run_diff_{files,index}(): update calling convention.

diff --git a/builtin-diff-files.c b/builtin-diff-files.c
index 5d4a5c5828d1202b6d6b2eadffc51fc131a37dc5..3ee26059fcf1fb23147fc41971438a823042b9c1 100644 (file)
--- a/builtin-diff-files.c
+++ b/builtin-diff-files.c
@@ -47,5 +47,9 @@ int cmd_diff_files(int argc, const char **argv, const char *prefix)
        if (rev.pending.nr ||
            rev.min_age != -1 || rev.max_age != -1)
                usage(diff_files_usage);
+       if (read_cache() < 0) {
+               perror("read_cache");
+               return -1;
+       }
        return run_diff_files(&rev, silent);
 }