repo.submodule_update fails with relative module URLs

[david0]

I tried to use repo.submodule_update on an freshly cloned repository that uses a relative url in the submodule. That fails with fatal: repository '../submodule-test-module' does not exist.

It looks like some path handling is wrong, as a plain git submodule update --init --recursive works fine.

repo = Repo.clone_from("https://github.com/david0/submodule-test-root.git", "repo")
repo.submodule_update(init=True, recursive=True)

Traceback (most recent call last):
  File "/private/tmp/reproduce/venv/lib/python3.13/site-packages/git/objects/submodule/base.py", line 1417, in module
    repo = git.Repo(module_checkout_abspath)
  File "/private/tmp/reproduce/venv/lib/python3.13/site-packages/git/repo/base.py", line 289, in __init__
    raise InvalidGitRepositoryError(epath)
git.exc.InvalidGitRepositoryError: /private/tmp/reproduce/repo/submodule-test-module

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/private/tmp/reproduce/venv/lib/python3.13/site-packages/git/objects/submodule/base.py", line 739, in update
    mrepo = self.module()
  File "/private/tmp/reproduce/venv/lib/python3.13/site-packages/git/util.py", line 176, in wrapper
    return func(self, *args, **kwargs)
  File "/private/tmp/reproduce/venv/lib/python3.13/site-packages/git/objects/submodule/base.py", line 1422, in module
    raise InvalidGitRepositoryError("No valid repository at %s" % module_checkout_abspath) from e
git.exc.InvalidGitRepositoryError: No valid repository at /private/tmp/reproduce/repo/submodule-test-module

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/private/tmp/reproduce/main.py", line 8, in <module>
    repo.submodule_update(init=True, recursive=True)
    ~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/private/tmp/reproduce/venv/lib/python3.13/site-packages/git/repo/base.py", line 533, in submodule_update
    return RootModule(self).update(*args, **kwargs)
           ~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^
  File "/private/tmp/reproduce/venv/lib/python3.13/site-packages/git/objects/submodule/root.py", line 427, in update
    sm.update(
    ~~~~~~~~~^
        recursive=False,
        ^^^^^^^^^^^^^^^^
    ...<5 lines>...
        keep_going=keep_going,
        ^^^^^^^^^^^^^^^^^^^^^^
    )
    ^
  File "/private/tmp/reproduce/venv/lib/python3.13/site-packages/git/objects/submodule/base.py", line 797, in update
    mrepo = self._clone_repo(
        self.repo,
    ...<7 lines>...
        allow_unsafe_protocols=allow_unsafe_protocols,
    )
  File "/private/tmp/reproduce/venv/lib/python3.13/site-packages/git/objects/submodule/base.py", line 356, in _clone_repo
    clone = git.Repo.clone_from(
        url,
    ...<3 lines>...
        **kwargs,
    )
  File "/private/tmp/reproduce/venv/lib/python3.13/site-packages/git/repo/base.py", line 1541, in clone_from
    return cls._clone(
           ~~~~~~~~~~^
        git,
        ^^^^
    ...<7 lines>...
        **kwargs,
        ^^^^^^^^^
    )
    ^
  File "/private/tmp/reproduce/venv/lib/python3.13/site-packages/git/repo/base.py", line 1412, in _clone
    finalize_process(proc, stderr=stderr)
    ~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^
  File "/private/tmp/reproduce/venv/lib/python3.13/site-packages/git/util.py", line 504, in finalize_process
    proc.wait(**kwargs)
    ~~~~~~~~~^^^^^^^^^^
  File "/private/tmp/reproduce/venv/lib/python3.13/site-packages/git/cmd.py", line 834, in wait
    raise GitCommandError(remove_password_if_present(self.args), status, errstr)
git.exc.GitCommandError: Cmd('git') failed due to: exit code(128)
  cmdline: git clone -v -n --separate-git-dir=/private/tmp/reproduce/repo/.git/modules/submodule-test-module -- ../submodule-test-module /private/tmp/reproduce/repo/submodule-test-module
  stderr: 'fatal: repository '../submodule-test-module' does not exist
'

[david0]

I noticed this is a duplicate of #730