Repository navigation
pickling fails for typing.Tuple[()] #94245
Description
Bug report
A clear and concise description of what the bug is.
Include a minimal, reproducible example (https://stackoverflow.com/help/minimal-reproducible-example), if possible.
import pickle from typing import Tuple j = Tuple[()] serialized = pickle.dumps(j) loaded = pickle.loads(serialized)
Error message:
Traceback (most recent call last):
File "/Users/ryanthompson/PycharmProjects/learningProjects/dill_regression/regression_test.py", line 6, in <module>
loaded = dill.loads(serialized)
File "/Users/ryanthompson/.pyenv/versions/3.8.11/lib/python3.8/site-packages/dill/_dill.py", line 387, in loads
return load(file, ignore, **kwds)
File "/Users/ryanthompson/.pyenv/versions/3.8.11/lib/python3.8/site-packages/dill/_dill.py", line 373, in load
return Unpickler(file, ignore=ignore, **kwds).load()
File "/Users/ryanthompson/.pyenv/versions/3.8.11/lib/python3.8/site-packages/dill/_dill.py", line 646, in load
obj = StockUnpickler.load(self)
File "/Users/ryanthompson/.pyenv/versions/3.8.11/lib/python3.8/typing.py", line 804, in __getitem__
return self.__getitem_inner__(params)
File "/Users/ryanthompson/.pyenv/versions/3.8.11/lib/python3.8/typing.py", line 261, in inner
return func(*args, **kwds)
File "/Users/ryanthompson/.pyenv/versions/3.8.11/lib/python3.8/typing.py", line 830, in __getitem_inner__
params = tuple(_type_check(p, msg) for p in params)
File "/Users/ryanthompson/.pyenv/versions/3.8.11/lib/python3.8/typing.py", line 830, in <genexpr>
params = tuple(_type_check(p, msg) for p in params)
File "/Users/ryanthompson/.pyenv/versions/3.8.11/lib/python3.8/typing.py", line 149, in _type_check
raise TypeError(f"{msg} Got {arg!r:.100}.")
TypeError: Tuple[t0, t1, ...]: each t must be a type. Got ().
Your environment
python 3.8
- CPython versions tested on:
3.6 & 3.8 - Operating system and architecture:
Mac OS
Activity
JelleZijlstra commented on Jun 24, 2022
Thanks for the report. I can reproduce on 3.9 and 3.10, but not a recent build of 3.11. I assume @serhiy-storchaka's changes to the representation of empty tuples fixed this issue.
We're not going to fix this for 3.9 and lower because those branches are in security fix-only mode, but we can still fix it on 3.10.
mmckerns commented on Jun 24, 2022
Just for completeness... here's a little more information on the bug (from the OP issue at dill):
>>> import pickle >>> import typing >>> t = typing.Tuple[()] >>> t typing.Tuple[()] >>> t = t.copy_with(()) >>> t typing.Tuple[] >>> s = pickle.dumps(t) >>> pickle.loads(s) typing.Tuple[()] >>> typing.Tuple[] File "<stdin>", line 1 typing.Tuple[] ^ SyntaxError: invalid syntaxpythongh-94245: Test pickling and copying of typing.Tuple[()]
pythongh-94245: Fix pickling and copying of typing.Tuple[()]
serhiy-storchaka commented on Jun 25, 2022
Backporting #31836 can fix this issue. #94260 is an alternate fix. #94259 contains tests, they should be added in all versions.
[3.10] gh-94245: Fix pickling and copying of typing.Tuple[()] (GH-94260)
gh-94245: Test pickling and copying of typing.Tuple[()] (GH-94259)
pythongh-94245: Test pickling and copying of typing.Tuple[()] (python…
pythongh-94245: Test pickling and copying of typing.Tuple[()] (python…
gh-94245: Test pickling and copying of typing.Tuple[()] (GH-94259)
gh-94245: Test pickling and copying of typing.Tuple[()] (GH-94259) (G…
Revert 30935 defer bpo45162 to 312 (#94285)
fix: #517 special handling of typing module