45 files changed, 150 insertions, 102 deletions
diff --git a/plumbing/format/commitgraph/commitgraph_test.go b/plumbing/format/commitgraph/commitgraph_test.go
index 7d7444b..de61ae9 100644
--- a/plumbing/format/commitgraph/commitgraph_test.go
+++ b/plumbing/format/commitgraph/commitgraph_test.go
@@ -6,10 +6,11 @@ import (
 	"path"
 	"testing"
 
-	. "gopkg.in/check.v1"
-	fixtures "github.com/go-git/go-git-fixtures/v4"
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/format/commitgraph"
+
+	fixtures "github.com/go-git/go-git-fixtures/v4"
+	. "gopkg.in/check.v1"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/plumbing/format/config/option.go b/plumbing/format/config/option.go
index d4775e4..218f992 100644
--- a/plumbing/format/config/option.go
+++ b/plumbing/format/config/option.go
@@ -19,7 +19,7 @@ type Options []*Option
 // IsKey returns true if the given key matches
 // this option's key in a case-insensitive comparison.
 func (o *Option) IsKey(key string) bool {
-	return strings.ToLower(o.Key) == strings.ToLower(key)
+	return strings.EqualFold(o.Key, key)
 }
 
 func (opts Options) GoString() string {
diff --git a/plumbing/format/config/section.go b/plumbing/format/config/section.go
index 4a17e3b..f743da6 100644
--- a/plumbing/format/config/section.go
+++ b/plumbing/format/config/section.go
@@ -61,7 +61,7 @@ func (s Subsections) GoString() string {
 
 // IsName checks if the name provided is equals to the Section name, case insensitive.
 func (s *Section) IsName(name string) bool {
-	return strings.ToLower(s.Name) == strings.ToLower(name)
+	return strings.EqualFold(s.Name, name)
 }
 
 // Option return the value for the specified key. Empty string is returned if
diff --git a/plumbing/format/idxfile/encoder_test.go b/plumbing/format/idxfile/encoder_test.go
index 81abb3b..32b60f9 100644
--- a/plumbing/format/idxfile/encoder_test.go
+++ b/plumbing/format/idxfile/encoder_test.go
@@ -6,8 +6,8 @@ import (
 
 	. "github.com/go-git/go-git/v5/plumbing/format/idxfile"
 
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 func (s *IdxfileSuite) TestDecodeEncode(c *C) {
diff --git a/plumbing/format/idxfile/idxfile_test.go b/plumbing/format/idxfile/idxfile_test.go
index 5ef73d7..7a3d6bb 100644
--- a/plumbing/format/idxfile/idxfile_test.go
+++ b/plumbing/format/idxfile/idxfile_test.go
@@ -10,8 +10,8 @@ import (
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/format/idxfile"
 
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 func BenchmarkFindOffset(b *testing.B) {
diff --git a/plumbing/format/idxfile/writer_test.go b/plumbing/format/idxfile/writer_test.go
index f86342f..fba3e42 100644
--- a/plumbing/format/idxfile/writer_test.go
+++ b/plumbing/format/idxfile/writer_test.go
@@ -9,8 +9,8 @@ import (
 	"github.com/go-git/go-git/v5/plumbing/format/idxfile"
 	"github.com/go-git/go-git/v5/plumbing/format/packfile"
 
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 type WriterSuite struct {
diff --git a/plumbing/format/index/decoder.go b/plumbing/format/index/decoder.go
index 79d0b9e..d341d59 100644
--- a/plumbing/format/index/decoder.go
+++ b/plumbing/format/index/decoder.go
@@ -390,7 +390,9 @@ func (d *treeExtensionDecoder) readEntry() (*TreeEntry, error) {
 
 	e.Trees = i
 	_, err = io.ReadFull(d.r, e.Hash[:])
-
+	if err != nil {
+		return nil, err
+	}
 	return e, nil
 }
 
diff --git a/plumbing/format/index/decoder_test.go b/plumbing/format/index/decoder_test.go
index 4e47dde..39ab336 100644
--- a/plumbing/format/index/decoder_test.go
+++ b/plumbing/format/index/decoder_test.go
@@ -6,8 +6,8 @@ import (
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/filemode"
 
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/plumbing/format/index/encoder_test.go b/plumbing/format/index/encoder_test.go
index 17585a0..b7a73cb 100644
--- a/plumbing/format/index/encoder_test.go
+++ b/plumbing/format/index/encoder_test.go
@@ -5,9 +5,10 @@ import (
 	"strings"
 	"time"
 
+	"github.com/go-git/go-git/v5/plumbing"
+
 	"github.com/google/go-cmp/cmp"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git/v5/plumbing"
 )
 
 func (s *IndexSuite) TestEncode(c *C) {
diff --git a/plumbing/format/objfile/common_test.go b/plumbing/format/objfile/common_test.go
index ec8c280..de76902 100644
--- a/plumbing/format/objfile/common_test.go
+++ b/plumbing/format/objfile/common_test.go
@@ -4,8 +4,9 @@ import (
 	"encoding/base64"
 	"testing"
 
-	. "gopkg.in/check.v1"
 	"github.com/go-git/go-git/v5/plumbing"
+
+	. "gopkg.in/check.v1"
 )
 
 type objfileFixture struct {
diff --git a/plumbing/format/objfile/reader_test.go b/plumbing/format/objfile/reader_test.go
index 48e7f1c..d697d54 100644
--- a/plumbing/format/objfile/reader_test.go
+++ b/plumbing/format/objfile/reader_test.go
@@ -7,8 +7,9 @@ import (
 	"io"
 	"io/ioutil"
 
-	. "gopkg.in/check.v1"
 	"github.com/go-git/go-git/v5/plumbing"
+
+	. "gopkg.in/check.v1"
 )
 
 type SuiteReader struct{}
diff --git a/plumbing/format/objfile/writer_test.go b/plumbing/format/objfile/writer_test.go
index 73ee662..35a9510 100644
--- a/plumbing/format/objfile/writer_test.go
+++ b/plumbing/format/objfile/writer_test.go
@@ -6,8 +6,9 @@ import (
 	"fmt"
 	"io"
 
-	. "gopkg.in/check.v1"
 	"github.com/go-git/go-git/v5/plumbing"
+
+	. "gopkg.in/check.v1"
 )
 
 type SuiteWriter struct{}
diff --git a/plumbing/format/packfile/encoder_advanced_test.go b/plumbing/format/packfile/encoder_advanced_test.go
index 21bf3ae..95db5c0 100644
--- a/plumbing/format/packfile/encoder_advanced_test.go
+++ b/plumbing/format/packfile/encoder_advanced_test.go
@@ -6,7 +6,6 @@ import (
 	"math/rand"
 	"testing"
 
-	"github.com/go-git/go-billy/v5/memfs"
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/cache"
 	"github.com/go-git/go-git/v5/plumbing/format/idxfile"
@@ -14,8 +13,9 @@ import (
 	"github.com/go-git/go-git/v5/plumbing/storer"
 	"github.com/go-git/go-git/v5/storage/filesystem"
 
+	"github.com/go-git/go-billy/v5/memfs"
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 type EncoderAdvancedSuite struct {
diff --git a/plumbing/format/packfile/encoder_test.go b/plumbing/format/packfile/encoder_test.go
index 2689762..d2db892 100644
--- a/plumbing/format/packfile/encoder_test.go
+++ b/plumbing/format/packfile/encoder_test.go
@@ -5,13 +5,13 @@ import (
 	"io"
 	stdioutil "io/ioutil"
 
-	"github.com/go-git/go-billy/v5/memfs"
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/format/idxfile"
 	"github.com/go-git/go-git/v5/storage/memory"
 
+	"github.com/go-git/go-billy/v5/memfs"
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 type EncoderSuite struct {
diff --git a/plumbing/format/packfile/patch_delta.go b/plumbing/format/packfile/patch_delta.go
index 1dc8b8b..9e90f30 100644
--- a/plumbing/format/packfile/patch_delta.go
+++ b/plumbing/format/packfile/patch_delta.go
@@ -49,7 +49,6 @@ func ApplyDelta(target, base plumbing.EncodedObject, delta []byte) (err error) {
 		return err
 	}
 
-
 	target.SetSize(int64(dst.Len()))
 
 	b := byteSlicePool.Get().([]byte)
@@ -113,7 +112,7 @@ func patchDelta(dst *bytes.Buffer, src, delta []byte) error {
 				invalidOffsetSize(offset, sz, srcSz) {
 				break
 			}
-			dst.Write(src[offset:offset+sz])
+			dst.Write(src[offset : offset+sz])
 			remainingTargetSz -= sz
 		} else if isCopyFromDelta(cmd) {
 			sz := uint(cmd) // cmd is the size itself
diff --git a/plumbing/memory.go b/plumbing/memory.go
index b8e1e1b..21337cc 100644
--- a/plumbing/memory.go
+++ b/plumbing/memory.go
@@ -3,7 +3,6 @@ package plumbing
 import (
 	"bytes"
 	"io"
-	"io/ioutil"
 )
 
 // MemoryObject on memory Object implementation
@@ -39,9 +38,11 @@ func (o *MemoryObject) Size() int64 { return o.sz }
 // afterwards
 func (o *MemoryObject) SetSize(s int64) { o.sz = s }
 
-// Reader returns a ObjectReader used to read the object's content.
+// Reader returns an io.ReadCloser used to read the object's content.
+//
+// For a MemoryObject, this reader is seekable.
 func (o *MemoryObject) Reader() (io.ReadCloser, error) {
-	return ioutil.NopCloser(bytes.NewBuffer(o.cont)), nil
+	return nopCloser{bytes.NewReader(o.cont)}, nil
 }
 
 // Writer returns a ObjectWriter used to write the object's content.
@@ -59,3 +60,13 @@ func (o *MemoryObject) Write(p []byte) (n int, err error) {
 // Close releases any resources consumed by the object when it is acting as a
 // ObjectWriter.
 func (o *MemoryObject) Close() error { return nil }
+
+// nopCloser exposes the extra methods of bytes.Reader while nopping Close().
+//
+// This allows clients to attempt seeking in a cached Blob's Reader.
+type nopCloser struct {
+	*bytes.Reader
+}
+
+// Close does nothing.
+func (nc nopCloser) Close() error { return nil }
diff --git a/plumbing/memory_test.go b/plumbing/memory_test.go
index 879ed37..2a141f4 100644
--- a/plumbing/memory_test.go
+++ b/plumbing/memory_test.go
@@ -1,6 +1,7 @@
 package plumbing
 
 import (
+	"io"
 	"io/ioutil"
 
 	. "gopkg.in/check.v1"
@@ -56,6 +57,33 @@ func (s *MemoryObjectSuite) TestReader(c *C) {
 	c.Assert(b, DeepEquals, []byte("foo"))
 }
 
+func (s *MemoryObjectSuite) TestSeekableReader(c *C) {
+	const pageSize = 4096
+	const payload = "foo"
+	content := make([]byte, pageSize+len(payload))
+	copy(content[pageSize:], []byte(payload))
+
+	o := &MemoryObject{cont: content}
+
+	reader, err := o.Reader()
+	c.Assert(err, IsNil)
+	defer func() { c.Assert(reader.Close(), IsNil) }()
+
+	rs, ok := reader.(io.ReadSeeker)
+	c.Assert(ok, Equals, true)
+
+	_, err = rs.Seek(pageSize, io.SeekStart)
+	c.Assert(err, IsNil)
+
+	b, err := ioutil.ReadAll(rs)
+	c.Assert(err, IsNil)
+	c.Assert(b, DeepEquals, []byte(payload))
+
+	// Check that our Reader isn't also accidentally writable
+	_, ok = reader.(io.WriteSeeker)
+	c.Assert(ok, Equals, false)
+}
+
 func (s *MemoryObjectSuite) TestWriter(c *C) {
 	o := &MemoryObject{}
 
diff --git a/plumbing/object/commit.go b/plumbing/object/commit.go
index 113cb29..98664a1 100644
--- a/plumbing/object/commit.go
+++ b/plumbing/object/commit.go
@@ -243,16 +243,16 @@ func (c *Commit) Decode(o plumbing.EncodedObject) (err error) {
 }
 
 // Encode transforms a Commit into a plumbing.EncodedObject.
-func (b *Commit) Encode(o plumbing.EncodedObject) error {
-	return b.encode(o, true)
+func (c *Commit) Encode(o plumbing.EncodedObject) error {
+	return c.encode(o, true)
 }
 
 // EncodeWithoutSignature export a Commit into a plumbing.EncodedObject without the signature (correspond to the payload of the PGP signature).
-func (b *Commit) EncodeWithoutSignature(o plumbing.EncodedObject) error {
-	return b.encode(o, false)
+func (c *Commit) EncodeWithoutSignature(o plumbing.EncodedObject) error {
+	return c.encode(o, false)
 }
 
-func (b *Commit) encode(o plumbing.EncodedObject, includeSig bool) (err error) {
+func (c *Commit) encode(o plumbing.EncodedObject, includeSig bool) (err error) {
 	o.SetType(plumbing.CommitObject)
 	w, err := o.Writer()
 	if err != nil {
@@ -261,11 +261,11 @@ func (b *Commit) encode(o plumbing.EncodedObject, includeSig bool) (err error) {
 
 	defer ioutil.CheckClose(w, &err)
 
-	if _, err = fmt.Fprintf(w, "tree %s\n", b.TreeHash.String()); err != nil {
+	if _, err = fmt.Fprintf(w, "tree %s\n", c.TreeHash.String()); err != nil {
 		return err
 	}
 
-	for _, parent := range b.ParentHashes {
+	for _, parent := range c.ParentHashes {
 		if _, err = fmt.Fprintf(w, "parent %s\n", parent.String()); err != nil {
 			return err
 		}
@@ -275,7 +275,7 @@ func (b *Commit) encode(o plumbing.EncodedObject, includeSig bool) (err error) {
 		return err
 	}
 
-	if err = b.Author.Encode(w); err != nil {
+	if err = c.Author.Encode(w); err != nil {
 		return err
 	}
 
@@ -283,11 +283,11 @@ func (b *Commit) encode(o plumbing.EncodedObject, includeSig bool) (err error) {
 		return err
 	}
 
-	if err = b.Committer.Encode(w); err != nil {
+	if err = c.Committer.Encode(w); err != nil {
 		return err
 	}
 
-	if b.PGPSignature != "" && includeSig {
+	if c.PGPSignature != "" && includeSig {
 		if _, err = fmt.Fprint(w, "\n"+headerpgp+" "); err != nil {
 			return err
 		}
@@ -296,14 +296,14 @@ func (b *Commit) encode(o plumbing.EncodedObject, includeSig bool) (err error) {
 		// newline. Use join for this so it's clear that a newline should not be
 		// added after this section, as it will be added when the message is
 		// printed.
-		signature := strings.TrimSuffix(b.PGPSignature, "\n")
+		signature := strings.TrimSuffix(c.PGPSignature, "\n")
 		lines := strings.Split(signature, "\n")
 		if _, err = fmt.Fprint(w, strings.Join(lines, "\n ")); err != nil {
 			return err
 		}
 	}
 
-	if _, err = fmt.Fprintf(w, "\n\n%s", b.Message); err != nil {
+	if _, err = fmt.Fprintf(w, "\n\n%s", c.Message); err != nil {
 		return err
 	}
 
diff --git a/plumbing/object/commit_stats_test.go b/plumbing/object/commit_stats_test.go
index bce2953..4078ce8 100644
--- a/plumbing/object/commit_stats_test.go
+++ b/plumbing/object/commit_stats_test.go
@@ -11,8 +11,9 @@ import (
 
 	"github.com/go-git/go-billy/v5/memfs"
 	"github.com/go-git/go-billy/v5/util"
+
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 type CommitStatsSuite struct {
diff --git a/plumbing/object/commit_walker_bfs_filtered.go b/plumbing/object/commit_walker_bfs_filtered.go
index e87c3db..9d51813 100644
--- a/plumbing/object/commit_walker_bfs_filtered.go
+++ b/plumbing/object/commit_walker_bfs_filtered.go
@@ -173,4 +173,3 @@ func (w *filterCommitIter) addToQueue(
 
 	return nil
 }
-
diff --git a/plumbing/object/commit_walker_path.go b/plumbing/object/commit_walker_path.go
index af6f745..aa0ca15 100644
--- a/plumbing/object/commit_walker_path.go
+++ b/plumbing/object/commit_walker_path.go
@@ -4,7 +4,6 @@ import (
 	"io"
 
 	"github.com/go-git/go-git/v5/plumbing"
-
 	"github.com/go-git/go-git/v5/plumbing/storer"
 )
 
@@ -29,7 +28,7 @@ func NewCommitPathIterFromIter(pathFilter func(string) bool, commitIter CommitIt
 	return iterator
 }
 
-// this function is kept for compatibilty, can be replaced with NewCommitPathIterFromIter
+// NewCommitFileIterFromIter is kept for compatibility, can be replaced with NewCommitPathIterFromIter
 func NewCommitFileIterFromIter(fileName string, commitIter CommitIter, checkParent bool) CommitIter {
 	return NewCommitPathIterFromIter(
 		func(path string) bool {
diff --git a/plumbing/object/commitgraph/commitnode_test.go b/plumbing/object/commitgraph/commitnode_test.go
index 38d3bce..6c9a643 100644
--- a/plumbing/object/commitgraph/commitnode_test.go
+++ b/plumbing/object/commitgraph/commitnode_test.go
@@ -4,13 +4,14 @@ import (
 	"path"
 	"testing"
 
-	. "gopkg.in/check.v1"
-	fixtures "github.com/go-git/go-git-fixtures/v4"
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/cache"
 	"github.com/go-git/go-git/v5/plumbing/format/commitgraph"
 	"github.com/go-git/go-git/v5/plumbing/format/packfile"
 	"github.com/go-git/go-git/v5/storage/filesystem"
+
+	fixtures "github.com/go-git/go-git-fixtures/v4"
+	. "gopkg.in/check.v1"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/plumbing/object/commitgraph/commitnode_walker_ctime.go b/plumbing/object/commitgraph/commitnode_walker_ctime.go
index f2ed663..281f10b 100644
--- a/plumbing/object/commitgraph/commitnode_walker_ctime.go
+++ b/plumbing/object/commitgraph/commitnode_walker_ctime.go
@@ -3,10 +3,10 @@ package commitgraph
 import (
 	"io"
 
-	"github.com/emirpasic/gods/trees/binaryheap"
-
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/storer"
+
+	"github.com/emirpasic/gods/trees/binaryheap"
 )
 
 type commitNodeIteratorByCTime struct {
diff --git a/plumbing/object/file_test.go b/plumbing/object/file_test.go
index 4dfd950..ada6654 100644
--- a/plumbing/object/file_test.go
+++ b/plumbing/object/file_test.go
@@ -9,8 +9,8 @@ import (
 	"github.com/go-git/go-git/v5/plumbing/storer"
 	"github.com/go-git/go-git/v5/storage/filesystem"
 
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 type FileSuite struct {
diff --git a/plumbing/object/patch.go b/plumbing/object/patch.go
index 1135a40..9b5f438 100644
--- a/plumbing/object/patch.go
+++ b/plumbing/object/patch.go
@@ -121,12 +121,12 @@ type Patch struct {
 	filePatches []fdiff.FilePatch
 }
 
-func (t *Patch) FilePatches() []fdiff.FilePatch {
-	return t.filePatches
+func (p *Patch) FilePatches() []fdiff.FilePatch {
+	return p.filePatches
 }
 
-func (t *Patch) Message() string {
-	return t.message
+func (p *Patch) Message() string {
+	return p.message
 }
 
 func (p *Patch) Encode(w io.Writer) error {
@@ -198,12 +198,12 @@ func (tf *textFilePatch) Files() (from fdiff.File, to fdiff.File) {
 	return
 }
 
-func (t *textFilePatch) IsBinary() bool {
-	return len(t.chunks) == 0
+func (tf *textFilePatch) IsBinary() bool {
+	return len(tf.chunks) == 0
 }
 
-func (t *textFilePatch) Chunks() []fdiff.Chunk {
-	return t.chunks
+func (tf *textFilePatch) Chunks() []fdiff.Chunk {
+	return tf.chunks
 }
 
 // textChunk is an implementation of fdiff.Chunk interface
diff --git a/plumbing/object/patch_test.go b/plumbing/object/patch_test.go
index d4b6cd6..2cff795 100644
--- a/plumbing/object/patch_test.go
+++ b/plumbing/object/patch_test.go
@@ -1,11 +1,12 @@
 package object
 
 import (
-	. "gopkg.in/check.v1"
-	fixtures "github.com/go-git/go-git-fixtures/v4"
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/cache"
 	"github.com/go-git/go-git/v5/storage/filesystem"
+
+	fixtures "github.com/go-git/go-git-fixtures/v4"
+	. "gopkg.in/check.v1"
 )
 
 type PatchSuite struct {
diff --git a/plumbing/object/rename.go b/plumbing/object/rename.go
index 35af1d6..7fed72c 100644
--- a/plumbing/object/rename.go
+++ b/plumbing/object/rename.go
@@ -536,7 +536,7 @@ var errIndexFull = errors.New("index is full")
 // between two files.
 // To save space in memory, this index uses a space efficient encoding which
 // will not exceed 1MiB per instance. The index starts out at a smaller size
-// (closer to 2KiB), but may grow as more distinct blocks withing the scanned
+// (closer to 2KiB), but may grow as more distinct blocks within the scanned
 // file are discovered.
 // see: https://github.com/eclipse/jgit/blob/master/org.eclipse.jgit/src/org/eclipse/jgit/diff/SimilarityIndex.java
 type similarityIndex struct {
@@ -709,7 +709,7 @@ func (i *similarityIndex) common(dst *similarityIndex) uint64 {
 }
 
 func (i *similarityIndex) add(key int, cnt uint64) error {
-	key = int(uint32(key)*0x9e370001 >> 1)
+	key = int(uint32(key) * 0x9e370001 >> 1)
 
 	j := i.slot(key)
 	for {
@@ -769,7 +769,7 @@ func (i *similarityIndex) slot(key int) int {
 	// We use 31 - hashBits because the upper bit was already forced
 	// to be 0 and we want the remaining high bits to be used as the
 	// table slot.
-	return int(uint32(key) >> uint(31 - i.hashBits))
+	return int(uint32(key) >> uint(31-i.hashBits))
 }
 
 func shouldGrowAt(hashBits int) int {
diff --git a/plumbing/protocol/packp/ulreq.go b/plumbing/protocol/packp/ulreq.go
index 44db8e4..ddec06e 100644
--- a/plumbing/protocol/packp/ulreq.go
+++ b/plumbing/protocol/packp/ulreq.go
@@ -109,42 +109,42 @@ func NewUploadRequestFromCapabilities(adv *capability.List) *UploadRequest {
 //   - is a DepthReference is given capability.DeepenNot MUST be present
 //   - MUST contain only maximum of one of capability.Sideband and capability.Sideband64k
 //   - MUST contain only maximum of one of capability.MultiACK and capability.MultiACKDetailed
-func (r *UploadRequest) Validate() error {
-	if len(r.Wants) == 0 {
+func (req *UploadRequest) Validate() error {
+	if len(req.Wants) == 0 {
 		return fmt.Errorf("want can't be empty")
 	}
 
-	if err := r.validateRequiredCapabilities(); err != nil {
+	if err := req.validateRequiredCapabilities(); err != nil {
 		return err
 	}
 
-	if err := r.validateConflictCapabilities(); err != nil {
+	if err := req.validateConflictCapabilities(); err != nil {
 		return err
 	}
 
 	return nil
 }
 
-func (r *UploadRequest) validateRequiredCapabilities() error {
+func (req *UploadRequest) validateRequiredCapabilities() error {
 	msg := "missing capability %s"
 
-	if len(r.Shallows) != 0 && !r.Capabilities.Supports(capability.Shallow) {
+	if len(req.Shallows) != 0 && !req.Capabilities.Supports(capability.Shallow) {
 		return fmt.Errorf(msg, capability.Shallow)
 	}
 
-	switch r.Depth.(type) {
+	switch req.Depth.(type) {
 	case DepthCommits:
-		if r.Depth != DepthCommits(0) {
-			if !r.Capabilities.Supports(capability.Shallow) {
+		if req.Depth != DepthCommits(0) {
+			if !req.Capabilities.Supports(capability.Shallow) {
 				return fmt.Errorf(msg, capability.Shallow)
 			}
 		}
 	case DepthSince:
-		if !r.Capabilities.Supports(capability.DeepenSince) {
+		if !req.Capabilities.Supports(capability.DeepenSince) {
 			return fmt.Errorf(msg, capability.DeepenSince)
 		}
 	case DepthReference:
-		if !r.Capabilities.Supports(capability.DeepenNot) {
+		if !req.Capabilities.Supports(capability.DeepenNot) {
 			return fmt.Errorf(msg, capability.DeepenNot)
 		}
 	}
@@ -152,15 +152,15 @@ func (r *UploadRequest) validateRequiredCapabilities() error {
 	return nil
 }
 
-func (r *UploadRequest) validateConflictCapabilities() error {
+func (req *UploadRequest) validateConflictCapabilities() error {
 	msg := "capabilities %s and %s are mutually exclusive"
-	if r.Capabilities.Supports(capability.Sideband) &&
-		r.Capabilities.Supports(capability.Sideband64k) {
+	if req.Capabilities.Supports(capability.Sideband) &&
+		req.Capabilities.Supports(capability.Sideband64k) {
 		return fmt.Errorf(msg, capability.Sideband, capability.Sideband64k)
 	}
 
-	if r.Capabilities.Supports(capability.MultiACK) &&
-		r.Capabilities.Supports(capability.MultiACKDetailed) {
+	if req.Capabilities.Supports(capability.MultiACK) &&
+		req.Capabilities.Supports(capability.MultiACKDetailed) {
 		return fmt.Errorf(msg, capability.MultiACK, capability.MultiACKDetailed)
 	}
 
diff --git a/plumbing/protocol/packp/ulreq_decode.go b/plumbing/protocol/packp/ulreq_decode.go
index 449b729..895a3bf 100644
--- a/plumbing/protocol/packp/ulreq_decode.go
+++ b/plumbing/protocol/packp/ulreq_decode.go
@@ -14,9 +14,9 @@ import (
 
 // Decode reads the next upload-request form its input and
 // stores it in the UploadRequest.
-func (u *UploadRequest) Decode(r io.Reader) error {
+func (req *UploadRequest) Decode(r io.Reader) error {
 	d := newUlReqDecoder(r)
-	return d.Decode(u)
+	return d.Decode(req)
 }
 
 type ulReqDecoder struct {
diff --git a/plumbing/protocol/packp/ulreq_encode.go b/plumbing/protocol/packp/ulreq_encode.go
index 4863076..c451e23 100644
--- a/plumbing/protocol/packp/ulreq_encode.go
+++ b/plumbing/protocol/packp/ulreq_encode.go
@@ -15,9 +15,9 @@ import (
 // All the payloads will end with a newline character.  Wants and
 // shallows are sorted alphabetically.  A depth of 0 means no depth
 // request is sent.
-func (u *UploadRequest) Encode(w io.Writer) error {
+func (req *UploadRequest) Encode(w io.Writer) error {
 	e := newUlReqEncoder(w)
-	return e.Encode(u)
+	return e.Encode(req)
 }
 
 type ulReqEncoder struct {
diff --git a/plumbing/protocol/packp/updreq.go b/plumbing/protocol/packp/updreq.go
index b63b023..4d927d8 100644
--- a/plumbing/protocol/packp/updreq.go
+++ b/plumbing/protocol/packp/updreq.go
@@ -68,12 +68,12 @@ func NewReferenceUpdateRequestFromCapabilities(adv *capability.List) *ReferenceU
 	return r
 }
 
-func (r *ReferenceUpdateRequest) validate() error {
-	if len(r.Commands) == 0 {
+func (req *ReferenceUpdateRequest) validate() error {
+	if len(req.Commands) == 0 {
 		return ErrEmptyCommands
 	}
 
-	for _, c := range r.Commands {
+	for _, c := range req.Commands {
 		if err := c.validate(); err != nil {
 			return err
 		}
diff --git a/plumbing/protocol/packp/updreq_encode.go b/plumbing/protocol/packp/updreq_encode.go
index 6a79653..2545e93 100644
--- a/plumbing/protocol/packp/updreq_encode.go
+++ b/plumbing/protocol/packp/updreq_encode.go
@@ -14,33 +14,33 @@ var (
 )
 
 // Encode writes the ReferenceUpdateRequest encoding to the stream.
-func (r *ReferenceUpdateRequest) Encode(w io.Writer) error {
-	if err := r.validate(); err != nil {
+func (req *ReferenceUpdateRequest) Encode(w io.Writer) error {
+	if err := req.validate(); err != nil {
 		return err
 	}
 
 	e := pktline.NewEncoder(w)
 
-	if err := r.encodeShallow(e, r.Shallow); err != nil {
+	if err := req.encodeShallow(e, req.Shallow); err != nil {
 		return err
 	}
 
-	if err := r.encodeCommands(e, r.Commands, r.Capabilities); err != nil {
+	if err := req.encodeCommands(e, req.Commands, req.Capabilities); err != nil {
 		return err
 	}
 
-	if r.Packfile != nil {
-		if _, err := io.Copy(w, r.Packfile); err != nil {
+	if req.Packfile != nil {
+		if _, err := io.Copy(w, req.Packfile); err != nil {
 			return err
 		}
 
-		return r.Packfile.Close()
+		return req.Packfile.Close()
 	}
 
 	return nil
 }
 
-func (r *ReferenceUpdateRequest) encodeShallow(e *pktline.Encoder,
+func (req *ReferenceUpdateRequest) encodeShallow(e *pktline.Encoder,
 	h *plumbing.Hash) error {
 
 	if h == nil {
@@ -51,7 +51,7 @@ func (r *ReferenceUpdateRequest) encodeShallow(e *pktline.Encoder,
 	return e.Encodef("%s%s", shallow, objId)
 }
 
-func (r *ReferenceUpdateRequest) encodeCommands(e *pktline.Encoder,
+func (req *ReferenceUpdateRequest) encodeCommands(e *pktline.Encoder,
 	cmds []*Command, cap *capability.List) error {
 
 	if err := e.Encodef("%s\x00%s",
diff --git a/plumbing/protocol/packp/uppackresp_test.go b/plumbing/protocol/packp/uppackresp_test.go
index 8950fa9..260dc57 100644
--- a/plumbing/protocol/packp/uppackresp_test.go
+++ b/plumbing/protocol/packp/uppackresp_test.go
@@ -4,10 +4,10 @@ import (
 	"bytes"
 	"io/ioutil"
 
+	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/protocol/packp/capability"
 
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git/v5/plumbing"
 )
 
 type UploadPackResponseSuite struct{}
diff --git a/plumbing/storer/object_test.go b/plumbing/storer/object_test.go
index 8dc3623..30424ff 100644
--- a/plumbing/storer/object_test.go
+++ b/plumbing/storer/object_test.go
@@ -4,8 +4,9 @@ import (
 	"fmt"
 	"testing"
 
-	. "gopkg.in/check.v1"
 	"github.com/go-git/go-git/v5/plumbing"
+
+	. "gopkg.in/check.v1"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/plumbing/storer/reference_test.go b/plumbing/storer/reference_test.go
index 0660043..7a4d8b4 100644
--- a/plumbing/storer/reference_test.go
+++ b/plumbing/storer/reference_test.go
@@ -4,8 +4,9 @@ import (
 	"errors"
 	"io"
 
-	. "gopkg.in/check.v1"
 	"github.com/go-git/go-git/v5/plumbing"
+
+	. "gopkg.in/check.v1"
 )
 
 type ReferenceSuite struct{}
diff --git a/plumbing/transport/file/receive_pack_test.go b/plumbing/transport/file/receive_pack_test.go
index 2ee4b86..686bdcc 100644
--- a/plumbing/transport/file/receive_pack_test.go
+++ b/plumbing/transport/file/receive_pack_test.go
@@ -5,8 +5,8 @@ import (
 
 	"github.com/go-git/go-git/v5/plumbing/transport/test"
 
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 type ReceivePackSuite struct {
diff --git a/plumbing/transport/git/common_test.go b/plumbing/transport/git/common_test.go
index 551b50d..3391aaf 100644
--- a/plumbing/transport/git/common_test.go
+++ b/plumbing/transport/git/common_test.go
@@ -13,8 +13,8 @@ import (
 
 	"github.com/go-git/go-git/v5/plumbing/transport"
 
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/plumbing/transport/git/receive_pack_test.go b/plumbing/transport/git/receive_pack_test.go
index 1f730a4..b661d71 100644
--- a/plumbing/transport/git/receive_pack_test.go
+++ b/plumbing/transport/git/receive_pack_test.go
@@ -3,8 +3,8 @@ package git
 import (
 	"github.com/go-git/go-git/v5/plumbing/transport/test"
 
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 type ReceivePackSuite struct {
diff --git a/plumbing/transport/git/upload_pack_test.go b/plumbing/transport/git/upload_pack_test.go
index bbfdf58..5200953 100644
--- a/plumbing/transport/git/upload_pack_test.go
+++ b/plumbing/transport/git/upload_pack_test.go
@@ -3,8 +3,8 @@ package git
 import (
 	"github.com/go-git/go-git/v5/plumbing/transport/test"
 
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 type UploadPackSuite struct {
diff --git a/plumbing/transport/http/common_test.go b/plumbing/transport/http/common_test.go
index 5811139..4122e62 100644
--- a/plumbing/transport/http/common_test.go
+++ b/plumbing/transport/http/common_test.go
@@ -17,8 +17,8 @@ import (
 
 	"github.com/go-git/go-git/v5/plumbing/transport"
 
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/plumbing/transport/http/receive_pack_test.go b/plumbing/transport/http/receive_pack_test.go
index b977908..7e70986 100644
--- a/plumbing/transport/http/receive_pack_test.go
+++ b/plumbing/transport/http/receive_pack_test.go
@@ -3,8 +3,8 @@ package http
 import (
 	"github.com/go-git/go-git/v5/plumbing/transport/test"
 
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 type ReceivePackSuite struct {
diff --git a/plumbing/transport/http/upload_pack_test.go b/plumbing/transport/http/upload_pack_test.go
index b34441d..6fae443 100644
--- a/plumbing/transport/http/upload_pack_test.go
+++ b/plumbing/transport/http/upload_pack_test.go
@@ -11,8 +11,8 @@ import (
 	"github.com/go-git/go-git/v5/plumbing/transport"
 	"github.com/go-git/go-git/v5/plumbing/transport/test"
 
+	fixtures "github.com/go-git/go-git-fixtures/v4"
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git-fixtures/v4"
 )
 
 type UploadPackSuite struct {
diff --git a/plumbing/transport/server/receive_pack_test.go b/plumbing/transport/server/receive_pack_test.go
index 2c5b0ae..6c704bd 100644
--- a/plumbing/transport/server/receive_pack_test.go
+++ b/plumbing/transport/server/receive_pack_test.go
@@ -60,4 +60,5 @@ func (s *ReceivePackSuite) TestReceivePackWithNilPackfile(c *C) {
 
 	report, err := r.ReceivePack(context.Background(), req)
 	c.Assert(report, IsNil, comment)
+	c.Assert(err, NotNil, comment)
 }
diff --git a/plumbing/transport/ssh/common_test.go b/plumbing/transport/ssh/common_test.go
index 22a8243..87c1148 100644
--- a/plumbing/transport/ssh/common_test.go
+++ b/plumbing/transport/ssh/common_test.go
@@ -3,12 +3,11 @@ package ssh
 import (
 	"testing"
 
-	"github.com/kevinburke/ssh_config"
+	"github.com/go-git/go-git/v5/plumbing/transport"
 
+	"github.com/kevinburke/ssh_config"
 	"golang.org/x/crypto/ssh"
-
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git/v5/plumbing/transport"
 )
 
 func Test(t *testing.T) { TestingT(t) }
diff --git a/plumbing/transport/test/upload_pack.go b/plumbing/transport/test/upload_pack.go
index ee7b067..3ee029d 100644
--- a/plumbing/transport/test/upload_pack.go
+++ b/plumbing/transport/test/upload_pack.go
@@ -13,11 +13,11 @@ import (
 	"github.com/go-git/go-git/v5/plumbing"
 	"github.com/go-git/go-git/v5/plumbing/format/packfile"
 	"github.com/go-git/go-git/v5/plumbing/protocol/packp"
+	"github.com/go-git/go-git/v5/plumbing/protocol/packp/capability"
 	"github.com/go-git/go-git/v5/plumbing/transport"
 	"github.com/go-git/go-git/v5/storage/memory"
 
 	. "gopkg.in/check.v1"
-	"github.com/go-git/go-git/v5/plumbing/protocol/packp/capability"
 )
 
 type UploadPackSuite struct {