Unresolvable reference when .git is a file (git worktree support)

Git will sometimes configure the .git file to be a file, instead of a directory. This file has contents similar to:

gitdir: /home/awwright/repo.git/worktrees/work

This happens, among other cases, when a working tree is created with git-worktree. Here is a script showing the difference in behavior:

NAME=$(uuidgen).test
mkdir $NAME
pushd $NAME
git clone https://github.com/isomorphic-git/test.empty repo
git --git-dir=repo/.git worktree add work master

echo '{"dependencies":{"isomorphic-git":"0.55.0"}}' > package.json
yarn install

pushd work
echo
echo 'Git works:'
git log -1
echo
echo 'isomorphic-git bails:'
node -e 'require("isomorphic-git").log({depth:1, fs:require("fs"), dir:process.cwd(), ref:"HEAD"}).then(console.log, console.error);'
popd

pushd repo
echo
echo 'but it works in the default working tree:'
node -e 'require("isomorphic-git").log({depth:1, fs:require("fs"), dir:process.cwd(), ref:"HEAD"}).then(console.log, console.error);'
popd
popd

I would expect both calls to work, but only the second one does, with the first producing an error:

GitError [ResolveRefError]: Could not resolve reference "master".

[mojavelinux]

Yes, Antora supports git worktrees. See https://docs.antora.org/antora/latest/playbook/content-worktrees/ Please direct follow-up questions to the Antora project chat at https://chat.antora.org as we don’t want to bog down this issue talking about Antora.

[wmhilton]

Ahhhh… hmm. Two more implementation notes for myself or whoever implements this feature.

1. default argument values can’t be awaited. Since this will involve filesystem read, we’ll have to move initializing it into the body of the function.
2. canonical git follows this “link” even if GIT_DIR is explicitly set. So really we should leave it there and it should look more like this:

import { join } from '../utils/join.js'
import { resolveGitDir } from '../utils/resolveGitDir.js'

function commit ({
  dir,
  gitdir = join(dir, '.git'),
  fs: _fs = cores.get(core).get('fs'),
  ...
}) {
  const fs = new FileSystem(_fs)
  gitdir = await resolveGitDir({ gitdir, fs })
  // do things with `dir` and `gitdir`
}