segfault with defaultdict and pickle

[erickt]

BPO	4170
Nosy	@amauryfa
Files	fix_defaultdict_reduce.patch fix_defaultdict_reduce_v2.patch: also test with HIGHEST_PROTOCOL

^{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 2008-10-30.20:58:54.660>
created_at = <Date 2008-10-22.09:26:46.700>
labels = ['library', 'type-crash']
title = 'segfault with defaultdict and pickle'
updated_at = <Date 2008-10-30.20:58:54.659>
user = 'https://bugs.python.org/erickt'

bugs.python.org fields:

activity = <Date 2008-10-30.20:58:54.659>
actor = 'amaury.forgeotdarc'
assignee = 'none'
closed = True
closed_date = <Date 2008-10-30.20:58:54.660>
closer = 'amaury.forgeotdarc'
components = ['Library (Lib)']
creation = <Date 2008-10-22.09:26:46.700>
creator = 'erickt'
dependencies = []
files = ['11856', '11864']
hgrepos = []
issue_num = 4170
keywords = ['patch']
message_count = 7.0
messages = ['75073', '75076', '75086', '75087', '75095', '75126', '75380']
nosy_count = 3.0
nosy_names = ['amaury.forgeotdarc', 'ocean-city', 'erickt']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = None
status = 'closed'
superseder = None
type = 'crash'
url = 'https://bugs.python.org/issue4170'
versions = ['Python 3.0']

[erickt]

It seems like there's a bug with defaultdict. This is segfaulting with
the latest python 3.0 svn checkout:

import collections, pickle
d=collections.defaultdict(int)
d[1]
pickle.dumps(d)

It errors out with:

Assertion failed: (PyIter_Check(iter)), function PyIter_Next, file
Objects/abstract.c, line 2751.
zsh: abort /tmp/python/bin/python3.0 foo.py

[ocean-city]

On py3k, defaultdict#items() returns dict_items object not
dict_itemiterator object. I hope attached patch will fix this bug.

[amauryfa]

The pickle protocol should also check that __reduce__ returns iterators
(iterables are not enough).
The code below crashes the interpreter (twice ;-)

class C:
    def __reduce__(self):
        return C, (), None, None, []
class D:
    def __reduce__(self):
        return D, (), None, [], None
import pickle
pickle.dumps(C())
pickle.dumps(D())

[amauryfa]

My previous example also crashes python 2.4 & 2.6 (the classes have to
inherit from 'object')

[ocean-city]

My previous example also crashes python 2.4 & 2.6 (the classes have to
inherit from 'object')

I created new tracker item for this. (See bpo-4176)

[ocean-city]

I created test case referring to test_bytes, but I noticed
range(pickle.HIGHETST_PROTOCOL) doesn't test HIGHEST_PROTOCOL itself. So
patch revised. I created another tracker item for other tests using
range(pickle.HIGHETST_PROTOCOL). See bpo-4183.

[amauryfa]

Fixed with r67048.