[bug, typing] MyPy doesn't like attrs.converters

[henryiii]

In MyPy, using attrs.converters gives:

error: Module has no attribute "converters"  [attr-defined]

Adding an import attrs.converters (not needed at runtime) gives:

error: Module has no attribute "optional"

I think part of the problem is the __init__.pyi isn't synced with __init__.py for importing submodules. Not sure why the star import isn't working inside converters.py, though.

[hynek]

Ugh, looks like our import tests in typing_examples are NOPs.

Each symbol has to be explicitly "re-exported". We've missed filters too.

#931 should fix it.

[henryiii]

Fantastic, thanks!

I think * imports don't need to be explicitly reexported inside .pyi files, but they do in .py files.

[hynek]

I mean then your bug wouldn't have happened? :) And yes, the fixed examples triggered the error too.

I'm somewhat OK with being explicit, but in this case it's very annoying. :-/

[danjac]

I'm seeing the same issue with mypy 0.961 and attrs 21.4.0:

import attrs

@attrs.define(kw_only=True)
class Item:
    length: int | None = attrs.field(
        converter=attrs.converters.optional(
            attrs.converters.pipe(float, int),
        ),
        default=None,
    )

Running in mypy, getting these (possibly related?) errors:

Unsupported converter, only named functions and types are currently supported

error: Module has no attribute "converters" [attr-defined]

[hynek]

Yes, sorry there hasn't been a release since this has been fixed yet.