Initial calculation of unicode table is not atomic

[DRMacIver]

If you're using e.g. pytest-xdist this can result in a corrupt unicode table, which is bad. Instead the file should be created under a temporary name then moved atomically.

[DRMacIver]

Relevant code is https://github.com/DRMacIver/hypothesis/blob/master/src/hypothesis/internal/charmap.py#L56

[cristicbz]

I think we hit this in CI all the time. Here's the stack trace if helpful:

reinfer/models/voc/label/tests/test_batch.py:17: in <module>
    from ...shared.tests.test_prediction_store import s_predictions
/env/local/lib/python2.7/site-packages/_pytest/assertion/rewrite.py:171: in load_module
    py.builtin.exec_(co, mod.__dict__)
reinfer/models/voc/shared/tests/test_prediction_store.py:46: in <module>
    s.tuples(s.text(min_size=1, max_size=3).map(lambda t: t.encode('utf-8')),
/env/local/lib/python2.7/site-packages/hypothesis/searchstrategy/strategies.py:130: in map
    pack=pack, strategy=self
/env/local/lib/python2.7/site-packages/hypothesis/searchstrategy/strategies.py:245: in __init__
    self.is_empty = strategy.is_empty
/env/local/lib/python2.7/site-packages/hypothesis/searchstrategy/deferred.py:59: in is_empty
    return self.wrapped_strategy.is_empty
/env/local/lib/python2.7/site-packages/hypothesis/searchstrategy/deferred.py:67: in wrapped_strategy
    **self.__kwargs
/env/local/lib/python2.7/site-packages/hypothesis/strategies.py:655: in text
    max_size=max_size
/env/local/lib/python2.7/site-packages/hypothesis/searchstrategy/strings.py:104: in __init__
    strategy=list_of_one_char_strings_strategy
/env/local/lib/python2.7/site-packages/hypothesis/searchstrategy/strategies.py:245: in __init__
    self.is_empty = strategy.is_empty
/env/local/lib/python2.7/site-packages/hypothesis/searchstrategy/deferred.py:59: in is_empty
    return self.wrapped_strategy.is_empty
/env/local/lib/python2.7/site-packages/hypothesis/searchstrategy/deferred.py:67: in wrapped_strategy
    **self.__kwargs
/env/local/lib/python2.7/site-packages/hypothesis/strategies.py:439: in lists
    if elements.is_empty:
/env/local/lib/python2.7/site-packages/hypothesis/searchstrategy/deferred.py:59: in is_empty
    return self.wrapped_strategy.is_empty
/env/local/lib/python2.7/site-packages/hypothesis/searchstrategy/deferred.py:67: in wrapped_strategy
    **self.__kwargs
/env/local/lib/python2.7/site-packages/hypothesis/strategies.py:620: in characters
    max_codepoint=max_codepoint)
/env/local/lib/python2.7/site-packages/hypothesis/searchstrategy/strings.py:46: in __init__
    max_codepoint=max_codepoint,
/env/local/lib/python2.7/site-packages/hypothesis/internal/charmap.py:143: in query
    catkey = _category_key(exclude_categories, include_categories)
/env/local/lib/python2.7/site-packages/hypothesis/internal/charmap.py:104: in _category_key
    cs = categories()
/env/local/lib/python2.7/site-packages/hypothesis/internal/charmap.py:70: in categories
    cm = charmap()
/env/local/lib/python2.7/site-packages/hypothesis/internal/charmap.py:59: in charmap
    _charmap = dict(pickle.loads(i.read()))
/usr/lib/python2.7/pickle.py:1388: in loads
    return Unpickler(file).load()
/usr/lib/python2.7/pickle.py:864: in load
    dispatch[key](self)
/usr/lib/python2.7/pickle.py:886: in load_eof
    raise EOFError
E   EOFError

[bcroq]

I still randomly get this error using hypothesis 3.1.0.

[DRMacIver]

Do you still get this error when using a more recent version of Hypothesis? The latest is 3.6.0

[bcroq]

@DRMacIver I bump the requirements to hypothesis==3.6.0... let's wait and see.

Thanks.

[bcroq]

@DRMacIver 3 days later, I confirm I don't get this error anymore.

Thanks again.