2 files changed, 184 insertions, 10 deletions
diff --git a/plumbing/object/commit_walker.go b/plumbing/object/commit_walker.go
index 40ad258..0eff059 100644
--- a/plumbing/object/commit_walker.go
+++ b/plumbing/object/commit_walker.go
@@ -1,10 +1,12 @@
 package object
 
 import (
+	"container/list"
 	"io"
 
 	"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"
 )
 
 type commitPreIterator struct {
@@ -181,3 +183,145 @@ func (w *commitPostIterator) ForEach(cb func(*Commit) error) error {
 }
 
 func (w *commitPostIterator) Close() {}
+
+// commitAllIterator stands for commit iterator for all refs.
+type commitAllIterator struct {
+	// currCommit points to the current commit.
+	currCommit *list.Element
+}
+
+// NewCommitAllIter returns a new commit iterator for all refs.
+// repoStorer is a repo Storer used to get commits and references.
+// commitIterFunc is a commit iterator function, used to iterate through ref commits in chosen order
+func NewCommitAllIter(repoStorer storage.Storer, commitIterFunc func(*Commit) CommitIter) (CommitIter, error) {
+	commitsPath := list.New()
+	commitsLookup := make(map[plumbing.Hash]*list.Element)
+	head, err := storer.ResolveReference(repoStorer, plumbing.HEAD)
+	if err == nil {
+		err = addReference(repoStorer, commitIterFunc, head, commitsPath, commitsLookup)
+	}
+
+	if err != nil && err != plumbing.ErrReferenceNotFound {
+		return nil, err
+	}
+
+	// add all references along with the HEAD
+	refIter, err := repoStorer.IterReferences()
+	if err != nil {
+		return nil, err
+	}
+	defer refIter.Close()
+
+	for {
+		ref, err := refIter.Next()
+		if err == io.EOF {
+			break
+		}
+
+		if err == plumbing.ErrReferenceNotFound {
+			continue
+		}
+
+		if err != nil {
+			return nil, err
+		}
+
+		if err = addReference(repoStorer, commitIterFunc, ref, commitsPath, commitsLookup); err != nil {
+			return nil, err
+		}
+	}
+
+	return &commitAllIterator{commitsPath.Front()}, nil
+}
+
+func addReference(
+	repoStorer storage.Storer,
+	commitIterFunc func(*Commit) CommitIter,
+	ref *plumbing.Reference,
+	commitsPath *list.List,
+	commitsLookup map[plumbing.Hash]*list.Element) error {
+
+	_, exists := commitsLookup[ref.Hash()]
+	if exists {
+		// we already have it - skip the reference.
+		return nil
+	}
+
+	refCommit, _ := GetCommit(repoStorer, ref.Hash())
+	if refCommit == nil {
+		// if it's not a commit - skip it.
+		return nil
+	}
+
+	var (
+		refCommits []*Commit
+		parent     *list.Element
+	)
+	// collect all ref commits to add
+	commitIter := commitIterFunc(refCommit)
+	for c, e := commitIter.Next(); e == nil; {
+		parent, exists = commitsLookup[c.Hash]
+		if exists {
+			break
+		}
+		refCommits = append(refCommits, c)
+		c, e = commitIter.Next()
+	}
+	commitIter.Close()
+
+	if parent == nil {
+		// common parent - not found
+		// add all commits to the path from this ref (maybe it's a HEAD and we don't have anything, yet)
+		for _, c := range refCommits {
+			parent = commitsPath.PushBack(c)
+			commitsLookup[c.Hash] = parent
+		}
+	} else {
+		// add ref's commits to the path in reverse order (from the latest)
+		for i := len(refCommits) - 1; i >= 0; i-- {
+			c := refCommits[i]
+			// insert before found common parent
+			parent = commitsPath.InsertBefore(c, parent)
+			commitsLookup[c.Hash] = parent
+		}
+	}
+
+	return nil
+}
+
+func (it *commitAllIterator) Next() (*Commit, error) {
+	if it.currCommit == nil {
+		return nil, io.EOF
+	}
+
+	c := it.currCommit.Value.(*Commit)
+	it.currCommit = it.currCommit.Next()
+
+	return c, nil
+}
+
+func (it *commitAllIterator) ForEach(cb func(*Commit) error) error {
+	for {
+		c, err := it.Next()
+		if err == io.EOF {
+			break
+		}
+		if err != nil {
+			return err
+		}
+
+		err = cb(c)
+		if err == storer.ErrStop {
+			break
+		}
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}
+
+func (it *commitAllIterator) Close() {
+	it.currCommit = nil
+}
diff --git a/plumbing/object/commit_walker_file.go b/plumbing/object/commit_walker_file.go
index 84e738a..6f16e61 100644
--- a/plumbing/object/commit_walker_file.go
+++ b/plumbing/object/commit_walker_file.go
@@ -1,23 +1,30 @@
 package object
 
 import (
-	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 	"io"
+
+	"gopkg.in/src-d/go-git.v4/plumbing"
+
+	"gopkg.in/src-d/go-git.v4/plumbing/storer"
 )
 
 type commitFileIter struct {
 	fileName      string
 	sourceIter    CommitIter
 	currentCommit *Commit
+	checkParent   bool
 }
 
 // NewCommitFileIterFromIter returns a commit iterator which performs diffTree between
 // successive trees returned from the commit iterator from the argument. The purpose of this is
 // to find the commits that explain how the files that match the path came to be.
-func NewCommitFileIterFromIter(fileName string, commitIter CommitIter) CommitIter {
+// If checkParent is true then the function double checks if potential parent (next commit in a path)
+// is one of the parents in the tree (it's used by `git log --all`).
+func NewCommitFileIterFromIter(fileName string, commitIter CommitIter, checkParent bool) CommitIter {
 	iterator := new(commitFileIter)
 	iterator.sourceIter = commitIter
 	iterator.fileName = fileName
+	iterator.checkParent = checkParent
 	return iterator
 }
 
@@ -71,20 +78,14 @@ func (c *commitFileIter) getNextFileCommit() (*Commit, error) {
 			return nil, diffErr
 		}
 
-		foundChangeForFile := false
-		for _, change := range changes {
-			if change.name() == c.fileName {
-				foundChangeForFile = true
-				break
-			}
-		}
+		found := c.hasFileChange(changes, parentCommit)
 
 		// Storing the current-commit in-case a change is found, and
 		// Updating the current-commit for the next-iteration
 		prevCommit := c.currentCommit
 		c.currentCommit = parentCommit
 
-		if foundChangeForFile == true {
+		if found {
 			return prevCommit, nil
 		}
 
@@ -95,6 +96,35 @@ func (c *commitFileIter) getNextFileCommit() (*Commit, error) {
 	}
 }
 
+func (c *commitFileIter) hasFileChange(changes Changes, parent *Commit) bool {
+	for _, change := range changes {
+		if change.name() != c.fileName {
+			continue
+		}
+
+		// filename matches, now check if source iterator contains all commits (from all refs)
+		if c.checkParent {
+			if parent != nil && isParentHash(parent.Hash, c.currentCommit) {
+				return true
+			}
+			continue
+		}
+
+		return true
+	}
+
+	return false
+}
+
+func isParentHash(hash plumbing.Hash, commit *Commit) bool {
+	for _, h := range commit.ParentHashes {
+		if h == hash {
+			return true
+		}
+	}
+	return false
+}
+
 func (c *commitFileIter) ForEach(cb func(*Commit) error) error {
 	for {
 		commit, nextErr := c.Next()