Add a repository management plugin (#27)

README.md

@@ -150,7 +150,7 @@ neoForge {
 
             // You can change the name used for this run in your IDE
             ideName = "Run Game Tests"
-        
+
             // Changes the source set whose runtime classpath is used for this run. This defaults to "main"
             // Eclipse does not support having multiple runtime classpaths per project (except for unit tests).
             sourceSet = sourceSets.main
@@ -283,6 +283,29 @@ public class TestClass {
 }
 ```
 
+### Centralizing Repositories Declaration
+
+This plugin supports Gradle's [centralized repositories declaration](https://docs.gradle.org/current/userguide/declaring_repositories.html#sub:centralized-repository-declaration) in settings.gradle
+by offering a separate plugin to apply the repositories to develop mods.
+It can be used in the following way in `settings.gradle`:
+
+```groovy
+plugins {
+    id 'net.neoforged.moddev.repositories' version '<version>'
+}
+
+dependencyResolutionManagement {
+    repositories {
+        mavenCentral()
+    }
+}
+```
+
+Please note that defining any repository in build.gradle will completely disable
+the centrally managed repositories for that project.
+You can also use the repositories plugin in a project to add the repositories there,
+even if dependency management has been overridden.
+
 ## Advanced Tips & Tricks
 
 ### Overriding Platform Libraries

build.gradle

@@ -162,6 +162,13 @@ gradlePlugin {
             description = "This plugin helps you create Minecraft mods using the NeoForge platform"
             tags = ["minecraft", "neoforge", "java", "mod"]
         }
+        repositories {
+            id = 'net.neoforged.moddev.repositories'
+            implementationClass = 'net.neoforged.moddevgradle.boot.RepositoriesPlugin'
+            displayName = "NeoForge Mod Development Repositories Plugin"
+            description = "This plugin adds the repositories needed for developing Minecraft mods. It is applied automatically by the moddev plugin, but can be applied manually in settings.gradle to make use of Gradle dependency management."
+            tags = ["minecraft", "neoforge", "java", "mod"]
+        }
     }
 }
 

src/java8/java/net/neoforged/moddevgradle/boot/RepositoryPlugin.java

@@ -0,0 +1,9 @@
+package net.neoforged.moddevgradle.boot;
+
+import org.gradle.api.Project;
+
+public class RepositoryPlugin extends TrampolinePlugin<Project> {
+    public RepositoryPlugin() {
+        super("net.neoforged.moddevgradle.internal.RepositoryPlugin");
+    }
+}

src/main/java/net/neoforged/moddevgradle/internal/ModDevPlugin.java

@@ -102,12 +102,18 @@ public class ModDevPlugin implements Plugin<Project> {
     @Override
     public void apply(Project project) {
         project.getPlugins().apply(JavaLibraryPlugin.class);
+        // Do not apply the repositories automatically if they have been applied at the settings-level.
+        // It's still possible to apply them manually, though.
+        if (!project.getGradle().getPlugins().hasPlugin(RepositoryPlugin.class)) {
+            project.getPlugins().apply(RepositoryPlugin.class);
+        } else {
+            project.getLogger().info("Not enabling NeoForged repositories since they were applied at the settings level");
+        }
         var javaExtension = ExtensionUtils.getExtension(project, "java", JavaPluginExtension.class);
 
         var configurations = project.getConfigurations();
         var layout = project.getLayout();
         var tasks = project.getTasks();
-        var repositories = project.getRepositories();
 
         // We use this directory to store intermediate files used during moddev
         var modDevBuildDir = layout.getBuildDirectory().dir("moddev");
@@ -130,31 +136,6 @@ public void apply(Project project) {
                     });
         }));
 
-        var mojangMaven = repositories.maven(repo -> {
-            repo.setName("Mojang Minecraft Libraries");
-            repo.setUrl(URI.create("https://libraries.minecraft.net/"));
-            repo.metadataSources(sources -> sources.mavenPom());
-            repo.content(MojangRepositoryFilter::filter);
-        });
-        // Make sure that Mojang's repository is first
-        if (repositories.getAsMap().size() > 1) {
-            repositories.remove(mojangMaven);
-            repositories.add(0, mojangMaven);
-        }
-
-        repositories.maven(repo -> {
-            repo.setName("Mojang Meta");
-            repo.setUrl("https://maven.neoforged.net/mojang-meta/");
-            repo.metadataSources(sources -> sources.gradleMetadata());
-            repo.content(content -> {
-                content.includeModule("net.neoforged", "minecraft-dependencies");
-            });
-        });
-        repositories.maven(repo -> {
-            repo.setName("NeoForged Releases");
-            repo.setUrl(URI.create("https://maven.neoforged.net/releases/"));
-        });
-
         project.getDependencies().attributesSchema(attributesSchema -> {
             attributesSchema.attribute(ATTRIBUTE_DISTRIBUTION).getDisambiguationRules().add(DistributionDisambiguation.class);
             attributesSchema.attribute(ATTRIBUTE_OPERATING_SYSTEM).getDisambiguationRules().add(OperatingSystemDisambiguation.class);

src/main/java/net/neoforged/moddevgradle/internal/RepositoryPlugin.java

@@ -0,0 +1,67 @@
+package net.neoforged.moddevgradle.internal;
+
+import net.neoforged.moddevgradle.internal.generated.MojangRepositoryFilter;
+import org.gradle.api.GradleException;
+import org.gradle.api.Plugin;
+import org.gradle.api.Project;
+import org.gradle.api.artifacts.dsl.RepositoryHandler;
+import org.gradle.api.artifacts.repositories.MavenArtifactRepository;
+import org.gradle.api.initialization.Settings;
+import org.gradle.api.invocation.Gradle;
+import org.gradle.api.plugins.PluginAware;
+
+import java.net.URI;
+
+/**
+ * This plugin acts in different roles depending on where it is applied:
+ * <ul>
+ *     <li>At the project-level, it will add the required repositories for moddev.</li>
+ *     <li>At the settings-level, it will add the required repositories to the dependency management block, and add a marker plugin to the Gradle instance to prevent the
+ *     repositories from being added again at the project-level.</li>
+ * </ul>
+ */
+public class RepositoryPlugin implements Plugin<PluginAware> {
+    @Override
+    public void apply(PluginAware target) {
+        if (target instanceof Project project) {
+            applyRepositories(project.getRepositories());
+        } else if (target instanceof Settings settings) {
+            applyRepositories(settings.getDependencyResolutionManagement().getRepositories());
+            settings.getGradle().getPlugins().apply(getClass()); // Add a marker to Gradle
+        } else if (target instanceof Gradle gradle) {
+            // Do nothing
+        } else {
+            throw new GradleException("This plugin does not support being applied to " + target);
+        }
+    }
+
+    private void applyRepositories(RepositoryHandler repositories) {
+        var mojangMaven = repositories.maven(repo -> {
+            repo.setName("Mojang Minecraft Libraries");
+            repo.setUrl(URI.create("https://libraries.minecraft.net/"));
+            repo.metadataSources(sources -> sources.mavenPom());
+            repo.content(MojangRepositoryFilter::filter);
+        });
+        sortFirst(repositories, mojangMaven);
+
+        var mojangMetaMaven = repositories.maven(repo -> {
+            repo.setName("Mojang Meta");
+            repo.setUrl("https://maven.neoforged.net/mojang-meta/");
+            repo.metadataSources(sources -> sources.gradleMetadata());
+            repo.content(content -> {
+                content.includeModule("net.neoforged", "minecraft-dependencies");
+            });
+        });
+        sortFirst(repositories, mojangMetaMaven);
+
+        repositories.maven(repo -> {
+            repo.setName("NeoForged Releases");
+            repo.setUrl(URI.create("https://maven.neoforged.net/releases/"));
+        });
+    }
+
+    private static void sortFirst(RepositoryHandler repositories, MavenArtifactRepository repo) {
+        repositories.remove(repo);
+        repositories.add(0, repo);
+    }
+}