Add support for external forks of CPython

[johnslavik]

To basically make

every-python/every_python/main.py

Line 31 in 0506f8a

CPYTHON_REPO = "https://github.com/python/cpython.git"

configurable.

Perhaps also resolve remotes from the current Git repo? That would be a breeze when working on something outside of the CPython repo, e.g. lazy imports from https://github.com/LazyImportsCabal/cpython.git.

every-python install --remote=lazy 8639e50

That would rock.

OTOH maybe this and #8 could be addressed by simply adding the possibility to customize what's passed to Git?

[savannahostrowski]

Totally! I've had this on my TODO list for awhile. I'm thinking it'd be nice to have support for both full URLs and shorthand.

# Use a fork
every-python install --repo=https://github.com/user/cpython-fork.git branch/tag/SHA

# Could also support shorthand for GitHub
every-python install --repo=user/cpython-fork branch/tag/SHA

I think the trickiest bit here would probably be validating this is in fact a fork of CPython but maybe it's enough to check for some expected files like configure or PCBuild/build.bat, etc. and then error out with a helpful message?

...On the other hand, ehhhhh, user error so maybe we just don't even bother and let it fail out 😄 ?

What do you think?

[savannahostrowski]

I'm going to rev on this a bit, stay tuned!

[johnslavik]

I think the trickiest bit here would probably be validating this is in fact a fork of CPython but maybe it's enough to check for some expected files like configure or PCBuild/build.bat, etc. and then error out with a helpful message?

...On the other hand, ehhhhh, user error so maybe we just don't even bother and let it fail out 😄 ?

What do you think?

I think I'd let it fail out, yes :)

typeshed_client does something analogous by operating on typeshed repos and simply bubbles up an exception when it cannot find the necessary VERSIONS file intrinsic to typesheds:

Example traceback

~ 
❯ uvx --with typeshed-client python -c 'import typeshed_client, pathlib; typeshed_client.get_stub_file("ast", search_context=typeshed_client.get_search_context(typeshed=pathlib.Path("foobarbizbaz")))'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
    import typeshed_client, pathlib; typeshed_client.get_stub_file("ast", search_context=typeshed_client.get_search_context(typeshed=pathlib.Path("foobarbizbaz")))
                                     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/bswck/.cache/uv/archive-v0/All-DsPLm1RrRi33ocByR/lib64/python3.13/site-packages/typeshed_client/finder.py", line 98, in get_stub_file
    return get_stub_file_name(ModulePath(tuple(module_name.split("."))), search_context)
  File "/home/bswck/.cache/uv/archive-v0/All-DsPLm1RrRi33ocByR/lib64/python3.13/site-packages/typeshed_client/finder.py", line 269, in get_stub_file_name
    stub = _find_stub_in_typeshed(module_name, search_context)
  File "/home/bswck/.cache/uv/archive-v0/All-DsPLm1RrRi33ocByR/lib64/python3.13/site-packages/typeshed_client/finder.py", line 300, in _find_stub_in_typeshed
    versions = get_typeshed_versions(search_context.typeshed)
  File "/home/bswck/.cache/uv/archive-v0/All-DsPLm1RrRi33ocByR/lib64/python3.13/site-packages/typeshed_client/finder.py", line 333, in get_typeshed_versions
    with (typeshed / "VERSIONS").open() as f:
         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^
  File "/usr/lib64/python3.13/pathlib/_local.py", line 537, in open
    return io.open(self, mode, buffering, encoding, errors, newline)
           ~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
FileNotFoundError: [Errno 2] No such file or directory: 'foobarbizbaz/VERSIONS'