On Mon, Oct 09, 2023 at 05:05:33PM -0400, Jeff King wrote:

+static int can_use_midx_ridx_chunk(struct multi_pack_index *m)
+{
+	if (!m->chunk_revindex)
+		return 0;
+	if (m->chunk_revindex_len != st_mult(sizeof(uint32_t), m->num_objects)) {
+		error(_("multi-pack-index reverse-index chunk is the wrong size"));
+		return 0;
+	}
+	return 1;
+}

This all looks good to me. I was going to suggest that it might be worth
just NULL-ing out the chunk_revindex field here altogether. I think that
we have some prior art for doing that in the commit-graph code (though
I'd have to look to be sure...), but that's all within the same
compilation unit.

Having the pack-revindex machinery NULL out a field of the MIDX
structure feels icky to me, so I think that having a "can we use this
function?" instead makes much more sense.

Thanks,
Taylor