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Description
With code such as:
import enum
class Flag(enum.Flag):
A = 0x01
B = 0x02
Mask = 0xff
print(~Flag.A)Python 3.10.11 prints Flag.B, and so does Python 3.11.3. However, with Python 3.11.4, this happens instead:
Traceback (most recent call last):
File "/home/florian/tmp/f.py", line 9, in <module>
print(~Flag.A)
^^^^^^^
File "/usr/lib/python3.11/enum.py", line 1542, in __invert__
self._inverted_ = self.__class__(self._flag_mask_ ^ self._value_)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.11/enum.py", line 711, in __call__
return cls.__new__(cls, value)
^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.11/enum.py", line 1136, in __new__
raise exc
File "/usr/lib/python3.11/enum.py", line 1113, in __new__
result = cls._missing_(value)
^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.11/enum.py", line 1454, in _missing_
raise ValueError('%r: no members with value %r' % (cls, unknown))
ValueError: <flag 'Flag'>: no members with value 252As a workaround, a detour via .value works in this case:
>>> Flag((Flag.A | Flag.B).value & ~Flag.A.value)
<Flag.B: 2>This causes issues with PyQt, which has the following flags (as bindings from C++):
>>> from PyQt6.QtCore import Qt
>>> for e in Qt.KeyboardModifier:
... print(f"{e.name} = {hex(e.value)}")
...
NoModifier = 0x0
ShiftModifier = 0x2000000
ControlModifier = 0x4000000
AltModifier = 0x8000000
MetaModifier = 0x10000000
KeypadModifier = 0x20000000
GroupSwitchModifier = 0x40000000
KeyboardModifierMask = 0xfe000000(Output from Python 3.10 - with Python 3.11, KeyboardModifierMask goes missing in the output, and so does Flag.Mask above, but that seems like a different issue?)
With my project, I'm trying to remove a modifier from the given flags. With Python 3.10.11 and 3.11.3:
>>> (Qt.KeyboardModifier.ShiftModifier | Qt.KeyboardModifier.ControlModifier) & ~Qt.KeyboardModifier.ControlModifier
<KeyboardModifier.ShiftModifier: 33554432>But with Python 3.11.4, same issue as above:
>>> from PyQt6.QtCore import Qt
>>> (Qt.KeyboardModifier.ShiftModifier | Qt.KeyboardModifier.ControlModifier) & ~Qt.KeyboardModifier.ControlModifier
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/usr/lib/python3.11/enum.py", line 1542, in __invert__
self._inverted_ = self.__class__(self._flag_mask_ ^ self._value_)
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.11/enum.py", line 711, in __call__
return cls.__new__(cls, value)
^^^^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.11/enum.py", line 1136, in __new__
raise exc
File "/usr/lib/python3.11/enum.py", line 1113, in __new__
result = cls._missing_(value)
^^^^^^^^^^^^^^^^^^^^
File "/usr/lib/python3.11/enum.py", line 1454, in _missing_
raise ValueError('%r: no members with value %r' % (cls, unknown))
ValueError: <flag 'KeyboardModifier'>: no members with value 2147483648As a culprit, I suspect:
- enum.CONFORM behavior breaks backwards compatibility #103365
- gh-103365: [Enum] STRICT boundary corrections #103494
- [3.11] gh-103365: [Enum] STRICT boundary corrections (GH-103494) #103513
Linked PRs
- gh-105497: [Enum] Fix flag inversion when alias/mask members exist. #105542
- [3.11] gh-105497: [Enum] Fix Flag inversion when alias/mask members exist. (GH-105542) #105571
- [3.12] gh-105497: [Enum] Fix Flag inversion when alias/mask members exist. (GH-105542) #105572
- gh-105497: [Enum] Fix flag mask inversion when unnamed flags exist #106468
- [3.12] gh-105497: [Enum] Fix flag mask inversion when unnamed flags exist (GH-106468) #106620
- [3.11] gh-105497: [Enum] Fix flag mask inversion when unnamed flags exist (GH-106468) #106621
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