Meta issue for cleaning up import system cruft

[warsaw]

This is a meta issue tracking all the things that need to be cleaned up in the import system. From removing long deprecated APIs to migrating internal access to __spec__, we'll have several task lists for each related set of clean ups.

@brettcannon @ericsnowcurrently for visibility.

Removing deprecated APIs

Over in What's New for Python 3.11 there's a long list of things that have been deprecated long enough that they can be removed in Python 3.12. Here's that task list for tracking purposes. Watch for linked PRs (maybe one big one or many small ones -- we'll see!).

@brettcannon @ericsnowcurrently for visibility.

• importlib.find_loader()
• importlib.util.module_for_loader()
• importlib.util.set_loader_wrapper()
• importlib.util.set_package_wrapper()
• importlib.abc.Loader.module_repr() (3.12: gh-97850: Remove all known instances of module_repr() #97876)
• importlib.abc.MetaPathFinder.find_module()
• importlib.abc.MetaPathFinder.find_module()
• importlib.abc.PathEntryFinder.find_loader()
• importlib.abc.PathEntryFinder.find_module()
• importlib.machinery.BuiltinImporter.find_module()
• importlib.machinery.BuiltinLoader.module_repr() (3.12: gh-97850: Remove all known instances of module_repr() #97876)
• importlib.machinery.FileFinder.find_loader()
• importlib.machinery.FileFinder.find_module()
• importlib.machinery.FrozenImporter.find_module()
• importlib.machinery.FrozenLoader.module_repr() (3.12: gh-97850: Remove all known instances of module_repr() #97876)
• importlib.machinery.PathFinder.find_module()
• importlib.machinery.WindowsRegistryFinder.find_module()
• Remove pkgutil.ImpImporter (3.12: already deprecated)
• Remove pkgutil.ImpLoader
• Remove the imp module (3.12: Remove more deprecated importlib APIs from Python 3.12 #98040)
• importlib.abc.Finder

Update docs

• Make sure examples and details from PEP 302 are covered in the importlib docs (/cc @Yhg1s )
• Remove https://docs.python.org/3/reference/import.html#open-issues (PR)
• It would be really nice to have a diagram.
• (import_machinery.rst) how about a section devoted just to the attributes of modules and packages, perhaps expanding upon or supplanting the related entries in the data model reference page?
• runpy, pkgutil, et al in the library manual should all get “See Also” links at the top pointing to the new import system section.
• Add more explanation regarding the different ways in which __main__ is initialized?
• Add more info on __main__ quirks/pitfalls (i.e. copy from PEP 395).

Missing deprecations

Here's a list of related APIs that have not yet been deprecated, but should be. We'll deprecate them in 3.12 and remove them in 3.14.

• pkgutil.find_loader()
• pkgutil.get_loader() (or it needs to be reimplemented to not use find_loader())

Other:

• Do we need to define importlib.abc.PathEntryFinder.find_spec() #103999

• PR: gh-97850: Deprecate find_loader and get_loader in pkgutil #98520

• PR: GH-97850: Suppress cross-references to the removed module_repr method #104133

• PR: GH-97850: Suppress cross-references to removed importlib.util functions #104134

• PR: gh-97850: Note in py312 whatsnew that importlib.util.set_loader and importlib.util.module_for_loader have been removed #108719

• PR: [3.12] gh-97850: Note in py312 whatsnew that importlib.util.set_loader and importlib.util.module_for_loader have been removed (GH-108719) #108723

• PR: gh-97850: remove find_loader and get_loader from pkgutil #119656

• PR: gh-97850: Suggest TraversableResources as the alternative for ResourceLoader. #128601

• PR: gh-97850: Remove the mention of removal from ResourceReader docs #128602

• PR: [3.13] gh-97850: Remove the mention of removal from ResourceReader docs (GH-128602) #128654

• PR: [3.12] gh-97850: Remove the mention of removal from ResourceReader docs (GH-128602) #128655

• PR: [3.13] gh-97850: Suggest TraversableResources as the alternative for ResourceLoader (GH-128601) #128895

• PR: [3.12] gh-97850: Suggest TraversableResources as the alternative for ResourceLoader (GH-128601) #128896

[sobolevn]

I've removed importlib.utils.set_loader, importlib.utils.set_package, and
importlib.utils.module_for_loader from importlib.utils in #97898 🎉