VarCouldBeVal: Add configuration flag ignoreLateinitVar (#4745)

detekt · Apr 24, 2022 · 1e506d3 · 1e506d3
1 parent b8bc050
commit 1e506d3
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Showing 3 changed files with 34 additions and 3 deletions.
diff --git a/detekt-core/src/main/resources/default-detekt-config.yml b/detekt-core/src/main/resources/default-detekt-config.yml
@@ -675,6 +675,7 @@ style:
     active: true
   VarCouldBeVal:
     active: true
+    ignoreLateinitVar: false
   WildcardImport:
     active: true
     excludes: ['**/test/**', '**/androidTest/**', '**/commonTest/**', '**/jvmTest/**', '**/jsTest/**', '**/iosTest/**']

diff --git a/detekt-rules-style/src/main/kotlin/io/gitlab/arturbosch/detekt/rules/style/VarCouldBeVal.kt b/detekt-rules-style/src/main/kotlin/io/gitlab/arturbosch/detekt/rules/style/VarCouldBeVal.kt
@@ -8,8 +8,11 @@ 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.ActiveByDefault
+import io.gitlab.arturbosch.detekt.api.internal.Configuration
 import io.gitlab.arturbosch.detekt.api.internal.RequiresTypeResolution
+import io.gitlab.arturbosch.detekt.rules.isLateinit
 import io.gitlab.arturbosch.detekt.rules.isOverride
 import org.jetbrains.kotlin.descriptors.DeclarationDescriptor
 import org.jetbrains.kotlin.lexer.KtTokens
@@ -68,10 +71,13 @@ class VarCouldBeVal(config: Config = Config.empty) : Rule(config) {
         Debt.FIVE_MINS
     )
 
+    @Configuration("Whether to ignore uninitialized lateinit vars")
+    private val ignoreLateinitVar: Boolean by config(defaultValue = false)
+
     override fun visitKtFile(file: KtFile) {
         super.visitKtFile(file)
         if (bindingContext == BindingContext.EMPTY) return
-        val assignmentVisitor = AssignmentVisitor(bindingContext)
+        val assignmentVisitor = AssignmentVisitor(bindingContext, ignoreLateinitVar)
         file.accept(assignmentVisitor)
 
         assignmentVisitor.getNonReAssignedDeclarations().forEach {
@@ -80,7 +86,10 @@ class VarCouldBeVal(config: Config = Config.empty) : Rule(config) {
     }
 
     @Suppress("TooManyFunctions")
-    private class AssignmentVisitor(private val bindingContext: BindingContext) : DetektVisitor() {
+    private class AssignmentVisitor(
+        private val bindingContext: BindingContext,
+        private val ignoreLateinitVar: Boolean
+    ) : DetektVisitor() {
 
         private val declarationCandidates = mutableSetOf<KtNamedDeclaration>()
         private val assignments = mutableMapOf<String, MutableSet<KtExpression>>()
@@ -197,7 +206,7 @@ class VarCouldBeVal(config: Config = Config.empty) : Rule(config) {
 
         private fun KtProperty.isDeclarationCandidate(): Boolean {
             return when {
-                !isVar || isOverride() -> false
+                !isVar || isOverride() || (ignoreLateinitVar && isLateinit()) -> false
                 isLocal || isPrivate() -> true
                 else -> {
                     // Check for whether property belongs to an anonymous object

diff --git a/...-rules-style/src/test/kotlin/io/gitlab/arturbosch/detekt/rules/style/VarCouldBeValSpec.kt b/...-rules-style/src/test/kotlin/io/gitlab/arturbosch/detekt/rules/style/VarCouldBeValSpec.kt
@@ -1,6 +1,7 @@
 package io.gitlab.arturbosch.detekt.rules.style
 
 import io.gitlab.arturbosch.detekt.rules.KotlinCoreEnvironmentTest
+import io.gitlab.arturbosch.detekt.test.TestConfig
 import io.gitlab.arturbosch.detekt.test.compileAndLint
 import io.gitlab.arturbosch.detekt.test.compileAndLintWithContext
 import org.assertj.core.api.Assertions.assertThat
@@ -491,4 +492,24 @@ class VarCouldBeValSpec(val env: KotlinCoreEnvironment) {
             }
         }
     }
+
+    @Nested
+    inner class `lateinit vars - #4731` {
+        val code = """
+            public class A {
+                private lateinit var test: String
+            }
+        """.trimIndent()
+
+        @Test
+        fun `reports uninitialized lateinit vars by default`() {
+            assertThat(subject.compileAndLintWithContext(env, code)).hasSize(1)
+        }
+
+        @Test
+        fun `does not report uninitialized lateinit vars if disabled in config`() {
+            val subject = VarCouldBeVal(TestConfig("ignoreLateinitVar" to true))
+            assertThat(subject.compileAndLintWithContext(env, code)).isEmpty()
+        }
+    }
 }