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From: Emily Shaffer <emilyshaffer@google.com>
To: Jonathan Tan <jonathantanmy@google.com>
Cc: git@vger.kernel.org
Subject: Re: [PATCH v2 2/4] introduce submodule.superprojectGitDir cache
Date: Thu, 19 Aug 2021 10:53:04 -0700	[thread overview]
Message-ID: <YR6agG3pwNJpCakh@google.com> (raw)
In-Reply-To: <20210727174650.2462099-1-jonathantanmy@google.com>

On Tue, Jul 27, 2021 at 10:46:50AM -0700, Jonathan Tan wrote:
> 
> > Teach submodules a reference to their superproject's gitdir. This allows
> > us to A) know that we're running from a submodule, and B) have a
> > shortcut to the superproject's vitals, for example, configs.
> 
> The first sentence is probably better "Introduce a new config variable
> storing a submodule's reference to its superproject's gitdir, and teach
> 'git submodule add' to write it".
> 
> Also, I think there should be more detail about the planned use both
> here in the commit message and in the config documentation. Is the plan
> just to use it for best-effort explanatory messages? (Using it as a true
> cache is probably too performance-intensive, I would think, since in its
> absence, we have no idea whether the repo is a submodule and would
> always have to search to the root of the filesystem.) If it is just for
> best-effort explanatory messages, maybe write:
> 
>   If present, commands like "git status" in this submodule may print
>   additional information about this submodule's status with respect to
>   its superproject.
> 
> This would further reinforce that this variable being missing is OK.

Ok, I'll expand the commit message. The first use case for this extra
pointer is for a shared config between superproject and submodule, which
I've sent a series for already; I'll mention that in the commit message
too.

> 
> > diff --git a/Documentation/config/submodule.txt b/Documentation/config/submodule.txt
> > index d7a63c8c12..7c459cc19e 100644
> > --- a/Documentation/config/submodule.txt
> > +++ b/Documentation/config/submodule.txt
> > @@ -90,3 +90,15 @@ submodule.alternateErrorStrategy::
> >  	`ignore`, `info`, `die`. Default is `die`. Note that if set to `ignore`
> >  	or `info`, and if there is an error with the computed alternate, the
> >  	clone proceeds as if no alternate was specified.
> > +
> > +submodule.superprojectGitDir::
> > +	The relative path from the submodule's worktree  to the superproject's
> > +	gitdir. This config should only be present in projects which are
> > +	submodules, but is not guaranteed to be present in every submodule. It
> > +	is set automatically during submodule creation.
> > ++
> > +	In situations where more than one superproject references the same
> > +	submodule worktree, the value of this config and the behavior of
> > +	operations which use it are undefined. To reference a single project
> > +	from multiple superprojects, it is better to create a worktree of the
> > +	submodule for each superproject.
> 
> So my suggestion would be:
> 
>   The relative path from this repository's worktree to its
>   superproject's gitdir. When Git is run in a repository, it usually
>   makes no difference whether this repository is standalone or a
>   submodule, but if this configuration variable is present, commands
>   like "git status" in this submodule may print additional information
>   about this submodule's status with respect to its superproject.
> 
> (I believe Junio has commented on the second paragraph - I don't have
> additional comments on that.)

The spirit of this suggestion seems to be "describe a possible side
effect of this config", so I'll do that, although the wording may not be
exactly the same. Thanks.

 - Emily

  reply	other threads:[~2021-08-19 17:53 UTC|newest]

Thread overview: 51+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-06-11 22:54 [RFC PATCH 0/4] cache parent project's gitdir in submodules Emily Shaffer
2021-06-11 22:54 ` [RFC PATCH 1/4] t7400-submodule-basic: modernize inspect() helper Emily Shaffer
2021-06-14  4:52   ` Junio C Hamano
2021-06-11 22:54 ` [RFC PATCH 2/4] introduce submodule.superprojectGitDir cache Emily Shaffer
2021-06-14  5:09   ` Junio C Hamano
2021-06-15 22:00     ` Emily Shaffer
2021-06-11 22:54 ` [RFC PATCH 3/4] submodule: cache superproject gitdir during absorbgitdirs Emily Shaffer
2021-06-14  6:18   ` Junio C Hamano
2021-06-11 22:54 ` [RFC PATCH 4/4] submodule: cache superproject gitdir during 'update' Emily Shaffer
2021-06-14  6:22   ` Junio C Hamano
2021-06-15 21:27     ` Emily Shaffer
2021-06-12 20:12 ` [RFC PATCH 0/4] cache parent project's gitdir in submodules Jacob Keller
2021-06-14  7:26 ` Junio C Hamano
2021-06-15 21:18   ` Emily Shaffer
2021-06-16  0:45 ` [PATCH v2 " Emily Shaffer
2021-06-16  0:45   ` [PATCH v2 1/4] t7400-submodule-basic: modernize inspect() helper Emily Shaffer
2021-07-27 17:12     ` Jonathan Tan
2021-08-19 17:46       ` Emily Shaffer
2021-06-16  0:45   ` [PATCH v2 2/4] introduce submodule.superprojectGitDir cache Emily Shaffer
2021-06-16  4:40     ` Junio C Hamano
2021-06-16  4:43       ` Junio C Hamano
2021-06-18  0:03         ` Emily Shaffer
2021-06-18  0:00       ` Emily Shaffer
2021-07-27 17:46     ` Jonathan Tan
2021-08-19 17:53       ` Emily Shaffer [this message]
2021-10-14 19:25     ` Ævar Arnfjörð Bjarmason
2021-06-16  0:45   ` [PATCH v2 3/4] submodule: cache superproject gitdir during absorbgitdirs Emily Shaffer
2021-06-16  0:45   ` [PATCH v2 4/4] submodule: cache superproject gitdir during 'update' Emily Shaffer
2021-07-27 17:51     ` Jonathan Tan
2021-08-19 18:02       ` Emily Shaffer
2021-08-19 20:09   ` [PATCH v3 0/4] cache parent project's gitdir in submodules Emily Shaffer
2021-08-19 20:09     ` [PATCH v3 1/4] t7400-submodule-basic: modernize inspect() helper Emily Shaffer
2021-08-19 20:09     ` [PATCH v3 2/4] introduce submodule.superprojectGitDir record Emily Shaffer
2021-08-20  0:38       ` Derrick Stolee
2021-10-13 19:36         ` Emily Shaffer
2021-09-04 17:20       ` Matheus Tavares
2021-10-13 19:39         ` Emily Shaffer
2021-08-19 20:09     ` [PATCH v3 3/4] submodule: record superproject gitdir during absorbgitdirs Emily Shaffer
2021-08-20  0:50       ` Derrick Stolee
2021-10-13 19:42         ` Emily Shaffer
2021-09-04 17:27       ` Matheus Tavares
2021-10-14 18:40         ` Emily Shaffer
2021-08-19 20:09     ` [PATCH v3 4/4] submodule: record superproject gitdir during 'update' Emily Shaffer
2021-08-20  0:59       ` Derrick Stolee
2021-10-14 18:45         ` Emily Shaffer
2021-08-19 21:56     ` [PATCH v3 0/4] cache parent project's gitdir in submodules Junio C Hamano
2021-08-20  1:09     ` Derrick Stolee
2021-10-13 18:51       ` Emily Shaffer
2021-10-14 17:12         ` Derrick Stolee
2021-10-14 18:52           ` Emily Shaffer
2021-09-04 17:50     ` Matheus Tavares Bernardino

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