Remove the #372 workaround, since we don't need it anymore.

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

@@ -26,11 +26,9 @@
 
 import org.gradle.api.Project;
 import org.gradle.api.artifacts.Configuration;
-import org.gradle.api.artifacts.ConfigurationContainer;
 import org.gradle.api.artifacts.Dependency;
 
 import com.diffplug.common.base.Preconditions;
-import com.diffplug.common.base.StringPrinter;
 import com.diffplug.common.collect.ImmutableList;
 import com.diffplug.spotless.Provisioner;
 
@@ -39,6 +37,7 @@ public class GradleProvisioner {
 	private GradleProvisioner() {}
 
 	public static Provisioner fromProject(Project project) {
+		// TODO: this method is not necessary - we could remove it entirely for a small speedup
 		return project.getPlugins().apply(SpotlessPlugin.class).getExtension().registerDependenciesTask.rootProvisioner;
 	}
 
@@ -74,21 +73,15 @@ static Provisioner fromRootBuildscript(Project project) {
 						.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();
-				}
-				Configuration config = configContainer.detachedConfiguration(deps);
+				Configuration config = project.getRootProject().getBuildscript().getConfigurations().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.",
+				logger.log(
+						Level.SEVERE,
+						"You probably need to add a repository containing the '" + mavenCoords + "' artifact in the 'build.gradle' of your root project.\n" +
 								"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);
 				throw e;
 			}