default-impl

A Kotlin Symbol Processing tool generating default interface implementation constructor functions

@DefaultImpl(MyInterfaceImpl::class)
interface MyInterface

internal object MyInterfaceImpl

val obj = MyInterface() // this will be generated with all constructor parameters

Usage

In Kotlin Multiplatform projects

In your build.gradle.kts:

plugins {
    // ...
    id("com.google.devtools.ksp")
}

kotlin {
    // ...
    sourceSets {
        val commonMain by getting {
            kotlin.srcDir("build/generated/ksp/metadata/commonMain/kotlin") // optional: if you want to generate the code in commonMain
            dependencies {
                implementation("io.github.overpas:default-impl-annotations:0.0.2")
            }
        }
        // ...
    }
}

dependencies {
    add("kspCommonMainMetadata", "io.github.overpas:default-impl-processor:0.0.2")
    // other configurations (don't include any if you want to generate the code in commonMain):
    // add("kspJvm", "io.github.overpas:default-impl-processor:0.0.2")
    // add("kspAndroid", "io.github.overpas:default-impl-processor:0.0.2")
    // add("kspIosArm64", "io.github.overpas:default-impl-processor:0.0.2")
    // etc.
}

// optional: if you want to generate the code in commonMain
tasks.withType<org.jetbrains.kotlin.gradle.dsl.KotlinCompile<*>>().configureEach {
    if (name != "kspCommonMainKotlinMetadata") {
        dependsOn("kspCommonMainKotlinMetadata")
    }
}

In plain Kotlin projects

In your build.gradle.kts

plugins {
    // ...
    id("com.google.devtools.ksp")
}

dependencies {
    implementation("io.github.overpas:default-impl-annotations:0.0.2")
    ksp("io.github.overpas:default-impl-processor:0.0.2")
}

Troubleshooting

If you are using Detekt and detektMetadataMain fails with Reason: Task ':detektMetadataMain' uses this output of task ':kspCommonMainKotlinMetadata' without declaring an explicit or implicit dependency. This can lead to incorrect results being produced, depending on what order the tasks are executed. you might consider adding:

tasks.matching { it.name == "detektMetadataMain" }
    .configureEach {
        dependsOn(tasks.matching { it.name == "kspCommonMainKotlinMetadata" })
    }