Configure Compiler Arguments

I'm looking for a way to configure Kotlin compiler arguments in the build.gradle file of my Android Application project. I've seen on the Kotlin official documentation that it is p

Solution 1:

After a few days of search and experimentation, I finally found a way to configure the compiler based on the build variant.

Here is what worked for me :

buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'// Configure Kotlin compiler optimisations for releases
            kotlinOptions {
                freeCompilerArgs += [
                        '-Xno-param-assertions',
                        '-Xno-call-assertions',
                        '-Xno-receiver-assertions'
                ]
            }
        }
    }
}

It seems like the documentation for the Gradle Kotlin Android plugin is not correct: while it says that the compiler can be configured by adding, for instance, the compileReleaseKotlin closure for release builds, for Android you have to put a kotlinOptions block in release, as shown above.

Note that for a regular Kotlin project (without Android), the compileKotlin block described in the documentation works as intented.

Hope it helps !

Edit Added - prefix for arguments, as the compiler would silently ignore them otherwise.

Edit 2 Changed = to += to avoid overwriting compiler options from other configurations.

Solution 2:

For anyone looking for quick info in 2020 on how to add a compiler arg to a Kotlin Android project (I needed it to enable the experimental serialization API), this is how I did it:

(app build.gradle file)

android {
    ...
    compileOptions {
        ...
        kotlin {
            kotlinOptions {
                freeCompilerArgs += "-Xopt-in=kotlin.RequiresOptIn"
            }
        }
    }
}

Android Studio doesn't provide those as suggestions.

Solution 3:

Kotlin compiler options for all build types should be specified in the android closure. This is where Android Studio 4.1 places kotlinOptions { jvmTarget = '1.8' } by default:

android {
    ...
    kotlinOptions {
        jvmTarget = '1.8'
        freeCompilerArgs += ['-Xno-param-assertions']
    }
}

Compiler options for specific build type should be configured at the root level, wrapped in afterEvaluate, because the task is only registered once the Android Gradle plugin creates specific build variant, which is only done at the afterEvaluate phase:

afterEvaluate {
    compileReleaseKotlin {
        kotlinOptions {
            freeCompilerArgs += ['-Xno-param-assertions']
        }
    }
}