Message335041
It turns out that both pickle and _pickle implement this feature, but the behavior is inconsistent.
- As a reminder, instances of slotted classes do not have a dict attribute (1)
- On the other side, when pickling slotted class instances, __getstate__ can return a tuple of 2 dicts. The first dict represents the __dict__ attribute. Because of (1), this first dict should simply be a sentinel value. In pickle, the condition is that it evaluates to False, but in _pickle, it should be explicitly None.
(- Finally, The second dict in state contains the slotted attribute. )
Here are the lines in the two files causing the inconsistent behavior:
https://github.com/python/cpython/blob/master/Modules/_pickle.c#L6236
https://github.com/python/cpython/blob/master/Lib/pickle.py#L1549
I included an example that illustrates it. |
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Date |
User |
Action |
Args |
2019-02-07 20:59:06 | pierreglaser | set | recipients:
+ pierreglaser, pitrou, alexandre.vassalotti, docs@python, serhiy.storchaka |
2019-02-07 20:59:04 | pierreglaser | set | messageid: <1549573144.13.0.200174121083.issue35933@roundup.psfhosted.org> |
2019-02-07 20:59:04 | pierreglaser | link | issue35933 messages |
2019-02-07 20:59:03 | pierreglaser | create | |
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