Re: [RFC PATCH] midx.c: clean up .rev file

[Junio C Hamano <gitster@pobox.com>]

Ævar Arnfjörð Bjarmason <avarab@gmail.com> writes:

> On Wed, Jun 22 2022, haoyurenzhuxia@gmail.com wrote:
>
>> From: Xia XiaoWen <haoyurenzhuxia@gmail.com>
>>
>> The command: `git multi-pack-index write --bitmap` will create 3
>> files in `objects/pack/`:
>>     * multi-pack-index
>>     * multi-pack-index-*.bitmap
>>     * multi-pack-index-*.rev
>>
>> But if the command is terminated by the user (such as Ctl-C) or
>> the system, the midx reverse index file (`multi-pack-index-*.rev`)
>> is not removed and still exists in `objects/pack/`:
>>
>>     $ GIT_TEST_MIDX_WRITE_REV=1 git multi-pack-index write --bitmap
>>     Selecting bitmap commits: 133020, done.
>>     Building bitmaps:   0% (3/331)
>>     ^C^C
>>
>>     $ tree objects/pack/
>>     objects/pack/
>>     ├── multi-pack-index-3b048d1b965842cd866e10b6ec1a3035dbede0a5.rev
>>     ├── pack-b7d425f1b01727d5f364f5d9fbab2d1900fcd5c0.idx
>>     └── pack-b7d425f1b01727d5f364f5d9fbab2d1900fcd5c0.pack
>> ...
> Also, the commit message doesn't really say *why*, i.e. in cmd_repack()
> we've suffered from this already, but don't we have "git gc" cleaning
> these up? Maybe not (I didn't check), but maybe that was the previous
> assumption...

Exactly my thought.  Well said.

The _only_ case that might matter is if the next "write --bitmap" gets
confused ir there is a leftover file(s) from a previous run, but then
such a bug should be fixed on the reading side, I would think.

Thanks.