function.__type_params__ and type.__type_params__ should be writable #104600
Assignees
Labels
3.12
new features, bugs and security fixes
topic-typing
type-feature
A feature request or enhancement
Comments
Small correction: as noted in #104616, it's not actually writeable on class objects either at the moment (and probably should be, for similar reasons): Running Debug|x64 interpreter...
Python 3.12.0a7+ (heads/main:cfa517d5a6, May 18 2023, 17:12:51) [MSC v.1932 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> class Foo[T]: ...
...
>>> Foo.__type_params__ = ("bar",)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: attribute '__type_params__' of 'type' objects is not writable
>>> class Bar: ...
...
>>> Bar.__type_params__ = ("bar",)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
AttributeError: attribute '__type_params__' of 'type' objects is not writable |
JelleZijlstra
changed the title
JelleZijlstra
added a commit
to JelleZijlstra/cpython
that referenced
this issue
May 18, 2023
JelleZijlstra
added a commit
that referenced
this issue
May 18, 2023
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
The PEP-695 implementation added a new attribute
__type_params__to functions. I made this field read-only, but I realized there is a use case for writing to it:functools.wraps, when wrapping a generic function, should add the.__type_params__to the wrapper. Making it writable is also more consistent with other fields on functions, as even the__name__of functions is writable.The PEP also adds a
__type_params__attribute to classes and type aliases. For classes it's already writable (it's just stored in the type's__dict__). For type aliases it's readonly, but as I don't see a use case for mutating a type alias's__type_params__, I'd like to keep it that way.Linked PRs
The text was updated successfully, but these errors were encountered: