From: Jonathan Tan <jonathantanmy@google.com>
To: emilyshaffer@google.com
Cc: git@vger.kernel.org, gitster@pobox.com,
Jonathan Tan <jonathantanmy@google.com>
Subject: Re: [PATCH v6 2/5] introduce submodule.superprojectGitDir record
Date: Wed, 17 Nov 2021 15:43:00 -0800 [thread overview]
Message-ID: <20211117234300.2598132-1-jonathantanmy@google.com> (raw)
In-Reply-To: <20211117005701.371808-3-emilyshaffer@google.com>
Emily Shaffer <emilyshaffer@google.com> writes:
> 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.
If we're going with my proposal [1], I think it's worth further
explaining the concept right at the beginning of the commit message:
Teach submodules a config variable referencing their superproject's
gitdir. Git commands may rely on this reference to determine if the
current repo is a submodule to another repo: if this reference is
absent, Git may assume that the current repo is not a submodule. In
practice, commands and arguments that specifially reference the
submodule relationship (like "rev-parse
--show-superproject-working-tree") will still search the ancestor
directory, but others (say, a "git status" that prints the submodule's
status in relation to its superproject or a config option that lets
the superproject and submodule share config) would not.
[1] https://lore.kernel.org/git/20211117232846.2596110-1-jonathantanmy@google.com/
> By using a relative path instead of an absolute path, we can move the
> superproject directory around on the filesystem without breaking the
> submodule's pointer. And by using the path from gitdir to gitdir, we can
> move the submodule within the superproject's tree structure without
> breaking the submodule's pointer, too. Finally, by pointing at the
> superproject's worktree gitdir (if it exists), we ensure that we can
> tell which worktree contains our submodule.
OK.
> Since this hint value is only introduced during new submodule creation
> via `git submodule add`, though, there is more work to do to allow the
> record to be created at other times.
This is not a hint anymore. I would reword as:
This commit teaches "git submodule add" to add the aforementioned
config variable. Subsequent commits will teach other commands to do
so.
> Once this new config is reliably in place, we can use it to know
> definitively that we are working in a submodule, and to know which
> superproject we are a submodule of. This allows us to do some
> value-added behavior, like letting "git status" print additional info
> about the submodule's status in relation to its superproject, or like
> letting the superproject and submodule share an additional config file
> separate from either one's local config.
I folded this into the first paragraph above, so this would no longer
needed if you used my suggestion above.
> +submodule.superprojectGitDir::
> + The relative path from the submodule's gitdir 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, additional behavior may be
> + possible, such as "git status" printing additional information about
> + this submodule's status with respect to its superproject. This config
> + should only be present in projects which are submodules, but is not
> + guaranteed to be present in every submodule, so only optional
> + value-added behavior should be linked to it. It is set automatically
> + during submodule creation.
If we're going to rely on the variable more, this needs to be updated.
Maybe:
If this repository is a submodule, the relative path from this repo's
gitdir to its superproject's gitdir. Git commands may rely on this
reference to determine if the current repo is a submodule to another
repo: if this reference is absent, Git may assume that the current
repo is not a submodule (this does not make a difference to most Git
commands). It is set automatically during ??
(and probably each subsequent patch will need to update the ??)
next prev parent reply other threads:[~2021-11-17 23:43 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-11-17 0:56 [PATCH v6 0/5] teach submodules to know they're submodules Emily Shaffer
2021-11-17 0:56 ` [PATCH v6 1/5] t7400-submodule-basic: modernize inspect() helper Emily Shaffer
2021-11-17 0:56 ` [PATCH v6 2/5] introduce submodule.superprojectGitDir record Emily Shaffer
2021-11-17 23:43 ` Jonathan Tan [this message]
2021-11-17 0:56 ` [PATCH v6 3/5] submodule: record superproject gitdir during absorbgitdirs Emily Shaffer
2021-11-17 0:57 ` [PATCH v6 4/5] submodule: record superproject gitdir during 'update' Emily Shaffer
2021-11-17 0:57 ` [PATCH v6 5/5] submodule: use config to find superproject worktree Emily Shaffer
2021-11-17 11:43 ` [RFC PATCH 0/2] submodule: test what happens if submodule.superprojectGitDir isn't around Ævar Arnfjörð Bjarmason
2021-11-17 11:43 ` [RFC PATCH 1/2] submodule tests: fix potentially broken "config .. --unset" Ævar Arnfjörð Bjarmason
2021-11-17 11:43 ` [RFC PATCH 2/2] submodule: add test mode for checking absence of "superProjectGitDir" Ævar Arnfjörð Bjarmason
2021-11-23 20:08 ` [RFC PATCH 0/2] submodule: test what happens if submodule.superprojectGitDir isn't around Emily Shaffer
2021-11-24 1:38 ` Ævar Arnfjörð Bjarmason
2021-11-17 23:28 ` [PATCH v6 0/5] teach submodules to know they're submodules Jonathan Tan
2021-11-23 20:28 ` Emily Shaffer
2022-02-03 21:59 ` Emily Shaffer
2022-02-03 21:59 ` [PATCH v7 1/4] t7400-submodule-basic: modernize inspect() helper Emily Shaffer
2022-02-03 21:59 ` [PATCH v7 2/4] introduce submodule.superprojectGitDir record Emily Shaffer
2022-02-03 21:59 ` [PATCH v7 3/4] submodule: record superproject gitdir during absorbgitdirs Emily Shaffer
2022-02-03 21:59 ` [PATCH v7 4/4] submodule: record superproject gitdir during 'update' Emily Shaffer
2022-02-03 22:39 ` [PATCH v6 0/5] teach submodules to know they're submodules Junio C Hamano
2022-02-04 1:15 ` Ævar Arnfjörð Bjarmason
2022-02-04 16:20 ` Junio C Hamano
2022-02-07 19:56 ` Jonathan Nieder
2022-02-07 23:21 ` Junio C Hamano
2022-02-08 1:18 ` Jonathan Nieder
2022-02-08 18:24 ` Junio C Hamano
2022-02-10 22:12 ` Emily Shaffer
2022-02-10 22:53 ` Jonathan Nieder
2022-02-12 20:35 ` Ævar Arnfjörð Bjarmason
2022-02-13 6:25 ` Junio C Hamano
2022-03-01 0:26 ` [PATCH v8 0/3] " Emily Shaffer
2022-03-01 0:26 ` [PATCH v8 1/3] t7400-submodule-basic: modernize inspect() helper Emily Shaffer
2022-03-01 0:26 ` [PATCH v8 2/3] introduce submodule.hasSuperproject record Emily Shaffer
2022-03-01 7:00 ` Junio C Hamano
2022-03-08 20:04 ` Emily Shaffer
2022-03-08 22:13 ` Glen Choo
2022-03-08 22:29 ` Glen Choo
2022-03-01 0:26 ` [PATCH v8 3/3] rev-parse: short-circuit superproject worktree when config unset Emily Shaffer
2022-03-01 7:06 ` Junio C Hamano
2022-03-09 0:38 ` Emily Shaffer
2022-03-01 3:08 ` [PATCH v8 0/3] teach submodules to know they're submodules Junio C Hamano
2022-03-08 18:54 ` Emily Shaffer
2022-03-10 0:44 ` [PATCH v9 " Emily Shaffer
2022-03-10 0:44 ` [PATCH v9 1/3] t7400-submodule-basic: modernize inspect() helper Emily Shaffer
2022-03-10 0:44 ` [PATCH v9 2/3] introduce submodule.hasSuperproject record Emily Shaffer
2022-03-10 2:09 ` Junio C Hamano
2022-03-10 21:29 ` Glen Choo
2022-03-10 21:40 ` Glen Choo
2022-03-10 22:10 ` Junio C Hamano
2022-03-10 23:42 ` Glen Choo
2022-03-10 23:53 ` Glen Choo
2022-03-15 20:48 ` Emily Shaffer
2022-03-15 20:56 ` Emily Shaffer
2022-03-15 21:19 ` Glen Choo
2022-03-15 18:39 ` Emily Shaffer
2022-03-15 19:19 ` Junio C Hamano
2022-03-10 2:32 ` Junio C Hamano
2022-03-10 21:54 ` Glen Choo
2022-03-15 18:27 ` Emily Shaffer
2022-03-10 0:44 ` [PATCH v9 3/3] rev-parse: short-circuit superproject worktree when config unset Emily Shaffer
2022-03-10 1:47 ` Junio C Hamano
2022-03-10 4:39 ` Eric Sunshine
2022-03-11 9:09 ` [PATCH v9 0/3] teach submodules to know they're submodules Ævar Arnfjörð Bjarmason
2022-03-13 5:43 ` Junio C Hamano
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