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Crash when temporary base class is resolved from mypy cache #218

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@aberres

Description

@aberres

Describe the bug
Given the code below I regularly run into a mypy crash when the cache is warm.

Expected behavior
No crash

To Reproduce
I am having a hard time to isolate the crash. It seems to be a combination of different (namespace?) packages and a change of the cache is needed. I tried to come up with a minimal example but failed.

Maybe it does ring a bell nevertheless... As the class is created in a function there is no module which can be looked up.

We ran into the issue when introducing a new test which creates a base class within the test function. Whenever we switched branches mypy crashed. The workaound is to move the instantiation out into the model.

from __future__ import annotations

from sqlalchemy import Column, Integer, String
from sqlalchemy.ext.declarative import declarative_base


def test_soft():
    Base = declarative_base()

    class User(Base):
        __tablename__ = "user"

        id = Column(Integer, primary_key=True)
        name = Column(String)

Error

Traceback (most recent call last):
  File "/Users/armin/venv/weplan3.10/bin/mypy", line 8, in <module>
    sys.exit(console_entry())
  File "/Users/armin/venv/weplan3.10/lib/python3.10/site-packages/mypy/__main__.py", line 12, in console_entry
    main(None, sys.stdout, sys.stderr)
  File "mypy/main.py", line 96, in main
  File "mypy/main.py", line 173, in run_build
  File "mypy/build.py", line 154, in build
  File "mypy/build.py", line 230, in _build
  File "mypy/build.py", line 2729, in dispatch
  File "mypy/build.py", line 3080, in process_graph
  File "mypy/build.py", line 3158, in process_fresh_modules
  File "mypy/build.py", line 1991, in fix_cross_refs
  File "mypy/fixup.py", line 26, in fixup_module
  File "mypy/fixup.py", line 91, in visit_symbol_table
  File "mypy/fixup.py", line 49, in visit_type_info
  File "mypy/types.py", line 1174, in accept
  File "mypy/fixup.py", line 156, in visit_instance
  File "mypy/fixup.py", line 282, in lookup_fully_qualified_typeinfo
  File "mypy/lookup.py", line 29, in lookup_fully_qualified
AssertionError: Cannot find module for Base

Versions.

  • Python: 3.10
  • SQLAlchemy: 1.4.39
  • mypy: 0.961
  • SQLAlchemy2-stubs: 0.0.2a24

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    bugSomething isn't workingmypy pluginsomething that has to do with the sqlalchemy mypy plugin

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