add: error appropriately on repository with no commits

diff --git a/builtin/diff.c b/builtin/diff.c
index 74351a5757d399ddf251369a5be67bedbe2dfad7..9f6109224b7ea75689e9780c5f79343f55e1e3e5 100644 (file)
--- a/builtin/diff.c
+++ b/builtin/diff.c
@@ -103,7 +103,7 @@ static int builtin_diff_blobs(struct rev_info *revs,
                              int argc, const char **argv,
                              struct object_array_entry **blob)
 {
-       unsigned mode = canon_mode(S_IFREG | 0644);
+       const unsigned mode = canon_mode(S_IFREG | 0644);
 
        if (argc > 1)
                usage(builtin_diff_usage);