Hej! Im working with the Android side of a multipl...

# multiplatform

[Zoltan Demant]

Hej! Im working with the Android side of a multiplatform project, and Ive been completely pwned by the build times. To the point that Im fairly certain that something is terribly wrong.
• Compiling and running the desktop variant takes roughly 2 seconds on average. I dont have any data for this specifically, but its very quick.
• When it comes to Android, Im seeing average build times of around 5 minutes and looking at a build scan I can see that some very small modules take a few minutes to compile. This tells me that something is at odds, but I dont really understand what that might be?
More details in 🧵

[Zoltan Demant]

For example, in the timeline view of a build scan I can see that:

:navigator 3m 38.866s

That module is just a shared module between many other modules. It has one object, a sealed interface with ~50 classes and a dependency on coroutines + a very tiny in house library (which also just depends on coroutines).

This is the involved build.gradle.kts file:

plugins {
    alias(config.plugins.multiplatform.android)
    alias(config.plugins.multiplatform.jvm)
}

kotlin {
    sourceSets.commonMain.dependencies {
        api(config.aggregate.core)

        implementation(libs.coroutines)
    }
}

config.plugins.multiplatform.x are convention plugins that I share between my projects, containing stuff like:

configure<KotlinMultiplatformExtension> {
    applyDefaultHierarchyTemplate()

    compilerOptions {
        freeCompilerArgs.addAll(CompilerArgs)
    }
}

val CompilerArgs =
    listOf(
        "-Xskip-prerelease-check",
        "-Xexpect-actual-classes",
        "-Xcontext-receivers",
        "-opt-in=kotlinx.coroutines.ExperimentalCoroutinesApi",
    )

And jvm() android() etc.

Im really clueless unfortunately, this project is even just a subset of the whole project - ironically to speed up build times when developing a subset of its features.

[Andrey Beryukhov]

Hi. How do you build Android? Maybe you use too wide gradle task for that (e.g. assembleRelease, which may include minification,, obfuscation, signing, etc.)

[Zoltan Demant]

Hey Andrei! I'm using the default that you get when you add an Android run configuration. The slow task is compileDebugKotlinAndroid.

[ephemient]

does https://blog.jetbrains.com/kotlin/2022/06/introducing-kotlin-build-reports/ help narrow down what is slow within the kotlin compile?

[Zoltan Demant]

Awesome, that helps a lot:
No incremental compilation due to kotlin.compiler.execution.strategy=in-process (I added this yesterday after asking AI about the issues).
One of my convention plugins for multiplatform adds (by mistake) android-library to every module its applied to. Ive been using this for a lot of projects, I think the extra time just grows exponentially due to this project being ridiculous in size.

These two tweaks brought the build time down from 5 minutes to 5 seconds. thank you color