mypy base class compatibility

[jeremander]

There's some quirk in the definition of TextSerializable which causes mypy to error when inheriting from it along with some other base class.

Minimal example:

from fancy_dataclass.serialize import TextFileSerializable

class Mixin:
    pass

class A(TextFileSerializable):
    pass

class B(Mixin, TextFileSerializable):
    pass

Running mypy (version 1.14.1), I get:

error: Definition of "_from_bytes" in base class "TextSerializable" is incompatible with definition in base class "BinaryFileSerializable"  [misc]
error: Definition of "_to_bytes" in base class "TextSerializable" is incompatible with definition in base class "BinaryFileSerializable"  [misc]

The error only occurs on B, not A. My guess is that the type: ignore statement on TextFileSerializable (suppressing the error about incompatible method definitions) carries over to simple inheritance but not multiple inheritance.

Not sure if this is a bug in mypy or not, but ideally the method signatures could be fixed to be compatible.

[jeremander]

See also: python/mypy#18458

[jeremander]

Fixed as of 6f67d1a.