Repository.Resolution with short hash fails with repository opened by PlainOpen

[sinozu]

I tried to use the short hash resolution feature merged in #136.

When I clone the repository using PlainClone, short hash revision resolution succeed.
But short hash revision resolution failed with the repository opened by PlainOpen.

func main() {
	r, err := git.PlainClone("/tmp/foo", false, &git.CloneOptions{
		URL:      "https://github.com/go-git/go-git",
		Progress: os.Stdout,
	})
	if err != nil {
		log.Println(err.Error())
		return
	}
	// SUCCESS
	h, err := r.ResolveRevision("cded5b6")
	if err != nil {
		log.Println("ResolveRevision", err)
		return
	}
	log.Println(h)
	r, err = git.PlainOpen("/tmp/foo")
	if err != nil {
		log.Println(err.Error())
		return
	}
	// FAILED：reference not found
	h, err = r.ResolveRevision("cded5b6")
	if err != nil {
		log.Println("ResolveRevision", err)
		return
	}
	log.Println(h)
}

[mcuadros]

Maybe @dsymonds can help

[dsymonds]

Not sure what's happening there. I can only think it is taking a different code path, such as not using the index or searching for loose objects.

[sinozu]

@dsymonds
When using PlainClone, WritePackfileToObjectStorage is Called.

go-git/plumbing/format/packfile/common.go

Line 45 in 2637279

func WritePackfileToObjectStorage(

Packfile is written to object storage. So I think, short hash revision resolution succeed.

When using PlainOpen, it seems that Packfile is not written.

[liiri]

Any workaround to have ResolveRevision work with short sha and an existing clone?

[didn0t]

Also having this issue with PlainOpen - works with tags but not short hashes.

[didn0t]

I've noticed that this only appears to be a problem with the first call using a short hash and subsequent calls work.

I have therefore worked around this by adding:

phash, _:= repo.ResolveRevision(plumbing.Revision("HEAD"))
commit, _:= repo.CommitObject(*phash)
tree, _:= commit.Tree()
_ = tree

Using tags doesn't have this issue. Apologies if the above code isn't idiomatic golang but it's my first attempt.

[liiri]

Thanks @didn0t it worked for me too :)

[iamnoah]

Hit this as well. I noticed that the short sha that failed was a merge commit 🤷‍♂️

The create a commit and read tree workaround works for me.

[jeremy-ebler-vineti]

Simply this worked for me:

repo, _ := git.PlainOpen(path)
repo.ResolveRevision(plumbing.Revision("HEAD"))

I didn't need to grab the commit, tree, etc. Just resolving HEAD or a full hash after opening allowed short hashes to resolve later on.

[adg]

Just an update to say that the workarounds shared here only work if HEAD is in a packfile. If HEAD is among the objects/xx/xxxxxxx... directory hierarchy then the packfile indexes won't be read, and the workaround won't work.

A more reliable way is to attempt to resolve the zero hash:

repo, _ := git.PlainOpen(path)
repo.ResolveRevision(plumbing.Revision(plumbing.ZeroHash.String()))