Hey! I’m receiving this warnings (not always, didn...

# gradle

[Guilherme Delgado]

Hey!
I’m receiving this warnings (not always, didn’t found a pattern):

> Task module123compileDebugKotlin

warning: opt-in requirement marker kotlinx.coroutines.FlowPreview is unresolved. Please make sure it’s present in the module dependencies

warning: opt-in requirement marker kotlinx.coroutines.ExperimentalCoroutinesApi is unresolved. Please make sure it’s present in the module dependencies

warning: opt-in requirement marker kotlinx.serialization.ExperimentalSerializationApi is unresolved. Please make sure it’s present in the module dependencies

But I’ve a gradle script with it:

private fun KotlinJvmOptions.addOptions(options: List<String> = emptyList()) {
    jvmTarget = JavaVersion.VERSION_11.toString()
    freeCompilerArgs = freeCompilerArgs + listOf(
        "-opt-in=kotlin.RequiresOptIn",
        "-opt-in=kotlin.Experimental",
        "-opt-in=kotlinx.coroutines.FlowPreview",
        "-opt-in=kotlinx.coroutines.ExperimentalCoroutinesApi",
        "-opt-in=kotlinx.serialization.ExperimentalSerializationApi"
    ) + options
}

Why is it throwing that warning? 🤔

[Guilherme Delgado]

It’s applied like:

[Guilherme Delgado]

internal fun LibraryExtension.addKotlinJvmOptions(options: List<String> = emptyList()) {
    (this as ExtensionAware).extensions.configure<KotlinJvmOptions>("kotlinOptions") { addOptions(options) }
}

internal fun BaseAppModuleExtension.addKotlinJvmOptions(options: List<String> = emptyList()) {
    (this as ExtensionAware).extensions.configure<KotlinJvmOptions>("kotlinOptions") { addOptions(options) }
}

[Vampire]

From the message I'd guess because you do not have coroutines and serialization in your dependencies.

[Guilherme Delgado]

But I do have them imported, for instance:

import kotlinx.coroutines.FlowPreview

@FlowPreview
....

(actually I can remove them all now because I’m using stable versions, but they’re there 🤔 )

[Vampire]

Well, you answered yourself then.
If you use newer versions of these libs that do not have those opt-in switches anymore the message still makes sense.

[Guilherme Delgado]

Ok, makes sense. Thanks @Vampire 😉

[Guilherme Delgado]

Ok I’ve found one that still needs @ExperimentalSerializationApi:

@ExperimentalSerializationApi
@JvmName("create")
fun StringFormat.asConverterFactory(contentType: MediaType): Converter.Factory {
  return Factory(contentType, FromString(this))
}

If I remove it no warning is thrown in the IDE, only in the console build output

[Guilherme Delgado]

If I add it (and in the gradle script also) it throws randomly:

warning: opt-in requirement marker kotlinx.serialization.ExperimentalSerializationApi is unresolved. Please make sure it’s present in the module dependencies

[Guilherme Delgado]

my script it’s applied to all “app” and “libs” modules

[Guilherme Delgado]

ok i got it, it’s what you said, I was using it in module A but not in module B and this addOptions logic is applied regardless, so yeah, if we do not import the library that needs that flag it will show that warning 🙂

[Mustafa Ozhan]

You can vote this issue for that 🙂 https://youtrack.jetbrains.com/issue/KT-55258/Disable-Opt-in-requirement-marker-unresolved-warnings