incorrect results for copy.copy() of various Stackless picklable types #127
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Original comment by Anselm Kruis (Bitbucket: akruis, GitHub: akruis): I just discovered, that C-Python 3.3 can pickle the types iterator and callable_iterator. Why didn't Kristján comment them in 0bbd8721729f? I'm going to remove the pickling code, but I'll keep the unpickling code in 3.3-slp and 3.4-slp to stay compatible. |
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…ests. This change is based on f5f98595c6cc63b from 2.7-slp, but it is heavily modified for Python 3. - Pickle 'callable-iterator' objects correctly. Previously the unpickled object had the type '_stackless._wrap.callable-iterator'. - Fix pickling of 'method-wrapper' objects. Previously pickling them caused a SystemError exception. - Fix copy.copy() for 'callable-iterator', 'method', 'dict_keys', 'dict_values' and 'dict_items' objects. Previously the copied object had the type '_stackless._wrap....'. - Fix Stackless pickling tests. The method StacklessTestCase.dumps() didn't pass the pickle protocol to the pickler. - Remove dead code in prickelpit.c. The code was used in older Stackless versions.
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…d traceback objects __setstate__ must accept the state returned by __reduce__. This was not the case for generator and trace-back objects. This commit fixes this. The next commit (merge of issue #127) adds the relevant test cases. Additionally amends changelog.txt. https://bitbucket.org/stackless-dev/stackless/issues/107
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Disable the Stackless specific code for pickling 'iterator' and 'callable_iterator' objects. C-Python 3.3 already pickles them. Add tests to ensure, that Stackless can still unpickle old pickles. https://bitbucket.org/stackless-dev/stackless/issues/127
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Originally reported by: Anselm Kruis (Bitbucket: akruis, GitHub: akruis)
Affected versions: all
Problem
Stackless can pickle a few more types than C-Python. A pickleable object can also be copied by copy.copy(). Therefore copy.copy() should work for all Stackless-pickleable types. Unfortunately if you copy a callable-iterator, you get a copy of type '_stackless._wrap.callable-iterator'
For Stackless 2.7.13 this problem is caused by a bug in prickelpit.c calliter_reduce(). The reduce function returns only a 2-tuple without a state value. Without a state, Python does not call __setstate__() on the newly created object. But Stackless changes the object type of the newly created object in __setstate__(). The fix is simple: return an empty state.
But in some versions of Python 3.x (see bpo-25718) copy.copy() contains am incorrect optimization: If copy.copy() uses a reduce-method (either from copy_reg.dispatch_table or obj.__reduce__() or obj.__reduce_ex__()), it does not call newobj.__setstate__(state), if the boolean value of state is false.
This can break Stackless, because it depends on __setstate__() being called.
Additionally I found, that bug in the pickle tests of Stackless Python 3.x. The pickles protocol value isn't passed the the pickler. Therefore it always uses the default protocol.
Solution
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