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Adjust deprecation warning re: testing truth value of xml.etree.ElementTree.Element #119577

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jacobtylerwalls opened this issue May 26, 2024 · 7 comments
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Adjust deprecation warning re: testing truth value of xml.etree.ElementTree.Element #119577

jacobtylerwalls opened this issue May 26, 2024 · 7 comments
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3.14 bugs and security fixes topic-XML type-feature A feature request or enhancement

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@jacobtylerwalls
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jacobtylerwalls commented May 26, 2024 •
edited by bedevere-app bot
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Testing the truth value of an ElementTree.Element was deprecated in python 3.12 and scheduled for removal in 3.14. I have a patch ready.

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jacobtylerwalls added a commit to jacobtylerwalls/cpython that referenced this issue May 26, 2024
@jacobtylerwalls
pythongh-119577: Raise RuntimeError when testing element truth values…
f001275 
… in ElementTree
jacobtylerwalls added a commit to jacobtylerwalls/cpython that referenced this issue May 26, 2024
@jacobtylerwalls
pythongh-119577: Raise RuntimeError when testing element truth values…
052fe35 
… in ElementTree
@bedevere-app bedevere-app bot mentioned this issue May 26, 2024
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@AlexWaygood AlexWaygood added type-feature A feature request or enhancement 3.14 bugs and security fixes labels May 26, 2024
@serhiy-storchaka
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AFAIK, the plan was to return True instead of raising an exception.

@jacobtylerwalls
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In favor of raising an error: #83122 (comment)
In favor of DeprecationWarning being the choice for an exception vs. FutureWarning being the choice to for a behavior change: #83122 (comment)

cc/ @gpshead who reviewed #31149, which changed FutureWarning to DeprecationWarning and documented that an exception would be raised.

@serhiy-storchaka
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Raising an exception in __bool__() is extremely uncommon behavior. For now, there is only one special case -- NotImplemented, and it is a very special case. On other hand, there is a precedence of datetime.time -- the midnight had the false boolean value, and now it has lost its special meaning and has the same boolean value like all other datetime.time values.

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gpshead commented May 28, 2024 •
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We did document that it would raise an exception in the future. But I agree that that is unusual.

Lets be conservative and delay the __bool__ behavior change on Element for a few more releases until the 3.16 timeframe to let the DeprecationWarning be more widely seen and acted upon in existing code. In 3.16+ we can (edit updated:) make its __bool__ method return true. Thus making all instances truthy as most class instances are.

What that means is that we need a PR to update the docs and the DeprecationWarning error message to reflect the new plan.

bool raising an exception does have valid uses: Such as when a class that is commonly mistaken for an actual boolean value in some API designs is easily misused in the wrong context. Element doesn't seem like one of those.

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We cannot just remove __bool__. Element has __len__, and this is the reason why childless elements had the false boolean value, why this deprecation started. It should be a method that always returns True. Yes, inconsistency between __len__ and __bool__ is also unusual, but this considered lesser evil than having the false boolean value for otherwise normal elements.

@jacobtylerwalls jacobtylerwalls changed the title Make testing truth value of xml.etree.ElementTree.Element raise an exception Adjust deprecation warning re: testing truth value of xml.etree.ElementTree.Element May 30, 2024
jacobtylerwalls added a commit to jacobtylerwalls/cpython that referenced this issue May 30, 2024
@jacobtylerwalls
pythongh-119577: Adjust DeprecationWarning when testing element truth…
d31fd61 
… values in ElementTree
jacobtylerwalls added a commit to jacobtylerwalls/cpython that referenced this issue May 30, 2024
@jacobtylerwalls
pythongh-119577: Adjust DeprecationWarning when testing element truth…
e7da111 
… values in ElementTree
@bedevere-app bedevere-app bot mentioned this issue May 30, 2024
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@jacobtylerwalls
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What that means is that we need a PR to update the docs and the DeprecationWarning error message to reflect the new plan.

New PR: #119762

gpshead pushed a commit that referenced this issue Jun 7, 2024
@jacobtylerwalls
gh-119577: Adjust DeprecationWarning when testing element truth value…
6b60652 
…s in ElementTree (GH-119762)

Adjust DeprecationWarning when testing element truth values in ElementTree, we're planning to go with the more natural True return rather than a disruptive harder to code around exception raise, and are deferring the behavior change for a few more releases.
miss-islington pushed a commit to miss-islington/cpython that referenced this issue Jun 7, 2024
@jacobtylerwalls @miss-islington
pythongh-119577: Adjust DeprecationWarning when testing element truth…
19243a6 
… values in ElementTree (pythonGH-119762)

Adjust DeprecationWarning when testing element truth values in ElementTree, we're planning to go with the more natural True return rather than a disruptive harder to code around exception raise, and are deferring the behavior change for a few more releases.
(cherry picked from commit 6b60652)

Co-authored-by: Jacob Walls <[email protected]>
@bedevere-app bedevere-app bot mentioned this issue Jun 7, 2024
Merged
gpshead pushed a commit to gpshead/cpython that referenced this issue Jun 7, 2024
@jacobtylerwalls @gpshead
pythongh-119577: Adjust DeprecationWarning when testing element truth…
59f3369 
… values in ElementTree (pythonGH-119762)

Adjust DeprecationWarning when testing element truth values in
ElementTree, we're planning to go with the more natural True return
rather than a disruptive harder to code around exception raise, and are
deferring the behavior change for a few more releases.
@bedevere-app bedevere-app bot mentioned this issue Jun 7, 2024
Merged
gpshead pushed a commit that referenced this issue Jun 7, 2024
@miss-islington @jacobtylerwalls
[3.13] gh-119577: Adjust DeprecationWarning when testing element trut…
56a7e04 
…h values in ElementTree (GH-119762) (GH-120189)

gh-119577: Adjust DeprecationWarning when testing element truth values in ElementTree (GH-119762)

Adjust DeprecationWarning when testing element truth values in ElementTree, we're planning to go with the more natural True return rather than a disruptive harder to code around exception raise, and are deferring the behavior change for a few more releases.
(cherry picked from commit 6b60652)

Co-authored-by: Jacob Walls <[email protected]>
pygeek pushed a commit to pygeek/cpython that referenced this issue Jun 7, 2024
@jacobtylerwalls @pygeek
pythongh-119577: Adjust DeprecationWarning when testing element truth…
093ecc9 
… values in ElementTree (pythonGH-119762)

Adjust DeprecationWarning when testing element truth values in ElementTree, we're planning to go with the more natural True return rather than a disruptive harder to code around exception raise, and are deferring the behavior change for a few more releases.
noahbkim pushed a commit to hudson-trading/cpython that referenced this issue Jul 11, 2024
@jacobtylerwalls @noahbkim
pythongh-119577: Adjust DeprecationWarning when testing element truth…
ed1d058 
… values in ElementTree (pythonGH-119762)

Adjust DeprecationWarning when testing element truth values in ElementTree, we're planning to go with the more natural True return rather than a disruptive harder to code around exception raise, and are deferring the behavior change for a few more releases.
estyxx pushed a commit to estyxx/cpython that referenced this issue Jul 17, 2024
@jacobtylerwalls @estyxx
pythongh-119577: Adjust DeprecationWarning when testing element truth…
224eb4c 
… values in ElementTree (pythonGH-119762)

Adjust DeprecationWarning when testing element truth values in ElementTree, we're planning to go with the more natural True return rather than a disruptive harder to code around exception raise, and are deferring the behavior change for a few more releases.
Yhg1s pushed a commit that referenced this issue Aug 6, 2024
@gpshead @jacobtylerwalls
[3.12] gh-119577: Adjust DeprecationWarning when testing element trut…
b317641 
…h values in Element tree (GH-119762) (#120190)

gh-119577: Adjust DeprecationWarning when testing element truth values in ElementTree (GH-119762)

Adjust DeprecationWarning when testing element truth values in
ElementTree, we're planning to go with the more natural True return
rather than a disruptive harder to code around exception raise, and are
deferring the behavior change for a few more releases.

Co-authored-by: Jacob Walls <[email protected]>
@hugovk
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hugovk commented Aug 8, 2024

Triage: closing because the PR has been merged, please re-open if still needed. Thanks!

@hugovk hugovk closed this as completed Aug 8, 2024
millerdev added a commit to dimagi/commcare-hq that referenced this issue Apr 8, 2025
@millerdev
Testing an element's truth value is deprecated
bf62d8c 
DeprecationWarning: Testing an element's truth value will always return
True in future versions. Use specific 'len(elem)' or 'elem is not None'
test instead.

python/cpython#119577
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