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[Enum] verify'ing a Flag class with negative values results in MemoryError #99248
Description
Bug report
A clear and concise description of what the bug is.
Include a minimal, reproducible example (https://stackoverflow.com/help/minimal-reproducible-example), if possible.
Your environment
from enum import Flag, verify, NAMED_FLAGS
@verify(NAMED_FLAGS)
class Color(Flag):
RED = -1 # 0
GREEN = 2
BLUE = 4
WHITE = 9
NEON = 6
In this example, it is working good, if RED has value of 0, but is resulting in Memory Error, if its value is changed to -1
- CPython versions tested on: 3.11.0
- Operating system and architecture: Windows 10, 64 bit
Activity
JelleZijlstra commentedon Nov 8, 2022
The problem is that
enum._iter_bits_lsb(cpython/Lib/enum.py
Line 116 in c43714f
Negative numbers don't really make sense as OR-able flags (which are conceptually unsigned), but we should fail with an obvious error instead of using all available memory.
cc @ethanfurman for enums
[-]Enum Flag class with one negative value is resulting in Memory Error[/-][+][Enum] verify'ing a Flag class with negative values results in MemoryError[/+]gh-99248: [Enum] fix negative number infinite loop (GH-99256)
pythongh-99248: [Enum] fix negative number infinite loop (pythonGH-99256
gh-99248: [Enum] fix negative number infinite loop (GH-99256)
ethanfurman commentedon Nov 8, 2022
Thanks for the report. Fix merged into main and 3.11.