receive-pack: detect aliased updates which can occur with symrefs

diff --git a/builtin-log.c b/builtin-log.c
index 8d16832f7e9483f7903009459a72efc39e267c98..76962e1b08ec6a7e52320c97cc3b54887cc67ef9 100644 (file)
--- a/builtin-log.c
+++ b/builtin-log.c
@@ -1089,7 +1089,7 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
 
        /*
         * We cannot move this anywhere earlier because we do want to
-        * know if --root was given explicitly from the comand line.
+        * know if --root was given explicitly from the command line.
         */
        rev.show_root_diff = 1;
 
@@ -1106,8 +1106,15 @@ int cmd_format_patch(int argc, const char **argv, const char *prefix)
                        return 0;
        }
 
-       if (ignore_if_in_upstream)
+       if (ignore_if_in_upstream) {
+               /* Don't say anything if head and upstream are the same. */
+               if (rev.pending.nr == 2) {
+                       struct object_array_entry *o = rev.pending.objects;
+                       if (hashcmp(o[0].item->sha1, o[1].item->sha1) == 0)
+                               return 0;
+               }
                get_patch_ids(&rev, &ids, prefix);
+       }
 
        if (!use_stdout)
                realstdout = xfdopen(xdup(1), "w");