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functools.partial is not compatible between 2.7 and 3.5 #73718
Description
Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.
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GitHub fields:
assignee = None
closed_at = <Date 2017-02-22.09:53:25.891>
created_at = <Date 2017-02-11.07:20:01.590>
labels = ['3.7', 'type-bug', 'library']
title = 'functools.partial is not compatible between 2.7 and 3.5'
updated_at = <Date 2017-03-31.16:36:21.417>
user = 'https://github.com/naoyuki-kamo'bugs.python.org fields:
activity = <Date 2017-03-31.16:36:21.417>
actor = 'dstufft'
assignee = 'none'
closed = True
closed_date = <Date 2017-02-22.09:53:25.891>
closer = 'serhiy.storchaka'
components = ['Library (Lib)']
creation = <Date 2017-02-11.07:20:01.590>
creator = 'naoyuki'
dependencies = []
files = ['46633']
hgrepos = []
issue_num = 29532
keywords = ['patch']
message_count = 8.0
messages = ['287594', '287595', '287598', '287673', '287832', '288197', '288309', '288347']
nosy_count = 5.0
nosy_names = ['rhettinger', 'steven.daprano', 'methane', 'serhiy.storchaka', 'naoyuki']
pr_nums = ['190', '198', '209', '222', '703', '552']
priority = 'normal'
resolution = 'fixed'
stage = 'resolved'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue29532'
versions = ['Python 3.5', 'Python 3.6', 'Python 3.7']
Activity
naoyuki-kamo commentedon Feb 11, 2017
The code:
from functools import partial
def f(a):
print(a)
d = {'a': 3}
g = partial(f, **d)
g()
d['a'] = 5
g()
On python2.7, gets
3
but on python3.5, gets
5
is it a bug?
stevendaprano commentedon Feb 11, 2017
Confirmed that in Python 2.7 calling g() before and after modifying the dict prints 3 both times; calling g() before modifying the dict prints 3, then after modifying it prints 5.
Python 3.3 behaves like 2.7, so this sounds like a regression in 3.5 or maybe 3.4.
serhiy-storchaka commentedon Feb 11, 2017
Yes, this can be considered a bug. Following patch fixes it.
methane commentedon Feb 13, 2017
patch LGTM.
rhettinger commentedon Feb 15, 2017
Agree that this is a bug. Patch and test looks good.
serhiy-storchaka commentedon Feb 20, 2017
New changeset 9639e4a by GitHub in branch 'master':
bpo-29532: Altering a kwarg dictionary passed to functools.partial() (#190)
9639e4a
serhiy-storchaka commentedon Feb 21, 2017
New changeset e48fd93 by GitHub in branch '3.6':
bpo-29532: Altering a kwarg dictionary passed to functools.partial() no longer affects a partial object after creation. (#209)
e48fd93
serhiy-storchaka commentedon Feb 22, 2017
New changeset 5010a77 by GitHub in branch '3.5':
[3.5] bpo-29532: Altering a kwarg dictionary passed to functools.partial() no longer affects a partial object after creation. (#222)
5010a77