kotlinx.serialization: Fix interface delegation when delegate is initialized in a function (#4727)

Fixes https://github.com/Kotlin/kotlinx.serialization/issues/241

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/ir/SerializableIrGenerator.kt

@@ -12,11 +12,14 @@ import org.jetbrains.kotlin.descriptors.*
 import org.jetbrains.kotlin.ir.IrStatement
 import org.jetbrains.kotlin.ir.builders.*
 import org.jetbrains.kotlin.ir.declarations.*
-import org.jetbrains.kotlin.ir.expressions.IrExpression
+import org.jetbrains.kotlin.ir.expressions.*
-import org.jetbrains.kotlin.ir.expressions.IrExpressionBody
 import org.jetbrains.kotlin.ir.expressions.impl.IrDelegatingConstructorCallImpl
-import org.jetbrains.kotlin.ir.types.*
+import org.jetbrains.kotlin.ir.types.IrSimpleType
+import org.jetbrains.kotlin.ir.types.IrTypeProjection
+import org.jetbrains.kotlin.ir.types.classOrNull
+import org.jetbrains.kotlin.ir.types.isString
 import org.jetbrains.kotlin.ir.util.*
+import org.jetbrains.kotlin.ir.visitors.IrElementTransformerVoid
 import org.jetbrains.kotlin.js.resolve.diagnostics.findPsi
 import org.jetbrains.kotlin.resolve.BindingContext
 import org.jetbrains.kotlin.resolve.descriptorUtil.fqNameSafe
@@ -24,7 +27,10 @@ import org.jetbrains.kotlin.resolve.descriptorUtil.module
 import org.jetbrains.kotlin.util.OperatorNameConventions
 import org.jetbrains.kotlin.util.collectionUtils.filterIsInstanceAnd
 import org.jetbrains.kotlin.utils.getOrPutNullable
-import org.jetbrains.kotlinx.serialization.compiler.backend.common.*
+import org.jetbrains.kotlinx.serialization.compiler.backend.common.SerializableCodegen
+import org.jetbrains.kotlinx.serialization.compiler.backend.common.findTypeSerializerOrContext
+import org.jetbrains.kotlinx.serialization.compiler.backend.common.isStaticSerializable
+import org.jetbrains.kotlinx.serialization.compiler.backend.common.serialName
 import org.jetbrains.kotlinx.serialization.compiler.diagnostic.serializableAnnotationIsUseless
 import org.jetbrains.kotlinx.serialization.compiler.extensions.SerializationPluginContext
 import org.jetbrains.kotlinx.serialization.compiler.resolve.*
@@ -169,6 +175,20 @@ class SerializableIrGenerator(
 
                 statementsAfterSerializableProperty[prop.descriptor]?.forEach { +it }
             }
+
+            // Handle function-intialized interface delegates
+            irClass.declarations
+                .filterIsInstance<IrField>()
+                .filter { it.origin == IrDeclarationOrigin.DELEGATE }
+                .forEach {
+                    val receiver = if (!it.isStatic) irGet(thiz) else null
+                    +irSetField(
+                        receiver,
+                        it,
+                        initializerAdapter(it.initializer!!),
+                        IrStatementOrigin.INITIALIZE_FIELD
+                    )
+                }
         }
 
     private fun IrBlockBodyBuilder.getStaticSerialDescriptorExpr(): IrExpression {
@@ -263,8 +283,8 @@ class SerializableIrGenerator(
         val superProperties = bindingContext.serializablePropertiesFor(superClass.descriptor).serializableProperties
         val superSlots = superProperties.bitMaskSlotCount()
         val arguments = allValueParameters.subList(0, superSlots) +
-                    allValueParameters.subList(propertiesStart, propertiesStart + superProperties.size) +
+                allValueParameters.subList(propertiesStart, propertiesStart + superProperties.size) +
-                    allValueParameters.last() // SerializationConstructorMarker
+                allValueParameters.last() // SerializationConstructorMarker
         val call = IrDelegatingConstructorCallImpl.fromSymbolDescriptor(
             startOffset,
             endOffset,
@@ -290,7 +310,8 @@ class SerializableIrGenerator(
 
             // Since writeSelf is a static method, we have to replace all references to this in property initializers
             val thisSymbol = irClass.thisReceiver!!.symbol
-            val initializerAdapter: (IrExpressionBody) -> IrExpression = createInitializerAdapter(irClass, propertyByParamReplacer, thisSymbol to { irGet(objectToSerialize) })
+            val initializerAdapter: (IrExpressionBody) -> IrExpression =
+                createInitializerAdapter(irClass, propertyByParamReplacer, thisSymbol to { irGet(objectToSerialize) })
 
             // Compute offset of properties in superclass
             var ignoreIndexTo = -1

plugins/kotlin-serialization/kotlin-serialization-compiler/src/org/jetbrains/kotlinx/serialization/compiler/backend/jvm/SerializableCodegenImpl.kt

@@ -12,6 +12,7 @@ import org.jetbrains.kotlin.descriptors.FunctionDescriptor
 import org.jetbrains.kotlin.descriptors.PropertyDescriptor
 import org.jetbrains.kotlin.js.resolve.diagnostics.findPsi
 import org.jetbrains.kotlin.lexer.KtTokens
+import org.jetbrains.kotlin.psi.KtDelegatedSuperTypeEntry
 import org.jetbrains.kotlin.psi.KtExpression
 import org.jetbrains.kotlin.psi.KtParameter
 import org.jetbrains.kotlin.resolve.BindingContext
@@ -42,9 +43,9 @@ class SerializableCodegenImpl(
     companion object {
         fun generateSerializableExtensions(codegen: ImplementationBodyCodegen) {
             val serializableClass = codegen.descriptor
-            if (serializableClass.isInternalSerializable)
+            if (serializableClass.isInternalSerializable) {
                 SerializableCodegenImpl(codegen).generate()
-            else if (serializableClass.serializableAnnotationIsUseless) {
+            } else if (serializableClass.serializableAnnotationIsUseless) {
                 throw CompilationException(
                     "@Serializable annotation on $serializableClass would be ignored because it is impossible to serialize it automatically. " +
                             "Provide serializer manually via e.g. companion object", null, serializableClass.findPsi()
@@ -228,7 +229,7 @@ class SerializableCodegenImpl(
         }
 
         // these properties required to be manually invoked, because they are not in serializableProperties
-        val serializedProps = properties.serializableProperties.map { it.descriptor }
+        val serializedProps = properties.serializableProperties.map { it.descriptor }.toSet()
 
         (descToProps - serializedProps)
             .filter { classCodegen.shouldInitializeProperty(it.value) }
@@ -236,6 +237,24 @@ class SerializableCodegenImpl(
         (paramsToProps - serializedProps)
             .forEach { (t, u) -> exprCodegen.genInitParam(t, u) }
 
+        // Initialize delegates
+        var delegate = 0
+        for (specifier in classCodegen.myClass.superTypeListEntries) {
+            if (specifier is KtDelegatedSuperTypeEntry) {
+                val expr = specifier.delegateExpression!!
+
+                load(0, thisAsmType)
+                val stackValue = exprCodegen.gen(expr)
+                stackValue.put(exprCodegen.v)
+
+                putfield(
+                    thisAsmType.internalName,
+                    "\$\$delegate_${delegate++}",
+                    stackValue.type.descriptor
+                )
+            }
+        }
+
         // init blocks
         // todo: proper order with other initializers?
         classCodegen.myClass.anonymousInitializers()

plugins/kotlin-serialization/kotlin-serialization-compiler/test/org/jetbrains/kotlinx/serialization/SerializationIrBytecodeListingTestGenerated.java

@@ -34,6 +34,11 @@ public class SerializationIrBytecodeListingTestGenerated extends AbstractSeriali
         runTest("plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Basic.kt");
     }
 
+    @TestMetadata("Delegated.kt")
+    public void testDelegated() throws Exception {
+        runTest("plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Delegated.kt");
+    }
+
     @TestMetadata("Sealed.kt")
     public void testSealed() throws Exception {
         runTest("plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Sealed.kt");

plugins/kotlin-serialization/kotlin-serialization-compiler/test/org/jetbrains/kotlinx/serialization/SerializationPluginBytecodeListingTestGenerated.java

@@ -34,6 +34,11 @@ public class SerializationPluginBytecodeListingTestGenerated extends AbstractSer
         runTest("plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Basic.kt");
     }
 
+    @TestMetadata("Delegated.kt")
+    public void testDelegated() throws Exception {
+        runTest("plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Delegated.kt");
+    }
+
     @TestMetadata("Sealed.kt")
     public void testSealed() throws Exception {
         runTest("plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Sealed.kt");

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Delegated.ir.txt

@@ -0,0 +1,139 @@
+public abstract interface A : java/lang/Object {
+    public abstract java.lang.String getText()
+}
+
+public final class DelegatedKt : java/lang/Object {
+    public final static A generateImpl()
+
+    private final static java.lang.String generateImpl$lambda-0()
+}
+
+public final class Test$$serializer : java/lang/Object, kotlinx/serialization/internal/GeneratedSerializer {
+    public final static Test$$serializer INSTANCE
+
+    public final static kotlinx.serialization.descriptors.SerialDescriptor descriptor
+
+    static void <clinit>() {
+          NEW (Test$$serializer)
+          DUP
+          INVOKESPECIAL (Test$$serializer, <init>, ()V)
+          PUTSTATIC (Test$$serializer, INSTANCE, LTest$$serializer;)
+        LABEL (L0)
+        LINENUMBER (12)
+          NEW (kotlinx/serialization/internal/PluginGeneratedSerialDescriptor)
+          DUP
+          LDC (Test)
+          GETSTATIC (Test$$serializer, INSTANCE, LTest$$serializer;)
+          CHECKCAST (kotlinx/serialization/internal/GeneratedSerializer)
+          ICONST_0
+          INVOKESPECIAL (kotlinx/serialization/internal/PluginGeneratedSerialDescriptor, <init>, (Ljava/lang/String;Lkotlinx/serialization/internal/GeneratedSerializer;I)V)
+          CHECKCAST (kotlinx/serialization/descriptors/SerialDescriptor)
+          PUTSTATIC (Test$$serializer, descriptor, Lkotlinx/serialization/descriptors/SerialDescriptor;)
+        LABEL (L1)
+        LINENUMBER (13)
+          RETURN
+    }
+
+    private void <init>() {
+        LABEL (L0)
+        LINENUMBER (12)
+          ALOAD (0)
+          INVOKESPECIAL (java/lang/Object, <init>, ()V)
+          RETURN
+        LABEL (L1)
+    }
+
+    public kotlinx.serialization.KSerializer[] childSerializers()
+
+    public Test deserialize(kotlinx.serialization.encoding.Decoder decoder)
+
+    public java.lang.Object deserialize(kotlinx.serialization.encoding.Decoder decoder)
+
+    public kotlinx.serialization.descriptors.SerialDescriptor getDescriptor()
+
+    public void serialize(kotlinx.serialization.encoding.Encoder encoder, Test value)
+
+    public void serialize(kotlinx.serialization.encoding.Encoder encoder, java.lang.Object value)
+
+    public kotlinx.serialization.KSerializer[] typeParametersSerializers()
+}
+
+public final class Test$Companion : java/lang/Object {
+    private void <init>() {
+        LABEL (L0)
+        LINENUMBER (12)
+          ALOAD (0)
+          INVOKESPECIAL (java/lang/Object, <init>, ()V)
+          RETURN
+        LABEL (L1)
+    }
+
+    public void <init>(kotlin.jvm.internal.DefaultConstructorMarker $constructor_marker) {
+        LABEL (L0)
+          ALOAD (0)
+          INVOKESPECIAL (Test$Companion, <init>, ()V)
+          RETURN
+        LABEL (L1)
+    }
+
+    public final kotlinx.serialization.KSerializer serializer()
+}
+
+public final class Test : java/lang/Object, A {
+    private final A $$delegate_0
+
+    public final static Test$Companion Companion
+
+    static void <clinit>() {
+          NEW (Test$Companion)
+          DUP
+          ACONST_NULL
+          INVOKESPECIAL (Test$Companion, <init>, (Lkotlin/jvm/internal/DefaultConstructorMarker;)V)
+          PUTSTATIC (Test, Companion, LTest$Companion;)
+          RETURN
+    }
+
+    public void <init>() {
+        LABEL (L0)
+        LINENUMBER (12)
+          ALOAD (0)
+          INVOKESPECIAL (java/lang/Object, <init>, ()V)
+        LABEL (L1)
+        LINENUMBER (13)
+          ALOAD (0)
+          INVOKESTATIC (DelegatedKt, generateImpl, ()LA;)
+          PUTFIELD (Test, $$delegate_0, LA;)
+          RETURN
+        LABEL (L2)
+    }
+
+    public void <init>(int seen1, kotlinx.serialization.internal.SerializationConstructorMarker serializationConstructorMarker) {
+        LABEL (L0)
+        LINENUMBER (12)
+          ICONST_0
+          ILOAD (1)
+          IAND
+          IFEQ (L1)
+          ILOAD (1)
+          ICONST_0
+          GETSTATIC (Test$$serializer, INSTANCE, LTest$$serializer;)
+          INVOKEVIRTUAL (Test$$serializer, getDescriptor, ()Lkotlinx/serialization/descriptors/SerialDescriptor;)
+          INVOKESTATIC (kotlinx/serialization/internal/PluginExceptionsKt, throwMissingFieldException, (IILkotlinx/serialization/descriptors/SerialDescriptor;)V)
+        LABEL (L1)
+          ALOAD (0)
+          INVOKESPECIAL (java/lang/Object, <init>, ()V)
+          ALOAD (0)
+        LABEL (L2)
+        LINENUMBER (13)
+          INVOKESTATIC (DelegatedKt, generateImpl, ()LA;)
+        LABEL (L3)
+        LINENUMBER (12)
+          PUTFIELD (Test, $$delegate_0, LA;)
+          RETURN
+        LABEL (L4)
+    }
+
+    public java.lang.String getText()
+
+    public final static void write$Self(Test self, kotlinx.serialization.encoding.CompositeEncoder output, kotlinx.serialization.descriptors.SerialDescriptor serialDesc)
+}

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Delegated.kt

@@ -0,0 +1,13 @@
+// CURIOUS_ABOUT <init>, <clinit>
+// WITH_STDLIB
+
+import kotlinx.serialization.*
+
+fun interface A {
+    fun getText(): String
+}
+
+fun generateImpl() = A { "Hello, world!" }
+
+@Serializable
+class Test : A by generateImpl()

plugins/kotlin-serialization/kotlin-serialization-compiler/testData/codegen/Delegated.txt

@@ -0,0 +1,158 @@
+public abstract interface A : java/lang/Object {
+    public abstract java.lang.String getText()
+}
+
+final class DelegatedKt$generateImpl$1 : java/lang/Object, A {
+    public final static DelegatedKt$generateImpl$1 INSTANCE
+
+    static void <clinit>() {
+          NEW (DelegatedKt$generateImpl$1)
+          DUP
+          INVOKESPECIAL (DelegatedKt$generateImpl$1, <init>, ()V)
+          PUTSTATIC (DelegatedKt$generateImpl$1, INSTANCE, LDelegatedKt$generateImpl$1;)
+          RETURN
+    }
+
+    void <init>() {
+          ALOAD (0)
+          INVOKESPECIAL (java/lang/Object, <init>, ()V)
+          RETURN
+    }
+
+    public final java.lang.String getText()
+}
+
+public final class DelegatedKt : java/lang/Object {
+    public final static A generateImpl()
+}
+
+public final class Test$$serializer : java/lang/Object, kotlinx/serialization/internal/GeneratedSerializer {
+    private final static kotlinx.serialization.descriptors.SerialDescriptor $$serialDesc
+
+    public final static Test$$serializer INSTANCE
+
+    static void <clinit>() {
+        LABEL (L0)
+        LINENUMBER (13)
+          NEW (Test$$serializer)
+          DUP
+          INVOKESPECIAL (Test$$serializer, <init>, ()V)
+          ASTORE (0)
+          ALOAD (0)
+          PUTSTATIC (Test$$serializer, INSTANCE, LTest$$serializer;)
+          NEW (kotlinx/serialization/internal/PluginGeneratedSerialDescriptor)
+          DUP
+          LDC (Test)
+          GETSTATIC (Test$$serializer, INSTANCE, LTest$$serializer;)
+          CHECKCAST (kotlinx/serialization/internal/GeneratedSerializer)
+          LDC (0)
+          INVOKESPECIAL (kotlinx/serialization/internal/PluginGeneratedSerialDescriptor, <init>, (Ljava/lang/String;Lkotlinx/serialization/internal/GeneratedSerializer;I)V)
+          ASTORE (0)
+          ALOAD (0)
+          PUTSTATIC (Test$$serializer, $$serialDesc, Lkotlinx/serialization/descriptors/SerialDescriptor;)
+          RETURN
+    }
+
+    private void <init>() {
+        LABEL (L0)
+        LINENUMBER (13)
+          ALOAD (0)
+          INVOKESPECIAL (java/lang/Object, <init>, ()V)
+          RETURN
+        LABEL (L1)
+    }
+
+    public kotlinx.serialization.KSerializer[] childSerializers()
+
+    public Test deserialize(kotlinx.serialization.encoding.Decoder decoder)
+
+    public java.lang.Object deserialize(kotlinx.serialization.encoding.Decoder p0)
+
+    public kotlinx.serialization.descriptors.SerialDescriptor getDescriptor()
+
+    public void serialize(kotlinx.serialization.encoding.Encoder encoder, Test value)
+
+    public void serialize(kotlinx.serialization.encoding.Encoder p0, java.lang.Object p1)
+
+    public kotlinx.serialization.KSerializer[] typeParametersSerializers()
+}
+
+public final class Test$Companion : java/lang/Object {
+    private void <init>() {
+        LABEL (L0)
+        LINENUMBER (13)
+          ALOAD (0)
+          INVOKESPECIAL (java/lang/Object, <init>, ()V)
+          RETURN
+        LABEL (L1)
+    }
+
+    public void <init>(kotlin.jvm.internal.DefaultConstructorMarker $constructor_marker) {
+        LABEL (L0)
+        LINENUMBER (13)
+          ALOAD (0)
+          INVOKESPECIAL (Test$Companion, <init>, ()V)
+          RETURN
+        LABEL (L1)
+    }
+
+    public final kotlinx.serialization.KSerializer serializer()
+}
+
+public final class Test : java/lang/Object, A {
+    private final A $$delegate_0
+
+    public final static Test$Companion Companion
+
+    static void <clinit>() {
+          NEW (Test$Companion)
+          DUP
+          ACONST_NULL
+          INVOKESPECIAL (Test$Companion, <init>, (Lkotlin/jvm/internal/DefaultConstructorMarker;)V)
+          PUTSTATIC (Test, Companion, LTest$Companion;)
+          RETURN
+    }
+
+    public void <init>() {
+        LABEL (L0)
+        LINENUMBER (13)
+          ALOAD (0)
+          INVOKESPECIAL (java/lang/Object, <init>, ()V)
+          ALOAD (0)
+        LABEL (L1)
+        LINENUMBER (13)
+          INVOKESTATIC (DelegatedKt, generateImpl, ()LA;)
+          PUTFIELD (Test, $$delegate_0, LA;)
+          RETURN
+        LABEL (L2)
+    }
+
+    public void <init>(int seen1, kotlinx.serialization.internal.SerializationConstructorMarker serializationConstructorMarker) {
+        LABEL (L0)
+          ICONST_0
+          DUP
+          ILOAD (1)
+          IAND
+          IF_ICMPEQ (L1)
+          ILOAD (1)
+          ICONST_0
+          GETSTATIC (Test$$serializer, INSTANCE, LTest$$serializer;)
+          CHECKCAST (kotlinx/serialization/KSerializer)
+          INVOKEINTERFACE (kotlinx/serialization/KSerializer, getDescriptor, ()Lkotlinx/serialization/descriptors/SerialDescriptor;)
+          INVOKESTATIC (kotlinx/serialization/internal/PluginExceptionsKt, throwMissingFieldException, (IILkotlinx/serialization/descriptors/SerialDescriptor;)V)
+        LABEL (L1)
+          ALOAD (0)
+          INVOKESPECIAL (java/lang/Object, <init>, ()V)
+          ALOAD (0)
+        LABEL (L2)
+        LINENUMBER (13)
+          INVOKESTATIC (DelegatedKt, generateImpl, ()LA;)
+          PUTFIELD (Test, $$delegate_0, LA;)
+          RETURN
+        LABEL (L3)
+    }
+
+    public java.lang.String getText()
+
+    public final static void write$Self(Test self, kotlinx.serialization.encoding.CompositeEncoder output, kotlinx.serialization.descriptors.SerialDescriptor serialDesc)
+}