Optimise inspect.getattr_static · Issue #103193 · python/cpython (original) (raw)

Feature or enhancement

Following 6d59c9e, typing._ProtocolMeta.__instancecheck__ uses inspect.getattr_static in a tight loop, where it had previously used hasattr. This improves semantics in several highly desirable ways, but causes a considerable slowdown for _ProtocolMeta.__instancecheck__, as inspect.getattr_static is much slower than hasattr.

The performance hit to _ProtocolMeta.__instancecheck__ has already been mostly mitigated through several typing-specific optimisations that are tracked in this issue:

• Performance of typing._ProtocolMeta._get_protocol_attrs and isinstance #74690

However, it would be good to also see if we can improve the performance of inspect.getattr_static. This will not only improve the performance of isinstance() checks against classes subclassing typing.Protocol. It will also improve the performance of all other tools that use inspect.getattr_static for introspection without side effects.

Linked PRs

• gh-103193: Micro-optimise helper functions for inspect.getattr_static #103195
• gh-103193: Use LBYL idioms rather than EAFP in inspect.getattr_static #103318
• gh-103193: Speedup and inline inspect._is_type #103321
• gh-103193: Celebrate performance improvements to inspect.getattr_static in 'What's New in Python 3.12' #103349
• gh-103193: cache calls to inspect._shadowed_dict in inspect.getattr_static #104267
• gh-103193: Improve getattr_static test coverage #104286
• [3.11] gh-103193: Improve getattr_static test coverage (GH-104286) #104290
• gh-103193: Fix refleaks in test_inspect and test_typing #104320