err = fast_export_ls(path, mode_out, &buf);
        if (err) {
                if (errno != ENOENT)
-                       die_errno("BUG: unexpected fast_export_ls error");
+                       BUG("unexpected fast_export_ls error: %s",
+                           strerror(errno));
                /* Treat missing paths as directories. */
                *mode_out = S_IFDIR;
                return NULL;
        err = fast_export_ls_rev(revision, src, &mode, &data);
        if (err) {
                if (errno != ENOENT)
-                       die_errno("BUG: unexpected fast_export_ls_rev error");
+                       BUG("unexpected fast_export_ls_rev error: %s",
+                           strerror(errno));
                fast_export_delete(dst);
                return;
        }