1.12 regression related to TypedDictType

[torarvid]

Crash Report

Ran mypy as normal: uv run mypy --show-error-codes --show-column-numbers, and got an INTERNAL_ERROR. Never seen it before, so was surprised.

Traceback

❯ uv run mypy --show-error-codes --show-column-numbers --show-traceback
src/hamon/users/managers.py:15: 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: 1.12.0
Traceback (most recent call last):
  File "mypy/checkexpr.py", line 5847, in accept
  File "mypy/nodes.py", line 1969, in accept
  File "mypy/checkexpr.py", line 480, in visit_call_expr
  File "mypy/checkexpr.py", line 614, in visit_call_expr_inner
  File "mypy/checkexpr.py", line 1471, in check_call_expr_with_callee_type
  File "mypy/checkexpr.py", line 1565, in check_call
  File "mypy/checkexpr.py", line 1811, in check_callable_call
  File "mypy/checkexpr.py", line 1262, in apply_function_plugin
  File "/Users/torarvid/oda/hardware-monitoring/.venv/lib/python3.12/site-packages/mypy_django_plugin/transformers/querysets.py", line 278, in extract_proper_type_queryset_annotate
    fields_dict = helpers.make_typeddict(api, fields=field_types, required_keys=set(field_types.keys()))
                  ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/torarvid/oda/hardware-monitoring/.venv/lib/python3.12/site-packages/mypy_django_plugin/lib/helpers.py", line 405, in make_typeddict
    typed_dict_type = TypedDictType(fields, required_keys=required_keys, fallback=fallback_type)
                      ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: __init__() missing required argument 'readonly_keys' (pos 3)

To Reproduce

Sorry, this is in a company repo, so I don't think I'm allowed to just paste in the code. Hope the traceback is enough to help you find it.

Your Environment

• Mypy version used: 1.12
• Mypy command-line flags: uv run mypy --show-error-codes --show-column-numbers --show-traceback
• Mypy configuration options from mypy.ini (and other config files):

[tool.mypy]
python_version = "3.12"
plugins = [
    "mypy_django_plugin.main",
    "pydantic.mypy",
    "strawberry.ext.mypy_plugin",
]
files = ["./src/cli", "./src/hamon", "./src/shared"]
ignore_missing_imports = true
follow_imports = "normal"
strict = true

# Disable typing in migration files generated by Django
[[tool.mypy.overrides]]
module = "hamon.*.migrations.*"
ignore_errors = true

• Python version used: 3.12.6
• Operating system and version: macOS 15.0.1

[brianschubert]

The exception is coming from mypy_django_plugin, so this is likely an issue with that plugin and not mypy itself.

Looks like this issue was already reported on their tracker: typeddjango/django-stubs#2405

edit: taking a closer look, this looks related to a change in the representation of TypedDictType in #17644. That might qualify as a change in the “implicit plugin API”, so this should perhaps be documented in #6617

[JukkaL]

Documented the change to the implicit plugin API: #6617 (comment)