gh-135385: Do not reserve inline values for attributes stored in slots - #156656
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gh-135385: Do not reserve inline values for attributes stored in slots#156656serhiy-storchaka wants to merge 1 commit into
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…n slots __static_attributes__ contains every name assigned as self.X in the class body, and all of them were inserted into the shared keys of the class. An attribute stored in a slot is never stored in the instance dict, so the inline values reserved for it on every instance were never used.
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__static_attributes__contains every name assigned asself.Xin the class body, and_PyDict_NewKeysForClass()inserted all of them into the shared keys of the class. An attribute stored in a slot is never stored in the instance dict, so the inline values reserved for it on every instance were never used.For the example in the issue:
An
xml.dom.minidomelement node, where all 11 names in__static_attributes__are slots, goes from 328 to 232 bytes.The lookup is done once per attribute name at class creation, and I see no difference in benchmarks, including creating 100000 classes.
__slots__and__dict__have much larger size than needed (up to 4x) on Python 3.13 #135385