git pre push hook, task compatible with gradle configuration cache + parallel execution handling (#2570)

Author: nedtwigg

CHANGES.md

@@ -16,6 +16,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
   * Adds support for worktrees (fixes [#1765](https://github.com/diffplug/spotless/issues/1765))
 * Bump default `google-java-format` version to latest `1.24.0` -> `1.28.0`. ([#2345](https://github.com/diffplug/spotless/pull/2345))
 * Bump default `ktlint` version to latest `1.5.0` -> `1.7.1`. ([#2555](https://github.com/diffplug/spotless/pull/2555))
+* `GitPrePushHookInstaller` uses a lock to run gracefully if it is called many times in parallel. ([#2570](https://github.com/diffplug/spotless/pull/2570))
 * Bump default `jackson` version to latest `2.19.2` -> `2.20.0`. ([#2606](https://github.com/diffplug/spotless/pull/2606))
 * Bump default `gson` version to latest `2.13.1` -> `2.13.2`. ([#2615](https://github.com/diffplug/spotless/pull/2615))
 * **BREAKING** Bump default `ktfmt` version to latest `0.53` -> `0.58` ([#2613](https://github.com/diffplug/spotless/pull/2613))

lib/src/main/java/com/diffplug/spotless/GitPrePushHookInstaller.java

@@ -24,6 +24,8 @@
 import java.nio.file.Files;
 import java.util.Locale;
 
+import edu.umd.cs.findbugs.annotations.SuppressFBWarnings;
+
 /**
  * Abstract class responsible for installing a Git pre-push hook in a repository.
  * This class ensures that specific checks and logic are run before a push operation in Git.
@@ -35,6 +37,10 @@ public abstract class GitPrePushHookInstaller {
 	private static final String HOOK_HEADER = "##### SPOTLESS HOOK START #####";
 	private static final String HOOK_FOOTER = "##### SPOTLESS HOOK END #####";
 
+	private static final Object LOCK = new Object();
+
+	private static volatile boolean installing = false;
+
 	/**
 	 * Logger for recording informational and error messages during the installation process.
 	 */
@@ -56,6 +62,44 @@ public GitPrePushHookInstaller(GitPreHookLogger logger, File root) {
 		this.root = requireNonNull(root, "root file can not be null");
 	}
 
+	/**
+	 * Installs the Git pre-push hook while ensuring thread safety and preventing parallel installations.
+	 *
+	 * The method:
+	 * 1. Uses a thread-safe mechanism to prevent concurrent installations
+	 * 2. If a parallel installation is detected, logs a warning and skips the installation
+	 * 3. Uses a synchronized block with a static lock object to ensure thread safety
+	 *
+	 * The installation process sets a flag during installation and resets it afterwards,
+	 * using the {@link #doInstall()} method to perform the actual installation.
+	 *
+	 * @throws Exception if any error occurs during installation
+	 */
+	@SuppressFBWarnings(value = "ST_WRITE_TO_STATIC_FROM_INSTANCE_METHOD", justification = "This is a safe usage of a static lock object")
+	public void install() throws Exception {
+		if (installing) {
+			logger.warn("Parallel Spotless Git pre-push hook installation detected, skipping installation");
+			return;
+		}
+
+		// Since hook installation is a manual task triggered by the user,
+		// using synchronized locking is acceptable. It ensures thread safety
+		// without affecting overall performance, and provides a simple and reliable solution.
+		synchronized (LOCK) {
+			if (installing) {
+				logger.warn("Parallel Spotless Git pre-push hook installation detected, skipping installation");
+				return;
+			}
+
+			try {
+				installing = true;
+				doInstall();
+			} finally {
+				installing = false;
+			}
+		}
+	}
+
 	/**
 	 * Installs the Git pre-push hook into the repository.
 	 *
@@ -70,7 +114,7 @@ public GitPrePushHookInstaller(GitPreHookLogger logger, File root) {
 	 *
 	 * @throws Exception if any error occurs during installation.
 	 */
-	public void install() throws Exception {
+	private void doInstall() throws Exception {
 		logger.info("Installing git pre-push hook");
 
 		if (!isGitInstalled()) {

plugin-gradle/CHANGES.md

@@ -5,6 +5,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 ## [Unreleased]
 ### Changed
 * **BREAKING** Bump the required Gradle to `7.3` and required Java to `17`. ([#2375](https://github.com/diffplug/spotless/issues/2375), [#2540](https://github.com/diffplug/spotless/pull/2540))
+* **BREAKING** `spotlessInstallGitPrePushHook` task is now installed only on the root project. ([#2570](https://github.com/diffplug/spotless/pull/2570))
 * Bump JGit from `6.10.1` to `7.3.0` ([#2257](https://github.com/diffplug/spotless/pull/2257))
   * Adds support for worktrees (fixes [#1765](https://github.com/diffplug/spotless/issues/1765))
 * Bump default `google-java-format` version to latest `1.24.0` -> `1.28.0`. ([#2345](https://github.com/diffplug/spotless/pull/2345))
@@ -16,6 +17,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 
 ### Fixed
 * Respect system gitconfig when performing git operations ([#2404](https://github.com/diffplug/spotless/issues/2404))
+* `spotlessInstallGitPrePushHook` is now compatible with configuration cache. ([#2570](https://github.com/diffplug/spotless/pull/2570))
 
 ## [7.2.1] - 2025-07-21
 ### Fixed

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

@@ -41,6 +41,8 @@ public SpotlessExtensionImpl(Project project) {
 		rootInstallPreHook = project.getTasks().register(EXTENSION + INSTALL_GIT_PRE_PUSH_HOOK, SpotlessInstallPrePushHookTask.class, task -> {
 			task.setGroup(BUILD_SETUP_TASK_GROUP);
 			task.setDescription(INSTALL_GIT_PRE_PUSH_HOOK_DESCRIPTION);
+			task.getRootDir().set(project.getRootDir());
+			task.getIsRootExecution().set(project.equals(project.getRootProject()));
 		});
 
 		project.afterEvaluate(unused -> {

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

@@ -15,7 +15,11 @@
  */
 package com.diffplug.gradle.spotless;
 
+import java.io.File;
+
 import org.gradle.api.DefaultTask;
+import org.gradle.api.provider.Property;
+import org.gradle.api.tasks.Internal;
 import org.gradle.api.tasks.TaskAction;
 import org.gradle.work.DisableCachingByDefault;
 
@@ -30,7 +34,16 @@
  * <p>The task leverages {@link GitPrePushHookInstallerGradle} to implement the installation process.
  */
 @DisableCachingByDefault(because = "not worth caching")
-public class SpotlessInstallPrePushHookTask extends DefaultTask {
+public abstract class SpotlessInstallPrePushHookTask extends DefaultTask {
+
+	@Internal
+	abstract Property<File> getRootDir();
+
+	/**
+	 * Determines whether this task is being executed from the root project.
+	 */
+	@Internal
+	abstract Property<Boolean> getIsRootExecution();
 
 	/**
 	 * Executes the task to install the Git pre-push hook.
@@ -43,6 +56,12 @@ public class SpotlessInstallPrePushHookTask extends DefaultTask {
 	 */
 	@TaskAction
 	public void performAction() throws Exception {
+		// if is not root project, skip it
+		if (!getIsRootExecution().get()) {
+			getLogger().debug("Skipping Spotless pre-push hook installation because it is not being executed from the root project.");
+			return;
+		}
+
 		final var logger = new GitPreHookLogger() {
 			@Override
 			public void info(String format, Object... arguments) {
@@ -60,7 +79,7 @@ public void error(String format, Object... arguments) {
 			}
 		};
 
-		final var installer = new GitPrePushHookInstallerGradle(logger, getProject().getRootDir());
+		final var installer = new GitPrePushHookInstallerGradle(logger, getRootDir().get());
 		installer.install();
 	}
 }

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

@@ -35,7 +35,7 @@ public void should_create_pre_hook_file_when_hook_file_does_not_exists() throws
 
 		// when
 		var output = gradleRunner()
-				.withArguments("spotlessInstallGitPrePushHook")
+				.withArguments("spotlessInstallGitPrePushHook", "--system-prop=org.gradle.configuration-cache=true")
 				.build()
 				.getOutput();
 
@@ -65,7 +65,7 @@ public void should_append_to_existing_pre_hook_file_when_hook_file_exists() thro
 
 		// when
 		final var output = gradleRunner()
-				.withArguments("spotlessInstallGitPrePushHook")
+				.withArguments("spotlessInstallGitPrePushHook", "--system-prop=org.gradle.configuration-cache=true")
 				.build()
 				.getOutput();
 

plugin-maven/CHANGES.md

@@ -5,6 +5,7 @@ We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (
 ## [Unreleased]
 ### Changes
 * **BREAKING** Bump the required Java to `17`. ([#2375](https://github.com/diffplug/spotless/issues/2375), [#2540](https://github.com/diffplug/spotless/pull/2540))
+* **BREAKING** `spotless:install-git-pre-push-hook` task is now always installed in the root `.git/hooks` directory by resolving the top-level project base directory. ([#2570](https://github.com/diffplug/spotless/pull/2570))
 * Bump JGit from `6.10.1` to `7.3.0` ([#2257](https://github.com/diffplug/spotless/pull/2257))
   * Adds support for worktrees (fixes [#1765](https://github.com/diffplug/spotless/issues/1765))
 * Bump default `google-java-format` version to latest `1.24.0` -> `1.28.0`. ([#2345](https://github.com/diffplug/spotless/pull/2345))

plugin-maven/src/main/java/com/diffplug/spotless/maven/SpotlessInstallPrePushHookMojo.java

@@ -15,13 +15,12 @@
  */
 package com.diffplug.spotless.maven;
 
-import java.io.File;
-
 import org.apache.maven.plugin.AbstractMojo;
 import org.apache.maven.plugin.MojoExecutionException;
 import org.apache.maven.plugin.MojoFailureException;
 import org.apache.maven.plugins.annotations.Mojo;
 import org.apache.maven.plugins.annotations.Parameter;
+import org.apache.maven.project.MavenProject;
 
 import com.diffplug.spotless.GitPrePushHookInstaller.GitPreHookLogger;
 import com.diffplug.spotless.GitPrePushHookInstallerMaven;
@@ -37,12 +36,8 @@
 @Mojo(name = AbstractSpotlessMojo.GOAL_PRE_PUSH_HOOK, threadSafe = true)
 public class SpotlessInstallPrePushHookMojo extends AbstractMojo {
 
-	/**
-	 * The base directory of the Maven project where the Git pre-push hook will be installed.
-	 * This parameter is automatically set to the root directory of the current project.
-	 */
-	@Parameter(defaultValue = "${project.basedir}", readonly = true, required = true)
-	private File baseDir;
+	@Parameter(defaultValue = "${project}", readonly = true, required = true)
+	private MavenProject project;
 
 	/**
 	 * Executes the Mojo, installing the Git pre-push hook for the Spotless plugin.
@@ -56,6 +51,12 @@ public class SpotlessInstallPrePushHookMojo extends AbstractMojo {
 	 */
 	@Override
 	public void execute() throws MojoExecutionException, MojoFailureException {
+		// if is not root project, skip it
+		if (!project.isExecutionRoot()) {
+			getLog().debug("Skipping Spotless pre-push hook installation for non-root project: " + project.getName());
+			return;
+		}
+
 		final var logger = new GitPreHookLogger() {
 			@Override
 			public void info(String format, Object... arguments) {
@@ -74,7 +75,7 @@ public void error(String format, Object... arguments) {
 		};
 
 		try {
-			final var installer = new GitPrePushHookInstallerMaven(logger, baseDir);
+			final var installer = new GitPrePushHookInstallerMaven(logger, project.getBasedir());
 			installer.install();
 		} catch (Exception e) {
 			throw new MojoExecutionException("Unable to install pre-push hook", e);