Groovy to Kotlin in Buildscripts (Kotlin Night Berlin March 2018)

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Groovy to Kotlin in build scripts Nelson Osacky

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•Some Pros and Cons •Examples •How it works under the hood

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build.gradle -> build.gradle.kts

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Motivations

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Kotlin DSL v0.15.6

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Experiment

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Pros • Type safety • Auto complete • Kotlin Cons • Slower builds • Less examples • Pre-release state • Source digging

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type safety

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if (isCi) { foo }A

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if (isCi) { foo }A

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auto-complete

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• autocompletion gif

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Slower builds

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Less docs https://github.com/gradle/kotlin-dsl/tree/master/samples

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Must dig in source

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Pros • type safety • better auto complete • kotlin Cons • slower builds • less examples • pre-release state • source digging

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Examples

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settings.gradle.kts

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include ':app' include ':data' include ':service'

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include( ":app", ":data", ":service" )

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build.gradle.kts

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plugins

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apply plugin: 'java-library' apply plugin: 'kotlin' apply plugin: 'com.android.library' targetCompatibility = JavaVersion.VERSION_1_8 sourceCompatibility = JavaVersion.VERSION_1_8 dependencies { testCompile deps.junit compileOnly deps.support.annotations implementation deps.kotlin }

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apply plugin: 'java-library' apply plugin: 'kotlin' apply plugin: 'com.android.library'

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plugins { `java-library` kotlin("jvm") id("com.android.library") }A

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plugins { `java-library` kotlin("jvm") id("com.android.library") }A java { targetCompatibility = JavaVersion.VERSION_1_8 sourceCompatibility = JavaVersion.VERSION_1_8 }B dependencies { testImplementation(deps("junit")) compileOnly((deps("support") as Map<*, *>) ["annotations"].toString()) }C

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plugins { `java-library` kotlin("jvm") id("com.android.library") }A

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plugins { `java-library` kotlin("jvm") id("com.android.library") }A

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/** * Applies the given Kotlin plugin [module]. * * For example: `plugins { kotlin("jvm") version "1.2.21" }` * * @param module simple name of the Kotlin Gradle plugin module, for example "jvm", "android", "kapt", "plugin.allopen" etc... */ fun PluginDependenciesSpec.kotlin(module: String): PluginDependencySpec = id("org.jetbrains.kotlin.$module") org.gradle.kotlin.dsl.KotlinDependencyExtensions.kt

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""" /** * Applies the given Kotlin plugin [module]. * * For example: `plugins { kotlin("jvm") version "$embeddedKotlinVersion" }` * * Visit the [plugin portal](https://plugins.gradle.org/search? term=org.jetbrains.kotlin) to see the list of available plugins. * * @param module simple name of the Kotlin Gradle plugin module, for example "jvm", "android", "kapt", "plugin.allopen" etc... */ fun PluginDependenciesSpec.kotlin(module: String): PluginDependencySpec = id(“org.jetbrains.kotlin.${‘$’}module”) """   buildSrc/src/main/kotlin/codegen/GenerateKotlinDependencyExtensions.kt

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val generateKotlinDependencyExtensions by task { val publishedPluginsVersion: String by rootProject.extra outputFile = File(apiExtensionsOutputDir, "org/gradle/kotlin/dsl/ KotlinDependencyExtensions.kt") embeddedKotlinVersion = kotlinVersion kotlinDslPluginsVersion = publishedPluginsVersion kotlinDslRepository = kotlinRepo } provider/build.gradle.kts

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plugins { `java-library` kotlin("jvm") id("com.android.library") }A

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plugins { `java-library` kotlin("jvm") id("com.android.library") }A

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/** * The builtin Gradle plugin implemented by [org.gradle.api.plugins.JavaLibraryPlugin]. */ inline val PluginDependenciesSpec.`java-library`: PluginDependencySpec get() = id("org.gradle.java-library") BuiltInPluginExtensions.kt

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internal fun generateApiExtensionsJar(outputFile: File, gradleJars: Collection, onProgress: () -> Unit) { ApiExtensionsJarGenerator(onProgress = onProgress).generate(outputFile, gradleJars) } org.gradle.kotlin.dsl.codegen.ApiExtensionsJar.kt

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apply plugin: 'java-library' apply plugin: 'kotlin' targetCompatibility = JavaVersion.VERSION_1_8 sourceCompatibility = JavaVersion.VERSION_1_8 dependencies { testImplementation 'junit:junit:4.12' compileOnly 'com.android.support:support- annotations:27.1.0' }A

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dependencies { testImplementation 'junit:junit:4.12' }A

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dependencies { testImplementation("junit:junit:4.12") }A

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plugins { `java-library` kotlin("jvm") } java { targetCompatibility = JavaVersion.VERSION_1_8 sourceCompatibility = JavaVersion.VERSION_1_8 } dependencies { testImplementation("junit:junit:4.12") compileOnly("com.android.support:support- annotations:27.1.0") }A

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ext block

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ext.deps = [ 'junit' : "junit:junit:4.12", 'support' : [ 'annotations': "com.android.support:support-annotations:$ {versions.supportLibrary}", ], ]

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apply plugin: 'java-library' apply plugin: 'kotlin' targetCompatibility = JavaVersion.VERSION_1_8 sourceCompatibility = JavaVersion.VERSION_1_8 dependencies { testImplementation deps.junit compileOnly deps.support.annotations implementation deps.kotlin }W

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dependencies { testImplementation deps.junit compileOnly deps.support.annotations }W

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dependencies { testImplementation deps.junit }W

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dependencies { testImplementation(deps("junit")) }W

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dependencies { testImplementation deps.junit }Q   dependencies { testImplementation(deps("junit")) }W

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dependencies { testImplementation deps.junit }Q   dependencies { testImplementation(deps("junit")) }W fun Project.deps(key: String): Any { return (rootProject.ext["deps"] as Map<*, *>)[key]!! }D

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fun Project.deps(key: String): Any { return (rootProject.ext["deps"] as Map<*, *>)[key]!! }D

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fun Project.deps(key: String): Any { return (rootProject.ext["deps"] as Map<*, *>)[key]!! }D ext.deps = [ 'junit' : "junit:junit:4.12", 'support' : [ 'annotations': "com.android.support:support-annotations:$ {versions.supportLibrary}", ], ]

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fun Project.deps(key: String): Any { return (rootProject.ext["deps"] as Map<*, *>)[key]!! }D

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dependencies { testImplementation(deps(“junit")) compileOnly((deps("support") as Map<*, *>)["annotations"].toString()) }A fun Project.deps(key: String): Any { return (rootProject.ext["deps"] as Map<*, *>)[key]!! }D

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plugins { `java-library` kotlin("jvm") } java { targetCompatibility = JavaVersion.VERSION_1_8 sourceCompatibility = JavaVersion.VERSION_1_8 }A dependencies { testImplementation(deps("junit")) compileOnly((deps("support") as Map<*, *>)["annotations"].toString()) implementation(deps("kotlin")) }

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apply plugin: 'java-library' apply plugin: 'kotlin' targetCompatibility = JavaVersion.VERSION_1_8 sourceCompatibility = JavaVersion.VERSION_1_8 dependencies { testImplementation deps.junit compileOnly deps.support.annotations implementation deps.kotlin }W

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targetCompatibility = JavaVersion.VERSION_1_8 sourceCompatibility = JavaVersion.VERSION_1_8

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java { targetCompatibility = JavaVersion.VERSION_1_8 sourceCompatibility = JavaVersion.VERSION_1_8 }A

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// Groovy ext.isCi = System.getenv("CI") == "true"

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// Kotlin extra.set("isCi", System.getenv("CI") == "true")

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// Groovy ext.isCi = System.getenv("CI") == “true" // Kotlin extra.set("isCi", System.getenv("CI") == "true")

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val ExtensionAware.isCi : Boolean get() = extra.properties["isCi"].toString().toBoolean()

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// Groovy if (isCi) { // Do stuff on CI }B

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// Kotlin if (isCi) { // Do stuff on CI }B

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// Groovy if (isCi) { // Do stuff on CI }A // Kotlin if (isCi) { // Do stuff on CI }B

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// Groovy if (isCi) { // Do stuff on CI }A // Kotlin if (isCi()) { // Do stuff on CI }B val ExtensionAware.isCi : Boolean get() = extra.properties["isCi"].toString().toBoolean()

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• Experiments are fun • Build speeds are slower • Kotlin DSL is still pre-release • Everything is an extension function

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Thanks nelson.osacky@zenjob.com  https://www.zenjob.de/careers/ Questions? https://github.com/gradle/kotlin-dsl/tree/master/samples

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targetCompatibility = JavaVersion.VERSION_1_8 sourceCompatibility = JavaVersion.VERSION_1_8

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java { targetCompatibility = JavaVersion.VERSION_1_8 sourceCompatibility = JavaVersion.VERSION_1_8 }A

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public void setSourceCompatibility(Object value) { setSourceCompatibility(JavaVersion.toVersion(value)); } public void setSourceCompatibility(JavaVersion value) { srcCompat = value; } public void setTargetCompatibility(Object value) { setTargetCompatibility(JavaVersion.toVersion(value)); } public void setTargetCompatibility(JavaVersion value) { targetCompat = value; } org.gradle.api.JavaPluginConvention.java

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public void apply(ProjectInternal project) { project.getPluginManager().apply(JavaBasePlugin.class); JavaPluginConvention javaConvention = project.getConvention() .getPlugin(JavaPluginConvention.class); } org.gradle.api.plugins.JavaPlugin.java

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/** * Retrieves the [java][org.gradle.api.plugins.JavaPluginConvention] project convention. */ val Project.`java`: org.gradle.api.plugins.JavaPluginConvention get() = convention.getPluginByName("java") /** * Configures the [java][org.gradle.api.plugins.JavaPluginConvention] project convention. */ fun Project.`java`(configure: org.gradle.api.plugins.JavaPluginConvention.() -> Unit): Unit = configure(`java`) org.gradle.kotlin.dsl.accessors.kt

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java { sourceCompatibility = JavaVersion.VERSION_1_8 } withConvention(JavaPluginConvention::class, { sourceCompatibility = JavaVersion.VERSION_1_8 }) (this as HasConvention).convention.getPlugin(JavaPluginConvention::class).run { sourceCompatibility = JavaVersion.VERSION_1_8 }

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// Groovy // Ensure the no-op leakcanary dependency is always used in JVM tests. configurations.all { config -> if (config.name.contains("UnitTest")) { config.resolutionStrategy.eachDependency { details -> if (details.requested.group == "com.squareup.leakcanary" && details.requested.name == "leakcanary-android") { details.useTarget(group: details.requested.group, name: "leakcanary-android-no-op", version: details.requested.version) }A }B }C }D

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// Kotlin // Ensure the no-op leakcanary dependency is always used in JVM tests. configurations.all { if (name.contains("UnitTest")) { resolutionStrategy.eachDependency { if (requested.group == "com.squareup.leakcanary" && requested.name == “leakcanary-android") { useTarget(mapOf("group" to requested.group, "name" to "leakcanary-android-no-op", "version" to requested.version)) }A }B }C }D