Wrong error message when failing to pass self-parameter to __post_init__

[bwagner]

Bug report

Bug description:

from dataclasses import dataclass

@dataclass
class PostInit:
    def __post_init__():
        pass

PostInit()

will yield this error message:

TypeError: PostInit.__post_init__() takes 0 positional arguments but 1 was given

where it should read:

TypeError: PostInit.__post_init__() takes 1 positional argument but 0 were given

CPython versions tested on:

3.14, 3.12, 3.13

Operating systems tested on:

macOS

[sharktide]

Would you like me to make a pull request?

[JelleZijlstra]

The existing error seems correct to me. The function is defined as taking zero arguments but is passed one (self).

[sharktide]

Got it

[picnixz]

The existing error seems correct to me. The function is defined as taking zero arguments but is passed one (self).

Ah right. I haven't actually checked the report (I forgot about it). So I'm closing it as a not an issue. (Should have triaged a bit more, so thanks Jelle).