fixup! git tag --contains : avoid stack overflow

Author: dscho

builtin/tag.c

@@ -73,11 +73,17 @@ static int in_commit_list(const struct commit_list *want, struct commit *c)
 	return 0;
 }
 
+enum contains_result {
+	CONTAINS_UNKNOWN = -1,
+	CONTAINS_NO = 0,
+	CONTAINS_YES = 1,
+};
+
 /*
  * Test whether the candidate or one of its parents is contained in the list.
  * Do not recurse to find out, though, but return -1 if inconclusive.
  */
-static int contains_test(struct commit *candidate,
+static enum contains_result contains_test(struct commit *candidate,
 			    const struct commit_list *want)
 {
 	/* was it previously marked as containing a want commit? */
@@ -121,12 +127,13 @@ static void push_to_stack(struct commit *candidate, struct stack *stack)
 	stack->stack[index].parents = candidate->parents;
 }
 
-static int contains(struct commit *candidate, const struct commit_list *want)
+static enum contains_result contains(struct commit *candidate,
+		const struct commit_list *want)
 {
 	struct stack stack = { 0, 0, NULL };
 	int result = contains_test(candidate, want);
 
-	if (result >= 0)
+	if (result != CONTAINS_UNKNOWN)
 		return result;
 
 	push_to_stack(candidate, &stack);
@@ -136,22 +143,22 @@ static int contains(struct commit *candidate, const struct commit_list *want)
 		struct commit_list *parents = entry->parents;
 
 		if (!parents) {
-			commit->object.flags = UNINTERESTING;
+			commit->object.flags |= UNINTERESTING;
 			stack.nr--;
 		}
 		/*
 		 * If we just popped the stack, parents->item has been marked,
 		 * therefore contains_test will return a meaningful 0 or 1.
 		 */
 		else switch (contains_test(parents->item, want)) {
-		case 1:
+		case CONTAINS_YES:
 			commit->object.flags |= TMP_MARK;
 			stack.nr--;
 			break;
-		case 0:
+		case CONTAINS_NO:
 			entry->parents = parents->next;
 			break;
-		default:
+		case CONTAINS_UNKNOWN:
 			push_to_stack(parents->item, &stack);
 			break;
 		}

t/t7004-tag.sh

@@ -1380,10 +1380,11 @@ test_expect_success 'multiple --points-at are OR-ed together' '
 	test_cmp expect actual
 '
 
+test_lazy_prereq BASH 'bash --version'
+
 >expect
-# ulimit is a bash builtin; we can rely on that in MinGW, but nowhere else
-test_expect_success MINGW '--contains works in a deep repo' '
-	ulimit -s 64
+# we require bash for its 'ulimit' builtin
+test_expect_success BASH '--contains works in a deep repo' '
 	i=1 &&
 	while test $i -lt 1000
 	do
@@ -1397,7 +1398,7 @@ EOF"
 	done | git fast-import &&
 	git checkout master &&
 	git tag far-far-away HEAD^ &&
-	git tag --contains HEAD >actual &&
+	bash -c "ulimit -s 64 && git tag --contains HEAD >actual" &&
 	test_cmp expect actual
 '