[New-bugs-announce] [issue38302] __rpow__ not reached when __ipow__ returns NotImplemented

[Adi]

New submission from Adi <deepspace2 at gmail.com>:

Due to shared code between the 2 and 3 forms of pow, the following code causes a TypeError:

class A:
    def __init__(self, val):
        self.val = val
    
    def __ipow__(self, other):
        return NotImplemented

class B:
    def __init__(self, val):
        self.val = val
    
    def __rpow__(self, other):
        return A(other.val ** self.val)

a = A(2)
b = B(2)
a **= b


(https://stackoverflow.com/questions/58141475/ipow-raising-typeerror-when-left-hand-side-object-returns-notimplemented)

----------
components: Interpreter Core
messages: 353419
nosy: DeepSpace
priority: normal
severity: normal
status: open
title: __rpow__ not reached when __ipow__ returns NotImplemented
versions: Python 3.6, Python 3.7

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue38302>
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