115 lines
2.6 KiB
Python
115 lines
2.6 KiB
Python
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"""
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Checks that value used in a subscript supports subscription
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(i.e. defines __getitem__ method).
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"""
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# pylint: disable=missing-docstring,pointless-statement,expression-not-assigned,wrong-import-position
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# pylint: disable=too-few-public-methods,import-error,invalid-name,wrong-import-order
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import six
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# primitives
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numbers = [1, 2, 3]
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numbers[0]
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"123"[0]
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u"123"[0]
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b"123"[0]
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bytearray(b"123")[0]
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dict(a=1, b=2)['a']
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(1, 2, 3)[0]
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# list/dict comprehensions are fine
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[x for x in range(10)][0]
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{x: 10 - x for x in range(10)}[0]
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# instances
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class NonSubscriptable(object):
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pass
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class Subscriptable(object):
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def __getitem__(self, key):
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return key + key
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NonSubscriptable()[0] # [unsubscriptable-object]
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NonSubscriptable[0] # [unsubscriptable-object]
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Subscriptable()[0]
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Subscriptable[0] # [unsubscriptable-object]
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# generators are not subscriptable
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def powers_of_two():
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k = 0
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while k < 10:
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yield 2 ** k
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k += 1
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powers_of_two()[0] # [unsubscriptable-object]
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powers_of_two[0] # [unsubscriptable-object]
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# check that primitive non subscriptable types are caught
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True[0] # [unsubscriptable-object]
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None[0] # [unsubscriptable-object]
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8.5[0] # [unsubscriptable-object]
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10[0] # [unsubscriptable-object]
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# sets are not subscriptable
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{x ** 2 for x in range(10)}[0] # [unsubscriptable-object]
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set(numbers)[0] # [unsubscriptable-object]
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frozenset(numbers)[0] # [unsubscriptable-object]
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# skip instances with unknown base classes
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from some_missing_module import LibSubscriptable
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class MaybeSubscriptable(LibSubscriptable):
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pass
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MaybeSubscriptable()[0]
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# subscriptable classes (through metaclasses)
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class MetaSubscriptable(type):
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def __getitem__(cls, key):
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return key + key
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class SubscriptableClass(six.with_metaclass(MetaSubscriptable, object)):
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pass
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SubscriptableClass[0]
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SubscriptableClass()[0] # [unsubscriptable-object]
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# functions are not subscriptable
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def test(*args, **kwargs):
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return args, kwargs
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test()[0]
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test[0] # [unsubscriptable-object]
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# deque
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from collections import deque
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deq = deque(maxlen=10)
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deq.append(42)
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deq[0]
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class AbstractClass(object):
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def __init__(self):
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self.ala = {i for i in range(10)}
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self.bala = [i for i in range(10)]
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self.portocala = None
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def test_unsubscriptable(self):
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self.bala[0]
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self.portocala[0]
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class ClassMixin(object):
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def __init__(self):
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self.ala = {i for i in range(10)}
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self.bala = [i for i in range(10)]
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self.portocala = None
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def test_unsubscriptable(self):
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self.bala[0]
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self.portocala[0]
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