Closed as duplicate of#18527
Closed as duplicate of#18527
Description
Crash Report
When being told to typecheck a module that contains a class which is both derived from NamedTuple and decorated with @dataclass (probably by mistake, but no matter), Mypy installed in a Python 3.13+ environment will crash.
It seems to work fine for Python < 3.13.
Traceback
Traceback (most recent call last):
File ".../bin/mypy", line 12, in <module>
sys.exit(console_entry())
~~~~~~~~~~~~~^^
File ".../mypy/__main__.py", line 15, in console_entry
main()
~~~~^^
File "mypy/main.py", line 119, in main
File "mypy/main.py", line 203, in run_build
File "mypy/build.py", line 191, in build
File "mypy/build.py", line 267, in _build
File "mypy/build.py", line 2937, in dispatch
File "mypy/build.py", line 3335, in process_graph
File "mypy/build.py", line 3430, in process_stale_scc
File "mypy/semanal_main.py", line 99, in semantic_analysis_for_scc
File "mypy/semanal_main.py", line 443, in apply_class_plugin_hooks
File "mypy/semanal_main.py", line 479, in apply_hooks_to_class
File "mypy/plugins/dataclasses.py", line 969, in dataclass_class_maker_callback
File "mypy/plugins/dataclasses.py", line 392, in transform
File "mypy/plugins/dataclasses.py", line 412, in _add_dunder_replace
File "mypy/plugins/common.py", line 238, in add_method_to_class
File "mypy/plugins/common.py", line 314, in _prepare_class_namespace
ValueError: list.remove(x): x not in listTo Reproduce
Create a file named bug.py with these contents:
from typing import NamedTuple
from dataclasses import dataclass
@dataclass
class A(NamedTuple):
a: int
b: strRun Mypy installed in a Python 3.13 environment on this file, e.g. using uvx:
uvx --python 3.13 --reinstall mypy --show-traceback bug.pyReplacing 3.13 with 3.12 or earlier, you can check that it worked fine for earlier Python versions.
Your Environment
- Mypy version used: 1.15.0 (compiled: yes)
- Mypy command-line flags: None needed
- Mypy configuration options from
mypy.ini(and other config files): None needed - Python version used: 3.13+ required to reproduce this
- Operating system and version: Debian Linux 12 (bookworm), but also happened on another machine running some version of Ubuntu