[PATCH v2] revision.c: fix possible null pointer access

[Stefan Naewe <stefan.naewe@gmail.com>]

mark_tree_uninteresting dereferences a tree pointer before checking
if the pointer is valid. Fix that by doing the check first.

Signed-off-by: Stefan Naewe <stefan.naewe@gmail.com>
---
 revision.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/revision.c b/revision.c
index 0fbb684..8c569cc 100644
--- a/revision.c
+++ b/revision.c
@@ -135,10 +135,12 @@ static void mark_tree_contents_uninteresting(struct tree *tree)
 
 void mark_tree_uninteresting(struct tree *tree)
 {
-	struct object *obj = &tree->object;
+	struct object *obj;
 
 	if (!tree)
 		return;
+
+	obj = &tree->object;
 	if (obj->flags & UNINTERESTING)
 		return;
 	obj->flags |= UNINTERESTING;
-- 
2.6.3