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Merged
merged 7 commits into from
Mar 3, 2024
Merged

gh-72971: Clarify the special no-TypeError behavior for equality #110729

merged 7 commits into from
Mar 3, 2024

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Gouvernathor
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@Gouvernathor Gouvernathor commented Oct 11, 2023 •
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Re:
https://discuss.python.org/t/notimplemented-and-operator-overloading/34935/
https://stackoverflow.com/questions/40780004/returning-notimplemented-from-eq

Math operators raise TypeErrors when the methods return NotImplemented and it is documented.
Comparison operators do the same but it was not explicitly written (even though it was heavily implied and understood).
Equality operators do not do that, and instead revert to non-overrideable operators. That was not documented, and troubled quite a number of people apparently.

📚 Documentation preview 📚: https://cpython-previews--110729.org.readthedocs.build/

@bedevere-app bedevere-app bot added docs Documentation in the Doc dir skip news awaiting review labels Oct 11, 2023
@bedevere-app bedevere-app bot mentioned this pull request Apr 10, 2022
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skirpichev
skirpichev reviewed Dec 24, 2023
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skirpichev approved these changes Jan 2, 2024
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LGTM, except maybe for note about TypeError.

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Note for reviewers : see the Shorten again commit. I removed that line because Skirpichev asked for that, but I'm not sold and I think it would make the explanation more clear, if a bit redundant.

carljm
carljm approved these changes Mar 1, 2024
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This looks correct to me, and also necessary, in that it closes a gap in the specification where we should specify the behavior. (The alternative would be to say that the behavior of == when all relevant dunder methods return NotImplementedError is implementation-defined, and I don't think that is desirable.)

@erlend-aasland erlend-aasland added needs backport to 3.11 only security fixes needs backport to 3.12 only security fixes labels Mar 3, 2024
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@erlend-aasland erlend-aasland enabled auto-merge (squash) March 3, 2024 00:41
@erlend-aasland erlend-aasland merged commit 67f742e into python:main Mar 3, 2024
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Thanks @Gouvernathor for the PR, and @erlend-aasland for merging it 🌮🎉.. I'm working now to backport this PR to: 3.11, 3.12.
🐍🍒⛏🤖

miss-islington pushed a commit to miss-islington/cpython that referenced this pull request Mar 3, 2024
@Gouvernathor @miss-islington
pythongh-72971: Clarify the special no-TypeError behavior for equality (
99e3be5 
pythonGH-110729)

(cherry picked from commit 67f742e)

Co-authored-by: Gouvernathor <44340603+Gouvernathor@users.noreply.github.com>
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bedevere-app bot commented Mar 3, 2024

GH-116254 is a backport of this pull request to the 3.12 branch.

@bedevere-app bedevere-app bot removed the needs backport to 3.12 only security fixes label Mar 3, 2024
miss-islington pushed a commit to miss-islington/cpython that referenced this pull request Mar 3, 2024
@Gouvernathor @miss-islington
pythongh-72971: Clarify the special no-TypeError behavior for equality (
0b2941c 
pythonGH-110729)

(cherry picked from commit 67f742e)

Co-authored-by: Gouvernathor <44340603+Gouvernathor@users.noreply.github.com>
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bedevere-app bot commented Mar 3, 2024

GH-116255 is a backport of this pull request to the 3.11 branch.

@bedevere-app bedevere-app bot removed the needs backport to 3.11 only security fixes label Mar 3, 2024
erlend-aasland pushed a commit that referenced this pull request Mar 3, 2024
@miss-islington @Gouvernathor
[3.12] gh-72971: Clarify the special no-TypeError behavior for equali…
5b73ed4 
…ty (GH-110729) (#116254)

(cherry picked from commit 67f742e)

Co-authored-by: Gouvernathor <44340603+Gouvernathor@users.noreply.github.com>
erlend-aasland pushed a commit that referenced this pull request Mar 3, 2024
@miss-islington @Gouvernathor
[3.11] gh-72971: Clarify the special no-TypeError behavior for equali…
82e7692 
…ty (GH-110729) (#116255)

(cherry picked from commit 67f742e)

Co-authored-by: Gouvernathor <44340603+Gouvernathor@users.noreply.github.com>
woodruffw pushed a commit to woodruffw-forks/cpython that referenced this pull request Mar 4, 2024
@Gouvernathor @woodruffw
pythongh-72971: Clarify the special no-TypeError behavior for equality (
eb161c5 
python#110729)
adorilson pushed a commit to adorilson/cpython that referenced this pull request Mar 25, 2024
@Gouvernathor @adorilson
pythongh-72971: Clarify the special no-TypeError behavior for equality (
05e9c0e 
python#110729)
@Gouvernathor Gouvernathor deleted the patch-7 branch April 14, 2024 17:04
diegorusso pushed a commit to diegorusso/cpython that referenced this pull request Apr 17, 2024
@Gouvernathor @diegorusso
pythongh-72971: Clarify the special no-TypeError behavior for equality (
fe69849 
python#110729)
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@erlend-aasland erlend-aasland erlend-aasland left review comments

@carljm carljm carljm approved these changes

@skirpichev skirpichev skirpichev approved these changes

@JelleZijlstra JelleZijlstra Awaiting requested review from JelleZijlstra

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