/
UnnecessarySafeCall.kt
67 lines (60 loc) · 2.18 KB
/
UnnecessarySafeCall.kt
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package io.gitlab.arturbosch.detekt.rules.bugs
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.internal.ActiveByDefault
import io.gitlab.arturbosch.detekt.api.internal.RequiresTypeResolution
import org.jetbrains.kotlin.com.intellij.psi.impl.source.tree.LeafPsiElement
import org.jetbrains.kotlin.diagnostics.Errors
import org.jetbrains.kotlin.lexer.KtTokens
import org.jetbrains.kotlin.psi.KtSafeQualifiedExpression
import org.jetbrains.kotlin.psi.psiUtil.getChildOfType
/**
* Reports unnecessary safe call operators (`?.`) that can be removed by the user.
*
* <noncompliant>
* val a: String = ""
* val b = a?.length
* </noncompliant>
*
* <compliant>
* val a: String? = null
* val b = a?.length
* </compliant>
*/
@RequiresTypeResolution
@ActiveByDefault(since = "1.16.0")
class UnnecessarySafeCall(config: Config = Config.empty) : Rule(config) {
override val issue: Issue = Issue(
"UnnecessarySafeCall",
Severity.Defect,
"Unnecessary safe call operator detected.",
Debt.FIVE_MINS
)
@Suppress("ReturnCount")
override fun visitSafeQualifiedExpression(expression: KtSafeQualifiedExpression) {
super.visitSafeQualifiedExpression(expression)
val safeAccessElement = expression.getChildOfType<LeafPsiElement>()
if (safeAccessElement == null || safeAccessElement.elementType != KtTokens.SAFE_ACCESS) {
return
}
val compilerReport = bindingContext
.diagnostics
.forElement(safeAccessElement)
.firstOrNull { it.factory == Errors.UNNECESSARY_SAFE_CALL }
if (compilerReport != null) {
report(
CodeSmell(
issue,
Entity.from(expression),
"${expression.text} contains an unnecessary " +
"safe call operator"
)
)
}
}
}