gh-108271, gh-108270: Argument Clinic: parameter aliases and deprecation - #155248
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serhiy-storchaka wants to merge 2 commits into
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gh-108271, gh-108270: Argument Clinic: parameter aliases and deprecation#155248serhiy-storchaka wants to merge 2 commits into
serhiy-storchaka wants to merge 2 commits into
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…and deprecation
A parameter can be given an alternative name by declaring a keyword-only
parameter with a default value which shares the C name of a preceding one:
a: object = None
*
b as a: object = None
Only one of the alternative names can be used in a call; passing both is
a TypeError. An alias is not shown in the signature.
The `[until X.Y]` prefix marks a parameter which will be removed in that
release. Passing it emits a DeprecationWarning, and the generated code
warns at compile time when that release is reached. A deprecated
parameter must have a default value, and only the last positional-only
parameters can be deprecated, because removing one would leave no way to
pass those which follow it.
serhiy-storchaka
requested review from
AA-Turner,
ericsnowcurrently and
erlend-aasland
as code owners
August 5, 2026 15:22
serhiy-storchaka
requested review from
gpshead
and removed request for
erlend-aasland
August 5, 2026 15:35
It re-emits the warnings which do not match, so the warning for the other parameter was raised as an error.
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A parameter can be given an alternative name by declaring a keyword-only parameter with a default value which shares the C name of a preceding one:
Only one of the alternative names can be used in a call; passing both is a
TypeError. An alias is not shown in the signature.The
[until X.Y]prefix marks a parameter which will be removed in that release. Passing it emits aDeprecationWarning, and the generated code warns at compile time when that release is reached. A deprecated parameter must have a default value, and only the last positional-only parameters can be deprecated, because removing one would leave no way to pass those which follow it.Combining the two deprecates an alias, which renames a parameter: