refs API: make files_copy_or_rename_ref() et al not set errno

None of the callers of rename_ref() and copy_ref() care about errno,
and as seen in the context here we already emit our own non-errno
using error() in the case where we'd use it.

So let's have it explicitly ignore errno, and do the same in
commit_ref_update(), which is only used within other code in
files_copy_or_rename_ref() itself which doesn't care about errno
either.

It might actually be sensible to have the callers use errno if the
failure was filesystem-specific, and with the upcoming reftable
backend we don't want to rely on that sort of thing, so let's keep
ignoring that for now.

Signed-off-by: Ævar Arnfjörð Bjarmason <[email protected]>
Signed-off-by: Junio C Hamano <[email protected]>

Author: avar

refs/files-backend.c

@@ -1410,9 +1410,9 @@ static int files_copy_or_rename_ref(struct ref_store *ref_store,
 		goto out;
 	}
 
-	if (!refs_resolve_ref_unsafe(&refs->base, oldrefname,
+	if (!refs_werrres_ref_unsafe(&refs->base, oldrefname,
 				     RESOLVE_REF_READING | RESOLVE_REF_NO_RECURSE,
-				&orig_oid, &flag)) {
+				     &orig_oid, &flag, &ignore_errno)) {
 		ret = error("refname %s not found", oldrefname);
 		goto out;
 	}
@@ -1823,10 +1823,12 @@ static int commit_ref_update(struct files_ref_store *refs,
 		 */
 		int head_flag;
 		const char *head_ref;
+		int ignore_errno;
 
-		head_ref = refs_resolve_ref_unsafe(&refs->base, "HEAD",
+		head_ref = refs_werrres_ref_unsafe(&refs->base, "HEAD",
 						   RESOLVE_REF_READING,
-						   NULL, &head_flag);
+						   NULL, &head_flag,
+						   &ignore_errno);
 		if (head_ref && (head_flag & REF_ISSYMREF) &&
 		    !strcmp(head_ref, lock->ref_name)) {
 			struct strbuf log_err = STRBUF_INIT;