On Mon, Jun 2, 2025, at 15:29, shejialuo wrote:

"git refs verify" doesn't work if there are worktrees created on Git
v2.43.0 or older versions. These versions don't automatically create the
"refs" directory, causing the error:

    error: cannot open directory .git/worktrees/<worktree name>/refs:
    No such file or directory

Good.

Since 8f4c00de95 (builtin/worktree: create refdb via ref backend,
2024-01-08), we automatically create the "refs" directory for new
worktrees. And in 7c78d819e6 (ref: support multiple worktrees check for
refs, 2024-11-20), we assume that all linked worktrees have this
directory and would wrongly report an error to the user, thus
introducing compatibility issue.

Okay, you don’t mention c1cf918d3ad (builtin/fsck: add `git refs verify`
child process, 2025-02-28) in the commit message because of your reply:

quoted

Because we would call "git refs verify" subprocess in "git-fsck(1)"
in this release cycle, I just want to fix this problem before the
release.  Thus, it won't affect the users.

https://lore.kernel.org/git/a2a50127-6ab9-4d8a-abcc-b1a741df293e@app.fastmail.com/T/#m01231abb77735b0f480743e0d2adecc172e1f170 (local)

Which I just mention here for completeness and my own memory.  ;)

All good.

Check for ENOENT errno before reporting directory access errors for
linked worktrees to maintain backward compatibility.

Reported-by: Kristoffer Haugsbakk <redacted>
Signed-off-by: shejialuo <redacted>
[snip]
+test_expect_success 'no refs directory of worktree should not cause problems' '
+	test_when_finished "rm -rf repo" &&
+	git init repo &&
+	(
+		cd repo &&
+		test_commit initial &&
+		git worktree add --detach ./worktree &&
+
+		cd worktree &&

Now in this version you change-directory into `worktree`.  You would
need a new subshell for that (test style).  But I don’t see the need to
chdir in the first place?

+		worktree_refdir="$(git rev-parse --git-dir)/refs" &&
+		# Simulate old directory layout
+		rmdir "$worktree_refdir" &&
+		git refs verify 2>err &&
+		test_must_be_empty err
+	)
+'
+
 test_expect_success 'ref name check should work for multiple worktrees' '
 	test_when_finished "rm -rf repo" &&
 	git init repo &&
--
2.49.0

The test passes for me.  Also when applying only the test (and not the
fix) the test fails as expected.  Good.