mirrors/cpython
1
0
Fork 0
mirror of https://github.com/python/cpython.git synced 2025-08-04 08:59:19 +00:00
Code Issues Projects Releases Packages Wiki Activity Actions 11

closes issue29167: fix race condition in (Int)Flag

Browse source
This commit is contained in:
Ethan Furman 2017-01-24 12:12:06 -08:00
parent 3831b0a066
commit 28cf663ff0
2 changed files with 99 additions and 6 deletions
Download patch file Download diff file Expand all files Collapse all files

15
Lib/enum.py
View file

@ -690,7 +690,9 @@ class Flag(Enum):
pseudo_member = object.__new__(cls)
pseudo_member._name_ = None
pseudo_member._value_ = value
cls._value2member_map_[value] = pseudo_member
# use setdefault in case another thread already created a composite
# with this value
pseudo_member = cls._value2member_map_.setdefault(value, pseudo_member)
return pseudo_member
def __contains__(self, other):
@ -785,7 +787,9 @@ class IntFlag(int, Flag):
pseudo_member = int.__new__(cls, value)
pseudo_member._name_ = None
pseudo_member._value_ = value
cls._value2member_map_[value] = pseudo_member
# use setdefault in case another thread already created a composite
# with this value
pseudo_member = cls._value2member_map_.setdefault(value, pseudo_member)
return pseudo_member
def __or__(self, other):
@ -835,18 +839,21 @@ def _decompose(flag, value):
# _decompose is only called if the value is not named
not_covered = value
negative = value < 0
# issue29167: wrap accesses to _value2member_map_ in a list to avoid race
# conditions between iterating over it and having more psuedo-
# members added to it
if negative:
# only check for named flags
flags_to_check = [
(m, v)
for v, m in flag._value2member_map_.items()
for v, m in list(flag._value2member_map_.items())
if m.name is not None
]
else:
# check for named flags and powers-of-two flags
flags_to_check = [
(m, v)
for v, m in flag._value2member_map_.items()
for v, m in list(flag._value2member_map_.items())
if m.name is not None or _power_of_two(v)
]
members = []