gh-102936: typing: document performance pitfalls of protocols decorated with @runtime_checkable
#102937
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…untime_checkable`
AlexWaygood
requested review from
gvanrossum,
Fidget-Spinner and
JelleZijlstra
as code owners
AlexWaygood
added
needs backport to 3.10
| @@ -1584,16 +1584,31 @@ These are not used in annotations. They are building blocks for creating generic | |||
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| assert isinstance(open('/some/file'), Closable) | |||
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| @runtime_checkable | |||
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I think many users aren't too familiar with OSError's constructor / we can't use kwargs and it's unclear what the second argument is. Maybe we could use int and HasNumerator instead?
(I know it's not writeable, but OSError's errno also is maybe not writeable? Writing to errno doesn't affect repr)
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Yeah, I was really struggling to think of a good example for this! I'll ponder some more and see if I can come up with something better...
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Perhaps unsurprisingly, not too many good cases of writeable attributes in stdlib. Maybe Thread.name? It's explicitly documented as something you can write to.
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That works! I'll make the change tomorrow (it's late here)
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Thanks @AlexWaygood for the PR 🌮🎉.. I'm working now to backport this PR to: 3.10, 3.11. |
…ecorated with `@runtime_checkable` (pythonGH-102937) (cherry picked from commit 58d2b30) Co-authored-by: Alex Waygood <[email protected]>
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GH-102963 is a backport of this pull request to the 3.11 branch. |
…ecorated with `@runtime_checkable` (pythonGH-102937) (cherry picked from commit 58d2b30) Co-authored-by: Alex Waygood <[email protected]>
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GH-102964 is a backport of this pull request to the 3.10 branch. |
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Thanks all for the reviews! |
…ed with `@runtime_checkable` (GH-102937) (cherry picked from commit 58d2b30) Co-authored-by: Alex Waygood <[email protected]>
…ed with `@runtime_checkable` (GH-102937) (cherry picked from commit 58d2b30) Co-authored-by: Alex Waygood <[email protected]>
…ecorated with `@runtime_checkable` (python#102937)
…ecorated with `@runtime_checkable` (python#102937)
@runtime_checkable#102936