Data class with ByteArray in kotlin

Question

I created a Data class in Kotlin that contains an image as a ByteArray. When I build I have the following error:

Error:Kotlin: [Internal Error] java.lang.IllegalStateException: Backend Internal error: Exception during code generation
Cause: An operation is not implemented: primitive arrays are not supported yet
File being compiled at position: file:///my/home/Project/my-generator/src/main/kotlin/com/myapp/domain/Alert.kt
The root cause was thrown at: JVMCodegenUtil.kt:364
    at org.jetbrains.kotlin.codegen.CompilationErrorHandler.lambda$static$0(CompilationErrorHandler.java:24)
    at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generate(PackageCodegenImpl.java:76)
    at org.jetbrains.kotlin.codegen.DefaultCodegenFactory.generatePackage(CodegenFactory.kt:96)
    at org.jetbrains.kotlin.codegen.DefaultCodegenFactory.generateModule(CodegenFactory.kt:67)
    at org.jetbrains.kotlin.codegen.KotlinCodegenFacade.doGenerateFiles(KotlinCodegenFacade.java:47)
    at org.jetbrains.kotlin.codegen.KotlinCodegenFacade.compileCorrectFiles(KotlinCodegenFacade.java:39)
    at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.generate(KotlinToJVMBytecodeCompiler.kt:476)
    at org.jetbrains.kotlin.cli.jvm.compiler.KotlinToJVMBytecodeCompiler.compileModules$cli(KotlinToJVMBytecodeCompiler.kt:164)
    at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:166)
    at org.jetbrains.kotlin.cli.jvm.K2JVMCompiler.doExecute(K2JVMCompiler.kt:56)
    at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.kt:84)
    at org.jetbrains.kotlin.cli.common.CLICompiler.execImpl(CLICompiler.kt:42)
    at org.jetbrains.kotlin.cli.common.CLITool.exec(CLITool.kt:104)
    at org.jetbrains.kotlin.daemon.CompileServiceImpl$compile$$inlined$ifAlive$lambda$1.invoke(CompileServiceImpl.kt:436)
    at org.jetbrains.kotlin.daemon.CompileServiceImpl$compile$$inlined$ifAlive$lambda$1.invoke(CompileServiceImpl.kt:102)
    at org.jetbrains.kotlin.daemon.CompileServiceImpl$doCompile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:1005)
    at org.jetbrains.kotlin.daemon.CompileServiceImpl$doCompile$$inlined$ifAlive$lambda$2.invoke(CompileServiceImpl.kt:102)
    at org.jetbrains.kotlin.daemon.common.DummyProfiler.withMeasure(PerfUtils.kt:138)
    at org.jetbrains.kotlin.daemon.CompileServiceImpl.checkedCompile(CompileServiceImpl.kt:1047)
    at org.jetbrains.kotlin.daemon.CompileServiceImpl.doCompile(CompileServiceImpl.kt:1004)
    at org.jetbrains.kotlin.daemon.CompileServiceImpl.compile(CompileServiceImpl.kt:434)
    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$Worker.run(ThreadPoolExecutor.java:624)
    at java.lang.Thread.run(Thread.java:748)
Caused by: kotlin.NotImplementedError: An operation is not implemented: primitive arrays are not supported yet
    at org.jetbrains.kotlinx.serialization.compiler.backend.jvm.JVMCodegenUtilKt.getSerialTypeInfo(JVMCodegenUtil.kt:364)
    at org.jetbrains.kotlinx.serialization.compiler.backend.jvm.SerializerCodegenImpl$generateLoad$1.invoke(SerializerCodegenImpl.kt:365)
    at org.jetbrains.kotlinx.serialization.compiler.backend.jvm.SerializerCodegenImpl$generateLoad$1.invoke(SerializerCodegenImpl.kt:32)
    at org.jetbrains.kotlinx.serialization.compiler.backend.jvm.JVMCodegenUtilKt$generateMethod$1.doGenerateBody(JVMCodegenUtil.kt:153)
    at org.jetbrains.kotlin.codegen.FunctionGenerationStrategy$CodegenBased.generateBody(FunctionGenerationStrategy.java:84)
    at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:666)
    at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethodBody(FunctionCodegen.java:473)
    at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:260)
    at org.jetbrains.kotlin.codegen.FunctionCodegen.generateMethod(FunctionCodegen.java:176)
    at org.jetbrains.kotlinx.serialization.compiler.backend.jvm.JVMCodegenUtilKt.generateMethod(JVMCodegenUtil.kt:150)
    at org.jetbrains.kotlinx.serialization.compiler.backend.jvm.SerializerCodegenImpl.generateLoad(SerializerCodegenImpl.kt:287)
    at org.jetbrains.kotlinx.serialization.compiler.backend.common.SerializerCodegen.generateLoadIfNeeded(SerializerCodegen.kt:121)
    at org.jetbrains.kotlinx.serialization.compiler.backend.common.SerializerCodegen.generate(SerializerCodegen.kt:48)
    at org.jetbrains.kotlinx.serialization.compiler.backend.jvm.SerializerCodegenImpl$Companion.generateSerializerExtensions(SerializerCodegenImpl.kt:49)
    at org.jetbrains.kotlinx.serialization.compiler.extensions.SerializationCodegenExtension.generateClassSyntheticParts(SerializationCodegenExtension.kt:30)
    at org.jetbrains.kotlin.codegen.ImplementationBodyCodegen.generateSyntheticPartsAfterBody(ImplementationBodyCodegen.java:438)
    at org.jetbrains.kotlin.codegen.MemberCodegen.generate(MemberCodegen.java:132)
    at org.jetbrains.kotlin.codegen.MemberCodegen.genClassOrObject(MemberCodegen.java:302)
    at org.jetbrains.kotlin.codegen.MemberCodegen.genSyntheticClassOrObject(MemberCodegen.java:316)
    at org.jetbrains.kotlin.codegen.ClassBodyCodegen.generateBody(ClassBodyCodegen.java:111)
    at org.jetbrains.kotlin.codegen.MemberCodegen.generate(MemberCodegen.java:129)
    at org.jetbrains.kotlin.codegen.MemberCodegen.genClassOrObject(MemberCodegen.java:302)
    at org.jetbrains.kotlin.codegen.MemberCodegen.genClassOrObject(MemberCodegen.java:286)
    at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generateClassesAndObjectsInFile(PackageCodegenImpl.java:118)
    at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generateFile(PackageCodegenImpl.java:137)
    at org.jetbrains.kotlin.codegen.PackageCodegenImpl.generate(PackageCodegenImpl.java:68)
    ... 36 more

The main message in the error seems to be primitive arrays are not supported yet. If a remove the ByteArray of the data class, this is compiling correctly.

Is there a way to create a data class with ByteArray ? Or is there a way to convert a ByteArray to Array<Byte> ?

Thanks for your help

Answer 1

The kotlinx.serialization library isn't finished and you're running into one of the outstanding issues: https://github.com/Kotlin/kotlinx.serialization/issues/52

Simply put the maintainers of the serialization library haven't decided the best way to handle primitive arrays yet so they cause issues during compilation, you will need to write your own encoder or convert it to a supported type like List<Byte> (the issue linked above says this doesn't happen because it would cause performance issues)