[PATCH] refs.c: repack_without_refs may be called without error string buffer

[Stefan Beller <sbeller@google.com>]

If we don't pass in the error string buffer, we skip over all
parts dealing with preparing error messages.

Signed-off-by: Stefan Beller <sbeller@google.com>
---

This goes ontop of [PATCH v5] refs.c: use a stringlist for repack_without_refs
if that makes sense.

 refs.c | 8 ++++----
 refs.h | 1 -
 2 files changed, 4 insertions(+), 5 deletions(-)

diff --git a/refs.c b/refs.c
index ebcd90f..3c85ea6 100644
--- a/refs.c
+++ b/refs.c
@@ -2646,8 +2646,6 @@ int repack_without_refs(struct string_list *without, struct strbuf *err)
 	struct string_list_item *ref_to_delete;
 	int ret, needs_repacking = 0, removed = 0;
 
-	assert(err);
-
 	/* Look for a packed ref */
 	for_each_string_list_item(ref_to_delete, without) {
 		if (get_packed_ref(ref_to_delete->string)) {
@@ -2661,7 +2659,9 @@ int repack_without_refs(struct string_list *without, struct strbuf *err)
 		return 0;
 
 	if (lock_packed_refs(0)) {
-		unable_to_lock_message(git_path("packed-refs"), errno, err);
+		if (err)
+			unable_to_lock_message(git_path("packed-refs"),
+					       errno, err);
 		return -1;
 	}
 	packed = get_packed_refs(&ref_cache);
@@ -2688,7 +2688,7 @@ int repack_without_refs(struct string_list *without, struct strbuf *err)
 
 	/* Write what remains */
 	ret = commit_packed_refs();
-	if (ret)
+	if (ret && err)
 		strbuf_addf(err, "unable to overwrite old ref-pack file: %s",
 			    strerror(errno));
 	return ret;
diff --git a/refs.h b/refs.h
index c7323ff..b71fb79 100644
--- a/refs.h
+++ b/refs.h
@@ -170,7 +170,6 @@ int pack_refs(unsigned int flags);
  * strbuf.
  *
  * The refs in 'without' may have any order.
- * The err buffer must not be omitted.
  */
 extern int repack_without_refs(struct string_list *without, struct strbuf *err);
 
-- 
2.2.0.rc2.23.gca0107e