diff --git a/git/util.py b/git/util.py
@@ -150,6 +150,7 @@ def wrapper(self: "Remote", *args: Any, **kwargs: Any) -> T:

@contextlib.contextmanager
def cwd(new_dir: PathLike) -> Generator[PathLike, None, None]:
    old_dir = os.getcwd()
    os.chdir(new_dir)
    try:
@@ -158,6 +159,20 @@ def cwd(new_dir: PathLike) -> Generator[PathLike, None, None]:
        os.chdir(old_dir)


def rmtree(path: PathLike) -> None:
    """Remove the given recursively.

@@ -935,7 +950,7 @@ def _obtain_lock_or_raise(self) -> None:
            )

        try:
-            with open(lock_file, mode='w'):
                pass
        except OSError as e:
            raise IOError(str(e)) from e

diff --git a/test/fixtures/env_case.py b/test/fixtures/env_case.py
@@ -0,0 +1,13 @@