[issue43176] Dataclasses derived from empty frozen bases skip immutability checks

[Ulrich Petri]

Ulrich Petri <python at ulo.pe> added the comment:

Wether the original behaviour was intentional or not this change introduces backwards incompatibility (and in our case, breakage) between 3.8.10 and previous releases (I expect the same to be true for the equivalent 3.9 releases).

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nosy: +ulope

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue43176>
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