Re: [PATCH 02/38] rename_ref_available(): add docstring
flat view
From: Junio C Hamano <hidden>
Date: 2016-06-16 02:19:47
Michael Haggerty [off-list ref] writes:
quoted hunk ↗ jump to hunk
From: David Turner <redacted> Signed-off-by: David Turner <redacted> Signed-off-by: Junio C Hamano <redacted> Signed-off-by: Michael Haggerty <redacted> --- refs/refs-internal.h | 5 +++++ 1 file changed, 5 insertions(+)diff --git a/refs/refs-internal.h b/refs/refs-internal.h index efe5847..d8a2606 100644 --- a/refs/refs-internal.h +++ b/refs/refs-internal.h@@ -240,6 +240,11 @@ const char *find_descendant_ref(const char *dirname, const struct string_list *extras, const struct string_list *skip); +/* + * Check if the new name does not conflict with any existing refs + * (other than possibly the old ref). Return 0 if the ref can be + * renamed to the new name. + */ int rename_ref_available(const char *oldname, const char *newname);
I do not quite understand the comment. Partly because it is unclear
what "conflict" means here, but I guess it means a D/F conflict that
is explained near verify_refname_available()?
A new name can conflict with an existing, possibly old ref? Are you
referring to this condition?
You are trying to rename "refs/a/b" to "refs/a", which would
conflict, but as long as there is no other ref that share the
prefix "refs/a/", e.g. "refs/a/c", the new name "refs/a" is
available.
I wonder if it is necessary to document that this function is not
meant to protect us from others racing with us. That is, when you
are renaming something to "refs/a", you call this function and it
finds, by calling verify_refname_available(), that the repository
has nothing that conflicts with the name and says "OK", but before
you actually do the rename, somebody may push from sideways to
create "refs/a/b", making the result of an earlier check with this
function invalid.
Or is this to be called only under a lock that protects us from such
a race?