/
LabeledExpression.kt
107 lines (99 loc) · 4.04 KB
/
LabeledExpression.kt
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package io.gitlab.arturbosch.detekt.rules.complexity
import io.gitlab.arturbosch.detekt.api.CodeSmell
import io.gitlab.arturbosch.detekt.api.Config
import io.gitlab.arturbosch.detekt.api.Debt
import io.gitlab.arturbosch.detekt.api.Entity
import io.gitlab.arturbosch.detekt.api.Issue
import io.gitlab.arturbosch.detekt.api.Rule
import io.gitlab.arturbosch.detekt.api.Severity
import io.gitlab.arturbosch.detekt.api.config
import io.gitlab.arturbosch.detekt.api.internal.Configuration
import org.jetbrains.kotlin.psi.KtClass
import org.jetbrains.kotlin.psi.KtElement
import org.jetbrains.kotlin.psi.KtExpressionWithLabel
import org.jetbrains.kotlin.psi.KtNamedFunction
import org.jetbrains.kotlin.psi.KtThisExpression
import org.jetbrains.kotlin.psi.psiUtil.containingClass
import org.jetbrains.kotlin.psi.psiUtil.getStrictParentOfType
import org.jetbrains.kotlin.psi.psiUtil.isExtensionDeclaration
/**
* This rule reports labeled expressions. Expressions with labels generally increase complexity and worsen the
* maintainability of the code. Refactor the violating code to not use labels instead.
* Labeled expressions referencing an outer class with a label from an inner class are allowed, because there is no
* way to get the instance of an outer class from an inner class in Kotlin.
*
* <noncompliant>
* val range = listOf<String>("foo", "bar")
* loop@ for (r in range) {
* if (r == "bar") break@loop
* println(r)
* }
*
* class Outer {
* inner class Inner {
* fun f() {
* val i = this@Inner // referencing itself, use `this instead
* }
* }
* }
* </noncompliant>
*
* <compliant>
* val range = listOf<String>("foo", "bar")
* for (r in range) {
* if (r == "bar") break
* println(r)
* }
*
* class Outer {
* inner class Inner {
* fun f() {
* val outer = this@Outer
* }
* fun Int.extend() {
* val inner = this@Inner // this would reference Int and not Inner
* }
* }
* }
* </compliant>
*/
class LabeledExpression(config: Config = Config.empty) : Rule(config) {
override val issue: Issue = Issue(
"LabeledExpression",
Severity.Maintainability,
"Expression with labels increase complexity and affect maintainability.",
Debt.TWENTY_MINS
)
@Configuration("allows to provide a list of label names which should be ignored by this rule")
private val ignoredLabels: List<String> by config(emptyList<String>()) { list ->
list.map { it.removePrefix("*").removeSuffix("*") }
}
override fun visitExpressionWithLabel(expression: KtExpressionWithLabel) {
super.visitExpressionWithLabel(expression)
if (expression !is KtThisExpression || isNotReferencingOuterClass(expression)) {
val label = expression.getTargetLabel()
val labelName = label?.getReferencedName()
if (labelName != null && ignoredLabels.none { labelName.contains(it, ignoreCase = true) }) {
report(CodeSmell(issue, Entity.from(label), issue.description))
}
}
}
private fun isNotReferencingOuterClass(expression: KtExpressionWithLabel): Boolean {
val containingClasses = mutableListOf<KtClass>()
val containingClass = expression.containingClass() ?: return false
if (isAllowedToReferenceContainingClass(containingClass, expression)) {
containingClasses.add(containingClass)
}
getClassHierarchy(containingClass, containingClasses)
return !containingClasses.any { it.name == expression.getLabelName() }
}
private fun isAllowedToReferenceContainingClass(klass: KtClass, expression: KtExpressionWithLabel): Boolean {
return !klass.isInner() ||
expression.getStrictParentOfType<KtNamedFunction>()?.isExtensionDeclaration() == true
}
private fun getClassHierarchy(element: KtElement, classes: MutableList<KtClass>) {
val containingClass = element.containingClass() ?: return
classes.add(containingClass)
getClassHierarchy(containingClass, classes)
}
}