Message211793
When I implemented pickle support I did not have a complete understanding of the pickle protocols nor how to best use them. As a result, I picked __getnewargs__ and only supported protocols 2 and 3 (4 didn't exist yet).
Serhiy came along and explained a bunch of it to me, so now I know that __reduce_ex__ is the best choice [1] as it supports all the protocol levels, and is always used. The patch removes __getnewargs__ and makes __reduce_ex__ The One Obvious Way, but if it does not go in to 3.4.0 then I won't be able to remove __getnewargs__ because of backwards compatibility.
All the tests still pass, and the new test for subclassing to pickle by name passes.
[1] pickle supports two low-level methods: __reduce__ and __reduce_ex__; __reduce_ex__ is more powerful and is the preferred method. If a mix-in class to Enum defines __reduce_ex__ and Enum only defines __reduce__, Enum's __reduce__ will not be called. |
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2014-02-21 02:36:15 | ethan.furman | set | recipients:
+ ethan.furman, gvanrossum, barry, pitrou, larry, alexandre.vassalotti, eli.bendersky, python-dev, serhiy.storchaka |
2014-02-21 02:36:15 | ethan.furman | set | messageid: <1392950175.7.0.623980151525.issue20653@psf.upfronthosting.co.za> |
2014-02-21 02:36:15 | ethan.furman | link | issue20653 messages |
2014-02-21 02:36:15 | ethan.furman | create | |
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