Python 3.13: TypedDict.__readonly_keys__ and __mutable_keys__ missing

[srittau]

Bug Report

Cf. python/typeshed#13638

mypy doesn't synthesize the __readonly_keys__ and __mutable_keys__ class attributes of TypedDict, introduced in Python 3.13. This leads to stubtest complaining about each instance of a TypedDict due to the attributes missing from the stubs.

To Reproduce

# foo.py

from typing import TypedDict

class Foo(TypedDict):
    bar: str
    
print(Foo.__readonly_keys__)  # at runtime: frozenset()
print(Foo.__mutable_keys__)  # at runtime: frozenset({'bar'})

Expected Behavior

Using mypy --python-version 3.13 foo.py: no errors.

Actual Behavior

foo.py:8: error: "type[Foo]" has no attribute "__readonly_keys__"  [attr-defined]
foo.py:9: error: "type[Foo]" has no attribute "__mutable_keys__"  [attr-defined]
Found 2 errors in 1 file (checked 1 source file)

Your Environment

• Mypy version used: 1.15.0
• Mypy command-line flags: --python-version 3.13
• Mypy configuration options from mypy.ini (and other config files): ./.
• Python version used: 3.12

[AlexWaygood]

Ah shoot, now that I look at this again, I think this is a typeshed bug? We should probably be listing these attributes in the typing._TypedDict stub here: https://github.com/python/typeshed/blob/205e993b52681f14fe38f3790f88e39e7cf3474b/stdlib/typing.pyi#L945-L952

same as we do in our stub for typing_extensions here: https://github.com/python/typeshed/blob/205e993b52681f14fe38f3790f88e39e7cf3474b/stdlib/typing_extensions.pyi#L225-L227

[srittau]

Good point, I'll send a PR. That will also make sure that it will work with any Python version.