Merge branch 'jc/push-follow-tag'

The new "--follow-tags" option tells "git push" to push relevant
annotated tags when pushing branches out.

* jc/push-follow-tag:
  push: --follow-tags
  commit.c: use clear_commit_marks_many() in in_merge_bases_many()
  commit.c: add in_merge_bases_many()
  commit.c: add clear_commit_marks_many()

1 files changed, 99 insertions, 0 deletions

diff --git a/remote.c b/remote.c
index 174e48eb74..57f36e14da 100644
--- a/remote.c
+++ b/remote.c
@@ -1195,6 +1195,101 @@ static struct ref **tail_ref(struct ref **head)
 	return tail;
 }
 
+struct tips {
+	struct commit **tip;
+	int nr, alloc;
+};
+
+static void add_to_tips(struct tips *tips, const unsigned char *sha1)
+{
+	struct commit *commit;
+
+	if (is_null_sha1(sha1))
+		return;
+	commit = lookup_commit_reference_gently(sha1, 1);
+	if (!commit || (commit->object.flags & TMP_MARK))
+		return;
+	commit->object.flags |= TMP_MARK;
+	ALLOC_GROW(tips->tip, tips->nr + 1, tips->alloc);
+	tips->tip[tips->nr++] = commit;
+}
+
+static void add_missing_tags(struct ref *src, struct ref **dst, struct ref ***dst_tail)
+{
+	struct string_list dst_tag = STRING_LIST_INIT_NODUP;
+	struct string_list src_tag = STRING_LIST_INIT_NODUP;
+	struct string_list_item *item;
+	struct ref *ref;
+	struct tips sent_tips;
+
+	/*
+	 * Collect everything we know they would have at the end of
+	 * this push, and collect all tags they have.
+	 */
+	memset(&sent_tips, 0, sizeof(sent_tips));
+	for (ref = *dst; ref; ref = ref->next) {
+		if (ref->peer_ref &&
+		    !is_null_sha1(ref->peer_ref->new_sha1))
+			add_to_tips(&sent_tips, ref->peer_ref->new_sha1);
+		else
+			add_to_tips(&sent_tips, ref->old_sha1);
+		if (!prefixcmp(ref->name, "refs/tags/"))
+			string_list_append(&dst_tag, ref->name);
+	}
+	clear_commit_marks_many(sent_tips.nr, sent_tips.tip, TMP_MARK);
+
+	sort_string_list(&dst_tag);
+
+	/* Collect tags they do not have. */
+	for (ref = src; ref; ref = ref->next) {
+		if (prefixcmp(ref->name, "refs/tags/"))
+			continue; /* not a tag */
+		if (string_list_has_string(&dst_tag, ref->name))
+			continue; /* they already have it */
+		if (sha1_object_info(ref->new_sha1, NULL) != OBJ_TAG)
+			continue; /* be conservative */
+		item = string_list_append(&src_tag, ref->name);
+		item->util = ref;
+	}
+	string_list_clear(&dst_tag, 0);
+
+	/*
+	 * At this point, src_tag lists tags that are missing from
+	 * dst, and sent_tips lists the tips we are pushing or those
+	 * that we know they already have. An element in the src_tag
+	 * that is an ancestor of any of the sent_tips needs to be
+	 * sent to the other side.
+	 */
+	if (sent_tips.nr) {
+		for_each_string_list_item(item, &src_tag) {
+			struct ref *ref = item->util;
+			struct ref *dst_ref;
+			struct commit *commit;
+
+			if (is_null_sha1(ref->new_sha1))
+				continue;
+			commit = lookup_commit_reference_gently(ref->new_sha1, 1);
+			if (!commit)
+				/* not pushing a commit, which is not an error */
+				continue;
+
+			/*
+			 * 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))
+				continue;
+
+			/* Add it in */
+			dst_ref = make_linked_ref(ref->name, dst_tail);
+			hashcpy(dst_ref->new_sha1, ref->new_sha1);
+			dst_ref->peer_ref = copy_ref(ref);
+		}
+	}
+	string_list_clear(&src_tag, 0);
+	free(sent_tips.tip);
+}
+
 /*
  * Given the set of refs the local repository has, the set of refs the
  * remote repository has, and the refspec used for push, determine
@@ -1257,6 +1352,10 @@ int match_push_refs(struct ref *src, struct ref **dst,
 	free_name:
 		free(dst_name);
 	}
+
+	if (flags & MATCH_REFS_FOLLOW_TAGS)
+		add_missing_tags(src, dst, &dst_tail);
+
 	if (send_prune) {
 		/* check for missing refs on the remote */
 		for (ref = *dst; ref; ref = ref->next) {