Re: [PATCH 0/2] midx: prevent bitmap corruption when permuting pack order

On Wed, Dec 08, 2021 at 02:55:13PM -0500, Jeff King wrote:

On Wed, Dec 08, 2021 at 02:30:17PM -0500, Derrick Stolee wrote:

quoted

quoted

Taylor Blau (2):
  t5326: demonstrate bitmap corruption after permutation
  midx.c: make changing the preferred pack safe

Just chiming in to say that I reviewed an earlier version of this series
and the version in this submission looks good to me.

Ditto. ;)

All three of us missed that this PORD chunk actually contains the
psuedo-pack position for every object in the MIDX. That is OK, but it's
definitely adding more than 4 bytes per pack to the MIDX (in practice,
it's adding 4 bytes per object).

I'm semi-OK with this direction, since it's tantamount to storing the
.rev file's contents in the MIDX itself. And even though we're not
reading from it, it is doing the thing we need it to which is causing
the MIDX to change its checksum when the object order changes.

But I'm curious what both of your thoughts are before moving forward.

Thanks,
Taylor