Add 'feature.shadow' convention plugin

Signed-off-by: Jendrik Johannes <jendrik.johannes@gmail.com>

build.gradle.kts

@@ -16,6 +16,7 @@ dependencies {
     implementation("com.google.protobuf:protobuf-gradle-plugin:0.9.4")
     implementation("com.gradle.publish:plugin-publish-plugin:1.3.0")
     implementation("com.gradle:develocity-gradle-plugin:3.19")
+    implementation("com.gradleup.shadow:shadow-gradle-plugin:8.3.5")
     implementation(
         "gradle.plugin.com.google.cloud.artifactregistry:artifactregistry-gradle-plugin:2.2.2"
     )

src/main/descriptions/org.hiero.gradle.feature.shadow.txt

@@ -0,0 +1 @@
+Conventions for 'com.gradleup.shadow' to be used to build a fat Jar of an application

src/main/kotlin/org.hiero.gradle.feature.shadow.gradle.kts

@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: Apache-2.0
+import com.github.jengelman.gradle.plugins.shadow.internal.DefaultDependencyFilter
+import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
+
+plugins {
+    id("application")
+    id("com.gradleup.shadow")
+}
+
+tasks.withType<ShadowJar>().configureEach {
+    group = "shadow"
+    mergeServiceFiles()
+
+    manifest { attributes("Multi-Release" to "true") }
+
+    // There is an issue in the shadow plugin that it automatically accesses the
+    // files in 'runtimeClasspath' while Gradle is building the task graph.
+    // See: https://github.com/GradleUp/shadow/issues/882
+    dependencyFilter = NoResolveDependencyFilter()
+}
+
+class NoResolveDependencyFilter : DefaultDependencyFilter(project) {
+    override fun resolve(configuration: FileCollection): FileCollection {
+        return configuration
+    }
+}