PEP 649: Deferred evaluation of annotations, tentatively accepted

[methane (Inada Naoki)]

@steven.daprano

What does that mean for string annotations with from __future__ import annotations? PEP 649 suggests that it gets deprecated and eventually removed. But future declarations are supposed to remain forever, so presumably it will just become a no-op.

I think we shouldn’t emit DeprecationWarning for PEP 563, at least 3 releases.

Library authors can not use PEP 649 until they drop Python 3.11 support. PEP 563 is the only efficient and convenient way to use type annotations.

@steven.daprano

During the deprecation period, how do we resolve the conflict if somebody enables both PEP 649 annotation descriptors and PEP 563 stringified annotations?

I think it should be syntax error.
Using PEP 649 means that source code doesn’t support Python 3.11. Allowing PEP 563 with PEP 649 doesn’t increase backward compatibility. Authors should chose one.