Update build configuration to reflect KGP improvements (#102)

I did a bit of a cleanup of the build scripts.  
Removed what wasn't necessary, centralized all dependencies in the root
version catalog, and applied a more specific configuration to the JVM
target.

build.gradle.kts

@@ -1,66 +1,81 @@
+@file:OptIn(ExperimentalKotlinGradlePluginApi::class)
+
 import io.github.petertrr.configurePublishing
+import io.github.petertrr.ext.booleanProperty
 import io.gitlab.arturbosch.detekt.Detekt
-import org.jetbrains.kotlin.gradle.targets.jvm.tasks.KotlinJvmTest
+import org.jetbrains.kotlin.gradle.ExperimentalKotlinGradlePluginApi
+import org.jetbrains.kotlin.gradle.dsl.JvmTarget
+import org.jetbrains.kotlin.gradle.dsl.KotlinVersion
 
 plugins {
     kotlin("multiplatform")
-    id("jacoco-convention")
     alias(libs.plugins.detekt)
+    id("jacoco-convention")
 }
 
 group = "io.github.petertrr"
 description = "A multiplatform Kotlin library for calculating text differences"
 
+dependencies {
+    detektPlugins(libs.detekt.formatting)
+}
+
 kotlin {
     explicitApi()
 
-    jvm()
-    js(IR) {
+    compilerOptions {
+        apiVersion = KotlinVersion.KOTLIN_1_9
+        languageVersion = KotlinVersion.KOTLIN_1_9
+    }
+
+    jvm {
+        compilations.configureEach {
+            compilerOptions.configure {
+                // Minimum bytecode level is 52
+                jvmTarget = JvmTarget.JVM_1_8
+
+                // Output interfaces with default methods
+                freeCompilerArgs.add("-Xjvm-default=all")
+            }
+        }
+
+        testRuns.configureEach {
+            executionTask.configure {
+                useJUnitPlatform()
+            }
+        }
+    }
+
+    js {
         browser()
         nodejs()
     }
-    // setup native compilation
+
     linuxX64()
     mingwX64()
     macosX64()
 
     sourceSets {
-        val commonTest by getting {
-            dependencies {
-                implementation(kotlin("test-common"))
-                implementation(kotlin("test-annotations-common"))
-            }
-        }
-        // platform-specific dependencies are needed to use actual test runners
-        val jvmTest by getting {
-            dependencies {
-                implementation(kotlin("test-junit5"))
-                implementation(libs.junit.jupiter.engine)
-                runtimeOnly("org.junit.platform:junit-platform-launcher")
-            }
-        }
-        val jsTest by getting {
+        commonTest {
             dependencies {
-                implementation(kotlin("test-js"))
+                implementation(kotlin("test"))
             }
         }
     }
 }
 
 configurePublishing()
 
-tasks.withType<KotlinJvmTest> {
-    useJUnitPlatform()
-}
-
 detekt {
     buildUponDefaultConfig = true
     config.setFrom(files("detekt.yml"))
-    autoCorrect = (findProperty("detektAutoCorrect") as String?)?.toBoolean() ?: true
-}
-dependencies {
-    detektPlugins(libs.detekt.formatting)
+    autoCorrect = booleanProperty("detektAutoCorrect", default = true)
 }
-tasks.withType<Detekt> {
-    tasks.getByName("check").dependsOn(this)
+
+tasks {
+    withType<Detekt> {
+        named("check") {
+            dependsOn(this@withType)
+        }
+    }
 }

buildSrc/build.gradle.kts

@@ -2,14 +2,8 @@ plugins {
     `kotlin-dsl`
 }
 
-repositories {
-    mavenCentral()
-    gradlePluginPortal()
-}
-
-val libs = extensions.getByType<VersionCatalogsExtension>().named("libs")
 dependencies {
-    implementation("org.jetbrains.dokka:dokka-gradle-plugin:1.9.10")
-    implementation("io.github.gradle-nexus:publish-plugin:1.3.0")
-    implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:${libs.findVersion("kotlin").get()}")
-}
+    implementation(libs.dokka.plugin)
+    implementation(libs.nexus.plugin)
+    implementation(libs.kotlin.plugin)
+}

buildSrc/settings.gradle.kts

@@ -1,4 +1,10 @@
 dependencyResolutionManagement {
+    @Suppress("UnstableApiUsage")
+    repositories {
+        mavenCentral()
+        gradlePluginPortal()
+    }
+
     versionCatalogs {
         create("libs") {
             from(files("../gradle/libs.versions.toml"))

buildSrc/src/main/kotlin/io/github/petertrr/ext/Project.ext.kt

@@ -0,0 +1,12 @@
+package io.github.petertrr.ext
+
+import org.gradle.api.Project
+
+/**
+ * Returns a project property as a boolean (`"true" == true`, else `false`).
+ */
+fun Project.booleanProperty(name: String, default: Boolean = false): Boolean {
+    val property = findProperty(name) ?: return default
+    val propertyStr = property as? String ?: return default
+    return propertyStr.trim().lowercase() == "true"
+}

gradle/libs.versions.toml

@@ -1,13 +1,16 @@
 [versions]
-kotlin = "1.9.22"
-junit = "5.10.1"
+kotlin = "1.9.23"
 detekt = "1.23.5"
+dokka = "1.9.10"
+nexus = "1.3.0"
 
 [plugins]
-kotlin-multiplatform = { id = "org.jetbrains.kotlin.multiplatform", version.ref = "kotlin" }
 detekt = { id = "io.gitlab.arturbosch.detekt", version.ref = "detekt" }
 
 [libraries]
-junit-jupiter-api = { module = "org.junit.jupiter:junit-jupiter-api", version.ref = "junit" }
-junit-jupiter-engine = { module = "org.junit.jupiter:junit-jupiter-engine", version.ref = "junit" }
-detekt-formatting = { module = "io.gitlab.arturbosch.detekt:detekt-formatting", version.ref = "detekt" }
+detekt-formatting = { group = "io.gitlab.arturbosch.detekt", name = "detekt-formatting", version.ref = "detekt" }
+
+# Gradle plugins
+kotlin-plugin = { group = "org.jetbrains.kotlin", name = "kotlin-gradle-plugin", version.ref = "kotlin" }
+dokka-plugin = { group = "org.jetbrains.dokka", name = "dokka-gradle-plugin", version.ref = "dokka" }
+nexus-plugin = { group = "io.github.gradle-nexus", name = "publish-plugin", version.ref = "nexus" }

settings.gradle.kts

@@ -13,6 +13,7 @@ plugins {
 rootProject.name = "kotlin-multiplatform-diff"
 
 dependencyResolutionManagement {
+    @Suppress("UnstableApiUsage")
     repositories {
         mavenCentral()
     }