Re: git checkout creates strange '(null)'-branch

[Junio C Hamano <gitster@pobox.com>]

Erik Faye-Lund <kusmabite@gmail.com> writes:

> +	test_create_repo empty-repo &&
> +	git submodule add ./empty-repo empty-submodule

You have an empty-repo but that is not part of the superproject; the
superproject will have empty-submodule submodule which is a clone of
empty-repo.

    $ git submodule add ./empty-repo empty-submodule
    Cloning into 'empty-submodule'...
    warning: You appear to have cloned an empty repository.
    done.

And after that, without you doing anything in empty-submodule, that
repository already exhibits the (null) problem.  Perhaps somebody, after
calling a successfull "git clone" of an empty repository (which is a silly
thing to do to begin with, with or without submodules involved, but at
least we do have a defined semantics of what happens when you do that),
tried to run "git checkout", even though there is nothing to be checked
out?  The culprit in that case to suspect would be "git submodule" script.
Does it blindly assume that it can do a "git checkout" and runs that
command?