Detect Unused returns

.github/workflows/ci.yml

@@ -2,7 +2,7 @@ name: Agoda Kraft CI
 on:
   push:
 env:
-  JAVA_VERSION: 11
+  JAVA_VERSION: 17
   JAVA_DISTRIBUTION: "adopt"
   MAJOR_MINOR_VERSION: 0.1.
 
@@ -19,6 +19,13 @@ jobs:
           distribution: ${{ env.JAVA_DISTRIBUTION }}
       - name: Build
         run: ./gradlew clean build
+        continue-on-error: true
+      - name: Archive production artifacts
+        uses: actions/upload-artifact@v4
+        with:
+          name: test-reports
+          path: |
+            build/reports
       - name: Test
         run: ./gradlew test
 

README.md

@@ -26,8 +26,8 @@ Add the following to your project's `build.gradle.kts`:
 
 ```kotlin
 dependencies {
-    implementation("io.agodadev:kraft-ktlint:1.0.0")
-    implementation("io.agodadev:kraft-detekt:1.0.0")
+    implementation("io.agodadev:agoda-kraft:0.1.X")
+
 }
 ```
 

build.gradle.kts

@@ -14,7 +14,7 @@ java {
     withJavadocJar()
     withSourcesJar()
     toolchain {
-        languageVersion.set(JavaLanguageVersion.of(11))  // To be compatible with lib consumers
+        languageVersion.set(JavaLanguageVersion.of(17))  // To be compatible with lib consumers
     }
 }
 
@@ -28,13 +28,16 @@ repositories {
 dependencies {
     implementation(kotlin("stdlib"))
     implementation("com.pinterest.ktlint:ktlint-core:0.48.2")
-    implementation("io.gitlab.arturbosch.detekt:detekt-api:1.22.0")
+    implementation("io.gitlab.arturbosch.detekt:detekt-api:1.23.0")
     implementation("com.fasterxml.jackson.core:jackson-databind:2.13.3")
 
+    testImplementation("org.jetbrains.kotlin:kotlin-compiler-embeddable:1.5.0")
     testImplementation("org.jetbrains.kotlin:kotlin-test-junit5")
-    testImplementation("io.gitlab.arturbosch.detekt:detekt-test:1.22.0")
+    testImplementation("io.gitlab.arturbosch.detekt:detekt-test:1.23.0")
     testImplementation("org.mockito:mockito-core:4.8.1")
-    testImplementation("org.junit.jupiter:junit-jupiter:5.7.1")
+    testImplementation("org.junit.jupiter:junit-jupiter-api:5.8.1")
+    testRuntimeOnly("org.junit.jupiter:junit-jupiter-engine:5.8.1")
+    testImplementation("org.assertj:assertj-core:3.24.2")
 }
 
 tasks.test {

jreleaser.yml

@@ -8,7 +8,7 @@ project:
     homepage: "https://github.com/agoda-com/agoda-kraft"
   java:
     groupId: io.agodadev
-    version: "11"
+    version: "17"
   maintainers:
     - Agoda
   copyright: 2024 Agoda

src/main/kotlin/io/agodadev/kraftdetekt/AgodaKraftDetektExtension.kt

@@ -0,0 +1,19 @@
+package io.agodadev.kraftdetekt
+
+import io.gitlab.arturbosch.detekt.api.Config
+import io.gitlab.arturbosch.detekt.api.RuleSet
+import io.gitlab.arturbosch.detekt.api.RuleSetProvider
+
+class AgodaKraftDetektExtension : RuleSetProvider {
+    override val ruleSetId: String = "agoda-kraft"
+
+    override fun instance(config: Config): RuleSet {
+        return RuleSet(
+            ruleSetId,
+            listOf(
+                IgnoredReturnValueRule(config)
+                // Add other rules here when there is new ones
+            )
+        )
+    }
+}

src/main/kotlin/io/agodadev/kraftdetekt/IgnoredReturnValueRule.kt

@@ -0,0 +1,71 @@
+package io.agodadev.kraftdetekt
+
+import io.gitlab.arturbosch.detekt.api.*
+import org.jetbrains.kotlin.com.intellij.psi.PsiElement
+import org.jetbrains.kotlin.psi.*
+import org.jetbrains.kotlin.resolve.calls.util.getResolvedCall
+import org.jetbrains.kotlin.types.typeUtil.isNothing
+import org.jetbrains.kotlin.types.typeUtil.isUnit
+
+class IgnoredReturnValueRule(config: Config) : Rule(config) {
+    override val issue = Issue(
+        javaClass.simpleName,
+        Severity.Warning,
+        "This rule reports when a function call's return value is ignored.",
+        Debt.FIVE_MINS
+    )
+
+    override fun visitCallExpression(expression: KtCallExpression) {
+        super.visitCallExpression(expression)
+
+        if (expression.calleeExpression is KtConstructorCalleeExpression || isWithinThrowExpression(expression)) {
+            return
+        }
+
+        val resolvedCall = expression.getResolvedCall(bindingContext) ?: return
+        val returnType = resolvedCall.resultingDescriptor.returnType ?: return
+
+        if (!returnType.isUnit() && !returnType.isNothing()) {
+            val parent = expression.parent
+            when {
+                parent is KtValueArgument -> return
+                parent is KtProperty -> return
+                parent is KtReturnExpression -> return
+                parent is KtBinaryExpression && parent.operationToken.toString() == "EQ" -> return
+                parent is KtIfExpression && expression == parent.condition -> return
+                parent is KtWhenConditionWithExpression -> return
+                parent is KtBinaryExpression && parent.operationToken.toString() in setOf("GT", "LT", "GTEQ", "LTEQ", "EQEQ", "EXCLEQ") -> return
+                parent is KtDotQualifiedExpression -> return
+                parent is KtBlockExpression -> {
+                    val isLastStatement = parent.statements.lastOrNull() == expression
+                    val isOnlyStatement = parent.statements.size == 1
+                    if (!isLastStatement && !isOnlyStatement) {
+                        report(CodeSmell(
+                            issue,
+                            Entity.from(expression),
+                            "The return value of this function call is ignored."
+                        ))
+                    }
+                }
+                else -> {
+                    report(CodeSmell(
+                        issue,
+                        Entity.from(expression),
+                        "The return value of this function call is ignored."
+                    ))
+                }
+            }
+        }
+    }
+
+    private fun isWithinThrowExpression(expression: KtExpression): Boolean {
+        var current: PsiElement? = expression
+        while (current != null && current !is KtFunction) {
+            if (current is KtThrowExpression) {
+                return true
+            }
+            current = current.parent
+        }
+        return false
+    }
+}

src/main/resources/META-INF/services/io.gitlab.arturbosch.detekt.api.RuleSetProvider

@@ -0,0 +1 @@
+io.agodadev.kraftdetekt.AgodaKraftDetektExtension