Re: [RFC PATCH 09/10] submodule: support reading .gitmodules even when it's not checked out

From: Stefan Beller <sbeller@google.com>
Date: May 15, 2018, 01:45 UTC
Message-ID: <CAGZ79kYP_ensQR6caaxCwabvcLDdvJNLu2C8DT-jzy+oP7BpJw@mail.gmail.com>
In-Reply-To: <20180514105823.8378-10-ao2@ao2.it>

On Mon, May 14, 2018 at 3:58 AM, Antonio Ospite <ao2@ao2.it> wrote:

> When the .gitmodules file is not available in the working directory, try
> using HEAD:.gitmodules from the index.

I think HEAD:.gitmodules is different than the index (the former is part of the latest commit, whereas the index could have changed via git-add, that is not committed yet).

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> This covers the case when the
> file is part of the repository but for some reason it is not checked
> out, for example because of a sparse checkout.
>
> This makes it possible to use at least the 'git submodule' commands
> which *read* the gitmodules configuration file without fully populating
> the work dir.

Instead of checking for an explicit sparse "hidden" could we just rely on the file missing? Then I could continue using submodules if I just "rm .gitmodules".

>
> Writing to .gitmodules wills still require that the file is checked out,
> so check for that in config_gitmodules_set.

That makes sense!

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>
> Signed-off-by: Antonio Ospite <ao2@ao2.it>
> ---
>
> I am doing the is_gitmodules_hidden() check in the open for now, I am not sure
> whether it is approprate to do that inside stage_updated_gitmodules.

Why do we need that check at all?

In your use case, you want to checkout *a* .gitmodules file, not necessarily the .gitmodules file of that repo you're currently working on. So it sort of makes sense to prevent cross-repo changes (i.e. committing the .gitmodules accidentally into the wrong repo)

Stefan