Re: [PATCH v3 04/19] refs.c: return error string from ref_update_reject_duplicates on failure

--- a/refs.c
+++ b/refs.c

@@ -3393,6 +3393,7 @@ static int ref_update_compare(const void *r1, const void *r2)
 }
 
 static int ref_update_reject_duplicates(struct ref_update **updates, int n,
+					char **err,
 					enum action_on_err onerr)
 {
 	int i;

@@ -3400,6 +3401,11 @@ static int ref_update_reject_duplicates(struct ref_update **updates, int n,
 		if (!strcmp(updates[i - 1]->refname, updates[i]->refname)) {
 			const char *str =
 				"Multiple updates for ref '%s' not allowed.";
+			if (err) {
+				*err = xmalloc(PATH_MAX + 41);
+				snprintf(*err, PATH_MAX + 41, str,
+					 updates[i]->refname);
+			}