Allow overriding the list of avoided build requirements

[agriyakhetarpal]

This PR adds a new configuration variable in pyodide config called ignored_build_requirements, which accepts whitespace-separated normalised dependency names, which will be ignored during the wheel build procedure. The default value is "patchelf oldest-supported-numpy".

Users may now utilise the IGNORED_BUILD_REQUIREMENTS environment variable or the ignored_build_requirements value in a [tool.pyodide.build] TOML table in pyproject.toml to set to a value of their choice, and the pyodide config get ignored_build_requirements CLI invocation to retrieve them.

As a by-product of this PR, the ConfigManager is now loaded more lazily in order to avoid circular imports across our build pipeline.

Closes #184

[agriyakhetarpal]

Argh, there's a problem with a circular import here because of the get_host_build_flag("AVOIDED_BUILD_REQUIREMENTS") calculation that is performed:

pyodide config get avoided_build_requirements

returns

Traceback (most recent call last):
  File "/Users/agriyakhetarpal/Desktop/pyodide-build/venv/bin/pyodide", line 8, in <module>
    sys.exit(main())
             ^^^^^^
  File "/Users/agriyakhetarpal/Desktop/pyodide-build/venv/lib/python3.12/site-packages/pyodide_cli/app.py", line 111, in main
    register_plugins()
  File "/Users/agriyakhetarpal/Desktop/pyodide-build/venv/lib/python3.12/site-packages/pyodide_cli/app.py", line 81, in register_plugins
    plugins = {ep.name: (ep.load(), ep) for ep in eps}
                         ^^^^^^^^^
  File "/opt/homebrew/Caskroom/miniforge/base/lib/python3.12/importlib/metadata/__init__.py", line 205, in load
    module = import_module(match.group('module'))
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/homebrew/Caskroom/miniforge/base/lib/python3.12/importlib/__init__.py", line 90, in import_module
    return _bootstrap._gcd_import(name[level:], package, level)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen importlib._bootstrap>", line 1387, in _gcd_import
  File "<frozen importlib._bootstrap>", line 1360, in _find_and_load
  File "<frozen importlib._bootstrap>", line 1331, in _find_and_load_unlocked
  File "<frozen importlib._bootstrap>", line 935, in _load_unlocked
  File "<frozen importlib._bootstrap_external>", line 995, in exec_module
  File "<frozen importlib._bootstrap>", line 488, in _call_with_frames_removed
  File "/Users/agriyakhetarpal/Desktop/pyodide-build/pyodide_build/cli/build.py", line 13, in <module>
    from pyodide_build.build_env import (
  File "/Users/agriyakhetarpal/Desktop/pyodide-build/pyodide_build/build_env.py", line 18, in <module>
    from pyodide_build.config import ConfigManager, CrossBuildEnvConfigManager
  File "/Users/agriyakhetarpal/Desktop/pyodide-build/pyodide_build/config.py", line 14, in <module>
    from pyodide_build.pypabuild import AVOIDED_REQUIREMENTS
  File "/Users/agriyakhetarpal/Desktop/pyodide-build/pyodide_build/pypabuild.py", line 18, in <module>
    from pyodide_build.build_env import (
ImportError: cannot import name 'get_build_flag' from partially initialized module 'pyodide_build.build_env' (most likely due to a circular import) (/Users/agriyakhetarpal/Desktop/pyodide-build/pyodide_build/build_env.py)

[ryanking13]

Thanks for working on this!

Argh, there's a problem with a circular import here because of the get_host_build_flag("AVOIDED_BUILD_REQUIREMENTS") calculation that is performed:

I think we can bypass it by importing AVOIDED_BUILD_REQUIREMENTS inside install_reqs or in other function.

[ryanking13]

BTW, I think the "avoided" is very poor name (I named it 🙄). How about renaming it to something like "skipped" or "ignored" or "filtered"?

[agriyakhetarpal]

Thanks, @ryanking13!

BTW, I think the "avoided" is very poor name (I named it 🙄). How about renaming it to something like "skipped" or "ignored" or "filtered"?

I agree with you. I've changed it to "ignored" for now. Though, I was thinking we could use "excluded"?

[ryanking13]

Thanks agriya! Maybe we can think about the better structure to handle circular dependencies later, for now it looks good to me.

[ryanking13]

(no action requird for this PR)

It would be great if we could support List types here. The question is how to support the list type in an env variable.

[agriyakhetarpal]

Yes, I agree – I faced this problem when implementing it. I feel there is no neat option to do it in this case, as cibuildwheel also largely suffers from the same limitation.

[agriyakhetarpal]

Thanks for the review, @ryanking13!