Serhiy Storchaka added the comment:
I afraid this is not a feature, but a bug. pickletools.optimize() can produce
invalid pickled data when *PUT and MEMOIZE opcodes are used.
>>> import pickle, pickletools
>>> p = b'\x80\x04]\x94(\x8c\x04spamq\x01\x8c\x03ham\x94h\x02e.'
>>> pickle.loads(p)
['spam', 'ham', 'ham']
>>> pickletools.dis(p)
0: \x80 PROTO 4
2: ] EMPTY_LIST
3: \x94 MEMOIZE
4: ( MARK
5: \x8c SHORT_BINUNICODE 'spam'
11: q BINPUT 1
13: \x8c SHORT_BINUNICODE 'ham'
18: \x94 MEMOIZE
19: h BINGET 2
21: e APPENDS (MARK at 4)
22: . STOP
highest protocol among opcodes = 4
>>> p2 = pickletools.optimize(p)
>>> p2
b'\x80\x04\x95\x13\x00\x00\x00\x00\x00\x00\x00]\x94(\x8c\x04spam\x8c\x03ham\x94h\x02e.'
>>> pickle.loads(p2)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
KeyError: 2
>>> pickletools.dis(p2)
0: \x80 PROTO 4
2: \x95 FRAME 19
11: ] EMPTY_LIST
12: \x94 MEMOIZE
13: ( MARK
14: \x8c SHORT_BINUNICODE 'spam'
20: \x8c SHORT_BINUNICODE 'ham'
25: \x94 MEMOIZE
26: h BINGET 2
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/home/serhiy/py/cpython/Lib/pickletools.py", line 2458, in dis
raise ValueError(errormsg)
ValueError: memo key 2 has never been stored into
----------
nosy: +serhiy.storchaka
_______________________________________
Python tracker <rep...@bugs.python.org>
<http://bugs.python.org/issue19858>
_______________________________________
_______________________________________________
Python-bugs-list mailing list
Unsubscribe:
https://mail.python.org/mailman/options/python-bugs-list/archive%40mail-archive.com
