[issue31550] Inconsistent error message for TypeError with subscripting
Serhiy Storchaka
report at bugs.python.org
Fri Sep 22 02:26:33 EDT 2017
Serhiy Storchaka added the comment:
I'm not sure that this is an enhancement. It makes an error message inconsistent with other error messages.
>>> class I(int): pass
...
>>> I()[0]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'I' object does not support indexing
>>> 0[0] = 0
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'int' object does not support item assignment
>>> del 0[0]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'int' object does not support item deletion
>>> ''['']
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: string indices must be integers, not str
>>> iter(0)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'int' object is not iterable
>>> reversed(0)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: argument to reversed() must be a sequence
>>> next(0)
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: int object is not an iterator
>>> {}[[]]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: unhashable type: 'list'
And actually this message is misleading. An attribute '__getitem__' is not looked up on objects.
>>> class I(int): pass
...
>>> x = I()
>>> x.__getitem__ = lambda *args: None
>>> I()[0:]
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: 'I' object has no attribute '__getitem__'
>>> x.__getitem__
<function <lambda> at 0x7f11b62dd648>
----------
nosy: +rhettinger, serhiy.storchaka
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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue31550>
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