[BUG] cocogitto fails with multiple git working trees

[andreabedini]

Thanks for this project, I have just started using it so I hope I am not just holding it wrong :)

Describe the bug

Adding a commit to one of my repositories, I was presented with misterious message:

~/work/cardano-haskell-packages-pr-441 pr/441* ⇡
❮ cog commit refactor "chap metadata is system-independent" flake
Error: Not a directory (os error 20)

Investigating further, I noticed that cog seems to be looking for .git/COMMIT_EDITMSG

❯ strace cog commit refactor "chap metadata is system-independent" flake >> /dev/null
...
newfstatat(AT_FDCWD, "/home/andrea/work/cardano-haskell-packages/.git/worktrees/cardano-haskell-packages-pr-441/", {st_mode=S_IFDIR|0755, st_size=122, ...}, AT_SYMLINK_NOFOLLOW) = 0
statx(AT_FDCWD, "/home/andrea/work/cardano-haskell-packages-pr-441/cog.toml", AT_STATX_SYNC_AS_STAT, STATX_ALL, 0x7fff0e5934f0) = -1 ENOENT (No such file or directory)
statx(AT_FDCWD, "/home/andrea/work/cardano-haskell-packages-pr-441/.git/hooks/pre-commit", AT_STATX_SYNC_AS_STAT, STATX_ALL, 0x7fff0e5941e0) = -1 ENOTDIR (Not a directory)
openat(AT_FDCWD, "/home/andrea/work/cardano-haskell-packages-pr-441/.git/COMMIT_EDITMSG", O_WRONLY|O_CREAT|O_TRUNC|O_CLOEXEC, 0666) = -1 ENOTDIR (Not a directory)
write(2, "Error: ", 7Error: )                  = 7
write(2, "Not a directory", 15Not a directory)         = 15

This .git is indeed not a directory because I am using multiple git working trees:

~/work/cardano-haskell-packages-pr-441 pr/441* ⇡
❯ git worktree list
/home/andrea/work/cardano-haskell-packages         a36b3a63 [main]
/home/andrea/work/cardano-haskell-packages-pr-441  8bad3070 [pr/441]

~/work/cardano-haskell-packages-pr-441 pr/441* ⇡
❯ cat .git
gitdir: /home/andrea/work/cardano-haskell-packages/.git/worktrees/cardano-haskell-packages-pr-441

The interesting thing is that cogitto seems to (partially) understand this because, at the top of the strace above, you can see it's accessing cardano-haskell-packages/.git/worktrees/cardano-haskell-packages-pr-441/ which only exists in presence of multile working trees.

To Reproduce

This seems to work:

mkdir cocogitto && cd cocogitto
git init && touch README.md && git add README.md && git commit -m "Initial commit"
git worktree add ../cocogitto-other && cd ../cocogitto-other
touch NEW_FILE.md && git add NEW_FILE.md && cog commit test

Expected behavior

The commit succeeds as it would normally do.

Additional context

None ☺️