Unable to get inline class serialized

I tried to serialize an inlined class. The class is implemented in the commons project of a MPP. The compiler arg “-XXLanguage:+InlineClasses” is defined in the JVM and JS project.

Class:

@Serializable
inline class DeviceId(val value: String) {
    override fun toString(): String = value
}

And get the following exception:

The root cause was thrown at: ImplementationBodyCodegen.java:863
	at org.jetbrains.kotlin.codegen.CompilationErrorHandler.lambda$static$0(CompilationErrorHandler.java:24)
	at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generate(PackageCodegenImpl.java:74)
	at org.jetbrains.kotlin.codegen.DefaultCodegenFactory.generatePackage(CodegenFactory.kt:97)
	at org.jetbrains.kotlin.codegen.DefaultCodegenFactory.generateModule(CodegenFactory.kt:68)
	at org.jetbrains.kotlin.codegen.KotlinCodegenFacade.doGenerateFiles(KotlinCodegenFacade.java:47)
	at org.jetbrains.kotlin.codegen.KotlinCodegenFacade.compileCorrectFiles(KotlinCodegenFacade.java:39)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.generate(KotlinToJVMBytecodeCompiler.kt:446)
	at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileModules$cli(KotlinToJVMBytecodeCompiler.kt:142)
	at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:161)
	at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:57)
	at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.java:96)
	at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.java:52)
	at org.jetbrains.kotlin.cli.common.CLITool.exec(CLITool.kt:93)
	at org.jetbrains.kotlin.incremental.IncrementalJvmCompilerRunner.runCompiler(IncrementalJvmCompilerRunner.kt:362)
	at org.jetbrains.kotlin.incremental.IncrementalJvmCompilerRunner.runCompiler(IncrementalJvmCompilerRunner.kt:102)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.compileIncrementally(IncrementalCompilerRunner.kt:225)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.access$compileIncrementally(IncrementalCompilerRunner.kt:39)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner$compile$2.invoke(IncrementalCompilerRunner.kt:91)
	at org.jetbrains.kotlin.incremental.IncrementalCompilerRunner.compile(IncrementalCompilerRunner.kt:103)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.execIncrementalCompiler(CompileServiceImpl.kt:606)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.access$execIncrementalCompiler(CompileServiceImpl.kt:102)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl$compile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:455)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl$compile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:102)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl$doCompile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:1029)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl$doCompile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:102)
	at org.jetbrains.kotlin.daemon.common.DummyProfiler.withMeasure(PerfUtils.kt:137)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.checkedCompile(CompileServiceImpl.kt:1071)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.doCompile(CompileServiceImpl.kt:1028)
	at org.jetbrains.kotlin.daemon.CompileServiceImpl.compile(CompileServiceImpl.kt:454)
	at sun.reflect.GeneratedMethodAccessor103.invoke(Unknown Source)
	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.ClassCastException: org.jetbrains.kotlin.codegen.ErasedInlineClassBodyCodegen cannot be cast to org.jetbrains.kotlin.codegen.ImplementationBodyCodegen
	at org.jetbrains.kotlin.codegen.ImplementationBodyCodegen.initializeObjects(ImplementationBodyCodegen.java:863)
	at org.jetbrains.kotlin.codegen.ImplementationBodyCodegen.generateSyntheticPartsAfterBody(ImplementationBodyCodegen.java:410)
	at org.jetbrains.kotlin.codegen.MemberCodegen.generate(MemberCodegen.java:130)
	at org.jetbrains.kotlin.codegen.MemberCodegen.genClassOrObject(MemberCodegen.java:300)
	at org.jetbrains.kotlin.codegen.MemberCodegen.genSyntheticClassOrObject(MemberCodegen.java:314)
	at org.jetbrains.kotlin.codegen.ClassBodyCodegen.generateBody(ClassBodyCodegen.java:100)
	at org.jetbrains.kotlin.codegen.MemberCodegen.generate(MemberCodegen.java:127)
	at org.jetbrains.kotlin.codegen.ImplementationBodyCodegen.generateErasedInlineClassIfNeeded(ImplementationBodyCodegen.java:263)
	at org.jetbrains.kotlin.codegen.ClassBodyCodegen.generateBody(ClassBodyCodegen.java:85)
	at org.jetbrains.kotlin.codegen.MemberCodegen.generate(MemberCodegen.java:127)
	at org.jetbrains.kotlin.codegen.MemberCodegen.genClassOrObject(MemberCodegen.java:300)
	at org.jetbrains.kotlin.codegen.MemberCodegen.genClassOrObject(MemberCodegen.java:284)
	at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generateClassOrObject(PackageCodegenImpl.java:161)
	at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generateClassesAndObjectsInFile(PackageCodegenImpl.java:86)
	at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generateFile(PackageCodegenImpl.java:119)
	at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generate(PackageCodegenImpl.java:66)
	... 43 more

[sandwwraith]

@aviadmini We’re trying to look into it

[sandwwraith]

@DaanVandenBosch @fluidsonic That’s the right point – since the class is inline and have only one property, it is reasonable to serialize it as an underlying value, not as a JSON object. It should be true even if the property of the inline type itself is boxed (in JVM terms).

I can say that we have finished inline classes design in serialization and it’s the next thing on a roadmap after sealed classes serialization, which has been released in 0.14.0.