[issue44905] Abstract instance and class attributes for abstract base classes

[Tomasz Rzepecki]

New submission from Tomasz Rzepecki <rzepecki.t at gmail.com>:

There seems to be no way to transparently make an abstract base class enforce instance attributes for subclasses (without creating a custom metaclass, see e.g. https://newbedev.com/python-abstract-class-shall-force-derived-classes-to-initialize-variable-in-init).

The analogous problem for enforcing *class* attributes in subclasses can be solved by creating an abstract class property (which can then be overridden by a class attribute), but this feels like a hack and possibly a bug (see https://bugs.python.org/issue44904 for a related bug).

The corresponding "solution" for instance attributes does not work (see attached file), and probably rightly so.

This seems like an oversight to me.

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files: example.py
messages: 399486
nosy: rzepecki.t
priority: normal
severity: normal
status: open
title: Abstract instance and class attributes for abstract base classes
type: enhancement
versions: Python 3.9
Added file: https://bugs.python.org/file50213/example.py

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<https://bugs.python.org/issue44905>
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