Avoid Git's dubious ownership error

[akaihola]

When running Git, don't remove any environment variables. Instead, just override LC_ALL=C.UTF-8. Also add a test which verifies that this is sufficient to ensure Git's output is in English.

Fixes akaihola/darker#524
Fixes akaihola/darker#590

---

The original flawed plan was:

add some environment variables which are needed to avoid Git's dubious ownership detection:

• $HOME on Windows/MinGW
• $EUID and $SUDO_UID on Unix

See:

• https://github.com/git/git/blob/39bf06ad/git-compat-util.h#L566-L585
• https://github.com/git/git/blob/39bf06ad/compat/mingw.c#L2740-L2858

[DeinAlptraum]

I've tested this via

pip install darkgraylib@git+https://github.com/akaihola/darkgraylib@git-dubious-ownership

like you said, but I am still getting the error. If I understood correctly, your change works specifically for the "ownership" case, i.e. when the "dubious" repo is owned by the user. That is not the case for me afaik, I am passing the check because I have an exemption for the directory in my ~/.gitconfig, but apparently the environment changes make git unable to find the config file. I.e. the relevant check in my case is this: https://github.com/git/git/blob/39bf06adf96da25b87c9aa7d35a32ef3683eb4a4/setup.c#L1281
rather than the one 10 lines above it

Side note: the installation command I quoted above produces errors due to version incompatibility with current darker, which I've fixed manually to test this

ERROR: pip's dependency resolver does not currently take into account all the packages that are installed. This behaviour is the source of the following dependency conflicts.
darker 2.1.1 requires darkgraylib~=1.2.0, but you have darkgraylib 2.0.0 which is incompatible.
graylint 1.1.1 requires darkgraylib~=1.2.0, but you have darkgraylib 2.0.0 which is incompatible.

and calling darker after that crashes with the following error:

Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "~/.local/share/virtualenvs/python-1_CbI4TK/lib/python3.12/site-packages/darker/__main__.py", line 641, in <module>
    RETVAL = main_with_error_handling()
             ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "~./local/share/virtualenvs/python-1_CbI4TK/lib/python3.12/site-packages/darker/__main__.py", line 633, in main_with_error_handling
    return main()
           ^^^^^^
  File "~/.local/share/virtualenvs/python-1_CbI4TK/lib/python3.12/site-packages/darker/__main__.py", line 495, in main
    show_config_if_debug(config, config_nondefault, args.log_level)
TypeError: show_config_if_debug() missing 1 required positional argument: 'section_name'

which I've fixed manually by passing None as a fourth argument

[akaihola]

Thanks @DeinAlptraum, this clarified the issue! I refreshed my memory from Darker's commit history, and the only reason for invoking Git with a clean environment was to ensure its terminal output is always in English. So I'll attack this from the opposite direction and only modify locale related variables while keeping the rest of the environment intact.

The Darker/Darkgraylib version incompatibility was expected, I'll make sure to take care of that one too.

[akaihola]

@DeinAlptraum, the latest fix in this branch now keeps the evironment and only modifies LC_ALL. You can try it out with:

pip install darker@git+https://github.com/akaihola/darker@master
pip install darkgraylib@git+https://github.com/akaihola/darkgraylib@git-dubious-ownership

[DeinAlptraum]

Small comments, but this looks good to me and fixes the issue on my end!