Re: [PATCH] unpack-trees: do not set SKIP_WORKTREE on submodules

From: Matheus Tavares Bernardino <matheus.bernardino@usp.br>
To: Elijah Newren <newren@gmail.com>
Cc: Elijah Newren via GitGitGadget <gitgitgadget@gmail.com>,
	git <git@vger.kernel.org>, Derrick Stolee <dstolee@microsoft.com>
Subject: Re: [PATCH] unpack-trees: do not set SKIP_WORKTREE on submodules
Date: Thu, 18 Jun 2020 11:34:11 -0300	[thread overview]
Message-ID: <CAHd-oW7tT7GhHz7mCH9Y66B=kriBKv8ZyrTXT-VTJgcXGa1Jzw@mail.gmail.com> (raw)
In-Reply-To: <CABPp-BHtwifTHXxoxTKvz0mx45e2N-4SBTTfoRePcmMFAn1O2g@mail.gmail.com>

On Wed, Jun 17, 2020 at 9:24 PM Elijah Newren <newren@gmail.com> wrote:
>
> If someone were
> to try do change their sparsity patterns or even just run a "git
> sparse-checkout reapply" when they had the above issues, they'd see
> something like:
>
>     $ git sparse-checkout reapply
>     warning: The following paths are unmerged and were left despite
> sparse patterns:
>             filename_with_conflicts
>
>     After fixing the above paths, you may want to run `git
> sparse-checkout reapply`.
>
> This basically suggests that we consider uncommitted and unmerged
> files to be "unclean" in some way (sparse-checkout wants to set the
> SKIP_WORKTREE bit on all files that do not match the sparsity
> specification, so "clean" means sparse-checkout is able to do so).  So
> I could amend my earlier comparison and say that IF the user has a
> clean directory, then "git grep --recurse-submodules $REVISION
> $PATTERN" should be equivalent to "git checkout $REVISION && git grep
> --recurse-submodules $PATTERN".  I could also say that given the big
> warnings we give users when we can't set the SKIP_WORKTREE bit, that
> we expect it to be a transient state and thus that we expect them to
> more likely than not clear it out by the time they do switch branches.
> That would lead us to the follow-up rule that if the user does not
> have a clean directory then "git grep --recurse-submodules $REVISION
> $PATTERN" should be equivalent to what you would get if the unclean
> entries were ignored (expecting them to be cleaned before the any `git
> checkout` could be run) and you then otherwise ran "git checkout
> $REVISION && git grep --recurse-submodules $PATTERN".

Makes sense, thanks! We haven't mentioned "git grep --cached" yet, but
it would behave in the same way of the worktree grep, in this case.
(I.e. searching the submodules, as their SKIP_WORTREE bit was not
set.) So I guess it should be fine, as well.

> That suggests that grep's implementation we agreed on earlier is still
> correct (when given a $REVISION ignore submodulees that do not match
> the sparsity patterns), but that unpack-trees/sparse-checkout still
> need an update:
>
> When we notice an initialized submodule that does not match the
> sparsity patterns, we should print a warning just like we do for
> unmerged and dirty entries.

Yeah, seems like a good approach. Thanks for the explanations. Some of
the test cases in mt/grep-sparse-checkout will have to be adjusted
with this change. Should I reroll the series based on the patch you
will send or do you prefer to adjust them in your patch (and make it
dependent on mt/grep-sparse-checkout)?

Thanks,
Matheus