Merge branch 'ds/add-missing-tags'

The history traversal used to implement the tag-following has been
optimized by introducing a new helper.

* ds/add-missing-tags:
  remote: make add_missing_tags() linear
  test-reach: test get_reachable_subset
  commit-reach: implement get_reachable_subset

commit-reach.c

@@ -690,3 +690,72 @@ int can_all_from_reach(struct commit_list *from, struct commit_list *to,
 	object_array_clear(&from_objs);
 	return result;
 }
+
+struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
+					 struct commit **to, int nr_to,
+					 unsigned int reachable_flag)
+{
+	struct commit **item;
+	struct commit *current;
+	struct commit_list *found_commits = NULL;
+	struct commit **to_last = to + nr_to;
+	struct commit **from_last = from + nr_from;
+	uint32_t min_generation = GENERATION_NUMBER_INFINITY;
+	int num_to_find = 0;
+
+	struct prio_queue queue = { compare_commits_by_gen_then_commit_date };
+
+	for (item = to; item < to_last; item++) {
+		struct commit *c = *item;
+
+		parse_commit(c);
+		if (c->generation < min_generation)
+			min_generation = c->generation;
+
+		if (!(c->object.flags & PARENT1)) {
+			c->object.flags |= PARENT1;
+			num_to_find++;
+		}
+	}
+
+	for (item = from; item < from_last; item++) {
+		struct commit *c = *item;
+		if (!(c->object.flags & PARENT2)) {
+			c->object.flags |= PARENT2;
+			parse_commit(c);
+
+			prio_queue_put(&queue, *item);
+		}
+	}
+
+	while (num_to_find && (current = prio_queue_get(&queue)) != NULL) {
+		struct commit_list *parents;
+
+		if (current->object.flags & PARENT1) {
+			current->object.flags &= ~PARENT1;
+			current->object.flags |= reachable_flag;
+			commit_list_insert(current, &found_commits);
+			num_to_find--;
+		}
+
+		for (parents = current->parents; parents; parents = parents->next) {
+			struct commit *p = parents->item;
+
+			parse_commit(p);
+
+			if (p->generation < min_generation)
+				continue;
+
+			if (p->object.flags & PARENT2)
+				continue;
+
+			p->object.flags |= PARENT2;
+			prio_queue_put(&queue, p);
+		}
+	}
+
+	clear_commit_marks_many(nr_to, to, PARENT1);
+	clear_commit_marks_many(nr_from, from, PARENT2);
+
+	return found_commits;
+}

commit-reach.h

@@ -75,4 +75,17 @@ int can_all_from_reach_with_flag(struct object_array *from,
 int can_all_from_reach(struct commit_list *from, struct commit_list *to,
 		       int commit_date_cutoff);
 
+
+/*
+ * Return a list of commits containing the commits in the 'to' array
+ * that are reachable from at least one commit in the 'from' array.
+ * Also add the given 'flag' to each of the commits in the returned list.
+ *
+ * This method uses the PARENT1 and PARENT2 flags during its operation,
+ * so be sure these flags are not set before calling the method.
+ */
+struct commit_list *get_reachable_subset(struct commit **from, int nr_from,
+					 struct commit **to, int nr_to,
+					 unsigned int reachable_flag);
+
 #endif

remote.c

@@ -1205,9 +1205,36 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds
 	 * sent to the other side.
 	 */
 	if (sent_tips.nr) {
+		const int reachable_flag = 1;
+		struct commit_list *found_commits;
+		struct commit **src_commits;
+		int nr_src_commits = 0, alloc_src_commits = 16;
+		ALLOC_ARRAY(src_commits, alloc_src_commits);
+
 		for_each_string_list_item(item, &src_tag) {
 			struct ref *ref = item->util;
+			struct commit *commit;
+
+			if (is_null_oid(&ref->new_oid))
+				continue;
+			commit = lookup_commit_reference_gently(the_repository,
+								&ref->new_oid,
+								1);
+			if (!commit)
+				/* not pushing a commit, which is not an error */
+				continue;
+
+			ALLOC_GROW(src_commits, nr_src_commits + 1, alloc_src_commits);
+			src_commits[nr_src_commits++] = commit;
+		}
+
+		found_commits = get_reachable_subset(sent_tips.tip, sent_tips.nr,
+						     src_commits, nr_src_commits,
+						     reachable_flag);
+
+		for_each_string_list_item(item, &src_tag) {
 			struct ref *dst_ref;
+			struct ref *ref = item->util;
 			struct commit *commit;
 
 			if (is_null_oid(&ref->new_oid))
@@ -1223,7 +1250,7 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds
 			 * Is this tag, which they do not have, reachable from
 			 * any of the commits we are sending?
 			 */
-			if (!in_merge_bases_many(commit, sent_tips.nr, sent_tips.tip))
+			if (!(commit->object.flags & reachable_flag))
 				continue;
 
 			/* Add it in */
@@ -1231,7 +1258,12 @@ static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***ds
 			oidcpy(&dst_ref->new_oid, &ref->new_oid);
 			dst_ref->peer_ref = copy_ref(ref);
 		}
+
+		clear_commit_marks_many(nr_src_commits, src_commits, reachable_flag);
+		free(src_commits);
+		free_commit_list(found_commits);
 	}
+
 	string_list_clear(&src_tag, 0);
 	free(sent_tips.tip);
 }

t/helper/test-reach.c

@@ -32,8 +32,8 @@ int cmd__reach(int ac, const char **av)
 	struct commit *A, *B;
 	struct commit_list *X, *Y;
 	struct object_array X_obj = OBJECT_ARRAY_INIT;
-	struct commit **X_array;
-	int X_nr, X_alloc;
+	struct commit **X_array, **Y_array;
+	int X_nr, X_alloc, Y_nr, Y_alloc;
 	struct strbuf buf = STRBUF_INIT;
 	struct repository *r = the_repository;
 
@@ -44,9 +44,10 @@ int cmd__reach(int ac, const char **av)
 
 	A = B = NULL;
 	X = Y = NULL;
-	X_nr = 0;
-	X_alloc = 16;
+	X_nr = Y_nr = 0;
+	X_alloc = Y_alloc = 16;
 	ALLOC_ARRAY(X_array, X_alloc);
+	ALLOC_ARRAY(Y_array, Y_alloc);
 
 	while (strbuf_getline(&buf, stdin) != EOF) {
 		struct object_id oid;
@@ -92,6 +93,8 @@ int cmd__reach(int ac, const char **av)
 
 			case 'Y':
 				commit_list_insert(c, &Y);
+				ALLOC_GROW(Y_array, Y_nr + 1, Y_alloc);
+				Y_array[Y_nr++] = c;
 				break;
 
 			default:
@@ -136,6 +139,29 @@ int cmd__reach(int ac, const char **av)
 			filter.with_commit_tag_algo = 0;
 
 		printf("%s(_,A,X,_):%d\n", av[1], commit_contains(&filter, A, X, &cache));
+	} else if (!strcmp(av[1], "get_reachable_subset")) {
+		const int reachable_flag = 1;
+		int i, count = 0;
+		struct commit_list *current;
+		struct commit_list *list = get_reachable_subset(X_array, X_nr,
+								Y_array, Y_nr,
+								reachable_flag);
+		printf("get_reachable_subset(X,Y)\n");
+		for (current = list; current; current = current->next) {
+			if (!(list->item->object.flags & reachable_flag))
+				die(_("commit %s is not marked reachable"),
+				    oid_to_hex(&list->item->object.oid));
+			count++;
+		}
+		for (i = 0; i < Y_nr; i++) {
+			if (Y_array[i]->object.flags & reachable_flag)
+				count--;
+		}
+
+		if (count < 0)
+			die(_("too many commits marked reachable"));
+
+		print_sorted_commit_ids(list);
 	}
 
 	exit(0);

t/t6600-test-reach.sh

@@ -265,4 +265,56 @@ test_expect_success 'commit_contains:miss' '
 	test_three_modes commit_contains --tag
 '
 
+test_expect_success 'get_reachable_subset:all' '
+	cat >input <<-\EOF &&
+	X:commit-9-1
+	X:commit-8-3
+	X:commit-7-5
+	X:commit-6-6
+	X:commit-1-7
+	Y:commit-3-3
+	Y:commit-1-7
+	Y:commit-5-6
+	EOF
+	(
+		echo "get_reachable_subset(X,Y)" &&
+		git rev-parse commit-3-3 \
+			      commit-1-7 \
+			      commit-5-6 | sort
+	) >expect &&
+	test_three_modes get_reachable_subset
+'
+
+test_expect_success 'get_reachable_subset:some' '
+	cat >input <<-\EOF &&
+	X:commit-9-1
+	X:commit-8-3
+	X:commit-7-5
+	X:commit-1-7
+	Y:commit-3-3
+	Y:commit-1-7
+	Y:commit-5-6
+	EOF
+	(
+		echo "get_reachable_subset(X,Y)" &&
+		git rev-parse commit-3-3 \
+			      commit-1-7 | sort
+	) >expect &&
+	test_three_modes get_reachable_subset
+'
+
+test_expect_success 'get_reachable_subset:none' '
+	cat >input <<-\EOF &&
+	X:commit-9-1
+	X:commit-8-3
+	X:commit-7-5
+	X:commit-1-7
+	Y:commit-9-3
+	Y:commit-7-6
+	Y:commit-2-8
+	EOF
+	echo "get_reachable_subset(X,Y)" >expect &&
+	test_three_modes get_reachable_subset
+'
+
 test_done