Re: [PATCH v5 00/27] multi-pack reachability bitmaps

On Wed, Sep 01, 2021 at 11:07:59AM -0700, Junio C Hamano wrote:

Taylor Blau [off-list ref] writes:

quoted

    +@@ Documentation/git-multi-pack-index.txt: OPTIONS
    + 	Use given directory for the location of Git objects. We check
    + 	`<dir>/packs/multi-pack-index` for the current MIDX file, and
    + 	`<dir>/packs` for the pack-files to index.
    +++
    ++`<dir>` must be an alternate of the current repository.

After replacing the previous round with this round and running "git
diff @{1}" on the branch, I noticed this documentation update, but
did't find any new code that tries to ensure that the requirement is
met.  It's a bit curious omission.

I think it is OK to allow running this command on <dir> and then add
it as a new alternate (iow, the <dir> being an alternate is not a
strict requirement for correct computation and writing of the midx,
even though it may be a requirement for correct use of the resulting
midx), so perhaps that is where the lack of validation comes from?

I wasn't sure whether to include it or not, since we technically will
still write a MIDX in that object directory (alternate or not), but we
won't load up an existing MIDX that is already there to reference. So
we'll get the same result, just slower.

I'm comfortable with saying what's written in the documentation, since
even though it happens to work today, we should leave ourselves open to
not supporting directories which aren't alternates.

But I'm equally OK if you would rather drop this hunk from the
documentation when staging.

Thanks,
Taylor