Terry J. Reedy <[email protected]> added the comment:
Nick and Raymond, I added both of you as nosy because, among other reasons, you
commented on the latest version of PEP575.
I agree that there is a bug in current CPython, in that the is* functions
should return, not raise, but I am not sure where is it, and hence if the PR is
the right fix. I am wondering if, instead, the bug is in m, the object
returned by MethodType, or in attribute lookup thereupon.
MethodType is the type of bound user-defined (Python-coded) functions and
ismethod is true for instances thereof. Consider 4 other bound methods, two
'normal'(callable is method of instance class) and two, like Jeroen's, 'odd'
(callable not related to int).
>>> cm = Callable().__call__
>>> cm.__code__
<code object __call__ at 0x00000202C1C53780, file "<pyshell#5>", line 2>
>>> cm.__name__
'__call__'
>>> cm2 = MethodType(Callable.__call__, Callable())
>>> cm2.__code__
<code object __call__ at 0x00000202C1C53780, file "<pyshell#5>", line 2>
>>> cm2.__name__
'__call__'
>>> m2 = MethodType(Callable.__call__, 42)
>>> m2.__code__
<code object __call__ at 0x00000202C1C53780, file "<pyshell#5>", line 2>
>>> m2.__name__
'__call__'
>>> m2()
()
>>> m3 = MethodType(Callable().__call__, 42)
>>> m3.__code__
<code object __call__ at 0x00000202C1C53780, file "<pyshell#5>", line 2>
>>> m3.__name__
'__call__'
>>> m3()
(42,)
>>> m = MethodType(Callable(), 42)
>>> m.__code__
... AttributeError: 'Callable' object has no attribute '__code__'
>>> m.__name__
... AttributeError: 'Callable' object has no attribute '__name__'
>>> m()
(42,)
They all have the same attributes exposed by dir(), which omits both'__name__',
promised in the docstring for ismethod*, and '__code__', assumed by the is---
functions under discussion.
>>> dir(cm) == dir(cm2) == dir(m) == dir(m2) == dir(m3)
True
>>> ('__code__' in dir(cm)) or ('__name__' in dir(cm))
False
However, accessing those names anyway, as (hidden) attributes, works for all
but m. Should doing so also work for m? (If not, the ismethod docstring
should not 'guarantee' .__name__.)
* " Instance method objects provide these attributes:
__doc__ documentation string
__name__ name with which this method was defined
..."
----------
nosy: +ncoghlan, rhettinger, terry.reedy
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Python tracker <[email protected]>
<https://bugs.python.org/issue33261>
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