New submission from Serhiy Storchaka <storchaka+cpyt...@gmail.com>:
The following PR makes pickles for typing types more portable. Type variables
no longer use _find_name() and can be unpickled in 3.6. Subscripted generics no
longer expose internals and can be unpickled in 3.6 and future versions with
changed internal implementation.
Before this PR:
>>> import pickle, pickletools, typing
>>>
>>> pickletools.dis(pickletools.optimize(pickle.dumps(typing.T, 4)))
>>>
0: \x80 PROTO 4
2: \x95 FRAME 30
11: \x8c SHORT_BINUNICODE 'typing'
19: \x94 MEMOIZE (as 0)
20: \x8c SHORT_BINUNICODE '_find_name'
32: \x93 STACK_GLOBAL
33: h BINGET 0
35: \x8c SHORT_BINUNICODE 'T'
38: \x86 TUPLE2
39: R REDUCE
40: . STOP
highest protocol among opcodes = 4
>>> pickletools.dis(pickletools.optimize(pickle.dumps(typing.Union[int, str],
>>> 4)))
0: \x80 PROTO 4
2: \x95 FRAME 198
11: \x8c SHORT_BINUNICODE 'copyreg'
20: \x8c SHORT_BINUNICODE '_reconstructor'
36: \x93 STACK_GLOBAL
37: \x8c SHORT_BINUNICODE 'typing'
45: \x94 MEMOIZE (as 0)
46: \x8c SHORT_BINUNICODE '_GenericAlias'
61: \x93 STACK_GLOBAL
62: \x8c SHORT_BINUNICODE 'builtins'
72: \x94 MEMOIZE (as 1)
73: \x8c SHORT_BINUNICODE 'object'
81: \x93 STACK_GLOBAL
82: N NONE
83: \x87 TUPLE3
84: R REDUCE
85: } EMPTY_DICT
86: ( MARK
87: \x8c SHORT_BINUNICODE '_inst'
94: \x88 NEWTRUE
95: \x8c SHORT_BINUNICODE '_special'
105: \x89 NEWFALSE
106: \x8c SHORT_BINUNICODE '_name'
113: N NONE
114: \x8c SHORT_BINUNICODE '__origin__'
126: h BINGET 0
128: \x8c SHORT_BINUNICODE 'Union'
135: \x93 STACK_GLOBAL
136: \x8c SHORT_BINUNICODE '__args__'
146: h BINGET 1
148: \x8c SHORT_BINUNICODE 'int'
153: \x93 STACK_GLOBAL
154: h BINGET 1
156: \x8c SHORT_BINUNICODE 'str'
161: \x93 STACK_GLOBAL
162: \x86 TUPLE2
163: \x8c SHORT_BINUNICODE '__parameters__'
179: ) EMPTY_TUPLE
180: \x8c SHORT_BINUNICODE '__slots__'
191: N NONE
192: \x8c SHORT_BINUNICODE '__module__'
204: h BINGET 0
206: u SETITEMS (MARK at 86)
207: b BUILD
208: . STOP
highest protocol among opcodes = 4
With this PR:
>>> import pickle, pickletools, typing
>>>
>>> pickletools.dis(pickletools.optimize(pickle.dumps(typing.T, 4)))
>>>
0: \x80 PROTO 4
2: \x95 FRAME 13
11: \x8c SHORT_BINUNICODE 'typing'
19: \x8c SHORT_BINUNICODE 'T'
22: \x93 STACK_GLOBAL
23: . STOP
highest protocol among opcodes = 4
>>> pickletools.dis(pickletools.optimize(pickle.dumps(typing.Union[int, str],
>>> 4)))
0: \x80 PROTO 4
2: \x95 FRAME 66
11: \x8c SHORT_BINUNICODE '_operator'
22: \x8c SHORT_BINUNICODE 'getitem'
31: \x93 STACK_GLOBAL
32: \x8c SHORT_BINUNICODE 'typing'
40: \x8c SHORT_BINUNICODE 'Union'
47: \x93 STACK_GLOBAL
48: \x8c SHORT_BINUNICODE 'builtins'
58: \x94 MEMOIZE (as 0)
59: \x8c SHORT_BINUNICODE 'int'
64: \x93 STACK_GLOBAL
65: h BINGET 0
67: \x8c SHORT_BINUNICODE 'str'
72: \x93 STACK_GLOBAL
73: \x86 TUPLE2
74: \x86 TUPLE2
75: R REDUCE
76: . STOP
highest protocol among opcodes = 4
If there is a chance it would be nice to merge these changes into 3.7.
Otherwise either pickles created in 3.7.0 will be incompatible not only with
older Python versions, but with future Python versions too, or we will need to
add complex code for supporting specific 3.7.0 pickles in future versions.
----------
components: Library (Lib)
messages: 317727
nosy: gvanrossum, levkivskyi, ned.deily, serhiy.storchaka
priority: normal
severity: normal
status: open
title: Improve pickling of typing types
versions: Python 3.7, Python 3.8
_______________________________________
Python tracker <rep...@bugs.python.org>
<https://bugs.python.org/issue33652>
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