60 lines
1.4 KiB
Plaintext
60 lines
1.4 KiB
Plaintext
Implementing the special method ``++__ne__++`` is not equivalent to implementing the special method ``++__eq__++``. By default ``++__ne__++`` will call ``++__eq__++``, but the default implementation of ``++__eq__++`` does not call ``++__ne__++``.
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This rule raises an issue when the special method ``++__ne__++`` is implemented but not the ``++__eq__++`` method.
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== Noncompliant Code Example
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----
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class Ne:
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def __ne__(self, other): # Noncompliant.
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return False
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myvar = Ne() == 1 # False. __ne__ is not called
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myvar = 1 == Ne() # False. __ne__ is not called
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myvar = Ne() != 1 # False
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myvar = 1 != Ne() # False
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----
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== Compliant Solution
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----
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# Recommended, as __ne__ delegates to __eq__ by default
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class Eq:
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def __eq__(self, other):
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return True
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myvar = Eq() == 1 # True
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myvar = 1 == Eq() # True
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myvar = Eq() != 1 # False. __eq__ is called
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myvar = 1 != Eq() # False. __eq__ is called
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# OR if __ne__ needs a special implementation
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class Eq:
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def __eq__(self, other):
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return True
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def __ne__(self, other):
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return False
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----
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:link-with-uscores1: https://docs.python.org/3/reference/datamodel.html#object.__ne__
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== See
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* Python documentation - {link-with-uscores1}[the ++__ne__++ special method]
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ifdef::env-github,rspecator-view[]
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'''
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== Implementation Specification
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(visible only on this page)
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include::highlighting.adoc[]
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endif::env-github,rspecator-view[]
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