GeezerVison is showing github.com — AttributeError when copying flags in the `re` module. · Issue #93820 · python/cpython
AttributeError when copying flags in the re module. #93820DescriptionBug report
In CPython 3.11, I've noticed that an attempt to copy (combined) regular expression flags fails with an attribute error; like so:
>>> import copy, re
>>> copy.copy(re.A | re.I)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "lib/python3.11/copy.py", line 102, in copy
return _reconstruct(x, None, *rv)
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "lib/python3.11/copy.py", line 265, in _reconstruct
y = func(*args)
^^^^^^^^^^^
File "lib/python3.11/enum.py", line 862, in __getattr__
raise AttributeError(name) from None
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: ASCII|IGNORECASE
Your environment
- CPython versions tested on: 3.11.0b3
- Operating system and architecture: macOS 10.15.7
Background
This behavior was detected from a CrossHair test failure here, in which we realize possibly symbolic arguments prior to regex compilation. (it's an esoteric use case, and I expect not very high priority) ActivityJelleZijlstra commented on Jun 14, 2022 Thanks for reporting! Confirmed that copy.copy(re.A | re.I) fails on 3.11 but works on 3.10. Marking as a release blocker since this is a regression.
cc @ethanfurman for enums Reacted by Phillip Schanely JelleZijlstra commented on Jun 14, 2022 Also repros with enum.IntFlag directly:
$ ./python.exe
Python 3.11.0b3+ (heads/3.11:7aa4038a6e, Jun 14 2022, 09:35:10) [Clang 13.0.0 (clang-1300.0.29.3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import copy, enum
>>> class F(enum.IntFlag):
... a = 2
... b = 4
...
>>> copy.copy(F.a | F.b)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Users/jelle/py/cpython/Lib/copy.py", line 102, in copy
return _reconstruct(x, None, *rv)
^^^^^^^^^^^^^^^^^^^^^^^^^^
File "/Users/jelle/py/cpython/Lib/copy.py", line 265, in _reconstruct
y = func(*args)
^^^^^^^^^^^
File "/Users/jelle/py/cpython/Lib/enum.py", line 862, in __getattr__
raise AttributeError(name) from None
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
AttributeError: a|b
dignissimus commented on Jun 15, 2022 tiran commented on Jun 15, 2022 In 3.11 the __reduce__ and __reduce_ex__ methods returns different values:
# 3.10
>>> import re
>>> flags = re.I | re.A
>>> flags.__reduce__()
(<function _reconstructor at 0x7f58bb775ea0>, (<enum 'RegexFlag'>, <class 'int'>, 258), {'_name_': None, '_value_': 258})
>>> flags.__reduce_ex__(1)
(<enum 'RegexFlag'>, (258,))
>>> flags._name_ is None
True
>>> flags.name is None
True# 3.11
>>> import re
>>> flags = re.I | re.A
>>> flags.__reduce__()
(<function _reconstructor at 0x7fd0b8d4f920>, (<flag 'RegexFlag'>, <class 'int'>, 258), {'_value_': 258, '_name_': 'ASCII|IGNORECASE'})
>>> flags.__reduce_ex__(1)
(<built-in function getattr>, (<flag 'RegexFlag'>, 'ASCII|IGNORECASE'))
>>> flags._name_
'ASCII|IGNORECASE'
>>> flags.name
'ASCII|IGNORECASE'tiran commented on Jun 15, 2022 I guess the regression was introduced by GH-26658 and commit 62f1d2b .
A quick fix would be to reduce flags by value instead of by name.
class Flag(Enum, boundary=STRICT):
def __reduce_ex__(self, proto):
return self.__class__, (self._value_, )
dignissimus commented on Jun 15, 2022 Running the example in 0507303 so works fine, so commit 62f1d2b introduced the issue dignissimus commented on Jun 15, 2022 Oh, it looks like we came across it at the same time 😂 Reacted by Christian Heimes tiran commented on Jun 15, 2022 serhiy-storchaka commented on Jun 16, 2022 Ideally, re.I | re.A should be reconstructed as operator.or_(re.ASCII, re.IGNORECASE). tiran commented on Jun 16, 2022 It gets a bit tricky when the flags have a residual member, e.g. re.A | re.I | 0x10000. IntFlag supports additional values that are not covered by an enum member.
MetadataMetadataDevelopmentNo branches or pull requestsIssue actions
|