Kotlinx.serialization: NPE in `ExpressionCodegen.generate`

[malachid]

Describe the bug
When trying to integrate kotlinx.serialization, unable to compile.

e: java.lang.IllegalStateException: Backend Internal error: Exception during code generation
File being compiled: /home/malachid/work/poc/src/main/kotlin/TestData.kt
The root cause java.lang.RuntimeException was thrown at: org.jetbrains.kotlin.backend.jvm.codegen.FunctionCodegen.generate(FunctionCodegen.kt:50)
        at org.jetbrains.kotlin.backend.common.CodegenUtil.reportBackendException(CodegenUtil.kt:239)
        at org.jetbrains.kotlin.backend.jvm.JvmBackendFacade.doGenerateFilesInternal$backend_jvm(JvmBackendFacade.kt:142)
        at org.jetbrains.kotlin.backend.jvm.JvmBackendFacade.doGenerateFilesInternal$backend_jvm$default(JvmBackendFacade.kt:108)
        at org.jetbrains.kotlin.backend.jvm.JvmBackendFacade.doGenerateFiles(JvmBackendFacade.kt:95)
        at org.jetbrains.kotlin.backend.jvm.JvmIrCodegenFactory.generateModule(JvmIrCodegenFactory.kt:40)
        at org.jetbrains.kotlin.codegen.KotlinCodegenFacade.compileCorrectFiles(KotlinCodegenFacade.java:35)
        at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.generate(KotlinToJVMBytecodeCompiler.kt:616)
        at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileModules$cli(KotlinToJVMBytecodeCompiler.kt:203)
        at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:164)
        at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:51)
        at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.kt:86)
        at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.kt:44)
        at org.jetbrains.kotlin.cli.common.CLITool.exec(CLITool.kt:98)
        at org.jetbrains.kotlin.incremental.IncrementalJvmCompilerRunner.runCompiler(IncrementalJvmCompilerRunner.kt:346)
        at org.jetbrains.kotlin.incremental.IncrementalJvmCompilerRunner.runCompiler(IncrementalJvmCompilerRunner.kt:102)
        at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.compileIncrementally(IncrementalCompilerRunner.kt:240)
        at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.access$compileIncrementally(IncrementalCompilerRunner.kt:39)
        at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner$compile$2.invoke(IncrementalCompilerRunner.kt:81)
        at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.compile(IncrementalCompilerRunner.kt:93)
        at org.jetbrains.kotlin.daemon.CompileServiceImplBase.execIncrementalCompiler(CompileServiceImpl.kt:601)
        at org.jetbrains.kotlin.daemon.CompileServiceImplBase.access$execIncrementalCompiler(CompileServiceImpl.kt:93)
        at org.jetbrains.kotlin.daemon.CompileServiceImpl.compile(CompileServiceImpl.kt:1633)
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62)
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
        at java.lang.reflect.Method.invoke(Method.java:498)
        at sun.rmi.server.UnicastServerRef.dispatch(UnicastServerRef.java:357)
        at sun.rmi.transport.Transport$1.run(Transport.java:200)
        at sun.rmi.transport.Transport$1.run(Transport.java:197)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.rmi.transport.Transport.serviceCall(Transport.java:196)
        at sun.rmi.transport.tcp.TCPTransport.handleMessages(TCPTransport.java:573)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run0(TCPTransport.java:834)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.lambda$run$0(TCPTransport.java:688)
        at java.security.AccessController.doPrivileged(Native Method)
        at sun.rmi.transport.tcp.TCPTransport$ConnectionHandler.run(TCPTransport.java:687)
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149)
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624)
        at java.lang.Thread.run(Thread.java:748)
Caused by: java.lang.RuntimeException: Exception while generating code for:
CONSTRUCTOR visibility:public <> (seen1:kotlin.Int, thing:kotlin.Int?, serializationConstructorMarker:kotlinx.serialization.internal.SerializationConstructorMarker?) returnType:<root>.TestData
  annotations:
    Deprecated(message = 'This synthesized declaration should not be used directly', replaceWith = ReplaceWith(expression = '', imports = []), level = GET_ENUM 'ENUM_ENTRY IR_EXTERNAL_DECLARATION_STUB name:HIDDEN' type=kotlin.DeprecationLevel)
  VALUE_PARAMETER name:seen1 index:0 type:kotlin.Int
  VALUE_PARAMETER name:thing index:1 type:kotlin.Int?
  VALUE_PARAMETER name:serializationConstructorMarker index:2 type:kotlinx.serialization.internal.SerializationConstructorMarker?

        at org.jetbrains.kotlin.backend.jvm.codegen.FunctionCodegen.generate(FunctionCodegen.kt:50)
        at org.jetbrains.kotlin.backend.jvm.codegen.ClassCodegen.generateMethodNode(ClassCodegen.kt:268)
        at org.jetbrains.kotlin.backend.jvm.codegen.ClassCodegen.generateMethod(ClassCodegen.kt:285)
        at org.jetbrains.kotlin.backend.jvm.codegen.ClassCodegen.generate(ClassCodegen.kt:123)
        at org.jetbrains.kotlin.backend.jvm.JvmBackendFacade.doGenerateFilesInternal$backend_jvm(JvmBackendFacade.kt:139)
        ... 37 more
Caused by: java.lang.NullPointerException
        at org.jetbrains.kotlin.backend.jvm.codegen.ExpressionCodegen.generate(ExpressionCodegen.kt:199)
        at org.jetbrains.kotlin.backend.jvm.codegen.FunctionCodegen.doGenerate(FunctionCodegen.kt:105)
        at org.jetbrains.kotlin.backend.jvm.codegen.FunctionCodegen.generate(FunctionCodegen.kt:48)
        ... 41 more


FAILURE: Build failed with an exception.

To Reproduce

1. copy this template https://github.com/JetBrains/compose-jb/tree/master/templates/desktop-template
2. add kotlin("plugin.serialization") version "1.4.10"
3. add implementation("org.jetbrains.kotlinx:kotlinx-serialization-json:1.0.1")
4. add a very basic model into src/main/kotlin:

import kotlinx.serialization.*

@Serializable
data class TestData(var thing: Int? = null)

(I have tested w/ and w/o the default value; with var and val)

Expected behavior
App should compile.
As a side note, you have to include json support - even if that isn't the intended target; or the IDE can't resolve @Serializable.

Environment

• Kotlin version: 1.4.10
• Library version: 1.4.10 and 1.0.1
• Kotlin platforms: JVM
• Gradle version: 6.5.1
• IDE version (if bug is related to the IDE) IntelliJ Ultimate 2020.3 EAP --or-- pure CLI
• Other relevant context: Ubuntu 18.04, JDK 11

[sandwwraith]

kotlinx.serialization currently is not fully compatible with Jetpack Compose

[sigmadeltasoftware]

I've currently encountered the same issue for a sealed class's child which uses the @Serializable annotation: Stacktrace Gist

The implementation was working before when I was purely using Kotlin Platform Mobile (along with Jetpack Compose for Android), but it started failing once I introduced Jetbrains Compose for Desktop (along with its modifications for :common's build.gradle.kts file).

Is there a timeline on when compatibility for these two might be introduced?

[korredor11]

i've got the same error, anyone has a way out of this. Kinda Brings me down things were working well. :/

[rossdanderson]

I put my serializable classes into a gradle subproject with the serialization plugin and no compose plugin, and then had the subproject with the compose plugin and no serialization plugin depend on that. Hope that helps.