Apparently you can not mark a common class with `@...

# webassembly

[andylamax]

Apparently you can not mark a common class with @JsExports and also have a wasm target.

e.g.
commonMain/kotlin/sample/User.kt

package sample

import kotlin.js.JsExport

@JsExport
class User

fails with

> Task compileKotlinWasm FAILED
e: sample/src/commonMain/kotlin/sample/User.kt This annotation is not applicable to target 'class'

If I move the annotation up, to file level, like so

@file:JsExport

@file:JsExport
package koncurrent

import kotlin.js.JsExport

class User

fails with

> Task compileKotlinWasm FAILED
e: sample/src/commonMain/kotlin/sample/User.kt This annotation is not applicable to target 'file' and use site target '@file'

Any known workarround?? Some supressions perhaps??

[andylamax]

@turansky So sorry for tagging you here. But you are the Suppress king that I know about. Any help?

[Svyatoslav Kuzmich [JB]]

Thank you for bringing this up, we need to fix this.

A workaround for defining annotation that works only in K/JS:

// common:
expect annotation class JsTargetOnlyJsExport() 

@JsTargetOnlyJsExport
class User

// js:
actual typealias JsTargetOnlyJsExport = JsExport  // Real JsExport

// wasm:
actual annotation class JsTargetOnlyJsExport  // Fake JsExport, does nothing

Alternatively you can use experimental @OptionalExpectation on JsTargetOnlyJsExport to avoid defining fake actuals in non-JS platforms.

[andylamax]

I thought about that, but then I was just adding wasm support to a very large code base. The efforts it would take migrate to the new JSTargetOnlyJsExport would be tremendous.

If fixing this won't take that much time, I can definitely wait

[Svyatoslav Kuzmich [JB]]

I see. I imagine that suppression via @Suppress("WRONG_ANNOTATION_TARGET") would take about the same effort, but it would be a lot more hacky.

[andylamax]

That's actually a better argument than mine. I think I'll take your approach then. at least for now

[andylamax]

Somehow I expected kotlin 1.9.0 will allow @JsExport on common main. Is there a ticket I can follow up with?

[andylamax]

@Svyatoslav Kuzmich [JB] is this fixed?? or do we still need a workaround?

[Svyatoslav Kuzmich [JB]]

Not fixed yet. Could you please file an issue?

[andylamax]

https://youtrack.jetbrains.com/issue/KT-62385/JsExport-doenst-play-well-with-the-WasmTarget

Help me up vote this one please