Re: [RFC PATCH v2 09/12] submodule: support reading .gitmodules even when it's not checked out

On Thu, Aug 2, 2018 at 6:47 AM Antonio Ospite [off-list ref] wrote:

When the .gitmodules file is not available in the working tree, try
using HEAD:.gitmodules from the current branch. 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 working tree.

The reading part shows how nice our internal config system is, once
everything is put in place.

Writing to .gitmodules will still require that the file is checked out,
so check for that before calling config_set_in_gitmodules_file_gently.