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Lynskylate opened this issue Aug 11, 2019 · 3 comments
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__new__ should be a static method #1230

Lynskylate opened this issue Aug 11, 2019 · 3 comments
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C-compat A discrepancy between RustPython and CPython

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@Lynskylate
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Lynskylate commented Aug 11, 2019 •
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In RustPython, __new__ is bound method but it should be a static method.

class A:
    def __new__(*args, **kwargs):
        print("Args Total: {}".format(len(args)+len(kwargs)))

class B(A):
    def __new__(cls, *args, **kwargs):
        return super().__new__(cls, *args, **kwargs)
"""
>>> B()
CPython output
Args Total: 1 
RustPython output
Args Total: 2
"""

super().new(cls, *args, **kwargs) will pass two same ype class(args[0] is same as cls).

object __new__ Python docuemtion
@Lynskylate Lynskylate added the C-compat A discrepancy between RustPython and CPython label Aug 11, 2019
@Lynskylate Lynskylate mentioned this issue Aug 12, 2019
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@cthulahoops
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I think this is probably a duplicate of #778 . Just trying to get this stuff fresh in my mind so I can review the work here.

@cthulahoops
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I've been considering this a problem with super as it works in the examples without super but finally got a simple example that shows the difference without using super:

CPython:

>>> (1).__new__(int, 5)
5

RustPython:

>>>>> (1).__new__(int, 5)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: Expected type <class 'type'>, not <class 'int'>

@Lynskylate
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Lynskylate commented Aug 16, 2019 •
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Incompact example code for RustPython object's __new__.

type(object.__new__)
type(object().__new__)

RustPython:

<class 'builtin_function_or_method'>
<class 'method'>

CPython

<class 'builtin_function_or_method'>
<class 'builtin_function_or_method'>

@isidentical isidentical mentioned this issue Sep 9, 2019
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[WIP]Convert method __new__ to staticmethod Lynskylate/RustPython
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@cthulahoops @Lynskylate