Mypy crashes when importing types_aiobotocore_s3

[Apakottur]

Crash report

Mypy 1.7.0 crashes when importing the most recent version of types_aiobotocore_s3 (2.7.0).

To reproduce:

I have the following file:

# test.py
import types_aiobotocore_s3

I'm getting a Mypy crash when running the following command:

mypy --show-traceback --disallow-any-unimported test.py

Getting same crash on mypy master branch.

Traceback

/opt/virtualenvs/cmd-N7MVwD3X-py3.11/lib/python3.11/site-packages/types_aiobotocore_s3/type_defs.pyi:565: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
Please report a bug at https://github.com/python/mypy/issues
version: 1.7.0
Traceback (most recent call last):
  File "mypy/semanal.py", line 6525, in accept
  File "mypy/nodes.py", line 1308, in accept
  File "mypy/semanal.py", line 2855, in visit_assignment_stmt
  File "mypy/semanal.py", line 3152, in analyze_typeddict_assign
  File "mypy/semanal_typeddict.py", line 359, in check_typeddict
  File "mypy/semanal_typeddict.py", line 460, in parse_typeddict_args
  File "mypy/messages.py", line 1745, in unimported_type_becomes_any
  File "mypy/messages.py", line 2714, in format_type
  File "mypy/messages.py", line 2731, in format_type_bare
  File "mypy/messages.py", line 2486, in format_type_inner
  File "mypy/types.py", line 3074, in get_proper_type
TypeError: mypy.types.ProperType object expected; got mypy.types.RequiredType
/opt/virtualenvs/cmd-N7MVwD3X-py3.11/lib/python3.11/site-packages/types_aiobotocore_s3/type_defs.pyi:565: : note: use --pdb to drop into pdb

Your Environment

• Mypy version used: 1.7.0
• Mypy command-line flags: --show-traceback --disallow-any-unimported
• Mypy configuration options from mypy.ini (and other config files): None
• Python version used: 3.11.6
• Operating system and version: Docker image python:3.11.6-slim-bullseye

[AlexWaygood]

Hmm, I can't reproduce locally on py311 or py312

[miikka]

I'm running into same issue with Python 3.11.6 and mypy 1.4.1 in a real project, but I was able to reproduce the issue using the instructions above with Python 3.12.0 and mypy 1.7.0. Note that --disallow-any-unimported must be enabled; it works if it's disabled.

[JelleZijlstra]

Reproduces for me in a clean venv.

I reduced it to a single file:

from typing import NotRequired, TypedDict
from thismoduledoesntexist import TransferConfig

B = TypedDict(
    "B",
    {
        "Config": NotRequired[TransferConfig],
    },
)

% mypy --show-traceback --disallow-any-unimported /tmp/type_defs.pyi
/tmp/type_defs.pyi:2: error: Cannot find implementation or library stub for module named "thismoduledoesntexist"  [import-not-found]
/tmp/type_defs.pyi:2: note: See https://mypy.readthedocs.io/en/stable/running_mypy.html#missing-imports
/tmp/type_defs.pyi:4: error: INTERNAL ERROR -- Please try using mypy master on GitHub:
https://mypy.readthedocs.io/en/stable/common_issues.html#using-a-development-mypy-build
Please report a bug at https://github.com/python/mypy/issues
version: 1.7.0
Traceback (most recent call last):
  File "mypy/semanal.py", line 6525, in accept
  File "mypy/nodes.py", line 1308, in accept
  File "mypy/semanal.py", line 2855, in visit_assignment_stmt
  File "mypy/semanal.py", line 3152, in analyze_typeddict_assign
  File "mypy/semanal_typeddict.py", line 359, in check_typeddict
  File "mypy/semanal_typeddict.py", line 460, in parse_typeddict_args
  File "mypy/messages.py", line 1745, in unimported_type_becomes_any
  File "mypy/messages.py", line 2714, in format_type
  File "mypy/messages.py", line 2731, in format_type_bare
  File "mypy/messages.py", line 2486, in format_type_inner
  File "mypy/types.py", line 3074, in get_proper_type
TypeError: mypy.types.ProperType object expected; got mypy.types.RequiredType
/tmp/type_defs.pyi:4: : note: use --pdb to drop into pdb

The problem seems to be a NotRequired containing an unimported type inside an old-stype TypedDict (class-style TypedDicts are fine).

[JelleZijlstra]

Also reproduces as far back as mypy 1.4.1 (as @miikka wrote). I haven't tried to see how far back it reproduces, but it's not a recent regression.

[AlexWaygood]

Oh, I can reproduce with compiled mypy, but not uncompiled mypy (I was using uncompiled mypy). Because it's one of those runtime checks inserted by mypyc that's failing. Fun.

[AlexWaygood]

FWIW, here's how to get it to repro with uncompiled mypy: apply this diff to master:

diff --git a/mypy/types.py b/mypy/types.py
index e7738bd7d..3eabce15d 100644
--- a/mypy/types.py
+++ b/mypy/types.py
@@ -3076,8 +3076,9 @@ def get_proper_type(typ: Type | None) -> ProperType | None:
         typ = typ.type_guard
     while isinstance(typ, TypeAliasType):
         typ = typ._expand_once()
+    assert isinstance(typ, ProperType), type(typ)
     # TODO: store the name of original type alias on this type, so we can show it in errors.
-    return cast(ProperType, typ)
+    return typ