Add spotless.resolveDependenciesIn as a workaround Gradle 6 constra…

…ints

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/GradleProvisioner.java

@@ -23,43 +23,79 @@
 import org.gradle.api.artifacts.Configuration;
 import org.gradle.api.artifacts.ConfigurationContainer;
 import org.gradle.api.artifacts.Dependency;
+import org.gradle.util.GradleVersion;
 
 import com.diffplug.common.base.StringPrinter;
+import com.diffplug.common.base.Unhandled;
 import com.diffplug.spotless.Provisioner;
 
 /** Gradle integration for Provisioner. */
 public class GradleProvisioner {
+	/** Determines where Spotless will resolve its dependencies. */
+	public enum ResolveDependenciesIn {
+		/** Spotless dependencies will be resolved from the root buildscript (deprecated for multi-project builds in 6.0). */
+		ROOT_BUILDSCRIPT,
+		/** Spotless dependencies will be resolved from the project buildscript (by default subprojects don't have even a single repository). */
+		PROJECT_BUILDSCRIPT,
+		/** Spotless dependencies will be resolved from the normal repositories of this project. */
+		PROJECT
+	}
+
+	static final GradleVersion STRICT_CONFIG_ACCESS = GradleVersion.version("6.0");
+
 	private GradleProvisioner() {}
 
 	public static Provisioner fromProject(Project project) {
+		ResolveDependenciesIn mode = project.getPlugins().getPlugin(SpotlessPlugin.class).getExtension().getResolveDependenciesIn();
 		Objects.requireNonNull(project);
 		return (withTransitives, mavenCoords) -> {
 			try {
 				Dependency[] deps = mavenCoords.stream()
 						.map(project.getBuildscript().getDependencies()::create)
 						.toArray(Dependency[]::new);
 
-				// #372 workaround: Accessing rootProject.configurations from multiple projects is not thread-safe
 				ConfigurationContainer configContainer;
-				synchronized (project.getRootProject()) {
-					configContainer = project.getRootProject().getBuildscript().getConfigurations();
+				if (mode == null || mode == ResolveDependenciesIn.ROOT_BUILDSCRIPT) {
+					// #372 workaround: Accessing rootProject.configurations from multiple projects is not thread-safe
+					synchronized (project.getRootProject()) {
+						configContainer = project.getRootProject().getBuildscript().getConfigurations();
+					}
+				} else if (mode == ResolveDependenciesIn.PROJECT_BUILDSCRIPT) {
+					configContainer = project.getBuildscript().getConfigurations();
+				} else if (mode == ResolveDependenciesIn.PROJECT) {
+					configContainer = project.getConfigurations();
+				} else {
+					throw Unhandled.enumException(mode);
 				}
 				Configuration config = configContainer.detachedConfiguration(deps);
 				config.setDescription(mavenCoords.toString());
 				config.setTransitive(withTransitives);
 				return config.resolve();
 			} catch (Exception e) {
-				logger.log(Level.SEVERE,
-						StringPrinter.buildStringFromLines("You probably need to add a repository containing the '" + mavenCoords + "' artifact in the 'build.gradle' of your root project.",
-								"E.g.: 'buildscript { repositories { mavenCentral() }}'",
-								"Note that included buildscripts (using 'apply from') do not share their buildscript repositories with the underlying project.",
-								"You have to specify the missing repository explicitly in the buildscript of the root project."),
-						e);
+				String errorMsg;
+				if (mode == null || mode == ResolveDependenciesIn.ROOT_BUILDSCRIPT) {
+					errorMsg = StringPrinter.buildStringFromLines(
+							"You need to add a repository containing the '" + mavenCoords + "' artifact to the `buildscript{}` block of the build.gradle of your root project.",
+							"E.g.: 'buildscript { repositories { mavenCentral() }}'",
+							"Note that included buildscripts (using 'apply from') do not share their buildscript repositories with the underlying project.",
+							"You have to specify the missing repository explicitly in the buildscript of the root project.");
+				} else if (mode == ResolveDependenciesIn.PROJECT_BUILDSCRIPT) {
+					errorMsg = StringPrinter.buildStringFromLines(
+							"You need to add a repository containing the '" + mavenCoords + "' artifact to the `buildscript{}` block of the build.gradle of this project.",
+							"E.g.: 'buildscript { repositories { mavenCentral() }}'",
+							"By default, subprojects dont have any repositories in their buildscript whatsoever.");
+				} else if (mode == ResolveDependenciesIn.PROJECT) {
+					errorMsg = StringPrinter.buildStringFromLines(
+							"You need to add a repository containing the '" + mavenCoords + "' artifact to the `repositories{}` block of the build.gradle of this project.",
+							"E.g.: 'repositories { mavenCentral() }'");
+				} else {
+					throw Unhandled.enumException(mode);
+				}
+				logger.log(Level.SEVERE, errorMsg);
 				throw e;
 			}
 		};
 	}
 
-	private static final Logger logger = Logger.getLogger(GradleProvisioner.class.getName());
-
+	static final Logger logger = Logger.getLogger(GradleProvisioner.class.getName());
 }

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/SpotlessExtension.java

@@ -23,6 +23,8 @@
 import java.util.LinkedHashMap;
 import java.util.Map;
 
+import javax.annotation.Nullable;
+
 import org.gradle.api.Action;
 import org.gradle.api.GradleException;
 import org.gradle.api.Project;
@@ -60,6 +62,18 @@ public SpotlessExtension(Project project) {
 		rootApplyTask.setDescription(APPLY_DESCRIPTION);
 	}
 
+	/** Repository mode. */
+	GradleProvisioner.ResolveDependenciesIn resolveDependenciesIn = null;
+
+	@Nullable
+	public GradleProvisioner.ResolveDependenciesIn getResolveDependenciesIn() {
+		return resolveDependenciesIn;
+	}
+
+	public void setResolveDependenciesIn(GradleProvisioner.ResolveDependenciesIn repositoryMode) {
+		this.resolveDependenciesIn = requireNonNull(repositoryMode);
+	}
+
 	/** Line endings (if any). */
 	LineEnding lineEndings = LineEnding.GIT_ATTRIBUTES;
 

plugin-gradle/src/main/java/com/diffplug/gradle/spotless/SpotlessPlugin.java

@@ -18,9 +18,13 @@
 import org.gradle.api.Plugin;
 import org.gradle.api.Project;
 import org.gradle.api.Task;
+import org.gradle.api.artifacts.dsl.RepositoryHandler;
+import org.gradle.api.artifacts.repositories.ArtifactRepository;
+import org.gradle.api.artifacts.repositories.MavenArtifactRepository;
 import org.gradle.api.plugins.BasePlugin;
 import org.gradle.util.GradleVersion;
 
+import com.diffplug.common.base.StringPrinter;
 import com.diffplug.spotless.SpotlessCache;
 
 public class SpotlessPlugin implements Plugin<Project> {
@@ -56,9 +60,61 @@ public void apply(Project project) {
 					SpotlessPluginLegacy.enforceCheck(spotlessExtension, project);
 				}
 			}
+
+			// the user hasn't specified where to resolve deps and they're going to get a deprecation warning
+			if (spotlessExtension.resolveDependenciesIn == null
+					&& project != project.getRootProject()
+					&& GradleVersion.current().compareTo(GradleProvisioner.STRICT_CONFIG_ACCESS) >= 0) {
+				boolean safeToForceProjectLocal = isMavenCentralSuperset(project.getRootProject().getBuildscript().getRepositories()) &&
+						isMavenCentralSuperset(project.getRepositories());
+				if (safeToForceProjectLocal) {
+					// if the root buildscript is just `gradlePluginPortal()` (a superset of mavenCental)
+					// and the project repositories are either empty or some superset of mavenCentral
+					// then there's no harm in defaulting them to project-local resolution
+					spotlessExtension.resolveDependenciesIn = GradleProvisioner.ResolveDependenciesIn.PROJECT;
+				} else {
+					GradleProvisioner.logger.severe(StringPrinter.buildStringFromLines(
+							"The way that Spotless resolves formatter dependencies was deprecated in Gradle 6.0.",
+							"To silence this warning, you need to set X: `spotless { resolveDependenciesIn 'X' }`",
+							"  'ROOT_BUILDSCRIPT' - current behavior, causes gradle to emit deprecation warnings.",
+							"  'PROJECT' *recommended* - uses this project's repositories to resolve dependencies.",
+							"                            Only drawback is for the uncommon case that you want your",
+							"                            build tools to draw from a different set of respositories than ",
+							"                            than your build artifacts.",
+							"  'PROJECT_BUILDSCRIPT' - uses this project's buildscript to resolve dependencies.",
+							"                          You will probably need to add this:",
+							"                            `buildscript { repositories { mavenCentral() } }`",
+							"                          to the top of the `build.gradle` in this subproject.",
+							"We're hoping to find a better resolution in the future, see issue below for more info",
+							"  https://github.com/diffplug/spotless/issues/502"));
+				}
+			}
 		});
 	}
 
+	private boolean isMavenCentralSuperset(RepositoryHandler repositories) {
+		return repositories.stream().allMatch(SpotlessPlugin::isMavenCentralSuperset);
+	}
+
+	private static boolean isMavenCentralSuperset(ArtifactRepository repository) {
+		if (!(repository instanceof MavenArtifactRepository)) {
+			return false;
+		}
+		MavenArtifactRepository maven = (MavenArtifactRepository) repository;
+		if ("MavenRepo".equals(maven.getName())
+				&& "https://repo.maven.apache.org/maven2/".equals(maven.getUrl().toString())) {
+			return true;
+		} else if ("BintrayJCenter".equals(maven.getName())
+				&& "https://jcenter.bintray.com/".equals(maven.getUrl().toString())) {
+			return true;
+		} else if ("Gradle Central Plugin Repository".equals(maven.getName())
+				&& "https://plugins.gradle.org/m2".equals(maven.getUrl().toString())) {
+			return true;
+		} else {
+			return false;
+		}
+	}
+
 	/** The extension for this plugin. */
 	public SpotlessExtension getExtension() {
 		return spotlessExtension;

plugin-gradle/src/test/java/com/diffplug/gradle/spotless/DefaultRepoConfig.java

@@ -0,0 +1,67 @@
+/*
+ * Copyright 2016 DiffPlug
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package com.diffplug.gradle.spotless;
+
+import java.io.IOException;
+
+import org.assertj.core.api.Assertions;
+import org.gradle.testkit.runner.GradleRunner;
+import org.junit.Test;
+
+import com.diffplug.spotless.ResourceHarness;
+
+public class DefaultRepoConfig extends ResourceHarness {
+	@Test
+	public void integration() throws IOException {
+		setFile("build.gradle").toLines(
+				"repositories {",
+				"    mavenCentral()",
+				"    jcenter()",
+				"    gradlePluginPortal()",
+				"}",
+				"",
+				"println('buildscriptSize=' + buildscript.repositories.size())",
+				"for (repo in buildscript.repositories) {",
+				"  println(repo.toString())",
+				"  println(repo.class)",
+				"}",
+				"println('projectSize=' + repositories.size())",
+				"for (repo in repositories) {",
+				"  println(repo.name)",
+				"  println(repo.url)",
+				"  println(repo.artifactUrls)",
+				"}");
+
+		String output = GradleRunner.create()
+				.withGradleVersion("6.0")
+				.withProjectDir(rootFolder())
+				.build().getOutput();
+		Assertions.assertThat(output.replace("\r\n", "\n")).startsWith("\n" +
+				"> Configure project :\n" +
+				"buildscriptSize=0\n" +
+				"projectSize=3\n" +
+				"MavenRepo\n" +
+				"https://repo.maven.apache.org/maven2/\n" +
+				"[]\n" +
+				"BintrayJCenter\n" +
+				"https://jcenter.bintray.com/\n" +
+				"[]\n" +
+				"Gradle Central Plugin Repository\n" +
+				"https://plugins.gradle.org/m2\n" +
+				"[]\n" +
+				"");
+	}
+}