describe: omit clearing marks on the last one.

When describing more than one, we need to clear the commit marks
before handling the next one, but most of the time we are
running it for only one commit, and in such a case this clearing
phase is totally unnecessary.

Signed-off-by: Junio C Hamano <junkio@cox.net>

1 files changed, 4 insertions, 2 deletions

diff --git a/commit.c b/commit.c
index 56efc69f1..b8bf35e86 100644
--- a/commit.c
+++ b/commit.c
@@ -359,8 +359,10 @@ void clear_commit_marks(struct commit *commit, unsigned int mark)
 	parents = commit->parents;
 	commit->object.flags &= ~mark;
 	while (parents) {
-		if (parents->item && parents->item->object.parsed)
-			clear_commit_marks(parents->item, mark);
+		struct commit *parent = parents->item;
+		if (parent && parent->object.parsed &&
+		    (parent->object.flags & mark))
+			clear_commit_marks(parent, mark);
 		parents = parents->next;
 	}
 }