Generate configuration parameters overview

documentation/documentation.gradle.kts

@@ -100,6 +100,7 @@ dependencies {
 	javadocClasspath(libs.picocli)
 	javadocClasspath(libs.fastcsv)
 	javadocClasspath(libs.openTestReporting.events)
+	javadocClasspath(libs.jakarta.json.api)
 	javadocClasspath(libs.kotlinx.coroutines.core)
 	javadocClasspath(kotlin("stdlib"))
 	javadocClasspath(kotlin("reflect"))
@@ -406,10 +407,11 @@ tasks {
 
 		args.addAll(
 			"--module", modularProjects.joinToString(",") { it.javaModuleName },
-			"--add-modules", "info.picocli,org.opentest4j.reporting.events,de.siegmar.fastcsv",
+			"--add-modules", "info.picocli,org.opentest4j.reporting.events,de.siegmar.fastcsv,jakarta.json",
 			"--add-reads", "org.junit.platform.console=info.picocli",
 			"--add-reads", "org.junit.platform.reporting=org.opentest4j.reporting.events",
 			"--add-reads", "org.junit.jupiter.params=de.siegmar.fastcsv",
+			"--add-reads", "org.junit.platform.configuration.processor=jakarta.json",
 		)
 
 		outputDirectory = layout.buildDirectory.dir("docs/javadoc")

gradle/libs.versions.toml

@@ -39,6 +39,8 @@ hamcrest = { module = "org.hamcrest:hamcrest", version = "3.0" }
 jackson-databind = { module = "tools.jackson.core:jackson-databind", version.ref = "jackson" }
 jackson-dataformat-yaml = { module = "tools.jackson.dataformat:jackson-dataformat-yaml", version.ref = "jackson" }
 jackson-module-kotlin = { module = "tools.jackson.module:jackson-module-kotlin", version.ref = "jackson" }
+jakarta-json-api = { module = "jakarta.json:jakarta.json-api", version = "2.1.3" }
+jakarta-json-implementation = { module = "org.eclipse.parsson:parsson", version = "1.1.9" }
 jaxb-api = { module = "jakarta.xml.bind:jakarta.xml.bind-api", version = "4.0.5" }
 jaxb-runtime = { module = "org.glassfish.jaxb:jaxb-runtime", version = "4.0.9" }
 jfrunit = { module = "org.moditect.jfrunit:jfrunit-core", version = "1.0.0.Alpha2" }

gradle/plugins/common/build.gradle.kts

@@ -10,6 +10,7 @@ dependencies {
 	implementation("junitbuild.base:build-parameters")
 	implementation(projects.backwardCompatibility)
 	implementation(projects.javadoc)
+	implementation(libs.jackson.databind)
 	implementation(libs.plugins.kotlin.markerCoordinates)
 	implementation(libs.plugins.bnd.markerCoordinates)
 	implementation(libs.plugins.develocity.markerCoordinates)

gradle/plugins/common/src/main/kotlin/junitbuild/shadow/ConfigurationMetadataMergingTransformer.kt

@@ -0,0 +1,66 @@
+package junitbuild.shadow
+
+import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
+import com.github.jengelman.gradle.plugins.shadow.transformers.ResourceTransformer
+import com.github.jengelman.gradle.plugins.shadow.transformers.TransformerContext
+import org.apache.tools.zip.ZipEntry
+import org.apache.tools.zip.ZipOutputStream
+import org.gradle.api.file.FileTreeElement
+import org.gradle.api.model.ObjectFactory
+import org.gradle.api.provider.Property
+import org.gradle.api.tasks.Input
+import tools.jackson.databind.json.JsonMapper
+import tools.jackson.databind.node.ArrayNode
+import tools.jackson.databind.node.ObjectNode
+import javax.inject.Inject
+
+/**
+ * Merges JUnit/Spring configuration metadata files by concatenating the array
+ * values of their top-level fields (`groups`, `properties`, and `hints`).
+ *
+ * @see <a href="https://docs.spring.io/spring-boot/specification/configuration-metadata/format.html">Configuration Metadata format</a>
+ */
+abstract class ConfigurationMetadataMergingTransformer @Inject constructor(
+    override val objectFactory: ObjectFactory
+) : ResourceTransformer {
+
+    @get:Input
+    abstract val resource: Property<String>
+
+    private var mergedTree: ObjectNode? = null
+
+    override fun canTransformResource(element: FileTreeElement): Boolean {
+        return resource.get().equals(element.path, ignoreCase = true)
+    }
+
+    override fun transform(context: TransformerContext) {
+        val tree = JsonMapper().readTree(context.inputStream) as ObjectNode
+        val merged = mergedTree
+        if (merged == null) {
+            mergedTree = tree
+        } else {
+            tree.properties().forEach { (name, value) ->
+                value as ArrayNode
+                val existing = merged.get(name)
+                if (existing == null) {
+                    merged.set(name, value)
+                } else {
+                    existing as ArrayNode
+                    existing.addAll(value)
+                }
+            }
+        }
+    }
+
+    override fun hasTransformedResource(): Boolean = mergedTree != null
+
+    override fun modifyOutputStream(os: ZipOutputStream, preserveFileTimestamps: Boolean) {
+        val entry = ZipEntry(resource.get())
+        entry.time = ShadowJar.CONSTANT_TIME_FOR_ZIP_ENTRIES
+        os.putNextEntry(entry)
+        os.write(JsonMapper().writeValueAsBytes(mergedTree))
+        os.closeEntry()
+        mergedTree = null
+    }
+
+}

junit-jupiter-api/junit-jupiter-api.gradle.kts

@@ -9,6 +9,8 @@ plugins {
 description = "JUnit Jupiter API"
 
 dependencies {
+	annotationProcessor(projects.junitPlatformConfigurationProcessor)
+
 	api(platform(projects.junitBom))
 	api(libs.opentest4j)
 	api(projects.junitPlatformCommons)
@@ -17,6 +19,7 @@ dependencies {
 	compileOnlyApi(libs.jspecify)
 
 	compileOnly(kotlin("stdlib"))
+	compileOnly(projects.junitPlatformConfigurationApi)
 
 	testFixturesImplementation(libs.assertj)
 	testFixturesImplementation(testFixtures(projects.junitPlatformCommons))
@@ -35,7 +38,7 @@ eclipseConventions {
 
 tasks {
 	compileJava {
-		options.compilerArgs.add("-Xlint:-module") // due to qualified exports
+		options.compilerArgs.add("-Xlint:-module,-processing") // -module: due to qualified exports, -processing: not all annotations need to be processed
 	}
 	jar {
 		bundle {

junit-jupiter-api/src/main/java/module-info.java

@@ -21,6 +21,7 @@
 	requires transitive org.junit.platform.commons;
 	requires transitive org.opentest4j;
 
+	requires static org.junit.platform.configuration.api;
 	requires static kotlin.stdlib;
 
 	exports org.junit.jupiter.api;