Tag Checkout and/or Reset not working as expected

[petergardfjall]

Hi, using go-git (v4.13.1) I'm trying to accomplish the equivalent of

git clone https://github.com/hamcrest/JavaHamcrest.git
cd JavaHamcrest
git checkout hamcrest-java-1.3

That is, checkout a certain repository tag.

However, I cannot seem to get this to work. I'm not sure if its an error on my part or an error of the library. Here is the code I'm running:

package main

import (
	"log"

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

func main() {
	remoteURL := "https://github.com/hamcrest/JavaHamcrest.git"
	localPath := "/tmp/hamcrest.git"
	tag := "hamcrest-java-1.3"

	repo, err := git.PlainClone(localPath, false /* isBare */, &git.CloneOptions{
		URL:               remoteURL,
		RecurseSubmodules: git.DefaultSubmoduleRecursionDepth,
		Tags:              git.AllTags,
	})
	if err != nil {
		log.Fatalf("clone of repo failed: %s", err)
	}

	tree, err := repo.Worktree()
	if err != nil {
		log.Fatalf("failed to get worktree: %s", err)
	}

	// check out the tag of interest. this will put us in a detached state
	err = tree.Checkout(&git.CheckoutOptions{
		Branch: plumbing.ReferenceName("refs/tags/" + tag),
		// if branch is changed, throw away any local changes
		Force: true,
	})
	if err != nil {
		log.Fatalf("failed to checkout repo tag %s: %s", tag, err)
	}
	tagHead, err := repo.Head()
	if err != nil {
		log.Fatalf("failed to get HEAD: %s", err)
	}

	if err := tree.Reset(&git.ResetOptions{Commit: tagHead.Hash(), Mode: git.HardReset}); err != nil {
		log.Fatalf("failed to reset repo to commit %s: %s", tagHead.Hash(), tag)
	}

	log.Printf("successfully checked out tag!")
}

After running the above code, I get

$ cd /tmp/hamcrest.git
$ git status
Not currently on any branch.
Changes not staged for commit:
  (use "git add/rm <file>..." to update what will be committed)
  (use "git checkout -- <file>..." to discard changes in working directory)

	deleted:    .idea/workspace.xml

no changes added to commit (use "git add" and/or "git commit -a")

So the work tree contains changes, even though I ran a hard reset.

Have I found a bug?

[sbourlon]

I am facing the same issue when resetting to a commit.