On 2020-03-23 at 15:09:39, Benjamin Shropshire wrote:
> $ git --version
> git version 2.20.1

Hmmm, it looks like that version has the same test, t0060, which has
this:

  test_submodule_relative_url "(null)" "user@host:path/to/repo" "../subrepo" "user@host:path/to/subrepo"
  test_submodule_relative_url "(null)" "user@host:repo" "../subrepo" "user@host:subrepo"
  test_submodule_relative_url "(null)" "user@host:repo" "../../subrepo" ".:subrepo"

I have confirmed that your test case does work for me on the version of
Git I mentioned above with the following repos:

  bmc@castro:foo/foo.git
  bmc@castro:bar/bar.git

And foo.git having the following .gitmodules:

  [submodule "bar.git"]
          path = bar.git
          url = ../../bar/bar.git

It's puzzling to me that this isn't working for you on 2.20.1 but it
works for me on a 2.26 prerelease, yet both versions have the same test.
-- 
brian m. carlson: Houston, Texas, US
OpenPGP: https://keybase.io/bk2204