coverity seems to dislike this part:
*** CID 1394367: Null pointer dereferences (NULL_RETURNS)
/builtin/grep.c: 625 in grep_submodule()
619 is_submodule_populated(path))) {
620 /*
621 * If searching history, check for the presense of the
622 * submodule's gitdir before skipping the submodule.
623 */
624 if (sha1) {
>>> CID 1394367: Null pointer dereferences (NULL_RETURNS)
>>> Dereferencing a null pointer "submodule_from_path(null_sha1, path)".
625 path = git_path("modules/%s",
626
submodule_from_path(null_sha1, path)->name);
627
628 if (!(is_directory(path) &&
is_git_directory(path)))
629 return 0;
630 } else {