http-push: push <remote> :<branch> deletes remote branch

This mirrors current ssh/git push syntax.

Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

http-push.c

@@ -2138,6 +2138,8 @@ static int delete_remote_branch(char *pattern, int force)
 
 	/* Send delete request */
 	fprintf(stderr, "Removing remote branch '%s'\n", remote_ref->name);
+	if (dry_run)
+		return 0;
 	url = xmalloc(strlen(remote->url) + strlen(remote_ref->name) + 1);
 	sprintf(url, "%s%s", remote->url, remote_ref->name);
 	slot = get_active_slot();
@@ -2311,6 +2313,16 @@ int main(int argc, char **argv)
 
 		if (!ref->peer_ref)
 			continue;
+
+		if (is_zero_sha1(ref->peer_ref->new_sha1)) {
+			if (delete_remote_branch(ref->name, 1) == -1) {
+				error("Could not remove %s", ref->name);
+				rc = -4;
+			}
+			new_refs++;
+			continue;
+		}
+
 		if (!hashcmp(ref->old_sha1, ref->peer_ref->new_sha1)) {
 			if (push_verbosely || 1)
 				fprintf(stderr, "'%s': up-to-date\n", ref->name);
@@ -2342,11 +2354,6 @@ int main(int argc, char **argv)
 			}
 		}
 		hashcpy(ref->new_sha1, ref->peer_ref->new_sha1);
-		if (is_zero_sha1(ref->new_sha1)) {
-			error("cannot happen anymore");
-			rc = -3;
-			continue;
-		}
 		new_refs++;
 		strcpy(old_hex, sha1_to_hex(ref->old_sha1));
 		new_hex = sha1_to_hex(ref->new_sha1);