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Created on 2020-05-05 18:34 by rhettinger, last changed 2022-04-11 14:59 by admin. This issue is now closed.
| Pull Requests | |||
|---|---|---|---|
| URL | Status | Linked | Edit |
| PR 19946 | merged | pablogsal, 2020-05-05 19:37 | |
| Messages (2) | |||
|---|---|---|---|
| msg368197 - (view) | Author: Raymond Hettinger (rhettinger) *  |
Date: 2020-05-05 18:34 | |
from weakref import proxy
class Alpha:
def __len__(self):
return 3
def __reversed__(self):
return iter('cba')
def __hash__(self):
return hash('abc')
a = Alpha()
# Direct use of the instance works
print(len(a))
print(list(reversed(a)))
print(hash(a))
# Proxies can use the dunder methods directly
r = proxy(a)
print(r.__len__())
print(list(r.__reversed__()))
print(r.__hash__())
# Proxy fails for __reversed__ and __hash__
print(len(r), 'This succeeds')
try:
print(list(reversed(r)))
except TypeError:
print('reverse(r) failed')
try:
print(hash(r))
except TypeError:
print('hash(r) failed')
|
|||
| msg368211 - (view) | Author: Pablo Galindo Salgado (pablogsal) * |
Date: 2020-05-05 21:58 | |
New changeset 96074de573f82fc66a2bd73c36905141a3f1d5c1 by Pablo Galindo in branch 'master': bpo-40523: Add pass-throughs for hash() and reversed() to weakref.proxy objects (GH-19946) https://github.com/python/cpython/commit/96074de573f82fc66a2bd73c36905141a3f1d5c1 |
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