name: "callback.c", Mode: 0x81a4,
-				Hash: core.Hash{0xd4, 0xc, 0x65, 0xcb, 0x92, 0x45, 0x80, 0x29, 0x6a, 0xd0, 0x69, 0xa0, 0x4b, 0xf9, 0xc9, 0xe9, 0x53, 0x4e, 0xca, 0xa7},
+				Hash: plumbing.Hash{0xd4, 0xc, 0x65, 0xcb, 0x92, 0x45, 0x80, 0x29, 0x6a, 0xd0, 0x69, 0xa0, 0x4b, 0xf9, 0xc9, 0xe9, 0x53, 0x4e, 0xca, 0xa7},
 			},
 			{
 				Name: "complete.c", Mode: 0x81a4,
-				Hash: core.Hash{0x9e, 0x91, 0x40, 0x8, 0x5c, 0x0, 0x46, 0xed, 0x3b, 0xf6, 0xf4, 0x48, 0x52, 0x20, 0x69, 0x2d, 0xca, 0x17, 0x43, 0xc5},
+				Hash: plumbing.Hash{0x9e, 0x91, 0x40, 0x8, 0x5c, 0x0, 0x46, 0xed, 0x3b, 0xf6, 0xf4, 0x48, 0x52, 0x20, 0x69, 0x2d, 0xca, 0x17, 0x43, 0xc5},
 			},
 			{
 				Name: "crypto.c", Mode: 0x81a4,
-				Hash: core.Hash{0x25, 0x51, 0xe6, 0xba, 0x2, 0x39, 0xf8, 0x5a, 0x35, 0x77, 0x96, 0xa8, 0xdd, 0xa8, 0xca, 0x3e, 0x29, 0x70, 0x93, 0xf8},
+				Hash: plumbing.Hash{0x25, 0x51, 0xe6, 0xba, 0x2, 0x39, 0xf8, 0x5a, 0x35, 0x77, 0x96, 0xa8, 0xdd, 0xa8, 0xca, 0x3e, 0x29, 0x70, 0x93, 0xf8},
 			},
 			{
 				Name: "crypto.h", Mode: 0x81a4,
-				Hash: core.Hash{0xf7, 0x1f, 0x53, 0x2c, 0xdc, 0x44, 0x8f, 0xa, 0x1d, 0xd5, 0xc6, 0xef, 0xf5, 0xfb, 0xd3, 0x3a, 0x91, 0x55, 0xaa, 0x97},
+				Hash: plumbing.Hash{0xf7, 0x1f, 0x53, 0x2c, 0xdc, 0x44, 0x8f, 0xa, 0x1d, 0xd5, 0xc6, 0xef, 0xf5, 0xfb, 0xd3, 0x3a, 0x91, 0x55, 0xaa, 0x97},
 			},
 			{
 				Name: "crypto_cc.c", Mode: 0x81a4,
-				Hash: core.Hash{0x53, 0x7d, 0xf7, 0xe3, 0xb3, 0x6a, 0xb5, 0xcf, 0xdd, 0x6f, 0xca, 0x40, 0x28, 0xeb, 0xca, 0xe1, 0x86, 0x87, 0xd6, 0x4d},
+				Hash: plumbing.Hash{0x53, 0x7d, 0xf7, 0xe3, 0xb3, 0x6a, 0xb5, 0xcf, 0xdd, 0x6f, 0xca, 0x40, 0x28, 0xeb, 0xca, 0xe1, 0x86, 0x87, 0xd6, 0x4d},
 			},
 			{
 				Name: "crypto_impl.c", Mode: 0x81a4,
-				Hash: core.Hash{0xa5, 0x89, 0x27, 0xc7, 0x6e, 0xf6, 0x20, 0x56, 0x77, 0xbe, 0x5c, 0x1a, 0x8e, 0x80, 0xc9, 0x83, 0x56, 0xb3, 0xa9, 0xd3},
+				Hash: plumbing.Hash{0xa5, 0x89, 0x27, 0xc7, 0x6e, 0xf6, 0x20, 0x56, 0x77, 0xbe, 0x5c, 0x1a, 0x8e, 0x80, 0xc9, 0x83, 0x56, 0xb3, 0xa9, 0xd3},
 			},
 			{
 				Name: "crypto_libtomcrypt.c", Mode: 0x81a4,
-				Hash: core.Hash{0x1a, 0x33, 0x83, 0xe0, 0x1, 0xa7, 0x21, 0x11, 0xc3, 0xf6, 0x61, 0x92, 0x22, 0xb0, 0x65, 0xf4, 0xbd, 0x1, 0xb, 0xe1},
+				Hash: plumbing.Hash{0x1a, 0x33, 0x83, 0xe0, 0x1, 0xa7, 0x21, 0x11, 0xc3, 0xf6, 0x61, 0x92, 0x22, 0xb0, 0x65, 0xf4, 0xbd, 0x1, 0xb, 0xe1},
 			},
 			{
 				Name: "crypto_openssl.c", Mode: 0x81a4,
-				Hash: core.Hash{0xd0, 0x19, 0x81, 0x3b, 0x47, 0x6c, 0x52, 0xd0, 0x20, 0xe2, 0xc0, 0xac, 0xd5, 0x24, 0xe9, 0xea, 0x3d, 0xf, 0xb9, 0xfe},
+				Hash: plumbing.Hash{0xd0, 0x19, 0x81, 0x3b, 0x47, 0x6c, 0x52, 0xd0, 0x20, 0xe2, 0xc0, 0xac, 0xd5, 0x24, 0xe9, 0xea, 0x3d, 0xf, 0xb9, 0xfe},
 			},
 			{
 				Name: "ctime.c", Mode: 0x81a4,
-				Hash: core.Hash{0x60, 0x59, 0x5f, 0xf8, 0x8d, 0x92, 0xf7, 0x8, 0x26, 0x4, 0xfb, 0xd9, 0xdf, 0x9a, 0xfe, 0xa1, 0x6a, 0xe8, 0x6f, 0xf},
+				Hash: plumbing.Hash{0x60, 0x59, 0x5f, 0xf8, 0x8d, 0x92, 0xf7, 0x8, 0x26, 0x4, 0xfb, 0xd9, 0xdf, 0x9a, 0xfe, 0xa1, 0x6a, 0xe8, 0x6f, 0xf},
 			},
 			{
 				Name: "date.c", Mode: 0x81a4,
-				Hash: core.Hash{0x75, 0x8d, 0xd7, 0xc8, 0x9b, 0xca, 0x39, 0x37, 0xa9, 0xd, 0x70, 0x6e, 0xa9, 0x82, 0xce, 0x3a, 0xcf, 0x11, 0xd1, 0x83},
+				Hash: plumbing.Hash{0x75, 0x8d, 0xd7, 0xc8, 0x9b, 0xca, 0x39, 0x37, 0xa9, 0xd, 0x70, 0x6e, 0xa9, 0x82, 0xce, 0x3a, 0xcf, 0x11, 0xd1, 0x83},
 			},
 			{
 				Name: "delete.c", Mode: 0x81a4,
-				Hash: core.Hash{0x63, 0x4e, 0x11, 0x55, 0x63, 0xae, 0x12, 0xba, 0x65, 0x58, 0xcc, 0xc5, 0x12, 0xae, 0xd6, 0x31, 0xc0, 0x66, 0xba, 0xd8},
+				Hash: plumbing.Hash{0x63, 0x4e, 0x11, 0x55, 0x63, 0xae, 0x12, 0xba, 0x65, 0x58, 0xcc, 0xc5, 0x12, 0xae, 0xd6, 0x31, 0xc0, 0x66, 0xba, 0xd8},
 			},
 			{
 				Name: "expr.c", Mode: 0x81a4,
-				Hash: core.Hash{0x66, 0x3, 0x97, 0xe0, 0x78, 0xae, 0x48, 0xb2, 0xe7, 0x17, 0x5e, 0x33, 0x85, 0x67, 0x78, 0x19, 0x72, 0x2d, 0xdd, 0x6c},
+				Hash: plumbing.Hash{0x66, 0x3, 0x97, 0xe0, 0x78, 0xae, 0x48, 0xb2, 0xe7, 0x17, 0x5e, 0x33, 0x85, 0x67, 0x78, 0x19, 0x72, 0x2d, 0xdd, 0x6c},
 			},
 			{
 				Name: "fault.c", Mode: 0x81a4,
-				Hash: core.Hash{0xc3, 0x2, 0x8c, 0x4f, 0x93, 0x6e, 0xdf, 0x96, 0x71, 0x2d, 0xbe, 0x73, 0xa0, 0x76, 0x62, 0xf0, 0xa2, 0x6b, 0x1d, 0xa},
+				Hash: plumbing.Hash{0xc3, 0x2, 0x8c, 0x4f, 0x93, 0x6e, 0xdf, 0x96, 0x71, 0x2d, 0xbe, 0x73, 0xa0, 0x76, 0x62, 0xf0, 0xa2, 0x6b, 0x1d, 0xa},
 			},
 			{
 				Name: "fkey.c", Mode: 0x81a4,
-				Hash: core.Hash{0xac, 0x35, 0xbc, 0x19, 0x4c, 0xde, 0xb1, 0x27, 0x98, 0x9b, 0x9, 0x40, 0x35, 0xce, 0xe0, 0x6f, 0x57, 0x37, 0x6f, 0x5e},
+				Hash: plumbing.Hash{0xac, 0x35, 0xbc, 0x19, 0x4c, 0xde, 0xb1, 0x27, 0x98, 0x9b, 0x9, 0x40, 0x35, 0xce, 0xe0, 0x6f, 0x57, 0x37, 0x6f, 0x5e},
 			},
 			{
 				Name: "func.c", Mode: 0x81a4,
-				Hash: core.Hash{0xc0, 0x2f, 0x9, 0x6a, 0xda, 0xd5, 0xbc, 0xe9, 0xac, 0x83, 0xd3, 0x5f, 0xf, 0x46, 0x9, 0xd6, 0xf6, 0xd4, 0x3b, 0xe5},
+				Hash: plumbing.Hash{0xc0, 0x2f, 0x9, 0x6a, 0xda, 0xd5, 0xbc, 0xe9, 0xac, 0x83, 0xd3, 0x5f, 0xf, 0x46, 0x9, 0xd6, 0xf6, 0xd4, 0x3b, 0xe5},
 			},
 			{
 				Name: "global.c", Mode: 0x81a4,
-				Hash: core.Hash{0x7b, 0x2, 0xcf, 0x21, 0x30, 0xe0, 0xd1, 0xa7, 0xb8, 0x89, 0xd8, 0x44, 0xc, 0xcc, 0x82, 0x8, 0xf7, 0xb6, 0x7b, 0xf9},
+				Hash: plumbing.Hash{0x7b, 0x2, 0xcf, 0x21, 0x30, 0xe0, 0xd1, 0xa7, 0xb8, 0x89, 0xd8, 0x44, 0xc, 0xcc, 0x82, 0x8, 0xf7, 0xb6, 0x7b, 0xf9},
 			},
 			{
 				Name: "hash.c", Mode: 0x81a4,
-				Hash: core.Hash{0xe8, 0x1d, 0xcf, 0x95, 0xe4, 0x38, 0x48, 0xfa, 0x70, 0x86, 0xb7, 0xf7, 0x81, 0xc0, 0x90, 0xad, 0xc7, 0xe6, 0xca, 0x8e},
+				Hash: plumbing.Hash{0xe8, 0x1d, 0xcf, 0x95, 0xe4, 0x38, 0x48, 0xfa, 0x70, 0x86, 0xb7, 0xf7, 0x81, 0xc0, 0x90, 0xad, 0xc7, 0xe6, 0xca, 0x8e},
 			},
 			{
 				Name: "hash.h", Mode: 0x81a4,
-				Hash: core.Hash{0x82, 0xb7, 0xc5, 0x8c, 0x71, 0x9, 0xb, 0x54, 0x7e, 0x10, 0x17, 0x42, 0xaa, 0x9, 0x51, 0x73, 0x9f, 0xf2, 0xee, 0xe7},
+				Hash: plumbing.Hash{0x82, 0xb7, 0xc5, 0x8c, 0x71, 0x9, 0xb, 0x54, 0x7e, 0x10, 0x17, 0x42, 0xaa, 0x9, 0x51, 0x73, 0x9f, 0xf2, 0xee, 0xe7},
 			},
 			{
 				Name: "hwtime.h", Mode: 0x81a4,
-				Hash: core.Hash{0xb8, 0xbc, 0x5a, 0x29, 0x5b, 0xe3, 0xfa, 0xc8, 0x35, 0x1f, 0xa9, 0xf0, 0x8a, 0x77, 0x57, 0x9d, 0x59, 0xc9, 0xa8, 0xe4},
+				Hash: plumbing.Hash{0xb8, 0xbc, 0x5a, 0x29, 0x5b, 0xe3, 0xfa, 0xc8, 0x35, 0x1f, 0xa9, 0xf0, 0x8a, 0x77, 0x57, 0x9d, 0x59, 0xc9, 0xa8, 0xe4},
 			},
 			{
 				Name: "insert.c", Mode: 0x81a4,
-				Hash: core.Hash{0x9a, 0x56, 0x61, 0xf5, 0x9a, 0x72, 0x95, 0x2b, 0xe6, 0xc1, 0x67, 0xa0, 0xc2, 0xdb, 0x15, 0x9b, 0x91, 0xb7, 0x1f, 0xae},
+				Hash: plumbing.Hash{0x9a, 0x56, 0x61, 0xf5, 0x9a, 0x72, 0x95, 0x2b, 0xe6, 0xc1, 0x67, 0xa0, 0xc2, 0xdb, 0x15, 0x9b, 0x91, 0xb7, 0x1f, 0xae},
 			},
 			{
 				Name: "journal.c", Mode: 0x81a4,
-				Hash: core.Hash{0xfe, 0xd2, 0x7b, 0xe3, 0xe3, 0x80, 0x55, 0xd2, 0x20, 0x43, 0x95, 0xcd, 0xe6, 0xff, 0xc9, 0x45, 0x89, 0xfb, 0xf5, 0xe8},
+				Hash: plumbing.Hash{0xfe, 0xd2, 0x7b, 0xe3, 0xe3, 0x80, 0x55, 0xd2, 0x20, 0x43, 0x95, 0xcd, 0xe6, 0xff, 0xc9, 0x45, 0x89, 0xfb, 0xf5, 0xe8},
 			},
 			{
 				Name: "legacy.c", Mode: 0x81a4,
-				Hash: core.Hash{0x94, 0x64, 0x9a, 0xe7, 0x5, 0xab, 0x93, 0x85, 0x10, 0x8d, 0xd, 0x88, 0x7a, 0xf0, 0x75, 0x92, 0x89, 0xfb, 0x23, 0xcb},
+				Hash: plumbing.Hash{0x94, 0x64, 0x9a, 0xe7, 0x5, 0xab, 0x93, 0x85, 0x10, 0x8d, 0xd, 0x88, 0x7a, 0xf0, 0x75, 0x92, 0x89, 0xfb, 0x23, 0xcb},
 			},
 			{
 				Name: "lempar.c", Mode: 0x81a4,
-				Hash: core.Hash{0x2a, 0xfa, 0xa6, 0xce, 0xa6, 0xd8, 0x29, 0x60, 0x2c, 0x27, 0x86, 0xc1, 0xf8, 0xa3, 0x7f, 0x56, 0x7c, 0xf6, 0xfd, 0x53},
+				Hash: plumbing.Hash{0x2a, 0xfa, 0xa6, 0xce, 0xa6, 0xd8, 0x29, 0x60, 0x2c, 0x27, 0x86, 0xc1, 0xf8, 0xa3, 0x7f, 0x56, 0x7c, 0xf6, 0xfd, 0x53},
 			},
 			{
 				Name: "loadext.c", Mode: 0x81a4,
-				Hash: core.Hash{0xcd, 0xcf, 0x6a, 0x93, 0xb8, 0xc4, 0xf, 0x91, 0x4b, 0x94, 0x24, 0xe, 0xf1, 0x4c, 0xb4, 0xa3, 0xa, 0x37, 0xec, 0xa1},
+				Hash: plumbing.Hash{0xcd, 0xcf, 0x6a, 0x93, 0xb8, 0xc4, 0xf, 0x91, 0x4b, 0x94, 0x24, 0xe, 0xf1, 0x4c, 0xb4, 0xa3, 0xa, 0x37, 0xec, 0xa1},
 			},
 			{
 				Name: "main.c", Mode: 0x81a4,
-				Hash: core.Hash{0x39, 0xf6, 0x4, 0x21, 0xe6, 0x81, 0x27, 0x7c, 0xc3, 0xdb, 0xa0, 0x9a, 0xbe, 0x7c, 0xf7, 0x90, 0xd5, 0x28, 0xf5, 0xc3},
+				Hash: plumbing.Hash{0x39, 0xf6, 0x4, 0x21, 0xe6, 0x81, 0x27, 0x7c, 0xc3, 0xdb, 0xa0, 0x9a, 0xbe, 0x7c, 0xf7, 0x90, 0xd5, 0x28, 0xf5, 0xc3},
 			},
 			{
 				Name: "malloc.c", Mode: 0x81a4,
-				Hash: core.Hash{0x35, 0xa4, 0x4e, 0x5f, 0x61, 0xc2, 0xe4, 0x4c, 0x48, 0x1c, 0x62, 0x51, 0xbd, 0xa, 0xae, 0x7a, 0xcd, 0xa4, 0xde, 0xb},
+				Hash: plumbing.Hash{0x35, 0xa4, 0x4e, 0x5f, 0x61, 0xc2, 0xe4, 0x4c, 0x48, 0x1c, 0x62, 0x51, 0xbd, 0xa, 0xae, 0x7a, 0xcd, 0xa4, 0xde, 0xb},
 			},
 			{
 				Name: "mem0.c", Mode: 0x81a4,
-				Hash: core.Hash{0xd, 0xb, 0x66, 0x67, 0xd6, 0xa, 0x95, 0x5a, 0x6, 0x96, 0xdf, 0x62, 0x89, 0xb4, 0x91, 0x78, 0x96, 0x93, 0x43, 0xaa},
+				Hash: plumbing.Hash{0xd, 0xb, 0x66, 0x67, 0xd6, 0xa, 0x95, 0x5a, 0x6, 0x96, 0xdf, 0x62, 0x89, 0xb4, 0x91, 0x78, 0x96, 0x93, 0x43, 0xaa},
 			},
 			{
 				Name: "mem1.c", Mode: 0x81a4,
-				Hash: core.Hash{0x35, 0x78, 0x49, 0x6f, 0x33, 0x3, 0x7, 0xb2, 0x31, 0xdf, 0xb5, 0x3c, 0xc, 0x2e, 0x1c, 0x6b, 0x32, 0x3d, 0x79, 0x1e},
+				Hash: plumbing.Hash{0x35, 0x78, 0x49, 0x6f, 0x33, 0x3, 0x7, 0xb2, 0x31, 0xdf, 0xb5, 0x3c, 0xc, 0x2e, 0x1c, 0x6b, 0x32, 0x3d, 0x79, 0x1e},
 			},
 			{
 				Name: "mem2.c", Mode: 0x81a4,
-				Hash: core.Hash{0x26, 0x44, 0x8e, 0xa8, 0xaa, 0xe0, 0x36, 0x6a, 0xf0, 0x54, 0x1a, 0xfe, 0xa4, 0x79, 0xb, 0x42, 0xf4, 0xa6, 0x9b, 0x5a},
+				Hash: plumbing.Hash{0x26, 0x44, 0x8e, 0xa8, 0xaa, 0xe0, 0x36, 0x6a, 0xf0, 0x54, 0x1a, 0xfe, 0xa4, 0x79, 0xb, 0x42, 0xf4, 0xa6, 0x9b, 0x5a},
 			},
 			{
 				Name: "mem3.c", Mode: 0x81a4,
-				Hash: core.Hash{0x1a, 0x1b, 0x79, 0x1f, 0x28, 0xf8, 0xcf, 0x3c, 0xe4, 0xf9, 0xa3, 0x5c, 0xda, 0xd7, 0xb7, 0x10, 0x75, 0x68, 0xc7, 0x15},
+				Hash: plumbing.Hash{0x1a, 0x1b, 0x79, 0x1f, 0x28, 0xf8, 0xcf, 0x3c, 0xe4, 0xf9, 0xa3, 0x5c, 0xda, 0xd7, 0xb7, 0x10, 0x75, 0x68, 0xc7, 0x15},
 			},
 			{
 				Name: "mem5.c", Mode: 0x81a4,
-				Hash: core.Hash{0x78, 0x3c, 0xef, 0x61, 0x76, 0xc5, 0x9c, 0xbf, 0x30, 0x91, 0x46, 0x31, 0x9, 0x5a, 0x1a, 0x54, 0xf4, 0xe4, 0x2e, 0x8},
+				Hash: plumbing.Hash{0x78, 0x3c, 0xef, 0x61, 0x76, 0xc5, 0x9c, 0xbf, 0x30, 0x91, 0x46, 0x31, 0x9, 0x5a, 0x1a, 0x54, 0xf4, 0xe4, 0x2e, 0x8},
 			},
 			{
 				Name: "memjournal.c", Mode: 0x81a4,
-				Hash: core.Hash{0x5, 0x72, 0x59, 0x48, 0xf6, 0x5d, 0x42, 0x7b, 0x7, 0xf7, 0xf9, 0x29, 0xac, 0xa3, 0xff, 0x22, 0x4b, 0x17, 0x53, 0xdf},
+				Hash: plumbing.Hash{0x5, 0x72, 0x59, 0x48, 0xf6, 0x5d, 0x42, 0x7b, 0x7, 0xf7, 0xf9, 0x29, 0xac, 0xa3, 0xff, 0x22, 0x4b, 0x17, 0x53, 0xdf},
 			},
 			{
 				Name: "mutex.c", Mode: 0x81a4,
-				Hash: core.Hash{0xb5, 0x67, 0xe7, 0xc2, 0x7e, 0xf2, 0x4, 0x10, 0x86, 0xaf, 0xe0, 0xf6, 0x96, 0x66, 0xe2, 0x7b, 0xf5, 0x9, 0x8a, 0x59},
+				Hash: plumbing.Hash{0xb5, 0x67, 0xe7, 0xc2, 0x7e, 0xf2, 0x4, 0x10, 0x86, 0xaf, 0xe0, 0xf6, 0x96, 0x66, 0xe2, 0x7b, 0xf5, 0x9, 0x8a, 0x59},
 			},
 			{
 				Name: "mutex.h", Mode: 0x81a4,
-				Hash: core.Hash{0x9, 0x78, 0x81, 0x22, 0x52, 0x77, 0x89, 0xa, 0x9c, 0x36, 0xc2, 0x4d, 0x41, 0xf6, 0x11, 0x4d, 0x64, 0xc0, 0x6d, 0xb3},
+				Hash: plumbing.Hash{0x9, 0x78, 0x81, 0x22, 0x52, 0x77, 0x89, 0xa, 0x9c, 0x36, 0xc2, 0x4d, 0x41, 0xf6, 0x11, 0x4d, 0x64, 0xc0, 0x6d, 0xb3},
 			},
 			{
 				Name: "mutex_noop.c", Mode: 0x81a4,
-				Hash: core.Hash{0x45, 0x6e, 0x82, 0xa2, 0x5e, 0x27, 0x1b, 0x6, 0x14, 0xe7, 0xf4, 0xf8, 0x3c, 0x22, 0x85, 0x53, 0xb7, 0xfa, 0x1, 0x58},
+				Hash: plumbing.Hash{0x45, 0x6e, 0x82, 0xa2, 0x5e, 0x27, 0x1b, 0x6, 0x14, 0xe7, 0xf4, 0xf8, 0x3c, 0x22, 0x85, 0x53, 0xb7, 0xfa, 0x1, 0x58},
 			},
 			{
 				Name: "mutex_unix.c", Mode: 0x81a4,
-				Hash: core.Hash{0xec, 0xa7, 0x29, 0x58, 0x31, 0xc2, 0xf0, 0xee, 0x48, 0xba, 0x54, 0xd0, 0x62, 0x91, 0x4d, 0x6, 0xa1, 0xdd, 0x8e, 0xbe},
+				Hash: plumbing.Hash{0xec, 0xa7, 0x29, 0x58, 0x31, 0xc2, 0xf0, 0xee, 0x48, 0xba, 0x54, 0xd0, 0x62, 0x91, 0x4d, 0x6, 0xa1, 0xdd, 0x8e, 0xbe},
 			},
 			{
 				Name: "mutex_w32.c", Mode: 0x81a4,
-				Hash: core.Hash{0x27, 0xd1, 0xa, 0xf5, 0xbd, 0x33, 0x1b, 0xdb, 0x97, 0x3f, 0x61, 0x45, 0xb7, 0x4f, 0x72, 0xb6, 0x7, 0xcf, 0xc4, 0x6e},
+				Hash: plumbing.Hash{0x27, 0xd1, 0xa, 0xf5, 0xbd, 0x33, 0x1b, 0xdb, 0x97, 0x3f, 0x61, 0x45, 0xb7, 0x4f, 0x72, 0xb6, 0x7, 0xcf, 0xc4, 0x6e},
 			},
 			{
 				Name: "notify.c", Mode: 0x81a4,
-				Hash: core.Hash{0xfc, 0xab, 0x5b, 0xfa, 0xf0, 0x19, 0x8, 0xd3, 0xde, 0x93, 0xfa, 0x88, 0xb5, 0xea, 0xe9, 0xe9, 0x6c, 0xa3, 0xc8, 0xe8},
+				Hash: plumbing.Hash{0xfc, 0xab, 0x5b, 0xfa, 0xf0, 0x19, 0x8, 0xd3, 0xde, 0x93, 0xfa, 0x88, 0xb5, 0xea, 0xe9, 0xe9, 0x6c, 0xa3, 0xc8, 0xe8},
 			},
 			{
 				Name: "os.c", Mode: 0x81a4,
-				Hash: core.Hash{0xbe, 0x2e, 0xa4, 0xcf, 0xc0, 0x19, 0x59, 0x93, 0xa3, 0x40, 0xc9, 0x2, 0xae, 0xdd, 0xf1, 0xbe, 0x4b, 0x8e, 0xd7, 0x3a},
+				Hash: plumbing.Hash{0xbe, 0x2e, 0xa4, 0xcf, 0xc0, 0x19, 0x59, 0x93, 0xa3, 0x40, 0xc9, 0x2, 0xae, 0xdd, 0xf1, 0xbe, 0x4b, 0x8e, 0xd7, 0x3a},
 			},
 			{
 				Name: "os.h", Mode: 0x81a4,
-				Hash: core.Hash{0x7, 0xa, 0x2d, 0xdd, 0x17, 0xf7, 0x71, 0xf9, 0x8f, 0xf8, 0xcc, 0xd6, 0xf0, 0x33, 0xbd, 0xac, 0xc5, 0xe9, 0xf6, 0xc},
+				Hash: plumbing.Hash{0x7, 0xa, 0x2d, 0xdd, 0x17, 0xf7, 0x71, 0xf9, 0x8f, 0xf8, 0xcc, 0xd6, 0xf0, 0x33, 0xbd, 0xac, 0xc5, 0xe9, 0xf6, 0xc},
 			},
 			{
 				Name: "os_common.h", Mode: 0x81a4,
-				Hash: core.Hash{0xf6, 0xc3, 0xe7, 0xff, 0x89, 0x46, 0x30, 0x86, 0x40, 0x18, 0x22, 0xf4, 0x81, 0xe7, 0xe3, 0xb8, 0x7b, 0x2c, 0x78, 0xc7},
+				Hash: plumbing.Hash{0xf6, 0xc3, 0xe7, 0xff, 0x89, 0x46, 0x30, 0x86, 0x40, 0x18, 0x22, 0xf4, 0x81, 0xe7, 0xe3, 0xb8, 0x7b, 0x2c, 0x78, 0xc7},
 			},
 			{
 				Name: "os_unix.c", Mode: 0x81a4,
-				Hash: core.Hash{0xab, 0xc2, 0x3a, 0x45, 0x2e, 0x72, 0xf7, 0x1c, 0x76, 0xaf, 0xa9, 0x98, 0x3c, 0x3a, 0xd9, 0xd4, 0x25, 0x61, 0x6c, 0x6d},
+				Hash: plumbing.Hash{0xab, 0xc2, 0x3a, 0x45, 0x2e, 0x72, 0xf7, 0x1c, 0x76, 0xaf, 0xa9, 0x98, 0x3c, 0x3a, 0xd9, 0xd4, 0x25, 0x61, 0x6c, 0x6d},
 			},
 			{
 				Name: "os_win.c", Mode: 0x81a4,
-				Hash: core.Hash{0xae, 0xb0, 0x88, 0x14, 0xb3, 0xda, 0xbe, 0x81, 0xb8, 0x4c, 0xda, 0x91, 0x85, 0x82, 0xb0, 0xf, 0xfd, 0x86, 0xe4, 0x87},
+				Hash: plumbing.Hash{0xae, 0xb0, 0x88, 0x14, 0xb3, 0xda, 0xbe, 0x81, 0xb8, 0x4c, 0xda, 0x91, 0x85, 0x82, 0xb0, 0xf, 0xfd, 0x86, 0xe4, 0x87},
 			},
 			{
 				Name: "pager.c", Mode: 0x81a4,
-				Hash: core.Hash{0x61, 0x72, 0x7f, 0xaa, 0x9c, 0xf, 0x3d, 0x56, 0x62, 0x65, 0xbe, 0x7e, 0xec, 0x5b, 0x2a, 0x35, 0xf6, 0xa4, 0xbc, 0x9f},
+				Hash: plumbing.Hash{0x61, 0x72, 0x7f, 0xaa, 0x9c, 0xf, 0x3d, 0x56, 0x62, 0x65, 0xbe, 0x7e, 0xec, 0x5b, 0x2a, 0x35, 0xf6, 0xa4, 0xbc, 0x9f},
 			},
 			{
 				Name: "pager.h", Mode: 0x81a4,
-				Hash: core.Hash{0x6f, 0x65, 0x91, 0x36, 0xe2, 0x76, 0x7, 0x9d, 0xa4, 0x3a, 0x2e, 0x39, 0xe1, 0xb6, 0x86, 0x37, 0xec, 0xad, 0xcf, 0x68},
+				Hash: plumbing.Hash{0x6f, 0x65, 0x91, 0x36, 0xe2, 0x76, 0x7, 0x9d, 0xa4, 0x3a, 0x2e, 0x39, 0xe1, 0xb6, 0x86, 0x37, 0xec, 0xad, 0xcf, 0x68},
 			},
 			{
 				Name: "parse.y", Mode: 0x81a4,
-				Hash: core.Hash{0x83, 0x10, 0xb2, 0x69, 0x89, 0xb0, 0x5b, 0xed, 0x1e, 0x1b, 0x3, 0xda, 0x80, 0xf5, 0xc0, 0xa5, 0x2e, 0x9a, 0xd1, 0xd2},
+				Hash: plumbing.Hash{0x83, 0x10, 0xb2, 0x69, 0x89, 0xb0, 0x5b, 0xed, 0x1e, 0x1b, 0x3, 0xda, 0x80, 0xf5, 0xc0, 0xa5, 0x2e, 0x9a, 0xd1, 0xd2},
 			},
 			{
 				Name: "pcache.c", Mode: 0x81a4,
-				Hash: core.Hash{0x48, 0x2a, 0x18, 0x8b, 0xee, 0x19, 0x91, 0xbc, 0x8a, 0xda, 0xc9, 0x6a, 0x19, 0x3a, 0x53, 0xe5, 0x46, 0x2a, 0x8c, 0x10},
+				Hash: plumbing.Hash{0x48, 0x2a, 0x18, 0x8b, 0xee, 0x19, 0x91, 0xbc, 0x8a, 0xda, 0xc9, 0x6a, 0x19, 0x3a, 0x53, 0xe5, 0x46, 0x2a, 0x8c, 0x10},
 			},
 			{
 				Name: "pcache.h", Mode: 0x81a4,
-				Hash: core.Hash{0xf4, 0xd4, 0xad, 0x71, 0xc1, 0xd, 0x78, 0xc6, 0xda, 0xbd, 0xe2, 0x52, 0x15, 0xcd, 0x41, 0x5a, 0x76, 0x1, 0x48, 0xca},
+				Hash: plumbing.Hash{0xf4, 0xd4, 0xad, 0x71, 0xc1, 0xd, 0x78, 0xc6, 0xda, 0xbd, 0xe2, 0x52, 0x15, 0xcd, 0x41, 0x5a, 0x76, 0x1, 0x48, 0xca},
 			},
 			{
 				Name: "pcache1.c", Mode: 0x81a4,
-				Hash: core.Hash{0x41, 0x47, 0xd2, 0xef, 0xf5, 0x5b, 0xdd, 0x9f, 0xf7, 0xc6, 0x86, 0xc, 0x60, 0x18, 0x10, 0x20, 0x16, 0x6c, 0x5f, 0x50},
+				Hash: plumbing.Hash{0x41, 0x47, 0xd2, 0xef, 0xf5, 0x5b, 0xdd, 0x9f, 0xf7, 0xc6, 0x86, 0xc, 0x60, 0x18, 0x10, 0x20, 0x16, 0x6c, 0x5f, 0x50},
 			},
 			{
 				Name: "pragma.c", Mode: 0x81a4,
-				Hash: core.Hash{0x22, 0x97, 0x71, 0x69, 0x61, 0x7d, 0x49, 0x22, 0xb3, 0x99, 0x3f, 0x76, 0x9d, 0x90, 0xfa, 0x7b, 0xc4, 0x41, 0xea, 0x50},
+				Hash: plumbing.Hash{0x22, 0x97, 0x71, 0x69, 0x61, 0x7d, 0x49, 0x22, 0xb3, 0x99, 0x3f, 0x76, 0x9d, 0x90, 0xfa, 0x7b, 0xc4, 0x41, 0xea, 0x50},
 			},
 			{
 				Name: "prepare.c", Mode: 0x81a4,
-				Hash: core.Hash{0xd7, 0x8d, 0x83, 0xcb, 0xd8, 0x78, 0x97, 0xf5, 0x73, 0x30, 0x3f, 0x9f, 0x57, 0xab, 0x8d, 0xe0, 0x24, 0xa6, 0xe3, 0xf8},
+				Hash: plumbing.Hash{0xd7, 0x8d, 0x83, 0xcb, 0xd8, 0x78, 0x97, 0xf5, 0x73, 0x30, 0x3f, 0x9f, 0x57, 0xab, 0x8d, 0xe0, 0x24, 0xa6, 0xe3, 0xf8},
 			},
 			{
 				Name: "printf.c", Mode: 0x81a4,
-				Hash: core.Hash{0x9f, 0x68, 0xd2, 0x4, 0xff, 0xdc, 0x9f, 0x3d, 0x42, 0x7f, 0x80, 0xa8, 0x23, 0x9a, 0x7f, 0xa3, 0xa9, 0x8a, 0xec, 0xbd},
+				Hash: plumbing.Hash{0x9f, 0x68, 0xd2, 0x4, 0xff, 0xdc, 0x9f, 0x3d, 0x42, 0x7f, 0x80, 0xa8, 0x23, 0x9a, 0x7f, 0xa3, 0xa9, 0x8a, 0xec, 0xbd},
 			},
 			{
 				Name: "random.c", Mode: 0x81a4,
-				Hash: core.Hash{0x23, 0x4e, 0xbd, 0xf6, 0x58, 0xf4, 0x36, 0xcc, 0x7c, 0x68, 0xf0, 0x27, 0xc4, 0x8b, 0xe, 0x1b, 0x9b, 0xa3, 0x4e, 0x98},
+				Hash: plumbing.Hash{0x23, 0x4e, 0xbd, 0xf6, 0x58, 0xf4, 0x36, 0xcc, 0x7c, 0x68, 0xf0, 0x27, 0xc4, 0x8b, 0xe, 0x1b, 0x9b, 0xa3, 0x4e, 0x98},
 			},
 			{
 				Name: "resolve.c", Mode: 0x81a4,
-				Hash: core.Hash{0x91, 0xef, 0xca, 0xa1, 0xa1, 0x6b, 0xfc, 0x98, 0xfb, 0x35, 0xd8, 0x5c, 0xad, 0x15, 0x6b, 0x93, 0x53, 0x3e, 0x4e, 0x6},
+				Hash: plumbing.Hash{0x91, 0xef, 0xca, 0xa1, 0xa1, 0x6b, 0xfc, 0x98, 0xfb, 0x35, 0xd8, 0x5c, 0xad, 0x15, 0x6b, 0x93, 0x53, 0x3e, 0x4e, 0x6},
 			},
 			{
 				Name: "rowset.c", Mode: 0x81a4,
-				Hash: core.Hash{0x57, 0x61, 0xf9, 0x85, 0x50, 0xb1, 0x76, 0xcc, 0xe1, 0x1d, 0xcb, 0xce, 0xc9, 0x38, 0x99, 0xa0, 0x75, 0xbb, 0x64, 0xfd},
+				Hash: plumbing.Hash{0x57, 0x61, 0xf9, 0x85, 0x50, 0xb1, 0x76, 0xcc, 0xe1, 0x1d, 0xcb, 0xce, 0xc9, 0x38, 0x99, 0xa0, 0x75, 0xbb, 0x64, 0xfd},
 			},
 			{
 				Name: "select.c", Mode: 0x81a4,
-				Hash: core.Hash{0xf3, 0xf1, 0x49, 0x9, 0x63, 0x95, 0x5b, 0x8e, 0xd0, 0xc9, 0xfe, 0x6e, 0x1e, 0xec, 0x83, 0x6c, 0x1a, 0x52, 0x94, 0xb4},
+				Hash: plumbing.Hash{0xf3, 0xf1, 0x49, 0x9, 0x63, 0x95, 0x5b, 0x8e, 0xd0, 0xc9, 0xfe, 0x6e, 0x1e, 0xec, 0x83, 0x6c, 0x1a, 0x52, 0x94, 0xb4},
 			},
 			{
 				Name: "shell.c", Mode: 0x81a4,
-				Hash: core.Hash{0x1b, 0xe2, 0x87, 0x1f, 0xed, 0x9a, 0x1f, 0xdf, 0x1d, 0xf7, 0x19, 0x8e, 0x11, 0x25, 0x36, 0x0, 0xec, 0xba, 0x76, 0xcc},
+				Hash: plumbing.Hash{0x1b, 0xe2, 0x87, 0x1f, 0xed, 0x9a, 0x1f, 0xdf, 0x1d, 0xf7, 0x19, 0x8e, 0x11, 0x25, 0x36, 0x0, 0xec, 0xba, 0x76, 0xcc},
 			},
 			{
 				Name: "sqlcipher.h", Mode: 0x81a4,
-				Hash: core.Hash{0x82, 0x75, 0x30, 0x95, 0xcd, 0x17, 0x23, 0xc5, 0xff, 0x4f, 0x11, 0x15, 0xe4, 0x97, 0x55, 0x91, 0xee, 0x34, 0xf5, 0xce},
+				Hash: plumbing.Hash{0x82, 0x75, 0x30, 0x95, 0xcd, 0x17, 0x23, 0xc5, 0xff, 0x4f, 0x11, 0x15, 0xe4, 0x97, 0x55, 0x91, 0xee, 0x34, 0xf5, 0xce},
 			},
 			{
 				Name: "sqlite.h.in", Mode: 0x81a4,
-				Hash: core.Hash{0x66, 0x8, 0x82, 0x31, 0x75, 0xde, 0x5b, 0x6a, 0xd, 0x37, 0x8f, 0xdb, 0xc, 0x38, 0x18, 0xb6, 0xab, 0x4f, 0xbf, 0x8e},
+				Hash: plumbing.Hash{0x66, 0x8, 0x82, 0x31, 0x75, 0xde, 0x5b, 0x6a, 0xd, 0x37, 0x8f, 0xdb, 0xc, 0x38, 0x18, 0xb6, 0xab, 0x4f, 0xbf, 0x8e},
 			},
 			{
 				Name: "sqlite3.rc", Mode: 0x81a4,
-				Hash: core.Hash{0x96, 0x98, 0x76, 0xda, 0x1e, 0x57, 0x14, 0x3d, 0xe0, 0xb4, 0xd1, 0xc7, 0x62, 0x9f, 0xd3, 0x35, 0x6f, 0x2e, 0x1c, 0x96},
+				Hash: plumbing.Hash{0x96, 0x98, 0x76, 0xda, 0x1e, 0x57, 0x14, 0x3d, 0xe0, 0xb4, 0xd1, 0xc7, 0x62, 0x9f, 0xd3, 0x35, 0x6f, 0x2e, 0x1c, 0x96},
 			},
 			{
 				Name: "sqlite3ext.h", Mode: 0x81a4,
-				Hash: core.Hash{0x92, 0x8b, 0xb3, 0xba, 0xd9, 0xdd, 0x64, 0x3c, 0x30, 0x1d, 0xd2, 0xb0, 0xac, 0x22, 0x28, 0x7a, 0x81, 0x28, 0x48, 0x84},
+				Hash: plumbing.Hash{0x92, 0x8b, 0xb3, 0xba, 0xd9, 0xdd, 0x64, 0x3c, 0x30, 0x1d, 0xd2, 0xb0, 0xac, 0x22, 0x28, 0x7a, 0x81, 0x28, 0x48, 0x84},
 			},
 			{
 				Name: "sqliteInt.h", Mode: 0x81a4,
-				Hash: core.Hash{0x59, 0x50, 0xf2, 0x37, 0xd9, 0xf9, 0xf2, 0xd3, 0xef, 0x6b, 0xd8, 0xbe, 0x34, 0x2d, 0xcf, 0x64, 0x89, 0x22, 0x51, 0x42},
+				Hash: plumbing.Hash{0x59, 0x50, 0xf2, 0x37, 0xd9, 0xf9, 0xf2, 0xd3, 0xef, 0x6b, 0xd8, 0xbe, 0x34, 0x2d, 0xcf, 0x64, 0x89, 0x22, 0x51, 0x42},
 			},
 			{
 				Name: "sqliteLimit.h", Mode: 0x81a4,
-				Hash: core.Hash{0xc7, 0xae, 0xe5, 0x3c, 0xeb, 0xca, 0x94, 0xda, 0x51, 0xe7, 0x1a, 0x82, 0x2e, 0xa5, 0xa6, 0xde, 0xb9, 0x3, 0x85, 0xdf},
+				Hash: plumbing.Hash{0xc7, 0xae, 0xe5, 0x3c, 0xeb, 0xca, 0x94, 0xda, 0x51, 0xe7, 0x1a, 0x82, 0x2e, 0xa5, 0xa6, 0xde, 0xb9, 0x3, 0x85, 0xdf},
 			},
 			{
 				Name: "status.c", Mode: 0x81a4,
-				Hash: core.Hash{0x28, 0x34, 0x9e, 0x6d, 0x3d, 0x20, 0x88, 0xe0, 0x0, 0x3b, 0x76, 0xf8, 0xa, 0x89, 0x54, 0xfa, 0xec, 0x59, 0x30, 0xba},
+				Hash: plumbing.Hash{0x28, 0x34, 0x9e, 0x6d, 0x3d, 0x20, 0x88, 0xe0, 0x0, 0x3b, 0x76, 0xf8, 0xa, 0x89, 0x54, 0xfa, 0xec, 0x59, 0x30, 0xba},
 			},
 			{
 				Name: "table.c", Mode: 0x81a4,
-				Hash: core.Hash{0x26, 0xbb, 0xfb, 0x4f, 0x45, 0x6c, 0x42, 0x98, 0x25, 0x29, 0xea, 0x1a, 0x63, 0xa0, 0x17, 0x51, 0xdd, 0x3e, 0xe9, 0x5a},
+				Hash: plumbing.Hash{0x26, 0xbb, 0xfb, 0x4f, 0x45, 0x6c, 0x42, 0x98, 0x25, 0x29, 0xea, 0x1a, 0x63, 0xa0, 0x17, 0x51, 0xdd, 0x3e, 0xe9, 0x5a},
 			},
 			{
 				Name: "tclsqlite.c", Mode: 0x81a4,
-				Hash: core.Hash{0xf1, 0xbb, 0x29, 0x21, 0xda, 0xc, 0x68, 0xa4, 0xf1, 0xc8, 0xe1, 0x5c, 0xf5, 0x66, 0xb2, 0x33, 0xe9, 0x2a, 0x51, 0x9f},
+				Hash: plumbing.Hash{0xf1, 0xbb, 0x29, 0x21, 0xda, 0xc, 0x68, 0xa4, 0xf1, 0xc8, 0xe1, 0x5c, 0xf5, 0x66, 0xb2, 0x33, 0xe9, 0x2a, 0x51, 0x9f},
 			},
 			{
 				Name: "test1.c", Mode: 0x81a4,
-				Hash: core.Hash{0xa6, 0x38, 0xe4, 0x80, 0xad, 0xdf, 0x14, 0x43, 0x9c, 0xdf, 0xa4, 0xee, 0x16, 0x4d, 0xc3, 0x1b, 0x79, 0xf8, 0xbc, 0xac},
+				Hash: plumbing.Hash{0xa6, 0x38, 0xe4, 0x80, 0xad, 0xdf, 0x14, 0x43, 0x9c, 0xdf, 0xa4, 0xee, 0x16, 0x4d, 0xc3, 0x1b, 0x79, 0xf8, 0xbc, 0xac},
 			},
 			{
 				Name: "test2.c", Mode: 0x81a4,
-				Hash: core.Hash{0xd1, 0x30, 0xe9, 0xd0, 0x1b, 0x70, 0x24, 0xa5, 0xec, 0x6d, 0x73, 0x5, 0x92, 0xee, 0x4d, 0x1f, 0xb0, 0x2c, 0xfd, 0xb4},
+				Hash: plumbing.Hash{0xd1, 0x30, 0xe9, 0xd0, 0x1b, 0x70, 0x24, 0xa5, 0xec, 0x6d, 0x73, 0x5, 0x92, 0xee, 0x4d, 0x1f, 0xb0, 0x2c, 0xfd, 0xb4},
 			},
 			{
 				Name: "test3.c", Mode: 0x81a4,
-				Hash: core.Hash{0xe3, 0xed, 0x31, 0xc, 0x81, 0x4, 0xfe, 0x36, 0x21, 0xce, 0xbb, 0xf, 0x51, 0xd1, 0x1, 0x45, 0x1, 0x8d, 0x4f, 0xac},
+				Hash: plumbing.Hash{0xe3, 0xed, 0x31, 0xc, 0x81, 0x4, 0xfe, 0x36, 0x21, 0xce, 0xbb, 0xf, 0x51, 0xd1, 0x1, 0x45, 0x1, 0x8d, 0x4f, 0xac},
 			},
 			{
 				Name: "test4.c", Mode: 0x81a4,
-				Hash: core.Hash{0xa6, 0x37, 0x5c, 0x7c, 0xc4, 0x3, 0xf6, 0xc, 0xaa, 0xb7, 0xe9, 0x59, 0x53, 0x3e, 0x3d, 0xb1, 0xff, 0x75, 0xa, 0xe4},
+				Hash: plumbing.Hash{0xa6, 0x37, 0x5c, 0x7c, 0xc4, 0x3, 0xf6, 0xc, 0xaa, 0xb7, 0xe9, 0x59, 0x53, 0x3e, 0x3d, 0xb1, 0xff, 0x75, 0xa, 0xe4},
 			},
 			{
 				Name: "test5.c", Mode: 0x81a4,
-				Hash: core.Hash{0x30, 0x3d, 0x12, 0x5, 0xb2, 0x26, 0x28, 0x42, 0x3d, 0x98, 0x6f, 0x71, 0xe2, 0x7c, 0x7c, 0xf7, 0x14, 0xa7, 0x45, 0xa6},
+				Hash: plumbing.Hash{0x30, 0x3d, 0x12, 0x5, 0xb2, 0x26, 0x28, 0x42, 0x3d, 0x98, 0x6f, 0x71, 0xe2, 0x7c, 0x7c, 0xf7, 0x14, 0xa7, 0x45, 0xa6},
 			},
 			{
 				Name: "test6.c", Mode: 0x81a4,
-				Hash: core.Hash{0xc1, 0x51, 0xea, 0x42, 0x98, 0x9b, 0xb, 0xe2, 0x4e, 0xe4, 0xb9, 0xa4, 0xbe, 0x37, 0x8b, 0x4f, 0x63, 0x6d, 0xb6, 0x41},
+				Hash: plumbing.Hash{0xc1, 0x51, 0xea, 0x42, 0x98, 0x9b, 0xb, 0xe2, 0x4e, 0xe4, 0xb9, 0xa4, 0xbe, 0x37, 0x8b, 0x4f, 0x63, 0x6d, 0xb6, 0x41},
 			},
 			{
 				Name: "test7.c", Mode: 0x81a4,
-				Hash: core.Hash{0x3c, 0xd4, 0xa2, 0x24, 0xd7, 0xe8, 0xe1, 0x6b, 0xd7, 0xcb, 0xe4, 0x9e, 0x2d, 0x3e, 0x94, 0xce, 0x9b, 0x17, 0xbd, 0x76},
+				Hash: plumbing.Hash{0x3c, 0xd4, 0xa2, 0x24, 0xd7, 0xe8, 0xe1, 0x6b, 0xd7, 0xcb, 0xe4, 0x9e, 0x2d, 0x3e, 0x94, 0xce, 0x9b, 0x17, 0xbd, 0x76},
 			},
 			{
 				Name: "test8.c", Mode: 0x81a4,
-				Hash: core.Hash{0xc5, 0x73, 0x93, 0x32, 0xd4, 0x6e, 0x57, 0x12, 0x1d, 0xa2, 0x7c, 0x3e, 0x88, 0xfd, 0xe7, 0x5a, 0xeb, 0x87, 0x10, 0xf7},
+				Hash: plumbing.Hash{0xc5, 0x73, 0x93, 0x32, 0xd4, 0x6e, 0x57, 0x12, 0x1d, 0xa2, 0x7c, 0x3e, 0x88, 0xfd, 0xe7, 0x5a, 0xeb, 0x87, 0x10, 0xf7},
 			},
 			{
 				Name: "test9.c", Mode: 0x81a4,
-				Hash: core.Hash{0xe5, 0x99, 0x3e, 0x8f, 0xf7, 0x8f, 0x61, 0xc2, 0x43, 0x5b, 0x6f, 0x97, 0xa3, 0xb4, 0x63, 0xe2, 0x27, 0xc7, 0x67, 0xac},
+				Hash: plumbing.Hash{0xe5, 0x99, 0x3e, 0x8f, 0xf7, 0x8f, 0x61, 0xc2, 0x43, 0x5b, 0x6f, 0x97, 0xa3, 0xb4, 0x63, 0xe2, 0x27, 0xc7, 0x67, 0xac},
 			},
 			{
 				Name: "test_async.c", Mode: 0x81a4,
-				Hash: core.Hash{0xb0, 0xb9, 0x43, 0x18, 0x5b, 0xfc, 0x23, 0xc1, 0x7f, 0xd0, 0x8f, 0x55, 0x76, 0x8c, 0xac, 0x12, 0xa9, 0xf5, 0x69, 0x51},
+				Hash: plumbing.Hash{0xb0, 0xb9, 0x43, 0x18, 0x5b, 0xfc, 0x23, 0xc1, 0x7f, 0xd0, 0x8f, 0x55, 0x76, 0x8c, 0xac, 0x12, 0xa9, 0xf5, 0x69, 0x51},
 			},
 			{
 				Name: "test_autoext.c", Mode: 0x81a4,
-				Hash: core.Hash{0xb5, 0x1, 0x3f, 0x31, 0x73, 0xa2, 0x17, 0x6e, 0x2d, 0x9f, 0xc, 0xaa, 0x99, 0x19, 0x30, 0x36, 0xbf, 0xc3, 0x7e, 0x91},
+				Hash: plumbing.Hash{0xb5, 0x1, 0x3f, 0x31, 0x73, 0xa2, 0x17, 0x6e, 0x2d, 0x9f, 0xc, 0xaa, 0x99, 0x19, 0x30, 0x36, 0xbf, 0xc3, 0x7e, 0x91},
 			},
 			{
 				Name: "test_backup.c", Mode: 0x81a4,
-				Hash: core.Hash{0xe9, 0x67, 0x42, 0x4a, 0x29, 0xf, 0x73, 0x8a, 0xec, 0xfd, 0xac, 0x57, 0x8e, 0x9b, 0x87, 0xa4, 0xc4, 0xae, 0x8d, 0x7f},
+				Hash: plumbing.Hash{0xe9, 0x67, 0x42, 0x4a, 0x29, 0xf, 0x73, 0x8a, 0xec, 0xfd, 0xac, 0x57, 0x8e, 0x9b, 0x87, 0xa4, 0xc4, 0xae, 0x8d, 0x7f},
 			},
 			{
 				Name: "test_btree.c", Mode: 0x81a4,
-				Hash: core.Hash{0xdb, 0x72, 0x88, 0x9b, 0x2a, 0xfb, 0x62, 0x72, 0x82, 0x8d, 0xda, 0x86, 0x6d, 0xcc, 0xf1, 0x22, 0xa4, 0x9a, 0x72, 0x99},
+				Hash: plumbing.Hash{0xdb, 0x72, 0x88, 0x9b, 0x2a, 0xfb, 0x62, 0x72, 0x82, 0x8d, 0xda, 0x86, 0x6d, 0xcc, 0xf1, 0x22, 0xa4, 0x9a, 0x72, 0x99},
 			},
 			{
 				Name: "test_config.c", Mode: 0x81a4,
-				Hash: core.Hash{0x53, 0x47, 0x27, 0xa0, 0x80, 0x42, 0xb6, 0xca, 0xd6, 0x7e, 0x26, 0x7e, 0x87, 0xb4, 0x3, 0xa4, 0x1a, 0x73, 0xb2, 0x99},
+				Hash: plumbing.Hash{0x53, 0x47, 0x27, 0xa0, 0x80, 0x42, 0xb6, 0xca, 0xd6, 0x7e, 0x26, 0x7e, 0x87, 0xb4, 0x3, 0xa4, 0x1a, 0x73, 0xb2, 0x99},
 			},
 			{
 				Name: "test_demovfs.c", Mode: 0x81a4,
-				Hash: core.Hash{0x63, 0x76, 0x27, 0x7, 0x1d, 0x9e, 0x28, 0xf4, 0xb3, 0x45, 0x1b, 0xbb, 0xdd, 0xf8, 0x8, 0xd1, 0xa9, 0x12, 0x0, 0xf8},
+				Hash: plumbing.Hash{0x63, 0x76, 0x27, 0x7, 0x1d, 0x9e, 0x28, 0xf4, 0xb3, 0x45, 0x1b, 0xbb, 0xdd, 0xf8, 0x8, 0xd1, 0xa9, 0x12, 0x0, 0xf8},
 			},
 			{
 				Name: "test_devsym.c", Mode: 0x81a4,
-				Hash: core.Hash{0x21, 0xf0, 0xf6, 0x84, 0xd8, 0x61, 0x11, 0x67, 0x70, 0xde, 0xfc, 0xde, 0xcd, 0x53, 0x2b, 0xa3, 0xee, 0xab, 0xa9, 0x75},
+				Hash: plumbing.Hash{0x21, 0xf0, 0xf6, 0x84, 0xd8, 0x61, 0x11, 0x67, 0x70, 0xde, 0xfc, 0xde, 0xcd, 0x53, 0x2b, 0xa3, 0xee, 0xab, 0xa9, 0x75},
 			},
 			{
 				Name: "test_fs.c", Mode: 0x81a4,
-				Hash: core.Hash{0x47, 0x8c, 0xad, 0x80, 0xb1, 0x6a, 0x90, 0x9b, 0x23, 0xbd, 0x3, 0xc2, 0xda, 0xd8, 0xb4, 0x49, 0xa7, 0x45, 0x87, 0xa1},
+				Hash: plumbing.Hash{0x47, 0x8c, 0xad, 0x80, 0xb1, 0x6a, 0x90, 0x9b, 0x23, 0xbd, 0x3, 0xc2, 0xda, 0xd8, 0xb4, 0x49, 0xa7, 0x45, 0x87, 0xa1},
 			},
 			{
 				Name: "test_func.c", Mode: 0x81a4,
-				Hash: core.Hash{0x6f, 0x9b, 0xb0, 0x3d, 0xc8, 0x8a, 0x21, 0xd6, 0x58, 0xbf, 0x99, 0x99, 0xba, 0xf6, 0x6d, 0xc1, 0xd5, 0x2e, 0xbc, 0x54},
+				Hash: plumbing.Hash{0x6f, 0x9b, 0xb0, 0x3d, 0xc8, 0x8a, 0x21, 0xd6, 0x58, 0xbf, 0x99, 0x99, 0xba, 0xf6, 0x6d, 0xc1, 0xd5, 0x2e, 0xbc, 0x54},
 			},
 			{
 				Name: "test_hexio.c", Mode: 0x81a4,
-				Hash: core.Hash{0xb2, 0xb, 0x5c, 0xe7, 0x30, 0xab, 0x7f, 0xa8, 0x0, 0xd2, 0xd0, 0xcc, 0x38, 0xc7, 0x72, 0x75, 0x59, 0x3e, 0xbd, 0xbb},
+				Hash: plumbing.Hash{0xb2, 0xb, 0x5c, 0xe7, 0x30, 0xab, 0x7f, 0xa8, 0x0, 0xd2, 0xd0, 0xcc, 0x38, 0xc7, 0x72, 0x75, 0x59, 0x3e, 0xbd, 0xbb},
 			},
 			{
 				Name: "test_init.c", Mode: 0x81a4,
-				Hash: core.Hash{0xe3, 0x72, 0x4d, 0x8b, 0xe3, 0x14, 0xdb, 0x9, 0xee, 0xa8, 0x4, 0xb, 0x9d, 0xdf, 0xc8, 0xa8, 0xbe, 0xee, 0x22, 0x91},
+				Hash: plumbing.Hash{0xe3, 0x72, 0x4d, 0x8b, 0xe3, 0x14, 0xdb, 0x9, 0xee, 0xa8, 0x4, 0xb, 0x9d, 0xdf, 0xc8, 0xa8, 0xbe, 0xee, 0x22, 0x91},
 			},
 			{
 				Name: "test_intarray.c", Mode: 0x81a4,
-				Hash: core.Hash{0xf5, 0xc3, 0xd9, 0xe4, 0x5, 0x9a, 0x16, 0x56, 0x7, 0x34, 0x7, 0xe4, 0x3a, 0x92, 0x11, 0x79, 0x99, 0x69, 0x7b, 0x93},
+				Hash: plumbing.Hash{0xf5, 0xc3, 0xd9, 0xe4, 0x5, 0x9a, 0x16, 0x56, 0x7, 0x34, 0x7, 0xe4, 0x3a, 0x92, 0x11, 0x79, 0x99, 0x69, 0x7b, 0x93},
 			},
 			{
 				Name: "test_intarray.h", Mode: 0x81a4,
-				Hash: core.Hash{0x69, 0x13, 0x37, 0xd1, 0xae, 0xd6, 0x37, 0x15, 0xd6, 0x2e, 0x76, 0x26, 0x6f, 0xf, 0x3b, 0x50, 0x8b, 0x1, 0xa, 0x34},
+				Hash: plumbing.Hash{0x69, 0x13, 0x37, 0xd1, 0xae, 0xd6, 0x37, 0x15, 0xd6, 0x2e, 0x76, 0x26, 0x6f, 0xf, 0x3b, 0x50, 0x8b, 0x1, 0xa, 0x34},
 			},
 			{
 				Name: "test_journal.c", Mode: 0x81a4,
-				Hash: core.Hash{0xe8, 0x70, 0x1a, 0x4e, 0xea, 0xdb, 0x8e, 0xad, 0x16, 0x9d, 0x60, 0x6, 0x40, 0x7d, 0x54, 0xa8, 0x98, 0x59, 0x2d, 0x70},
+				Hash: plumbing.Hash{0xe8, 0x70, 0x1a, 0x4e, 0xea, 0xdb, 0x8e, 0xad, 0x16, 0x9d, 0x60, 0x6, 0x40, 0x7d, 0x54, 0xa8, 0x98, 0x59, 0x2d, 0x70},
 			},
 			{
 				Name: "test_loadext.c", Mode: 0x81a4,
-				Hash: core.Hash{0x11, 0x37, 0xe3, 0xa9, 0xaa, 0xe9, 0x29, 0x6, 0xb8, 0x28, 0x9f, 0x6c, 0x3d, 0xaa, 0x61, 0xf0, 0xd0, 0x70, 0xf5, 0x5a},
+				Hash: plumbing.Hash{0x11, 0x37, 0xe3, 0xa9, 0xaa, 0xe9, 0x29, 0x6, 0xb8, 0x28, 0x9f, 0x6c, 0x3d, 0xaa, 0x61, 0xf0, 0xd0, 0x70, 0xf5, 0x5a},
 			},
 			{
 				Name: "test_malloc.c", Mode: 0x81a4,
-				Hash: core.Hash{0xcf, 0x98, 0xa8, 0xfb, 0x21, 0x82, 0xc0, 0xba, 0xf5, 0xa, 0xd5, 0x79, 0x79, 0xb6, 0x75, 0xbb, 0x70, 0x7a, 0x93, 0xb0},
+				Hash: plumbing.Hash{0xcf, 0x98, 0xa8, 0xfb, 0x21, 0x82, 0xc0, 0xba, 0xf5, 0xa, 0xd5, 0x79, 0x79, 0xb6, 0x75, 0xbb, 0x70, 0x7a, 0x93, 0xb0},
 			},
 			{
 				Name: "test_multiplex.c", Mode: 0x81a4,
-				Hash: core.Hash{0x62, 0x45, 0x41, 0xb3, 0x2a, 0x10, 0xd2, 0x1a, 0x2f, 0xd1, 0xa, 0x35, 0xee, 0x66, 0x32, 0xbd, 0xac, 0x55, 0x2d, 0x41},
+				Hash: plumbing.Hash{0x62, 0x45, 0x41, 0xb3, 0x2a, 0x10, 0xd2, 0x1a, 0x2f, 0xd1, 0xa, 0x35, 0xee, 0x66, 0x32, 0xbd, 0xac, 0x55, 0x2d, 0x41},
 			},
 			{
 				Name: "test_multiplex.h", Mode: 0x81a4,
-				Hash: core.Hash{0xb7, 0xe1, 0xaf, 0xea, 0x5f, 0xd7, 0x8b, 0x87, 0x58, 0x2, 0x65, 0xf8, 0x4c, 0x81, 0x61, 0x2c, 0xbd, 0x2, 0x5b, 0xaf},
+				Hash: plumbing.Hash{0xb7, 0xe1, 0xaf, 0xea, 0x5f, 0xd7, 0x8b, 0x87, 0x58, 0x2, 0x65, 0xf8, 0x4c, 0x81, 0x61, 0x2c, 0xbd, 0x2, 0x5b, 0xaf},
 			},
 			{
 				Name: "test_mutex.c", Mode: 0x81a4,
-				Hash: core.Hash{0xc9, 0xb4, 0xa2, 0x9a, 0xb7, 0x5c, 0x77, 0xea, 0x5f, 0x36, 0xb5, 0x19, 0x32, 0x56, 0xd7, 0xf, 0xe6, 0x58, 0xe, 0x95},
+				Hash: plumbing.Hash{0xc9, 0xb4, 0xa2, 0x9a, 0xb7, 0x5c, 0x77, 0xea, 0x5f, 0x36, 0xb5, 0x19, 0x32, 0x56, 0xd7, 0xf, 0xe6, 0x58, 0xe, 0x95},
 			},
 			{
 				Name: "test_onefile.c", Mode: 0x81a4,
-				Hash: core.Hash{0x69, 0x86, 0x74, 0x41, 0xb8, 0xcc, 0x9a, 0x62, 0x1a, 0xf3, 0x24, 0x13, 0xfc, 0x63, 0xda, 0x80, 0x99, 0x37, 0x64, 0xf4},
+				Hash: plumbing.Hash{0x69, 0x86, 0x74, 0x41, 0xb8, 0xcc, 0x9a, 0x62, 0x1a, 0xf3, 0x24, 0x13, 0xfc, 0x63, 0xda, 0x80, 0x99, 0x37, 0x64, 0xf4},
 			},
 			{
 				Name: "test_osinst.c", Mode: 0x81a4,
-				Hash: core.Hash{0x53, 0x14, 0x33, 0x31, 0x3e, 0xe3, 0x6c, 0x7, 0xeb, 0x21, 0xc0, 0x2f, 0x31, 0x15, 0xcb, 0x7a, 0x37, 0x48, 0x6c, 0x79},
+				Hash: plumbing.Hash{0x53, 0x14, 0x33, 0x31, 0x3e, 0xe3, 0x6c, 0x7, 0xeb, 0x21, 0xc0, 0x2f, 0x31, 0x15, 0xcb, 0x7a, 0x37, 0x48, 0x6c, 0x79},
 			},
 			{
 				Name: "test_pcache.c", Mode: 0x81a4,
-				Hash: core.Hash{0x8f, 0xcf, 0xe7, 0xe2, 0x6e, 0x3f, 0xf1, 0x74, 0x96, 0xb8, 0x40, 0xf5, 0xd6, 0x3c, 0x75, 0x78, 0x3a, 0xff, 0x81, 0x62},
+				Hash: plumbing.Hash{0x8f, 0xcf, 0xe7, 0xe2, 0x6e, 0x3f, 0xf1, 0x74, 0x96, 0xb8, 0x40, 0xf5, 0xd6, 0x3c, 0x75, 0x78, 0x3a, 0xff, 0x81, 0x62},
 			},
-			{Name: "test_quota.c", Mode: 0x81a4, Hash: core.Hash{
+			{Name: "test_quota.c", Mode: 0x81a4, Hash: plumbing.Hash{
 				0xe5, 0x90, 0x99, 0x6c, 0xa4, 0xb8, 0x57, 0x4a, 0xb1, 0xe4, 0x18, 0x5d, 0x57, 0x77, 0x56, 0x66, 0x4a, 0xd2, 0x49, 0x5f}}, {Name: "test_quota.h", Mode: 0x81a4,
-				Hash: core.Hash{0x2d, 0x7, 0x67, 0xa1, 0x9a, 0xb7, 0xc3, 0xa4, 0x21, 0xcd, 0xba, 0x6a, 0x3, 0x49, 0x20, 0x43, 0x67, 0xc2, 0x2c, 0x81},
+				Hash: plumbing.Hash{0x2d, 0x7, 0x67, 0xa1, 0x9a, 0xb7, 0xc3, 0xa4, 0x21, 0xcd, 0xba, 0x6a, 0x3, 0x49, 0x20, 0x43, 0x67, 0xc2, 0x2c, 0x81},
 			},
 			{
 				Name: "test_rtree.c", Mode: 0x81a4,
-				Hash: core.Hash{0xf5, 0x4a, 0xe9, 0xb0, 0x63, 0xbb, 0x73, 0x71, 0x2f, 0xcf, 0xc1, 0xc6, 0x83, 0x2e, 0x2a, 0x50, 0xf6, 0x2a, 0x97, 0xe7},
+				Hash: plumbing.Hash{0xf5, 0x4a, 0xe9, 0xb0, 0x63, 0xbb, 0x73, 0x71, 0x2f, 0xcf, 0xc1, 0xc6, 0x83, 0x2e, 0x2a, 0x50, 0xf6, 0x2a, 0x97, 0xe7},
 			},
 			{
 				Name: "test_schema.c", Mode: 0x81a4,
-				Hash: core.Hash{0x12, 0x64, 0x44, 0x67, 0x64, 0x7d, 0x51, 0x39, 0x4a, 0x1, 0xf9, 0xfa, 0x60, 0x37, 0x62, 0x98, 0x18, 0x54, 0x66, 0xfd},
+				Hash: plumbing.Hash{0x12, 0x64, 0x44, 0x67, 0x64, 0x7d, 0x51, 0x39, 0x4a, 0x1, 0xf9, 0xfa, 0x60, 0x37, 0x62, 0x98, 0x18, 0x54, 0x66, 0xfd},
 			},
 			{
 				Name: "test_server.c", Mode: 0x81a4,
-				Hash: core.Hash{0xed, 0x8, 0x18, 0xe6, 0xf6, 0x5f, 0x27, 0x28, 0x2d, 0xc7, 0xb1, 0xc1, 0x90, 0xec, 0x18, 0x8c, 0x89, 0x33, 0x0, 0x2b},
+				Hash: plumbing.Hash{0xed, 0x8, 0x18, 0xe6, 0xf6, 0x5f, 0x27, 0x28, 0x2d, 0xc7, 0xb1, 0xc1, 0x90, 0xec, 0x18, 0x8c, 0x89, 0x33, 0x0, 0x2b},
 			},
 			{
 				Name: "test_sqllog.c", Mode: 0x81a4,
-				Hash: core.Hash{0x4a, 0xa6, 0x8b, 0x7c, 0x42, 0x93, 0x23, 0xb8, 0xee, 0xbe, 0x6c, 0x9c, 0x2d, 0x7, 0xfc, 0x66, 0xd, 0x8d, 0x47, 0xc9},
+				Hash: plumbing.Hash{0x4a, 0xa6, 0x8b, 0x7c, 0x42, 0x93, 0x23, 0xb8, 0xee, 0xbe, 0x6c, 0x9c, 0x2d, 0x7, 0xfc, 0x66, 0xd, 0x8d, 0x47, 0xc9},
 			},
 			{
 				Name: "test_stat.c", Mode: 0x81a4,
-				Hash: core.Hash{0xd4, 0xc9, 0x2, 0xb5, 0xea, 0x11, 0x1a, 0xd5, 0x8a, 0x73, 0x71, 0x12, 0xc2, 0x8f, 0x0, 0x38, 0x43, 0x4c, 0x85, 0xc0},
+				Hash: plumbing.Hash{0xd4, 0xc9, 0x2, 0xb5, 0xea, 0x11, 0x1a, 0xd5, 0x8a, 0x73, 0x71, 0x12, 0xc2, 0x8f, 0x0, 0x38, 0x43, 0x4c, 0x85, 0xc0},
 			},
 			{
 				Name: "test_superlock.c", Mode: 0x81a4,
-				Hash: core.Hash{0x93, 0x6f, 0xca, 0xd0, 0xc5, 0x6f, 0x6b, 0xc8, 0x58, 0x9, 0x74, 0x2f, 0x6a, 0xe1, 0xc1, 0xee, 0xb8, 0xb7, 0xd2, 0xf1},
+				Hash: plumbing.Hash{0x93, 0x6f, 0xca, 0xd0, 0xc5, 0x6f, 0x6b, 0xc8, 0x58, 0x9, 0x74, 0x2f, 0x6a, 0xe1, 0xc1, 0xee, 0xb8, 0xb7, 0xd2, 0xf1},
 			},
 			{
 				Name: "test_syscall.c", Mode: 0x81a4,
-				Hash: core.Hash{0x7c, 0x8, 0x73, 0xc1, 0x6d, 0x84, 0x32, 0x2, 0xf3, 0xe, 0x2d, 0xb9, 0x45, 0x9f, 0xa2, 0x99, 0x75, 0xea, 0x5e, 0x68},
+				Hash: plumbing.Hash{0x7c, 0x8, 0x73, 0xc1, 0x6d, 0x84, 0x32, 0x2, 0xf3, 0xe, 0x2d, 0xb9, 0x45, 0x9f, 0xa2, 0x99, 0x75, 0xea, 0x5e, 0x68},
 			},
 			{
 				Name: "test_tclvar.c", Mode: 0x81a4,
-				Hash: core.Hash{0x12, 0x19, 0x19, 0xc, 0x3, 0x0, 0xfd, 0x5e, 0xc7, 0xa3, 0xc5, 0x84, 0x8, 0xf3, 0x38, 0x43, 0xd2, 0xe, 0xee, 0x15},
+				Hash: plumbing.Hash{0x12, 0x19, 0x19, 0xc, 0x3, 0x0, 0xfd, 0x5e, 0xc7, 0xa3, 0xc5, 0x84, 0x8, 0xf3, 0x38, 0x43, 0xd2, 0xe, 0xee, 0x15},
 			},
 			{
 				Name: "test_thread.c", Mode: 0x81a4,
-				Hash: core.Hash{0x2f, 0x93, 0x63, 0xb7, 0x50, 0x1e, 0x51, 0x19, 0x81, 0xfe, 0x32, 0x83, 0x1f, 0xf2, 0xe8, 0xfd, 0x2f, 0x30, 0xc4, 0x93},
+				Hash: plumbing.Hash{0x2f, 0x93, 0x63, 0xb7, 0x50, 0x1e, 0x51, 0x19, 0x81, 0xfe, 0x32, 0x83, 0x1f, 0xf2, 0xe8, 0xfd, 0x2f, 0x30, 0xc4, 0x93},
 			},
 			{
 				Name: "test_vfs.c", Mode: 0x81a4,
-				Hash: core.Hash{0xfc, 0xd5, 0x77, 0x43, 0x9c, 0xfd, 0x6c, 0x72, 0xdd, 0xe4, 0x83, 0x58, 0x92, 0x14, 0x20, 0xcf, 0x6e, 0xf1, 0xf8, 0x6d},
+				Hash: plumbing.Hash{0xfc, 0xd5, 0x77, 0x43, 0x9c, 0xfd, 0x6c, 0x72, 0xdd, 0xe4, 0x83, 0x58, 0x92, 0x14, 0x20, 0xcf, 0x6e, 0xf1, 0xf8, 0x6d},
 			},
 			{
 				Name: "test_vfstrace.c", Mode: 0x81a4,
-				Hash: core.Hash{0xa, 0xac, 0xc0, 0x1f, 0xe4, 0x2e, 0x77, 0xfe, 0xb8, 0x58, 0xe4, 0xbe, 0xd0, 0xcb, 0x7e, 0x4, 0xa4, 0x35, 0xb2, 0x10},
+				Hash: plumbing.Hash{0xa, 0xac, 0xc0, 0x1f, 0xe4, 0x2e, 0x77, 0xfe, 0xb8, 0x58, 0xe4, 0xbe, 0xd0, 0xcb, 0x7e, 0x4, 0xa4, 0x35, 0xb2, 0x10},
 			},
 			{
 				Name: "test_wsd.c", Mode: 0x81a4,
-				Hash: core.Hash{0x99, 0xe4, 0xa0, 0x56, 0x58, 0x1f, 0x58, 0xf4, 0x53, 0x6f, 0xdb, 0x5a, 0x5d, 0xf7, 0x5c, 0x74, 0x69, 0x8a, 0x81, 0x62},
+				Hash: plumbing.Hash{0x99, 0xe4, 0xa0, 0x56, 0x58, 0x1f, 0x58, 0xf4, 0x53, 0x6f, 0xdb, 0x5a, 0x5d, 0xf7, 0x5c, 0x74, 0x69, 0x8a, 0x81, 0x62},
 			},
 			{
 				Name: "tokenize.c", Mode: 0x81a4,
-				Hash: core.Hash{0xfa, 0xea, 0x5f, 0x26, 0xc7, 0x9c, 0x5e, 0x18, 0x8f, 0xa8, 0x7f, 0x2f, 0xdf, 0x6f, 0xf7, 0x6a, 0x7a, 0x60, 0x6, 0xc5},
+				Hash: plumbing.Hash{0xfa, 0xea, 0x5f, 0x26, 0xc7, 0x9c, 0x5e, 0x18, 0x8f, 0xa8, 0x7f, 0x2f, 0xdf, 0x6f, 0xf7, 0x6a, 0x7a, 0x60, 0x6, 0xc5},
 			},
 			{
 				Name: "trigger.c", Mode: 0x81a4,
-				Hash: core.Hash{0xf1, 0xff, 0x76, 0x6e, 0x20, 0x2a, 0x45, 0x18, 0xec, 0x10, 0xe5, 0x27, 0x12, 0xc, 0xd3, 0xe, 0x83, 0xfb, 0xd0, 0x34},
+				Hash: plumbing.Hash{0xf1, 0xff, 0x76, 0x6e, 0x20, 0x2a, 0x45, 0x18, 0xec, 0x10, 0xe5, 0x27, 0x12, 0xc, 0xd3, 0xe, 0x83, 0xfb, 0xd0, 0x34},
 			},
 			{
 				Name: "update.c", Mode: 0x81a4,
-				Hash: core.Hash{0x3a, 0xb1, 0xab, 0x2a, 0x4b, 0x65, 0xda, 0x3f, 0x19, 0x8c, 0x15, 0x84, 0xd5, 0x4d, 0x36, 0xf1, 0x8c, 0xa1, 0x21, 0x4a},
+				Hash: plumbing.Hash{0x3a, 0xb1, 0xab, 0x2a, 0x4b, 0x65, 0xda, 0x3f, 0x19, 0x8c, 0x15, 0x84, 0xd5, 0x4d, 0x36, 0xf1, 0x8c, 0xa1, 0x21, 0x4a},
 			},
 			{
 				Name: "utf.c", Mode: 0x81a4,
-				Hash: core.Hash{0x6d, 0x5b, 0x1b, 0xfe, 0x40, 0xc, 0x37, 0x48, 0xaa, 0x70, 0xa3, 0xb2, 0xfd, 0x5e, 0xe, 0xac, 0x5f, 0xc0, 0x4d, 0xe2},
+				Hash: plumbing.Hash{0x6d, 0x5b, 0x1b, 0xfe, 0x40, 0xc, 0x37, 0x48, 0xaa, 0x70, 0xa3, 0xb2, 0xfd, 0x5e, 0xe, 0xac, 0x5f, 0xc0, 0x4d, 0xe2},
 			},
 			{
 				Name: "util.c", Mode: 0x81a4,
-				Hash: core.Hash{0xd8, 0x3a, 0x63, 0x1, 0x5f, 0xd8, 0x7d, 0xcc, 0x4f, 0xb4, 0x41, 0x66, 0xfa, 0xbf, 0x2e, 0x9b, 0xc9, 0x67, 0x1e, 0xb8},
+				Hash: plumbing.Hash{0xd8, 0x3a, 0x63, 0x1, 0x5f, 0xd8, 0x7d, 0xcc, 0x4f, 0xb4, 0x41, 0x66, 0xfa, 0xbf, 0x2e, 0x9b, 0xc9, 0x67, 0x1e, 0xb8},
 			},
 			{
 				Name: "vacuum.c", Mode: 0x81a4,
-				Hash: core.Hash{0x4a, 0xfb, 0x2c, 0xca, 0x64, 0xdd, 0x60, 0x76, 0x11, 0x22, 0x2c, 0x7, 0x93, 0x2d, 0x12, 0xea, 0xcf, 0xa, 0x2c, 0x22},
+				Hash: plumbing.Hash{0x4a, 0xfb, 0x2c, 0xca, 0x64, 0xdd, 0x60, 0x76, 0x11, 0x22, 0x2c, 0x7, 0x93, 0x2d, 0x12, 0xea, 0xcf, 0xa, 0x2c, 0x22},
 			},
 			{
 				Name: "vdbe.c", Mode: 0x81a4,
-				Hash: core.Hash{0xf3, 0x43, 0xe1, 0x3d, 0x4e, 0x91, 0x78, 0x4b, 0x15, 0x88, 0x10, 0xc5, 0xb7, 0xd4, 0x46, 0x84, 0xdf, 0xbf, 0xa2, 0xa5},
+				Hash: plumbing.Hash{0xf3, 0x43, 0xe1, 0x3d, 0x4e, 0x91, 0x78, 0x4b, 0x15, 0x88, 0x10, 0xc5, 0xb7, 0xd4, 0x46, 0x84, 0xdf, 0xbf, 0xa2, 0xa5},
 			},
 			{
 				Name: "vdbe.h", Mode: 0x81a4,
-				Hash: core.Hash{0xfa, 0x7b, 0x31, 0xb7, 0x27, 0xa, 0x90, 0xd4, 0xf6, 0x37, 0x36, 0x5a, 0xfc, 0xc9, 0xbd, 0xa1, 0xd1, 0xb1, 0xe1, 0xd6},
+				Hash: plumbing.Hash{0xfa, 0x7b, 0x31, 0xb7, 0x27, 0xa, 0x90, 0xd4, 0xf6, 0x37, 0x36, 0x5a, 0xfc, 0xc9, 0xbd, 0xa1, 0xd1, 0xb1, 0xe1, 0xd6},
 			},
 			{
 				Name: "vdbeInt.h", Mode: 0x81a4,
-				Hash: core.Hash{0x3a, 0x5b, 0x40, 0x28, 0xbb, 0xd6, 0xc9, 0x56, 0x10, 0xd7, 0xc, 0xce, 0x3, 0x69, 0xdf, 0xcd, 0x60, 0x7a, 0xa9, 0x0},
+				Hash: plumbing.Hash{0x3a, 0x5b, 0x40, 0x28, 0xbb, 0xd6, 0xc9, 0x56, 0x10, 0xd7, 0xc, 0xce, 0x3, 0x69, 0xdf, 0xcd, 0x60, 0x7a, 0xa9, 0x0},
 			},
 			{
 				Name: "vdbeapi.c", Mode: 0x81a4,
-				Hash: core.Hash{0x7c, 0x86, 0x1e, 0x2d, 0x47, 0x21, 0x8c, 0x91, 0x63, 0x31, 0x77, 0x77, 0xc3, 0x7, 0x21, 0x99, 0xe9, 0xb4, 0x2, 0x80},
+				Hash: plumbing.Hash{0x7c, 0x86, 0x1e, 0x2d, 0x47, 0x21, 0x8c, 0x91, 0x63, 0x31, 0x77, 0x77, 0xc3, 0x7, 0x21, 0x99, 0xe9, 0xb4, 0x2, 0x80},
 			},
 			{
 				Name: "vdbeaux.c", Mode: 0x81a4,
-				Hash: core.Hash{0x2c, 0x42, 0x69, 0xa5, 0x9e, 0x6d, 0xbc, 0xe8, 0x67, 0x1c, 0x47, 0x4f, 0x34, 0x61, 0x90, 0xbe, 0x2a, 0xe, 0x18, 0x51},
+				Hash: plumbing.Hash{0x2c, 0x42, 0x69, 0xa5, 0x9e, 0x6d, 0xbc, 0xe8, 0x67, 0x1c, 0x47, 0x4f, 0x34, 0x61, 0x90, 0xbe, 0x2a, 0xe, 0x18, 0x51},
 			},
 			{
 				Name: "vdbeblob.c", Mode: 0x81a4,
-				Hash: core.Hash{0x2e, 0x8f, 0xd8, 0xee, 0x74, 0x47, 0xe6, 0x46, 0x46, 0xe3, 0x49, 0x4b, 0x4c, 0x4, 0x1d, 0x3a, 0x4a, 0xbb, 0x8, 0x85},
+				Hash: plumbing.Hash{0x2e, 0x8f, 0xd8, 0xee, 0x74, 0x47, 0xe6, 0x46, 0x46, 0xe3, 0x49, 0x4b, 0x4c, 0x4, 0x1d, 0x3a, 0x4a, 0xbb, 0x8, 0x85},
 			},
 			{
 				Name: "vdbemem.c", Mode: 0x81a4,
-				Hash: core.Hash{0x8f, 0xc2, 0x22, 0xe2, 0xde, 0x20, 0x50, 0x14, 0x50, 0xec, 0xea, 0x9d, 0x4e, 0xbf, 0xaa, 0xc9, 0x81, 0x4a, 0xae, 0x59},
+				Hash: plumbing.Hash{0x8f, 0xc2, 0x22, 0xe2, 0xde, 0x20, 0x50, 0x14, 0x50, 0xec, 0xea, 0x9d, 0x4e, 0xbf, 0xaa, 0xc9, 0x81, 0x4a, 0xae, 0x59},
 			},
 			{
 				Name: "vdbesort.c", Mode: 0x81a4,
-				Hash: core.Hash{0xfd, 0xfc, 0x4a, 0x79, 0xdd, 0xc9, 0x6e, 0x59, 0x9b, 0x1b, 0xe, 0xeb, 0xac, 0xbd, 0xb8, 0x45, 0xc6, 0x38, 0x13, 0xb2},
+				Hash: plumbing.Hash{0xfd, 0xfc, 0x4a, 0x79, 0xdd, 0xc9, 0x6e, 0x59, 0x9b, 0x1b, 0xe, 0xeb, 0xac, 0xbd, 0xb8, 0x45, 0xc6, 0x38, 0x13, 0xb2},
 			},
 			{
 				Name: "vdbetrace.c", Mode: 0x81a4,
-				Hash: core.Hash{0x35, 0x62, 0x77, 0xe8, 0xd2, 0x3b, 0xca, 0xdb, 0x67, 0x6b, 0x59, 0xd1, 0xa4, 0xdc, 0xf8, 0x42, 0xfd, 0xc4, 0xc9, 0x72},
+				Hash: plumbing.Hash{0x35, 0x62, 0x77, 0xe8, 0xd2, 0x3b, 0xca, 0xdb, 0x67, 0x6b, 0x59, 0xd1, 0xa4, 0xdc, 0xf8, 0x42, 0xfd, 0xc4, 0xc9, 0x72},
 			},
 			{
 				Name: "vtab.c", Mode: 0x81a4,
-				Hash: core.Hash{0x95, 0x82, 0x2, 0xc3, 0x1e, 0x24, 0x15, 0xb, 0x60, 0xf1, 0xa, 0x8a, 0xf, 0x74, 0x41, 0xaf, 0xac, 0x3f, 0xbb, 0x1c},
+				Hash: plumbing.Hash{0x95, 0x82, 0x2, 0xc3, 0x1e, 0x24, 0x15, 0xb, 0x60, 0xf1, 0xa, 0x8a, 0xf, 0x74, 0x41, 0xaf, 0xac, 0x3f, 0xbb, 0x1c},
 			},
 			{
 				Name: "wal.c", Mode: 0x81a4,
-				Hash: core.Hash{0xe6, 0x42, 0xea, 0x21, 0x5, 0xb5, 0xc5, 0x4a, 0xf3, 0x5, 0x88, 0x9, 0x62, 0x69, 0xab, 0x75, 0xcb, 0xef, 0x8f, 0xf2},
+				Hash: plumbing.Hash{0xe6, 0x42, 0xea, 0x21, 0x5, 0xb5, 0xc5, 0x4a, 0xf3, 0x5, 0x88, 0x9, 0x62, 0x69, 0xab, 0x75, 0xcb, 0xef, 0x8f, 0xf2},
 			},
 			{
 				Name: "wal.h", Mode: 0x81a4,
-				Hash: core.Hash{0x9, 0x25, 0x46, 0x35, 0x4b, 0x34, 0xc0, 0xab, 0x3d, 0x20, 0x5, 0x6a, 0x7f, 0x8a, 0x8a, 0x52, 0xe4, 0xd0, 0xb5, 0xf5},
+				Hash: plumbing.Hash{0x9, 0x25, 0x46, 0x35, 0x4b, 0x34, 0xc0, 0xab, 0x3d, 0x20, 0x5, 0x6a, 0x7f, 0x8a, 0x8a, 0x52, 0xe4, 0xd0, 0xb5, 0xf5},
 			},
 			{
 				Name: "walker.c", Mode: 0x81a4,
-				Hash: core.Hash{0xe7, 0x1e, 0xd2, 0xac, 0x48, 0x4c, 0x91, 0x6c, 0x1c, 0xc1, 0x0, 0x7e, 0x5e, 0x5, 0xda, 0x47, 0x1c, 0xb4, 0x95, 0x99},
+				Hash: plumbing.Hash{0xe7, 0x1e, 0xd2, 0xac, 0x48, 0x4c, 0x91, 0x6c, 0x1c, 0xc1, 0x0, 0x7e, 0x5e, 0x5, 0xda, 0x47, 0x1c, 0xb4, 0x95, 0x99},
 			},
 			{
 				Name: "where.c", Mode: 0x81a4,
-				Hash: core.Hash{0xe6, 0x14, 0xf4, 0xa6, 0xd8, 0x64, 0xe7, 0xe, 0xc4, 0x32, 0x8d, 0xb, 0xdb, 0x25, 0x4e, 0x3a, 0xc9, 0xf0, 0xd2, 0x87},
+				Hash: plumbing.Hash{0xe6, 0x14, 0xf4, 0xa6, 0xd8, 0x64, 0xe7, 0xe, 0xc4, 0x32, 0x8d, 0xb, 0xdb, 0x25, 0x4e, 0x3a, 0xc9, 0xf0, 0xd2, 0x87},
 			},
 		},
-		Hash: core.Hash{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+		Hash: plumbing.Hash{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
 		r:    (*Repository)(nil),
 		m:    map[string]*TreeEntry(nil),
 	}
diff --git a/utils/binary/read.go b/utils/binary/read.go
index 90ae41f..8aab3e5 100644
--- a/utils/binary/read.go
+++ b/utils/binary/read.go
@@ -6,7 +6,7 @@ import (
 	"encoding/binary"
 	"io"
 
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 // Read reads structured binary data from r into data. Bytes are read and
@@ -113,11 +113,11 @@ func ReadUint16(r io.Reader) (uint16, error) {
 	return v, nil
 }
 
-// ReadHash reads a core.Hash from r
-func ReadHash(r io.Reader) (core.Hash, error) {
-	var h core.Hash
+// ReadHash reads a plumbing.Hash from r
+func ReadHash(r io.Reader) (plumbing.Hash, error) {
+	var h plumbing.Hash
 	if err := binary.Read(r, binary.BigEndian, h[:]); err != nil {
-		return core.ZeroHash, err
+		return plumbing.ZeroHash, err
 	}
 
 	return h, nil
diff --git a/utils/binary/read_test.go b/utils/binary/read_test.go
index ad5ef29..59dbc30 100644
--- a/utils/binary/read_test.go
+++ b/utils/binary/read_test.go
@@ -6,7 +6,7 @@ import (
 	"testing"
 
 	. "gopkg.in/check.v1"
-	"gopkg.in/src-d/go-git.v4/core"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 )
 
 func Test(t *testing.T) { TestingT(t) }
@@ -76,7 +76,7 @@ func (s *BinarySuite) TestReadUint16(c *C) {
 }
 
 func (s *BinarySuite) TestReadHash(c *C) {
-	expected := core.NewHash("43aec75c611f22c73b27ece2841e6ccca592f285")
+	expected := plumbing.NewHash("43aec75c611f22c73b27ece2841e6ccca592f285")
 	buf := bytes.NewBuffer(nil)
 	err := binary.Write(buf, binary.BigEndian, expected)
 	c.Assert(err, IsNil)