Tests for serializable sealed interfaces (#1754)

buildSrc/build.gradle.kts

@@ -1,3 +1,7 @@
+/*
+ * Copyright 2017-2022 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
 import java.util.*
 import java.io.FileInputStream
 
@@ -7,12 +11,21 @@ plugins {
 
 repositories {
     mavenCentral()
+    mavenLocal()
 }
 
-val kotlinVersion = FileInputStream(file("../gradle.properties")).use { propFile ->
-    val ver = Properties().apply { load(propFile) }["kotlin.version"]
-    require(ver is String) { "kotlin.version must be string in ../gradle.properties, got $ver instead" }
-    ver
+val kotlinVersion = run {
+    if (project.hasProperty("build_snapshot_train")) {
+        val ver = project.properties["kotlin_snapshot_version"] as? String
+        require(!ver.isNullOrBlank()) {"kotlin_snapshot_version must be present if build_snapshot_train is used" }
+        return@run ver
+    }
+    val targetProp = if (project.hasProperty("bootstrap")) "kotlin.version.snapshot" else "kotlin.version"
+    FileInputStream(file("../gradle.properties")).use { propFile ->
+        val ver = Properties().apply { load(propFile) }[targetProp]
+        require(ver is String) { "$targetProp must be string in ../gradle.properties, got $ver instead" }
+        ver
+    }
 }
 
 dependencies {

core/commonTest/src/kotlinx/serialization/features/SealedInterfacesSerializationTest.kt

@@ -0,0 +1,100 @@
+/*
+ * Copyright 2017-2021 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+@file:Suppress("SERIALIZER_TYPE_INCOMPATIBLE")
+
+package kotlinx.serialization.features
+
+import kotlinx.serialization.*
+import kotlinx.serialization.descriptors.*
+import kotlinx.serialization.encoding.Decoder
+import kotlinx.serialization.encoding.Encoder
+import kotlinx.serialization.test.*
+import kotlin.test.Test
+import kotlin.test.assertEquals
+
+
+class SealedInterfacesSerializationTest {
+    interface A
+
+    sealed interface B
+
+    @Serializable
+    sealed interface C
+
+    @Serializable(DummySerializer::class)
+    sealed interface D
+
+    @Serializable(DummySerializer::class)
+    interface E
+
+    @Serializable
+    @Polymorphic
+    sealed interface F
+
+    @Serializable
+    class ImplA : A, B, C, D, E, F
+
+    @Serializable
+    class ImplB : A, B, C, D, E, F
+
+    @Serializable
+    class Holder(
+        val a: A,
+        val b: B,
+        val c: C,
+        val d: D,
+        val e: E,
+        @Polymorphic val polyC: C,
+        val f: F
+    )
+
+    class DummySerializer : KSerializer<Any> {
+        override val descriptor: SerialDescriptor = buildClassSerialDescriptor("Dummy")
+
+        override fun serialize(encoder: Encoder, value: Any) {
+            error("serialize")
+        }
+
+        override fun deserialize(decoder: Decoder): Any {
+            error("deserialize")
+        }
+    }
+
+    private fun SerialDescriptor.haveSealedSubclasses() {
+        assertEquals(PolymorphicKind.SEALED, kind)
+        val subclasses = getElementDescriptor(1).elementDescriptors.map { it.serialName.substringAfterLast('.') }
+        assertEquals(listOf("ImplA", "ImplB"), subclasses)
+    }
+
+    private fun SerialDescriptor.isDummy() = serialName == "Dummy"
+
+    private fun SerialDescriptor.isPolymorphic() = kind == PolymorphicKind.OPEN
+
+    operator fun SerialDescriptor.get(i: Int) = getElementDescriptor(i)
+
+    @Test
+    fun testInHolder() {
+        val desc = Holder.serializer().descriptor
+        desc[0].isPolymorphic()
+        desc[1].isPolymorphic()
+        desc[2].haveSealedSubclasses()
+        desc[3].isDummy()
+        desc[4].isDummy()
+        desc[5].isPolymorphic()
+        desc[6].isPolymorphic()
+    }
+
+    @Test
+    fun testGenerated() {
+        C.serializer().descriptor.haveSealedSubclasses()
+    }
+
+    @Test
+    fun testResolved() = noJsLegacy {
+        serializer<C>().descriptor.haveSealedSubclasses()
+    }
+
+
+}

core/jvmMain/src/kotlinx/serialization/internal/Platform.kt

@@ -1,5 +1,5 @@
 /*
- * Copyright 2017-2020 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ * Copyright 2017-2022 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
  */
 
 package kotlinx.serialization.internal

formats/json/commonTest/src/kotlinx/serialization/features/sealed/SealedInterfacesJsonSerializationTest.kt

@@ -0,0 +1,40 @@
+/*
+ * Copyright 2017-2022 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
+ */
+
+package kotlinx.serialization.features.sealed
+
+import kotlinx.serialization.*
+import kotlinx.serialization.json.*
+import kotlinx.serialization.test.*
+import kotlin.test.*
+
+class SealedInterfacesJsonSerializationTest : JsonTestBase() {
+    @Serializable
+    sealed interface I
+
+    @Serializable
+    sealed class Response: I {
+        @Serializable
+        @SerialName("ResponseInt")
+        data class ResponseInt(val i: Int): Response()
+
+        @Serializable
+        @SerialName("ResponseString")
+        data class ResponseString(val s: String): Response()
+    }
+
+    @Serializable
+    @SerialName("NoResponse")
+    object NoResponse: I
+
+    @Test
+    fun testSealedInterfaceJson() = noLegacyJs {
+        val messages = listOf(Response.ResponseInt(10), NoResponse, Response.ResponseString("foo"))
+        assertJsonFormAndRestored(
+            serializer(),
+            messages,
+            """[{"type":"ResponseInt","i":10},{"type":"NoResponse"},{"type":"ResponseString","s":"foo"}]"""
+        )
+    }
+}