The discussion in [1] pointed out that '.' is a faulty suggestion as
there is a corner case where it fails:
> "submodule deinit ." may have "worked" in the sense that you would
> have at least one path in your tree and avoided this "nothing
> matches" most of the time. It would have still failed with the
> exactly same error if run in an empty repository, i.e.
>
> $ E=/var/tmp/x/empty && rm -fr "$E" && mkdir -p "$E" && cd "$E"
> $ git init
> $ rungit v2.6.6 submodule deinit .
> error: pathspec '.' did not match any file(s) known to git.
> Did you forget to 'git add'?
> $ >file && git add file
> $ rungit v2.6.6 submodule deinit .
> $ echo $?
> 0
So instead of a pathspec add the '--all' option to deinit all submodules
and add a test to check for the corner case of an empty repository.
The code only needs to learn about the '--all' option and doesn't
require further changes as `git submodule--helper list "$@"` will list
all submodules when "$@" is empty.
Helped-by: Junio C Hamano <gitster@pobox.com> Signed-off-by: Stefan Beller <sbeller@google.com> Reviewed-by: Jonathan Nieder <jrnieder@gmail.com> Signed-off-by: Junio C Hamano <gitster@pobox.com>