Remove PyFilesystem2 dependency @W-21244194

[jstvz]

This PR removes PyFilesystem2. Importing fs emits a pkg_resources deprecation warning (see
pyfilesystem2#597). There are also open questions about the project’s maintenance status (see
pyfilesystem2#571). As far as I can tell, CumulusCI only relied on a small, local subset of functionality. That subset maps cleanly to Python’s standard library.

This PR introduces a local-only FSResource and open_fs_resource implemented with pathlib, os, and shutil. file:// URLs are supported for absolute and relative paths, and non-file schemes are rejected. All fs imports were removed and tests updated to expect FileExistsError instead of fs.errors.DirectoryExists.

[robertbwatson]

@jstvz will this fix #3907?

[davisagli]

@robertbwatson This doesn't look related to the pkg_resources namespace package that is the problem in #3907

[BrandonEnclude]

@robertbwatson This doesn't look related to the pkg_resources namespace package that is the problem in #3907

Are you sure? The dependency using pkg_resources is PyFileSystem2, so removing that dependency will solve the issue, won't it?

Here's my stack trace:

C:\Users\Me>cci version
Traceback (most recent call last):
  File "<frozen runpy>", line 198, in _run_module_as_main
  File "<frozen runpy>", line 88, in _run_code
  File "c:\users\Me\.local\bin\cci.exe\__main__.py", line 2, in <module>
    from cumulusci.cli.cci import main
  File "C:\Users\Me\pipx\venvs\cumulusci\Lib\site-packages\cumulusci\cli\cci.py", line 21, in <module>
    from .error import error
  File "C:\Users\Me\pipx\venvs\cumulusci\Lib\site-packages\cumulusci\cli\error.py", line 11, in <module>
    from cumulusci.cli.utils import warn_if_no_long_paths, win32_long_paths_enabled
  File "C:\Users\Me\pipx\venvs\cumulusci\Lib\site-packages\cumulusci\cli\utils.py", line 14, in <module>
    from cumulusci.core.config import UniversalConfig
  File "C:\Users\Me\pipx\venvs\cumulusci\Lib\site-packages\cumulusci\core\config\__init__.py", line 8, in <module>
    from cumulusci.core.utils import import_global
  File "C:\Users\Me\pipx\venvs\cumulusci\Lib\site-packages\cumulusci\core\utils.py", line 21, in <module>
    from cumulusci.utils.options import parse_list_of_pairs_dict_arg
  File "C:\Users\Me\pipx\venvs\cumulusci\Lib\site-packages\cumulusci\utils\options.py", line 8, in <module>
    from cumulusci.utils.yaml.model_parser import CCIDictModel
  File "C:\Users\Me\pipx\venvs\cumulusci\Lib\site-packages\cumulusci\utils\yaml\model_parser.py", line 7, in <module>
    from cumulusci.utils.yaml.safer_loader import load_from_source, load_yaml_data
  File "C:\Users\Me\pipx\venvs\cumulusci\Lib\site-packages\cumulusci\utils\yaml\safer_loader.py", line 11, in <module>
    from cumulusci.utils.fileutils import FSResource, load_from_source
  File "C:\Users\Me\pipx\venvs\cumulusci\Lib\site-packages\cumulusci\utils\fileutils.py", line 10, in <module>
    from fs import base, copy, open_fs
  File "C:\Users\Me\pipx\venvs\cumulusci\Lib\site-packages\fs\__init__.py", line 4, in <module>
    __import__("pkg_resources").declare_namespace(__name__)  # type: ignore
    ~~~~~~~~~~^^^^^^^^^^^^^^^^^
ModuleNotFoundError: No module named 'pkg_resources'

The crash happens in site-packages\fs which is PyFileSystem2, isn't it?

[davisagli]

@BrandonEnclude Oh, I see. I was remembering that cumulusci.tasks was also a pkg_resources namespace package, but it looks like that was updated several years ago. So this could help, as long as there are not other dependency packages with the same problem.

[yippie]

This needs to get merged like, last week.

[jstvz]

@vsbharath You still have write access to this repo. Can you review this PR?