Merge branch 'jk/describe-perf' into seen

"git describe" optimization.

* jk/describe-perf:
  describe: split "found all tags" and max_candidates logic

Author: gitster

builtin/describe.c

@@ -369,7 +369,8 @@ static void describe_commit(struct object_id *oid, struct strbuf *dst)
 
 		seen_commits++;
 
-		if (match_cnt == max_candidates) {
+		if (match_cnt == max_candidates ||
+		    match_cnt == hashmap_get_size(&names)) {
 			gave_up_on = c;
 			break;
 		}
@@ -669,8 +670,6 @@ int cmd_describe(int argc,
 			     NULL);
 	if (!hashmap_get_size(&names) && !always)
 		die(_("No names found, cannot describe anything."));
-	if (hashmap_get_size(&names) < max_candidates)
-		max_candidates = hashmap_get_size(&names);
 
 	if (argc == 0) {
 		if (broken) {

t/t6120-describe.sh

@@ -715,4 +715,14 @@ test_expect_success 'describe --broken --dirty with a file with changed stat' '
 	)
 '
 
+test_expect_success '--always with no refs falls back to commit hash' '
+	git rev-parse HEAD >expect &&
+	git describe --no-abbrev --always --match=no-such-tag >actual &&
+	test_cmp expect actual
+'
+
+test_expect_success '--exact-match does not show --always fallback' '
+	test_must_fail git describe --exact-match --always
+'
+
 test_done