"invalid config path selector" error when testing on pypy with MacOS arm64

[2bndy5]

pytest output

../venv-test-arm64/lib/pypy3.11/site-packages/pygit2/errors.py:67: GitError
__________________ ERROR at setup of test_rebuild_treebuilder __________________

    @pytest.fixture(scope='session', autouse=True)
    def global_git_config() -> None:
        # Do not use global config for better test reproducibility.
        # https://github.com/libgit2/pygit2/issues/989
        levels = [
            pygit2.enums.ConfigLevel.GLOBAL,
            pygit2.enums.ConfigLevel.XDG,
            pygit2.enums.ConfigLevel.SYSTEM,
        ]
        for level in levels:
>           pygit2.settings.search_path[level] = ''
            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

test/conftest.py:22: 
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 
../venv-test-arm64/lib/pypy3.11/site-packages/pygit2/settings.py:45: in __setitem__
    option(Option.SET_SEARCH_PATH, key, value)
../venv-test-arm64/lib/pypy3.11/site-packages/pygit2/options.py:373: in option
    check_error(err)
_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ 

err = -1, io = False

    def check_error(err: int, io: bool = False) -> None:
        if err >= 0:
            return
    
        # These are special error codes, they should never reach here
        test = err != C.GIT_EUSER and err != C.GIT_PASSTHROUGH
        assert test, f'Unexpected error code {err}'
    
        # Error message
        giterr = C.git_error_last()
        if giterr != ffi.NULL:
            message = ffi.string(giterr.message).decode('utf8', errors='surrogateescape')
        else:
            message = f'err {err} (no message provided)'
    
        # Translate to Python errors
        if err in value_errors:
            raise ValueError(message)
    
        if err == C.GIT_ENOTFOUND:
            if io:
                raise IOError(message)
    
            raise KeyError(message)
    
        if err == C.GIT_EINVALIDSPEC:
            raise ValueError(message)
    
        if err == C.GIT_ITEROVER:
            raise StopIteration()
    
        # Generic Git error
>       raise GitError(message)
E       _pygit2.GitError: invalid config path selector 0

../venv-test-arm64/lib/pypy3.11/site-packages/pygit2/errors.py:67: GitError
ERROR test/test_treebuilder.py::test_rebuild_treebuilder - _pygit2.GitError: invalid config path selector 0

---

As far as I can tell, this "invalid config path selector" error seems to be specific to pygit2 on pypy11. It seems that the int(level) passed to git_libgit2_opts()

pygit2/pygit2/options.py

Lines 359 to 374 in 890730c

	elif option_type == C.GIT_OPT_SET_SEARCH_PATH:
	check_args(option_type, arg1, arg2, 2)
	level = int(arg1) # Convert enum to int
	path = arg2
	path_cdata: ArrayC[char] | NULL_TYPE
	if path is None:
	path_cdata = ffi.NULL
	else:
	path_bytes = to_bytes(path)
	path_cdata = ffi.new('char[]', path_bytes)
	err = C.git_libgit2_opts(option_type, ffi.cast('int', level), path_cdata)
	check_error(err)
	return None

is not matching up with the libgit2 C constants of the same name:

static int config_level_to_sysdir(int *out, int config_level)
{
	switch (config_level) {
	case GIT_CONFIG_LEVEL_SYSTEM:
		*out = GIT_SYSDIR_SYSTEM;
		return 0;
	case GIT_CONFIG_LEVEL_XDG:
		*out = GIT_SYSDIR_XDG;
		return 0;
	case GIT_CONFIG_LEVEL_GLOBAL:
		*out = GIT_SYSDIR_GLOBAL;
		return 0;
	case GIT_CONFIG_LEVEL_PROGRAMDATA:
		*out = GIT_SYSDIR_PROGRAMDATA;
		return 0;
	default:
		break;
	}

	git_error_set(
		GIT_ERROR_INVALID, "invalid config path selector %d", config_level);
	return -1;
}

See libgit2 source

There was a similar issue in libgit2/libgit2sharp#1951 which was fixed by padding the va_args passed to git_libgit2_opts() (libgit2/libgit2sharp#1955).

Originally posted by @2bndy5 in #1441 (comment)