Create an embedded jar for metadata

This jar DOES NOT relocate packages due to exposing API dependencies. It
should only be used by the Gradle plugin. Do not use this.

Author: Jonathing

metadata/build.gradle

@@ -1,3 +1,9 @@
+import com.github.jengelman.gradle.plugins.shadow.tasks.ShadowJar
+
+plugins {
+    alias libs.plugins.shadow
+}
+
 dependencies {
     api libs.maven.artifact
     api libs.gson
@@ -7,3 +13,15 @@ dependencies {
     api libs.slf4j.api
     runtimeOnly libs.slf4j.simple
 }
+
+// NOTE: This shadow jar cannot have relocation as consuming projects would be unaware of the package changes of API dependencies.
+//       You should not use this. This is for the Gradle plugin, which uses it in an classloader-isolated task action.
+tasks.named('shadowJar', ShadowJar) {
+    archiveClassifier = 'fatjar'
+}
+
+// TODO [JarJarMetadata] Delete once the following PR is merged and included in a release
+//      https://github.com/GradleUp/shadow/pull/1766
+tasks.named({'assemble'.equals(it)} as Spec<String>).configureEach {
+    it.dependsOn(tasks.named('shadowJar', ShadowJar))
+}

settings.gradle

@@ -32,6 +32,7 @@ dependencyResolutionManagement {
         plugin 'gradleutils',   'net.minecraftforge.gradleutils' version '3.3.0'
         plugin 'changelog',     'net.minecraftforge.changelog'   version '3.1.1'
         plugin 'licenser',      'net.minecraftforge.licenser'    version '1.2.0'
+        plugin 'shadow',        'com.gradleup.shadow'            version '9.1.1-SNAPSHOT'
 
         library 'maven-artifact', 'org.apache.maven', 'maven-artifact' version '3.8.1'