When we lock a reference like "foo" we need to handle the case where
"foo" exists, but is an empty directory. That's what this code added
in bc7127ef0f (ref locking: allow 'foo' when 'foo/bar' used to exist
but not anymore., 2006-09-30) seems like it should be dealing with.
Except it doesn't, and we never take this branch. The reason is that
when bc7127ef0f was written this looked like:
ref = resolve_ref([...]);
if (!ref && errno == EISDIR) {
[...]
And in resolve_ref() we had this code:
fd = open(path, O_RDONLY);
if (fd < 0)
return NULL;
I.e. we would attempt to read "foo" with open(), which would fail with
EISDIR and we'd return NULL. We'd then take this branch, call
remove_empty_directories() and continue.
Since a1c1d8170d (refs_resolve_ref_unsafe: handle d/f conflicts for
writes, 2017-10-06) we don't. E.g. in the case of
files_copy_or_rename_ref() our callstack will look something like:
[...] ->
files_copy_or_rename_ref() ->
lock_ref_oid_basic() ->
refs_resolve_ref_unsafe()
At that point the first (now only) refs_resolve_ref_unsafe() call in
lock_ref_oid_basic() would do the equivalent of this in the resulting
call to refs_read_raw_ref() in refs_resolve_ref_unsafe():
/* Via refs_read_raw_ref() */
fd = open(path, O_RDONLY);
if (fd < 0)
/* get errno == EISDIR */
/* later, in refs_resolve_ref_unsafe() */
if ([...] && errno != EISDIR)
return NULL;
[...]
/* returns the refs/heads/foo to the caller, even though it's a directory */
return refname;
I.e. even though we got an "errno == EISDIR" we won't take this
branch, since in cases of EISDIR "resolved" is always
non-NULL. I.e. we pretend at this point as though everything's OK and
there is no "foo" directory.
We then proceed with the entire ref update and don't call
remove_empty_directories() until we call commit_ref_update(). See
5387c0d883 (commit_ref(): if there is an empty dir in the way, delete
it, 2016-05-05) for the addition of that code, and
a1c1d8170db (refs_resolve_ref_unsafe: handle d/f conflicts for writes,
2017-10-06) for the commit that changed the original codepath added in
bc7127ef0f to use this "EISDIR" handling.
Further historical commentary:
Before the two preceding commits the caller in files_reflog_expire()
was the only one out of our 4 callers that would pass non-NULL as an
oid. We would then set a (now gone) "resolve_flags" to
"RESOLVE_REF_READING" and just before that "errno != EISDIR" check do:
if (resolve_flags & RESOLVE_REF_READING)
return NULL;
There may have been some case where this ended up mattering and we
couldn't safely make this change before we removed the "oid"
parameter, but I don't think there was, see [1] for some discussion on
that.
In any case, now that we've removed the "oid" parameter in a preceding
commit we can be sure that this code is redundant, so let's remove it.
1. http://lore.kernel.org/git/871r801yp6.fsf@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@xxxxxxxxx>
---
refs/files-backend.c | 28 +++-------------------------
1 file changed, 3 insertions(+), 25 deletions(-)
diff --git a/refs/files-backend.c b/refs/files-backend.c
index 98d9aa1601..28cd8853f5 100644
--- a/refs/files-backend.c
+++ b/refs/files-backend.c
@@ -883,7 +883,6 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs,
struct strbuf ref_file = STRBUF_INIT;
struct ref_lock *lock;
int last_errno = 0;
- int resolved;
files_assert_main_repository(refs, "lock_ref_oid_basic");
assert(err);
@@ -891,30 +890,9 @@ static struct ref_lock *lock_ref_oid_basic(struct files_ref_store *refs,
CALLOC_ARRAY(lock, 1);
files_ref_path(refs, &ref_file, refname);
- resolved = !!refs_resolve_ref_unsafe(&refs->base, refname,
- RESOLVE_REF_NO_RECURSE,
- &lock->old_oid, type);
- if (!resolved && errno == EISDIR) {
- /*
- * we are trying to lock foo but we used to
- * have foo/bar which now does not exist;
- * it is normal for the empty directory 'foo'
- * to remain.
- */
- if (remove_empty_directories(&ref_file)) {
- last_errno = errno;
- if (!refs_verify_refname_available(
- &refs->base,
- refname, NULL, NULL, err))
- strbuf_addf(err, "there are still refs under '%s'",
- refname);
- goto error_return;
- }
- resolved = !!refs_resolve_ref_unsafe(&refs->base, refname,
- RESOLVE_REF_NO_RECURSE,
- &lock->old_oid, type);
- }
- if (!resolved) {
+ if (!refs_resolve_ref_unsafe(&refs->base, refname,
+ RESOLVE_REF_NO_RECURSE,
+ &lock->old_oid, type)) {
last_errno = errno;
if (last_errno != ENOTDIR ||
!refs_verify_refname_available(&refs->base, refname,
--
2.32.0.956.g6b0c84ceda8
