python / python/mypy

AssertionError: trying to find dataclass transform spec

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#16,062 1 comentario 2 reacciones 0 asignados Ver en GitHub

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crash topic-dataclasses
Lenguaje dominante
Python
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Descripción

Bug Report
mypy crashes on the example below instead of showing an error or not showing anything.

Encountered today while refactoring a pretty big codebase. Made an accidental mistake, hence the @dataclass(frozen=True)(kw_only=True), but the way Mypy fails won't allow me to find the culprit. I couldn't find a way to debug what was causing an error (--pdb option didn't work for me).

To Reproduce

from dataclasses import dataclass


@dataclass(frozen=True)(kw_only=True)
class Foo:
    bar: str

Gist URL: https://gist.github.com/mypy-play/5b29c7aec29cbab55262d61d8c440ef3
Playground URL: https://mypy-play.net/?mypy=latest&python=3.11&gist=5b29c7aec29cbab55262d61d8c440ef3

Expected Behavior
Correctly identified error in the code, or at least no crash

Actual Behavior

mypy mypy_bug.py 
Traceback (most recent call last):
  File "/Users/misha/Dev/python-playground/.venv/bin/mypy", line 8, in <module>
    sys.exit(console_entry())
             ^^^^^^^^^^^^^^^
  File "/Users/misha/Dev/python-playground/.venv/lib/python3.11/site-packages/mypy/__main__.py", line 15, in console_entry
    main()
  File "mypy/main.py", line 94, in main
  File "mypy/main.py", line 173, in run_build
  File "mypy/build.py", line 195, in build
  File "mypy/build.py", line 268, in _build
  File "mypy/build.py", line 2927, in dispatch
  File "mypy/build.py", line 3325, in process_graph
  File "mypy/build.py", line 3420, in process_stale_scc
  File "mypy/semanal_main.py", line 99, in semantic_analysis_for_scc
  File "mypy/semanal_main.py", line 439, in apply_class_plugin_hooks
  File "mypy/semanal_main.py", line 475, in apply_hooks_to_class
  File "mypy/plugins/dataclasses.py", line 930, in dataclass_class_maker_callback
    # contains additional info beyond (and possibly including) the
  File "mypy/plugins/dataclasses.py", line 948, in _get_transform_spec
    _is_kw_only))):
AssertionError: trying to find dataclass transform spec, but reason is neither dataclasses.dataclass nor decorated with typing.dataclass_transform

Your Environment

  • Mypy version used: 1.5.1 (also tried most recent from git, same)
  • Mypy command-line flags: None
  • Mypy configuration options from mypy.ini (and other config files): None
  • Python version used: 3.11.5

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Línea de trabajo

Reproduce el fallo con el ejemplo de dataclass y empieza en mypy/plugins/dataclasses.py, especialmente en dataclass_class_maker_callback y _get_transform_spec del traceback. Comprueba cómo se gestiona el @dataclass(frozen=True)(kw_only=True) malformado; la tarea está terminada cuando mypy informa de un error o finaliza sin un AssertionError.

Escrito por el modelo de indexación a partir del texto del issue.

Evaluación

Stack tecnológico
python
Área
devtools
Tipo de issue
Error
Dificultad
3/5
Tiempo estimado
1-2 días
Estado de actividad
Estancado
Claridad
Bien especificado
Aptitud para principiantes
48/100

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