Subject: Re: [PATCH] describe: enable sparse index for describe

From: Junio C Hamano <[email-masked]>
Date: Tue, 28 Mar 2023 13:24:12 -0700

Derrick Stolee <[email-masked]> writes:

>>>  			setup_work_tree();
>>> +			prepare_repo_settings(the_repository);
>>> +			the_repository->settings.command_requires_full_index = 0;
>> 
>> Offhand, the only case I know that "describe" even _needs_ a working
>> tree or the index is when asked to do the "--dirty" thing.  To
>> figure out if the working tree files are modified, the code calls
>> into run_diff_index(), but has that codepath been made sparse-index
>> aware already?
>
> It seems that this is a case where we can rely on the existing
> changes around run_diff_index(), which is nice. We get a very
> easy win for a narrow case.

Hmph, so "diff-index" is already sparse-index aware?  I looked for
any old commit that flips .command_requires_full_index to false for
the command and didn't find it, and if I recall correctly (I only
checked when I wrote the comment you are responding to),
cmd_diff_index() does not do that, either, so I assumed that nobody
has converted run_diff_index() yet.  And that was where my question
came from.

Thanks.