Should a method name shadow outer names when quoted or with PEP563?
Nessuno ha ancora preso questa issue.
- Lingua principale
- Python
- Stelle
- 20.6k
- Fork
- 3.3k
- Metriche di merge delle PR
- Metriche PR in attesa
Descrizione
Bug Report
If a class defines a method with a name shadowing outer name, mypy always rejects it in annotations.
To Reproduce
Consider the following snippet (playground):
#from __future__ import annotations
from typing import get_type_hints, get_origin
class Foo:
def list(self) -> None: ...
def method(self) -> list[str]: # E: Function "__main__.Foo.list" is not valid as a type [valid-type]
return [""]
Foo().method().append("") # E: "list?[builtins.str]" has no attribute "append" [attr-defined]
if get_origin(get_type_hints(Foo.method)['return']) is list:
print("Resolved to builtins.list")
else:
print("Resolved as something else")
When run against it, mypy is producing a correct valid-type error, matching runtime behaviour.
$ mypy a.py
a.py:8: error: Function "a.Foo.list" is not valid as a type [valid-type]
a.py:8: note: Perhaps you need "Callable[...]" or a callback protocol?
a.py:11: error: "list?[builtins.str]" has no attribute "append" [attr-defined]
Found 2 errors in 1 file (checked 1 source file)
$ pyright a.py
/tmp/tmp.StzhaQlnmA/a.py
/tmp/tmp.StzhaQlnmA/a.py:8:25 - error: Expected class but received "(self: Self@Foo) -> None" (reportGeneralTypeIssues)
1 error, 0 warnings, 0 informations
$ python a.py
Traceback (most recent call last):
File "/tmp/tmp.StzhaQlnmA/a.py", line 5, in <module>
class Foo:
...<3 lines>...
return [""]
File "/tmp/tmp.StzhaQlnmA/a.py", line 8, in Foo
def method(self) -> list[str]: # E: Function "__main__.Foo.list" is not valid as a type [valid-type]
~~~~^^^^^
TypeError: 'function' object is not subscriptable
Now let's uncomment the future import or quote list[int] (both behave equivalently).
from __future__ import annotations
from typing import get_type_hints, get_origin
class Foo:
def list(self) -> None: ...
def method(self) -> list[str]: # E: Function "__main__.Foo.list" is not valid as a type [valid-type]
return [""]
Foo().method().append("") # E: "list?[builtins.str]" has no attribute "append" [attr-defined]
if get_origin(get_type_hints(Foo.method)['return']) is list:
print("Resolved to builtins.list")
else:
print("Resolved as something else")
$ mypy a.py
a.py:8: error: Function "a.Foo.list" is not valid as a type [valid-type]
a.py:8: note: Perhaps you need "Callable[...]" or a callback protocol?
a.py:11: error: "list?[builtins.str]" has no attribute "append" [attr-defined]
Found 2 errors in 1 file (checked 1 source file)
$ pyright a.py
0 errors, 0 warnings, 0 informations
$ python a.py
Resolved to builtins.list
Runtime resolution also (unsurprisingly, probably) works as intended, so mypy does not model runtime semantics correctly?
Expected Behavior
Snippet with PEP563 enabled should pass mypy check
Actual Behavior
a.py:8: error: Function "a.Foo.list" is not valid as a type [valid-type]
a.py:8: note: Perhaps you need "Callable[...]" or a callback protocol?
a.py:11: error: "list?[builtins.str]" has no attribute "append" [attr-defined]
Found 2 errors in 1 file (checked 1 source file)
Your Environment
- Mypy version used: 1.14.1 and latest master
- Mypy command-line flags: N/A
- Mypy configuration options from
mypy.ini(and other config files): N/A - Python version used: 3.13
Guida per i contributori
Apri la guida per i contributori
Come iniziare
- Leggi tutta la issue e poi la guida ai contributi del progetto.
- Commenta sulla issue per dire che te ne occupi tu — evita che due persone facciano lo stesso lavoro.
- Fai un fork del repository e lavora su un branch.
- Apri una pull request che faccia riferimento al numero della issue.
Direzione di ricerca
Inizia eseguendo mypy sul riproduttore fornito con e senza annotazioni tra virgolette o con PEP 563 abilitato, confrontando il risultato con la risoluzione a runtime e pyright. Traccia il percorso di risoluzione dei nomi delle annotazioni per i nomi dei metodi che fanno shadowing di nomi esterni, quindi aggiungi la copertura per i casi mostrati e verifica che i controlli previsti vadano a buon fine.
Scritto dal modello di indicizzazione a partire dal testo della issue.
Valutazione
- Stack tecnologico
- python
- Ambito
- compilers
- Tipo di issue
- Bug
- Difficoltà
- 4/5
- Tempo stimato
- 3-5 giorni
- Stato di attività
- Ferma
- Chiarezza
- Abbastanza chiara
- Idoneità per principianti
- 42/100