Fix stackoverflow for scala traits (#9)

* Integration test for transitively Serializable objects

* Fix StackoverflowError for scala traits

* Up version to 1.4.1

README.md

@@ -14,7 +14,7 @@ The plugin adds `readResolve` method for every object which either:
 
 // plugins dsl
 plugins {
-  id "me.shika.kotlin-object-java-serialization" version "1.4.0"
+  id "me.shika.kotlin-object-java-serialization" version "1.4.1"
 }
 
 // or else
@@ -25,7 +25,7 @@ buildscript {
     }
   }
   dependencies {
-    classpath "me.shika:kotlin-object-java-serialization:1.4.0"
+    classpath "me.shika:kotlin-object-java-serialization:1.4.1"
   }
 }
 

build.gradle

@@ -13,5 +13,5 @@ allprojects {
     }
 
     group 'me.shika'
-    version '1.4.0'
+    version '1.4.1'
 }

gradle-plugin/src/main/kotlin/me/shika/ObjectSerializationPlugin.kt

@@ -36,7 +36,7 @@ class ObjectSerializationPlugin : KotlinCompilerPluginSupportPlugin {
         SubpluginArtifact(
             groupId = "me.shika",
             artifactId = "kotlin-object-java-serialization",
-            version = "1.4.0"
+            version = "1.4.1"
         )
 
     override fun isApplicable(kotlinCompilation: KotlinCompilation<*>): Boolean =

integration-test/build.gradle

@@ -1,8 +1,11 @@
-apply plugin: "org.jetbrains.kotlin.jvm"
+plugins {
+    id 'org.jetbrains.kotlin.jvm'
+}
 
 dependencies {
     implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk8"
+    implementation project('scala-module')
     testImplementation 'junit:junit:4.12'
 
     kotlinCompilerPluginClasspath project(':kotlin-plugin')
-}
+}

integration-test/scala-module/build.gradle

@@ -0,0 +1,8 @@
+plugins {
+    id 'scala'
+    id 'java-library'
+}
+
+dependencies {
+    api 'org.scala-lang:scala-library:2.12.17'
+}

integration-test/scala-module/src/main/scala/NotSerializableTrait.scala

@@ -0,0 +1 @@
+trait NotSerializableTrait

integration-test/scala-module/src/main/scala/SerializableTrait.scala

@@ -0,0 +1 @@
+trait SerializableTrait extends Serializable

integration-test/src/main/kotlin/ImplementScala.kt

@@ -0,0 +1,3 @@
+object SerializableFromScala: SerializableTrait
+
+object NotSerializableFromScala: NotSerializableTrait

integration-test/src/main/kotlin/TestInterface.kt

@@ -0,0 +1,11 @@
+import java.io.Serializable
+
+interface TestInterface: Serializable
+
+object DirectlyImplementsTestInterface: TestInterface
+
+abstract class ExtendsTestInterface: TestInterface
+
+object IndirectlyImplementsTestInterface: ExtendsTestInterface()
+
+object NotSerializable

integration-test/src/test/kotlin/DeserializationTest.kt

@@ -1,24 +1,33 @@
-import org.junit.Assert.assertEquals
+import org.junit.Assert.assertSame
 import org.junit.Test
-import java.io.ByteArrayInputStream
-import java.io.ByteArrayOutputStream
-import java.io.ObjectInputStream
-import java.io.ObjectOutputStream
-import java.io.Serializable
+import java.io.*
 
 class ObjectSerializationIntegrationTest {
     @Test
     fun `object instance is the same after deserialization`() {
-        assertEquals(TestObject, serializeDeserialize(TestObject))
+        assertSame(TestObject, serializeDeserialize(TestObject))
+        assertSame(DirectlyImplementsTestInterface, serializeDeserialize(DirectlyImplementsTestInterface))
+        assertSame(IndirectlyImplementsTestInterface, serializeDeserialize(IndirectlyImplementsTestInterface))
+        assertSame(SerializableFromScala, serializeDeserialize(SerializableFromScala))
     }
 
-    private fun serializeDeserialize(instance: Serializable): Serializable {
+    @Test(expected = NotSerializableException::class)
+    fun `cannot serialize non-serializable object`() {
+        serializeDeserialize(NotSerializable)
+    }
+
+    @Test(expected = NotSerializableException::class)
+    fun `cannot serialize non-serializable object from scala`() {
+        serializeDeserialize(NotSerializableFromScala)
+    }
+
+    private fun serializeDeserialize(instance: Any): Any? {
         val outputStream = ByteArrayOutputStream()
         ObjectOutputStream(outputStream).use {
             it.writeObject(instance)
         }
         return ObjectInputStream(ByteArrayInputStream(outputStream.toByteArray())).use {
-            it.readObject() as TestObject
+            it.readObject()
         }
     }
 }

kotlin-plugin/src/main/kotlin/me/shika/generation/utils.kt

@@ -40,7 +40,7 @@ fun IrClass.needSerializableFix(): Boolean {
 
 fun IrClass.isSerializable(): Boolean {
     return allSuperInterfaces()
-        .any { it.fqNameWhenAvailable == SERIALIZABLE_FQ_NAME || it.isSerializable() }
+        .any { it.fqNameWhenAvailable == SERIALIZABLE_FQ_NAME || it !== this && it.isSerializable() }
         || getAllSuperclasses().any { it.isSerializable() }
 }
 

settings.gradle

@@ -3,3 +3,4 @@ rootProject.name = 'kotlin-object-java-serialization'
 include ':gradle-plugin'
 include ':kotlin-plugin'
 include ':integration-test'
+include ':integration-test:scala-module'