Re: What's cooking in git.git (Jun 2026, #06)

[Taylor Blau <me@ttaylorr.com>]

On Wed, Jun 17, 2026 at 10:06:23AM -0700, Junio C Hamano wrote:
> * tb/midx-incremental-custom-base (2026-06-12) 3 commits
>  - midx-write: include packs above custom incremental base
>  - midx: pass custom '--base' through incremental writes
>  - t5334: expose shared `nth_line()` helper
>
>  The `git multi-pack-index write --incremental` command has been
>  corrected to properly honor the `--base` option. Previously, the
>  custom base was ignored by the normal write path, and the pack
>  exclusion logic incorrectly skipped packs from layers above the
>  selected base, breaking reachability closure for bitmaps.
>
>  Needs review.
>  source: <cover.1781294771.git.me@ttaylorr.com>

It would be nice to get this in before v2.55.0 is tagged, but I don't
think it's critical. In my analysis, the worst thing that could happen
is that generating MIDXs with a custom --base would result in a failure
to generate bitmaps, but not much else.

That's unlikely to be invoked manually, but does have the unfortunate
effect of rendering the new incremental MIDX-based repacking strategy as
useless in this release.

I'll add Peff to CC in case he has a moment to look it over.

Thanks,
Taylor