1 files changed, 1 insertions, 1 deletions

diff --git a/shared.c b/shared.c
index c7cd8a5..f20fb5c 100644
--- a/shared.c
+++ b/shared.c
@@ -357,13 +357,13 @@ void cgit_diff_tree(const unsigned char *old_sha1,
 	opt.detect_rename = 1;
 	opt.recursive = 1;
 	opt.format_callback = cgit_diff_tree_cb;
 	opt.format_callback_data = fn;
 	diff_setup_done(&opt);
 
-	if (old_sha1)
+	if (old_sha1 && !is_null_sha1(old_sha1))
 		ret = diff_tree_sha1(old_sha1, new_sha1, "", &opt);
 	else
 		ret = diff_root_tree_sha1(new_sha1, "", &opt);
 	diffcore_std(&opt);
 	diff_flush(&opt);
 }