Fix crash trying to print "this commit" on 404s

For example any URL that starts with a real repo name but isn't
valid.

1 files changed, 1 insertions, 1 deletions

diff --git a/ui-shared.c b/ui-shared.c
index 1858ea4..09c4c94 100644
--- a/ui-shared.c
+++ b/ui-shared.c
@@ -896,7 +896,7 @@ void cgit_add_clone_urls(void (*fn)(const char *))
 static int print_this_commit_option(void)
 {
 	struct object_id oid;
-	if (get_oid(ctx.qry.head, &oid))
+	if (!ctx.qry.head || get_oid(ctx.qry.head, &oid))
 		return 1;
 	html_option(oid_to_hex(&oid), "this commit", ctx.qry.head);
 	return 0;