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47 lines
1.6 KiB
Plaintext
47 lines
1.6 KiB
Plaintext
/**
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* @name Unused local variable
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* @description Local variable is defined but not used
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* @kind problem
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* @tags maintainability
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* useless-code
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* external/cwe/cwe-563
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* @problem.severity recommendation
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* @sub-severity high
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* @precision very-high
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* @id py/unused-local-variable
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*/
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import python
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import Definition
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predicate unused_local(Name unused, LocalVariable v) {
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forex(Definition def | def.getNode() = unused |
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def.getVariable() = v and
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def.isUnused() and
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not exists(def.getARedef()) and
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not exists(annotation_without_assignment(v)) and
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def.isRelevant() and
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not v = any(Nonlocal n).getAVariable() and
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not exists(def.getNode().getParentNode().(FunctionDef).getDefinedFunction().getADecorator()) and
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not exists(def.getNode().getParentNode().(ClassDef).getDefinedClass().getADecorator())
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)
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}
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/**
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* Gets any annotation of the local variable `v` that does not also reassign its value.
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*
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* TODO: This predicate should not be needed. Rather, annotated "assignments" that do not actually
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* assign a value should not result in the creation of an SSA variable (which then goes unused).
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*/
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private AnnAssign annotation_without_assignment(LocalVariable v) {
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result.getTarget() = v.getAStore() and
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not exists(result.getValue())
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}
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from Name unused, LocalVariable v
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where
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unused_local(unused, v) and
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// If unused is part of a tuple, count it as unused if all elements of that tuple are unused.
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forall(Name el | el = unused.getParentNode().(Tuple).getAnElt() | unused_local(el, _))
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select unused, "Variable " + v.getId() + " is not used."
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