diff options
Diffstat (limited to 'django/utils/functional.py')
| -rw-r--r-- | django/utils/functional.py | 19 |
1 files changed, 14 insertions, 5 deletions
diff --git a/django/utils/functional.py b/django/utils/functional.py index cab74886d3..0606c775ef 100644 --- a/django/utils/functional.py +++ b/django/utils/functional.py @@ -4,6 +4,7 @@ from functools import wraps import sys from django.utils import six +from django.utils.six.moves import copyreg # You can't trivially replace this with `functools.partial` because this binds @@ -328,15 +329,23 @@ class SimpleLazyObject(LazyObject): self._setup() return self._wrapped.__dict__ - # Python 3.3 will call __reduce__ when pickling; these methods are needed - # to serialize and deserialize correctly. They are not called in earlier - # versions of Python. + # Python 3.3 will call __reduce__ when pickling; this method is needed + # to serialize and deserialize correctly. @classmethod def __newobj__(cls, *args): return cls.__new__(cls, *args) - def __reduce__(self): - return (self.__newobj__, (self.__class__,), self.__getstate__()) + def __reduce_ex__(self, proto): + if proto >= 2: + # On Py3, since the default protocol is 3, pickle uses the + # ``__newobj__`` method (& more efficient opcodes) for writing. + return (self.__newobj__, (self.__class__,), self.__getstate__()) + else: + # On Py2, the default protocol is 0 (for back-compat) & the above + # code fails miserably (see regression test). Instead, we return + # exactly what's returned if there's no ``__reduce__`` method at + # all. + return (copyreg._reconstructor, (self.__class__, object, None), self.__getstate__()) # Return a meaningful representation of the lazy object for debugging # without evaluating the wrapped object. |