ref: support multiple worktrees check for refs

We have already set up the infrastructure to check the consistency for
refs, but we do not support multiple worktrees. However, "git-fsck(1)"
will check the refs of worktrees. As we decide to get feature parity
with "git-fsck(1)", we need to set up support for multiple worktrees.

Because each worktree has its own specific refs, instead of just showing
the users "refs/worktree/foo", we need to display the full name such as
"worktrees/<id>/refs/worktree/foo". So we should know the id of the
worktree to get the full name. Add a new parameter "struct worktree *"
for "refs-internal.h::fsck_fn". Then change the related functions to
follow this new interface.

The "packed-refs" only exists in the main worktree, so we should only
check "packed-refs" in the main worktree. Use "is_main_worktree" method
to skip checking "packed-refs" in "packed_fsck" function.

Then, enhance the "files-backend.c::files_fsck_refs_dir" function to add
"worktree/<id>/" prefix when we are not in the main worktree.

Last, add a new test to check the refname when there are multiple
worktrees to exercise the code.

Mentored-by: Patrick Steinhardt <ps@pks.im>
Mentored-by: Karthik Nayak <karthik.188@gmail.com>
Signed-off-by: shejialuo <shejialuo@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 2 insertions, 1 deletions

diff --git a/refs.h b/refs.h
index 108dfc93b3..341d43239c 100644
--- a/refs.h
+++ b/refs.h
@@ -549,7 +549,8 @@ int check_refname_format(const char *refname, int flags);
  * reflogs are consistent, and non-zero otherwise. The errors will be
  * written to stderr.
  */
-int refs_fsck(struct ref_store *refs, struct fsck_options *o);
+int refs_fsck(struct ref_store *refs, struct fsck_options *o,
+	      struct worktree *wt);
 
 /*
  * Apply the rules from check_refname_format, but mutate the result until it