34 lines
932 B
Plaintext
34 lines
932 B
Plaintext
While the assignment of default parameter values is typically a good thing, it can go very wrong very quickly when mutable objects are used. That's because a new instance of the object _is not_ created for each function invocation. Instead, all invocations share the same instance, and the changes made for one caller are made for all!
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== Noncompliant Code Example
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[source,python]
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----
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def get_attr_array(obj, arr=[]): # Noncompliant
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props = (name for name in dir(obj) if not name.startswith('_'))
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arr.extend(props) # after only a few calls, this is a big array!
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return arr
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----
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== Compliant Solution
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[source,python]
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----
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def get_attr_array(obj, arr):
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props = (name for name in dir(obj) if not name.startswith('_'))
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arr.extend(props)
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return arr
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----
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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::message.adoc[]
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endif::env-github,rspecator-view[]
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