git branch -D: give a better error message when lockfile creation fails

Previously the old error message just told the user that it was not
possible to delete the ref from the packed-refs file. Give instructions
on how to resolve the problem.

Signed-off-by: Miklos Vajna <vmiklos@frugalware.org>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Shawn O. Pearce <spearce@spearce.org>

1 files changed, 3 insertions, 1 deletions

diff --git a/refs.c b/refs.c
index 24865cf5a6..808f56bb27 100644
--- a/refs.c
+++ b/refs.c
@@ -972,8 +972,10 @@ static int repack_without_ref(const char *refname)
 	if (!found)
 		return 0;
 	fd = hold_lock_file_for_update(&packlock, git_path("packed-refs"), 0);
-	if (fd < 0)
+	if (fd < 0) {
+		unable_to_lock_error(git_path("packed-refs"), errno);
 		return error("cannot delete '%s' from packed refs", refname);
+	}
 
 	for (list = packed_ref_list; list; list = list->next) {
 		char line[PATH_MAX + 100];