ResolveRevision doesn't resolve annotated tags

[rykov]

Looking through the revision.Ref case for the switch statement in ResolveRevision, the tag is resolved, however, calling r.CommitObject fails with "object not found" error because the resolved commit is not a commit Hash. Seems like one needs to call r.resolveToCommitHash either before CommitObject or inside of it (depending on the intended API)

go-git/repository.go

Lines 914 to 930 in ecda5c1

	for _, rule := range append([]string{"%s"}, plumbing.RefRevParseRules...) {
	ref, err = storer.ResolveReference(r.Storer, plumbing.ReferenceName(fmt.Sprintf(rule, revisionRef)))
	if err == nil {
	break
	}
	}
	if ref == nil {
	return &plumbing.ZeroHash, plumbing.ErrReferenceNotFound
	}
	commit, err = r.CommitObject(ref.Hash())
	if err != nil {
	return &plumbing.ZeroHash, err
	}

[mcuadros]

Can you provide an example repository? Thanks

[rykov]

Here's a quick way to reproduce this:

$ git init 
$ git commit --allow-empty -m "Initial commit"
$ git tag -a ann-tag -m "Annotated!"
$ git tag reg-tag

And then run:

package main

import(
  "gopkg.in/src-d/go-git.v4"
  "gopkg.in/src-d/go-git.v4/plumbing"
  "fmt"
)

func main() {
  r, _ := git.PlainOpen(".")
  rev1, err := r.ResolveRevision(plumbing.Revision("reg-tag"))
  fmt.Println("Regular tag: ", rev1, err)
  rev2, err := r.ResolveRevision(plumbing.Revision("ann-tag"))
  fmt.Println("Annotated tag: ", rev2, err)
}

The output that I see with v4.1.1 is:

Regular tag:  7e454763ed760efa060937a9fd603a60b9fd2879 <nil>
Annotated tag:  0000000000000000000000000000000000000000 object not found

[orirawlings]

It seems like git rev-parse would resolve to the hash of the tag object in this case. So we probably want to mimic that behavior as well.

[rykov]

If you mean the hash of the annotated tag object, then it makes sense, but we also then need a public method to unpeel that to a commit hash. Something similar to r.resolveToCommitHash

[pinoniq]

In the meantime, is there another way to resolve annotated tags using go-git?

[pinoniq]

I did some digging and I managed to get it working "kind of".

repository.ResolveRevision expects the resolved reference to be a commit. This is the case for lightweight tags. But not at all for annotated tags.

replacing

			if ref != nil {
				refCommit, rErr = r.CommitObject(ref.Hash())
			} else {
				rErr = plumbing.ErrReferenceNotFound
			}

with

			if ref != nil {
				if ref.Name().IsTag() {
					refTagObject, rErr = r.TagObject(ref.Hash())
					refCommit, rErr = refTagObject.Commit()
				} else {
					refCommit, rErr = r.CommitObject(ref.Hash())
				}
			} else {
				rErr = plumbing.ErrReferenceNotFound
			}

seems to do the job.

I'm willing to open a PR if this solution seems acceptable for you

[mcuadros]

Solved