Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Jump to bottom

Refactor RedundantElseInWhen to use compiler warning #3214

Merged
merged 1 commit into from
Nov 8, 2020
Merged

Refactor RedundantElseInWhen to use compiler warning #3214

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
30 changes: 5 additions & 25 deletions ...-errorprone/src/main/kotlin/io/gitlab/arturbosch/detekt/rules/bugs/RedundantElseInWhen.kt
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -7,21 +7,10 @@ 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 org.jetbrains.kotlin.builtins.KotlinBuiltIns
import org.jetbrains.kotlin.cfg.WhenChecker
import org.jetbrains.kotlin.descriptors.ClassDescriptor
import org.jetbrains.kotlin.load.kotlin.toSourceElement
import org.jetbrains.kotlin.diagnostics.Errors
import org.jetbrains.kotlin.psi.KtWhenExpression
import org.jetbrains.kotlin.resolve.BindingContext
import org.jetbrains.kotlin.resolve.BindingContext.DECLARATION_TO_DESCRIPTOR
import org.jetbrains.kotlin.resolve.calls.callUtil.getType
import org.jetbrains.kotlin.resolve.descriptorUtil.module
import org.jetbrains.kotlin.resolve.source.getPsi

/*
* Based on code from Kotlin compiler:
* https://github.com/JetBrains/kotlin/blob/v1.3.30/compiler/frontend/src/org/jetbrains/kotlin/cfg/ControlFlowInformationProvider.kt
*/
/**
* Turn on this rule to flag `when` expressions that contain a redundant `else` case. This occurs when it can be
* verified that all cases are already covered when checking cases on an enum or sealed class.
Expand Down Expand Up @@ -83,19 +72,10 @@ class RedundantElseInWhen(config: Config = Config.empty) : Rule(config) {
super.visitWhenExpression(whenExpression)

if (bindingContext == BindingContext.EMPTY) return
if (whenExpression.elseExpression == null) return
val subjectType = whenExpression.subjectExpression?.getType(bindingContext)

if (subjectType != null && WhenChecker.getMissingCases(whenExpression, bindingContext).isEmpty()) {
val subjectClass = subjectType.constructor.declarationDescriptor as? ClassDescriptor
val pseudocodeDescriptor =
bindingContext[DECLARATION_TO_DESCRIPTOR, subjectClass?.toSourceElement?.getPsi()]
if (subjectClass == null ||
KotlinBuiltIns.isBooleanOrNullableBoolean(subjectType) ||
subjectClass.module == pseudocodeDescriptor?.module
) {
report(CodeSmell(issue, Entity.from(whenExpression), "When expression contains redundant `else` case."))
}
val elseEntry = whenExpression.entries.lastOrNull { it.isElse } ?: return
val compilerReports = bindingContext.diagnostics.forElement(elseEntry)
if (compilerReports.any { it.factory == Errors.REDUNDANT_ELSE_IN_WHEN }) {
report(CodeSmell(issue, Entity.from(whenExpression), "When expression contains redundant `else` case."))
}
}
}