[[!comment format=mdwn
 username="joey"
 subject="""comment 4"""
 date="2015-02-27T20:00:54Z"
 content="""
Also, git has only used gitfiles for submodules since git 1.7.8.

So, repos using submodules that were cloned with an older version of git
would use a .git directory. And, if some part of git only supports
gitfiles, it wouldn't work with such repositories. Which would probably be
considered a bug since git doesn't break support for existing checkouts.

git-mv and git-rm man pages have a SUBMODULES section documenting that.
Including the behavior when using git-rm to try to delete a submodule that
uses a .git directory, instead of a gitfile:

> Only submodules using a gitfile (which means they were cloned
> with a Git version 1.7.8 or newer) will be removed from the work
> tree, as their repository lives inside the .git directory of the
> superproject. If a submodule (or one of those nested inside it)
> still uses a .git directory, `git rm` will fail - no matter if forced
> or not - to protect the submodule's history.

So, I doubt that git is going to break support for .git directory (or symlink)
in a submodule. But, using that might prevent a few things, particularly
git-rm of a submodule.

<pre>
joey@darkstar:~/tmp/r2>git rm module
error: the following submodule (or one of its nested submodules)
uses a .git directory:
    module
(use 'rm -rf' if you really want to remove it including all of its history)
</pre>
"""]]