if (!repo->index)
repo->index = xcalloc(1, sizeof(*repo->index));
+ /* Complete the double-reference */
+ if (!repo->index->repo)
+ repo->index->repo = repo;
+ else if (repo->index->repo != repo)
+ BUG("repo's index should point back at itself");
+
return read_index_from(repo->index, repo->index_file, repo->gitdir);
}