On Mon, 23 Apr 2018 10:47:09 -0700
Jonathan Nieder [off-list ref] wrote:

Hi,

Hi Jonathan, thank you for your comment.

Antonio Ospite wrote:

quoted

vcsh[1] uses bare git repositories and detached work-trees to manage
*distinct* sets of configuration files directly into $HOME.

Cool!  I like the tooling you're creating for this, though keep in mind
that Git has some weaknesses as a tool for deployment.

I am not the author BTW, just a user trying to address the remaining
corner cases.

In particular, keep in mind that when git updates a file, there is a
period of time while it is missing from the filesystem, which can be
problematic for dotfiles.

Thanks for the reminder, it may be worth mentioning this in vcsh
documentation, however I don't have knowledge of users experiencing
problems related to that.

[...]

quoted

However when multiple repositories take turns using the same directory
as their work-tree, and more than one of them want to use submodules,
there could still be conflicts about the '.gitmodules' file because git
hardcodes this path.

For comparison, in case of '.gitignore' a similar conflict might arise,
but git has alternative ways to specify exclude files, so vcsh solves
this by setting core.excludesFile for each repository and track ignored
files somewhere else (in ~/.gitignore.d/$VCSH_REPO_NAME).

For reference:

	core.excludesFile
		Specifies the pathname to the file that contains
		patterns to describe paths that are not meant to be
		tracked, in addition to .gitignore (per-directory) and
		.git/info/exclude. Defaults to
		$XDG_CONFIG_HOME/git/ignore. If $XDG_CONFIG_HOME is
		either not set or empty, $HOME/.config/git/ignore is
		used instead. See gitignore(5).

Using this as a substitute for <worktree>/.gitignore is a bit of a
hack.  It happens to work, though, so reading on. :)

[...]

quoted

So this series proposes a mechanism to set an alternative path for the
submodules configuration file (from now on "gitmodules file").

I am nervous about this.  I wonder if there is another way to
accomplish the goal.

One possibility would be to handle the case where .gitmodules is
excluded by a sparse checkout specification and use .gitmodules from
the index in that case.  Would that work for you?

Since part of the problem is that .gitmodules *collide* between
repositories, a sparse-checkout approach make sense indeed.

As discussed[1] with Stefan Beller having git use .gitmodules from the
index without the need to have it checked out should work for us.

[1] https://www.spinics.net/lists/git/msg329153.html

Ideally git should also be able to write to that file when it's not
checked out (e.g. when running "git submodule add"), to save the
user from tedious sparse/unsparse rounds when operating with submodules.

As suggested by Stefan I'll first try to remove the hardcoded references
to .gitmodules in git-submodule.sh adding a helper sub-command to
access .gitmodules in a more robust way, and after that git could
be taught to use the file from the index, but this second part
is currently beyond my current git knowledge.

If this mechanism of using unchecked-out files from the index could be
extended to .gitignore (and .gitattributes), then vcsh might even stop
abusing core.excludesFile; sparse checkouts seem the more natural git
way to deal with colliding files in a shared-workdir scenario.

However, having users *write* to .gitignore and .gitattributes while
they are not checked out still sounds quite problematic to me, but maybe
this could be handled by vcsh itself, similarly to what is done for the
file pointed by core.excludesFile.

Ciao,
   Antonio

-- 
Antonio Ospite
https://ao2.it
https://twitter.com/ao2it

A: Because it messes up the order in which people normally read text.
   See http://en.wikipedia.org/wiki/Posting_style
Q: Why is top-posting such a bad thing?