Error compiling modules using dataclasses with mypyc #140704
Description
Bug report
I have a big project that uses dataclasses and compiles the code with mypyc for better speed.
I've noticed this exception, when running compiled code:
Here's the smallest repro:
import dataclasses
@dataclasses.dataclass(slots=True, frozen=True)
class User:
wrapper: 'type[list[int]]'
print(User, getattr(User, '__module__', None))With regular python it runs correctly:
» python ex.py
<class '__main__.User'> __main__
When compiled:
» mypyc ex.py && python -c 'import ex'
copying build/lib.macosx-15.6-arm64-cpython-313/ex.cpython-313-darwin.so ->
Traceback (most recent call last):
File "<string>", line 1, in <module>
import ex
File "ex.py", line 4, in <module>
class User:
File "/Users/sobolev/.pyenv/versions/3.13.7/lib/python3.13/dataclasses.py", line 1295, in wrap
return _process_class(cls, init, repr, eq, order, unsafe_hash,
frozen, match_args, kw_only, slots,
weakref_slot)
File "/Users/sobolev/.pyenv/versions/3.13.7/lib/python3.13/dataclasses.py", line 997, in _process_class
and _is_type(type, cls, dataclasses, dataclasses.KW_ONLY,
~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
_is_kw_only))):
^^^^^^^^^^^^
File "/Users/sobolev/.pyenv/versions/3.13.7/lib/python3.13/dataclasses.py", line 757, in _is_type
ns = sys.modules.get(cls.__module__).__dict__
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute '__dict__'. Did you mean: '__dir__'?I propose to fix this on dataclasses's side, because fix is quite trivial.