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UserDict __getitem__ behavior change between 3.11.1 and 3.12.0b2 #105524
Description
I define the following UserDict, that implements nested lookups (d['key.subkey']):
import collections
class DotDict(collections.UserDict):
def __getitem__(self, key):
subitem = self.data
for subkey in key.split("."):
try:
subitem = subitem[subkey]
except KeyError:
raise KeyError(f"`{key}` not found in configuration") from None
return subitemI expect the following to work as it did in Python 3.11, but it does not:
d = DotDict({'one': {'two': 'buckle my shoe'}})
d['one.two'] # works
d.get('one.two') # does not workI do not see any release notes indicating that __getitem__ is no longer the correct method to override.
Activity
Eclips4 commented on Jun 8, 2023
This also reproduced on the current main.
Seems that in 3.12 and newer versions __getitem__ isn't called in .get
Eclips4 commented on Jun 8, 2023
Also, if you define a __contains__ with the same behavior, it will work on 3.12.
Introduced in #17910
After some research of this issue, I came to the conclusion that the best solution here would be to add documentation of that.
stefanv commented on Jun 28, 2023
IUUC, the proposed fix is to change the implementation to the following:
Not ideal, but it works.
dholth commented on Dec 11, 2023
This also affects me.