Hi everyone, I'm working on a Kotlin Multiplatform project and encountering issues with .wasm file v...

# webassembly

[Anuta Vlad Sv]

Hi everyone,
I'm working on a Kotlin Multiplatform project and encountering issues with .wasm file validation. I created a minimal test setup with the following code:
kotlin

@JsExport
fun sayHello(): Int { return 42 }

When I validate the output with:
bash

wasm-validate multiplatformlib.wasm

I get the error:

000002a: error: expected valid result type (got -0xf)

Has anyone else encountered this issue with Kotlin 2.1.21 and WASM validation? Any suggestions on why the .wasm file validation is failing or how to fix it? Thanks!

[Anuta Vlad Sv]

My Gradle configuration:
kotlin

@file:OptIn(ExperimentalWasmDsl::class)
import org.jetbrains.kotlin.gradle.ExperimentalWasmDsl

plugins {
    id(libs.plugins.myapp.kotlin.multiplatform.get().pluginId)
}

kotlin {
    wasmJs {
        binaries.library()
        browser()
    }
    sourceSets {
        val wasmJsMain by getting {
            kotlin.srcDir("src/wasmJsMain/kotlin")
        }
    }
}

I'm using Kotlin version 2.1.21 and generating the .wasm file with:
bash

./gradlew :shared:data:minimalwasm:clean :shared:data:minimalwasm:wasmJsProductionLibraryCompileSync

[Igor Yakovlev]

Hi, how did you run it?

[Anuta Vlad Sv]

Hi! This is the command i used to validate the .wasm

bash

wasm-validate multiplatformlib.wasm

and to generate it i used
./gradlew shareddataminimalwasmclean shareddataminimalwasmwasmJsProductionLibraryCompileSync

[Igor Yakovlev]

I believe that wasm-validate could be outdated and not supporting wasm GC proposal

[Anuta Vlad Sv]

I see, is there another way i can check the .wasm file is valid?

[Igor Yakovlev]

Try to check if your wasm-validate supports wasm-gc proposal and update it if needed..you can also validate it with nodejs using https://developer.mozilla.org/en-US/docs/WebAssembly/Reference/JavaScript_interface/validate_static

[Anuta Vlad Sv]

Will try thank you color

[Anuta Vlad Sv]

So i used the WebAssembly.validate fun and it seems to be a valid file 🥳