[KPM] Consistently seal interfaces in :kotlin-gradle-plugin-idea

KT-51386

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinCompilationOutput.kt

@@ -8,7 +8,7 @@ package org.jetbrains.kotlin.gradle.kpm.idea
 import java.io.File
 import java.io.Serializable
 
-interface IdeaKotlinCompilationOutput : Serializable {
+sealed interface IdeaKotlinCompilationOutput : Serializable {
     val classesDirs: Set<File>
     val resourcesDir: File?
 }
@@ -18,6 +18,7 @@ data class IdeaKotlinCompilationOutputImpl(
     override val classesDirs: Set<File>,
     override val resourcesDir: File?
 ) : IdeaKotlinCompilationOutput {
+
     @InternalKotlinGradlePluginApi
     companion object {
         const val serialVersionUID = 0L

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinFragment.kt

@@ -8,7 +8,7 @@ package org.jetbrains.kotlin.gradle.kpm.idea
 import org.jetbrains.kotlin.gradle.kpm.KotlinExternalModelContainer
 import java.io.Serializable
 
-interface IdeaKotlinFragment : Serializable {
+sealed interface IdeaKotlinFragment : Serializable {
     val coordinates: IdeaKotlinFragmentCoordinates
     val platforms: Set<IdeaKotlinPlatform>
     val languageSettings: IdeaKotlinLanguageSettings?

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinLanguageSettings.kt

@@ -8,7 +8,7 @@ package org.jetbrains.kotlin.gradle.kpm.idea
 import java.io.File
 import java.io.Serializable
 
-interface IdeaKotlinLanguageSettings : Serializable {
+sealed interface IdeaKotlinLanguageSettings : Serializable {
     val languageVersion: String?
     val apiVersion: String?
     val isProgressiveMode: Boolean

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinModule.kt

@@ -7,7 +7,7 @@ package org.jetbrains.kotlin.gradle.kpm.idea
 
 import java.io.Serializable
 
-interface IdeaKotlinModule : Serializable {
+sealed interface IdeaKotlinModule : Serializable {
     val coordinates: IdeaKotlinModuleCoordinates
     val fragments: List<IdeaKotlinFragment>
 }

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinModuleCoordinates.kt

@@ -7,7 +7,7 @@ package org.jetbrains.kotlin.gradle.kpm.idea
 
 import java.io.Serializable
 
-interface IdeaKotlinModuleCoordinates : Serializable {
+sealed interface IdeaKotlinModuleCoordinates : Serializable {
     val buildId: String
     val projectPath: String
     val projectName: String

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinProjectModel.kt

@@ -8,7 +8,7 @@ package org.jetbrains.kotlin.gradle.kpm.idea
 import java.io.File
 import java.io.Serializable
 
-interface IdeaKotlinProjectModel : Serializable {
+sealed interface IdeaKotlinProjectModel : Serializable {
     val gradlePluginVersion: String
     val coreLibrariesVersion: String
     val explicitApiModeCliOption: String?

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinResourceDirectory.kt

@@ -8,7 +8,7 @@ package org.jetbrains.kotlin.gradle.kpm.idea
 import java.io.File
 import java.io.Serializable
 
-interface IdeaKotlinResourceDirectory : Serializable {
+sealed interface IdeaKotlinResourceDirectory : Serializable {
     val file: File
 }
 

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinSourceDirectory.kt

@@ -8,7 +8,7 @@ package org.jetbrains.kotlin.gradle.kpm.idea
 import java.io.File
 import java.io.Serializable
 
-interface IdeaKotlinSourceDirectory : Serializable {
+sealed interface IdeaKotlinSourceDirectory : Serializable {
     val file: File
 }
 

libraries/tools/kotlin-gradle-plugin-idea/src/main/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinVariant.kt

@@ -7,7 +7,7 @@ package org.jetbrains.kotlin.gradle.kpm.idea
 
 import java.io.Serializable
 
-interface IdeaKotlinVariant : IdeaKotlinFragment, Serializable {
+sealed interface IdeaKotlinVariant : IdeaKotlinFragment, Serializable {
     val platform: IdeaKotlinPlatform
     val variantAttributes: Map<String, String>
     val compilationOutputs: IdeaKotlinCompilationOutput

libraries/tools/kotlin-gradle-plugin-idea/src/test/kotlin/org/jetbrains/kotlin/gradle/kpm/idea/IdeaKotlinProjectModelObjectGraphTest.kt

@@ -31,6 +31,16 @@ class IdeaKotlinProjectModelObjectGraphTest(private val node: KClass<*>, @Suppre
         )
     }
 
+    @Test
+    fun `test - node is sealed`() {
+        if (node.java.isInterface) {
+            assertTrue(
+                node.isSealed,
+                "Expected $node to be sealed interface"
+            )
+        }
+    }
+
     @Test
     fun `test - node implementations contain serialVersionUID`() {
         if (!node.java.isInterface && !Modifier.isAbstract(node.java.modifiers)) {