Improve checkstyle task build avoidance (#80804) (#80848)

Co-authored-by: Elastic Machine <[email protected]>

Co-authored-by: Elastic Machine <[email protected]>

Author: mark-vieira

build-tools-internal/src/main/java/org/elasticsearch/gradle/internal/precommit/CheckstylePrecommitPlugin.java

@@ -12,22 +12,20 @@
 import org.elasticsearch.gradle.internal.InternalPlugin;
 import org.elasticsearch.gradle.internal.conventions.precommit.PrecommitPlugin;
 import org.gradle.api.Action;
-import org.gradle.api.GradleException;
 import org.gradle.api.Project;
 import org.gradle.api.Task;
 import org.gradle.api.artifacts.dsl.DependencyHandler;
 import org.gradle.api.plugins.quality.Checkstyle;
 import org.gradle.api.plugins.quality.CheckstyleExtension;
 import org.gradle.api.provider.Provider;
+import org.gradle.api.tasks.SourceSetContainer;
 import org.gradle.api.tasks.TaskProvider;
 
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
 import java.io.UncheckedIOException;
 import java.net.JarURLConnection;
-import java.net.URI;
-import java.net.URISyntaxException;
 import java.net.URL;
 import java.nio.file.Files;
 import java.nio.file.StandardCopyOption;
@@ -97,14 +95,17 @@ public void execute(Task task) {
             t.reports(r -> r.getHtml().getRequired().set(false));
         });
 
-        return checkstyleTask;
-    }
+        // Configure checkstyle tasks with an empty classpath to improve build avoidance.
+        // It's optional since our rules only rely on source files anyway.
+        project.getExtensions()
+            .getByType(SourceSetContainer.class)
+            .all(
+                sourceSet -> project.getTasks()
+                    .withType(Checkstyle.class)
+                    .named(sourceSet.getTaskName("checkstyle", null))
+                    .configure(t -> t.setClasspath(project.getObjects().fileCollection()))
+            );
 
-    private static URI getBuildSrcCodeSource() {
-        try {
-            return CheckstylePrecommitPlugin.class.getProtectionDomain().getCodeSource().getLocation().toURI();
-        } catch (URISyntaxException e) {
-            throw new GradleException("Error determining build tools JAR location", e);
-        }
+        return checkstyleTask;
     }
 }