On Thu, Jul 19, 2012 at 12:53 PM, M Stefan <mstefa...@gmail.com> wrote:
> Hey, > > As part of pickle4, I found it interesting to add the possibility > of pickling bound functions (instance methods). This is done by > pickling f.__self__ and f.__func__ separately, and then adding > a BIND opcode to tie them together. > > While this appears to work fine for python methods (non-builtin), some > issues arise with builtins. These are partly caused because > not all builtin function types support __func__, partly because > not all of them fill __module__ when they should and partly > because there are many (7) types a function can actually have: > > ClassMethodDescriptorType = type(??) > BuiltinFunctionType = type(len) > FunctionType = type(f) > MethodType = type(A().f()) > MethodDescriptorType = type(list.append) > WrapperDescriptorType = type(list.__add__) > MethodWrapperType = type([].__add__) > > AllFunctionTypes = (ClassMethodDescriptorType, BuiltinFunctionType, > FunctionType, MethodType, MethodDescriptorType, > WrapperDescriptorType, MethodWrapperType) > repr(AllFunctionTypes) = ( > <class 'classmethod_descriptor'>, > <class 'builtin_function_or_method'>, <class 'function'>, > <class 'method'>, <class 'method_descriptor'>, > <class 'wrapper_descriptor'>, <class 'method-wrapper'>) > > I have created a patch at [1], which adds __func__ to some other > function types, as well as: > 1) adds AllFunctionTypes etc. to Lib/types.py > 2) inspect.isanyfunction(), inspect.isanyboundfunction(), > inspect.isanyunboundfunction() > 3) functools.unbind > Note that I am not knowledgeable of cpython internals and therefore > the patch needs to be carefully reviewed. > > Possible issues: Should classmethods be considered bound or unbound? > If cm is a classmethod, then should > cm.__func__.__self__ = cm.__self__ or cm.__func__.__self__ = None? > Currently does the latter: > >>> cm.__self__, hasattr(cm,'__self__'), hasattr(cm.__func__, > '__self__') > (<class '__main__.A'>, True, False) > This requires treating classmethods separately when pickling, > so I'm not sure if this is ideal. > > Let me know if I should have opened an issue instead. I look > forward to hearing your opinions/suggestions on this matter. > Yes, open an issue for your patch and reply here with the issue #.
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