if (!revs->graph)
                fputs(get_revision_mark(revs, commit), stdout);
        if (revs->abbrev_commit && revs->abbrev)
-               fputs(find_unique_abbrev(commit->object.oid.hash, revs->abbrev),
+               fputs(find_unique_abbrev(&commit->object.oid, revs->abbrev),
                      stdout);
        else
                fputs(oid_to_hex(&commit->object.oid), stdout);