Teach ResolveRevision how to look up annotated tags

Author: novas0x2a

repository.go

@@ -484,7 +484,9 @@ func (r *Repository) DeleteBranch(name string) error {
 	return r.Storer.SetConfig(cfg)
 }
 
-func (r *Repository) resolveToCommitHash(h plumbing.Hash) (plumbing.Hash, error) {
+// ResolveToCommitHash takes any arbitrary hash and resolves it to a commit
+// hash, if possible.
+func (r *Repository) ResolveToCommitHash(h plumbing.Hash) (plumbing.Hash, error) {
 	obj, err := r.Storer.EncodedObject(plumbing.AnyObject, h)
 	if err != nil {
 		return plumbing.ZeroHash, err
@@ -495,7 +497,7 @@ func (r *Repository) resolveToCommitHash(h plumbing.Hash) (plumbing.Hash, error)
 		if err != nil {
 			return plumbing.ZeroHash, err
 		}
-		return r.resolveToCommitHash(t.Target)
+		return r.ResolveToCommitHash(t.Target)
 	case plumbing.CommitObject:
 		return h, nil
 	default:
@@ -676,7 +678,7 @@ func (r *Repository) updateReferences(spec []config.RefSpec,
 
 	if !resolvedRef.Name().IsBranch() {
 		// Detached HEAD mode
-		h, err := r.resolveToCommitHash(resolvedRef.Hash())
+		h, err := r.ResolveToCommitHash(resolvedRef.Hash())
 		if err != nil {
 			return false, err
 		}
@@ -1004,6 +1006,16 @@ func (r *Repository) Worktree() (*Worktree, error) {
 	return &Worktree{r: r, Filesystem: r.wt}, nil
 }
 
+func countTrue(vals ...bool) int {
+	sum := 0
+	for _, v := range vals {
+		if v {
+			sum++
+		}
+	}
+	return sum
+}
+
 // ResolveRevision resolves revision to corresponding hash.
 //
 // Implemented resolvers : HEAD, branch, tag, heads/branch, refs/heads/branch,
@@ -1024,8 +1036,9 @@ func (r *Repository) ResolveRevision(rev plumbing.Revision) (*plumbing.Hash, err
 		case revision.Ref:
 			revisionRef := item.(revision.Ref)
 			var ref *plumbing.Reference
+			var tag *object.Tag
 			var hashCommit, refCommit *object.Commit
-			var rErr, hErr error
+			var rErr, hErr, tErr error
 
 			for _, rule := range append([]string{"%s"}, plumbing.RefRevParseRules...) {
 				ref, err = storer.ResolveReference(r.Storer, plumbing.ReferenceName(fmt.Sprintf(rule, revisionRef)))
@@ -1036,24 +1049,33 @@ func (r *Repository) ResolveRevision(rev plumbing.Revision) (*plumbing.Hash, err
 			}
 
 			if ref != nil {
+				tag, tErr = r.TagObject(ref.Hash())
 				refCommit, rErr = r.CommitObject(ref.Hash())
 			} else {
 				rErr = plumbing.ErrReferenceNotFound
+				tErr = plumbing.ErrReferenceNotFound
 			}
 
-			isHash := plumbing.NewHash(string(revisionRef)).String() == string(revisionRef)
-
-			if isHash {
+			maybeHash := plumbing.NewHash(string(revisionRef)).String() == string(revisionRef)
+			if maybeHash {
 				hashCommit, hErr = r.CommitObject(plumbing.NewHash(string(revisionRef)))
+			} else {
+				hErr = plumbing.ErrReferenceNotFound
 			}
 
+			isTag := tErr == nil
+			isCommit := rErr == nil
+			isHash := hErr == nil
+
 			switch {
-			case rErr == nil && !isHash:
-				commit = refCommit
-			case rErr != nil && isHash && hErr == nil:
-				commit = hashCommit
-			case rErr == nil && isHash && hErr == nil:
+			case countTrue(isTag, isCommit, isHash) > 1:
 				return &plumbing.ZeroHash, fmt.Errorf(`refname "%s" is ambiguous`, revisionRef)
+			case isTag:
+				return &tag.Hash, nil
+			case isCommit:
+				return &refCommit.Hash, nil
+			case isHash:
+				return &hashCommit.Hash, nil
 			default:
 				return &plumbing.ZeroHash, plumbing.ErrReferenceNotFound
 			}