Reduce ratchet memory usage for multi-module projects (#1426)

Author: nedtwigg

CHANGES.md

@@ -10,13 +10,16 @@ This document is intended for Spotless developers.
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `1.27.0`).
 
 ## [Unreleased]
+### Fixed
+* Improve memory usage when using git ratchet ([#1426](https://github.com/diffplug/spotless/pull/1426))
 
 ## [2.31.0] - 2022-11-24
 ### Added
 * `importOrder` now support groups of imports without blank lines ([#1401](https://github.com/diffplug/spotless/pull/1401))
 ### Fixed
 * Don't treat `@Value` as a type annotation [#1367](https://github.com/diffplug/spotless/pull/1367)
 * Support `ktlint_disabled_rules` in `ktlint` 0.47.x [#1378](https://github.com/diffplug/spotless/pull/1378)
+* Share git repositories across projects when using ratchet ([#1426](https://github.com/diffplug/spotless/pull/1426))
 ### Changes
 * Bump default `ktfmt` version to latest `0.40` -> `0.41` ([#1340](https://github.com/diffplug/spotless/pull/1340))
 * Bump default `scalafmt` version to latest `3.5.9` -> `3.6.1` ([#1373](https://github.com/diffplug/spotless/pull/1373))

build.gradle

@@ -18,4 +18,4 @@ spotless {
 		trimTrailingWhitespace()
 		endWithNewline()
 	}
-}
+}

lib-extra/src/main/java/com/diffplug/spotless/extra/GitRatchet.java

@@ -1,5 +1,5 @@
 /*
- * Copyright 2020-2021 DiffPlug
+ * Copyright 2020-2022 DiffPlug
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,7 +19,6 @@
 import java.io.IOException;
 import java.util.HashMap;
 import java.util.Map;
-import java.util.Objects;
 import java.util.Optional;
 
 import javax.annotation.Nullable;
@@ -137,7 +136,7 @@ private static boolean worktreeIsCleanCheckout(TreeWalk treeWalk) {
 	private final static int INDEX = 1;
 	private final static int WORKDIR = 2;
 
-	Map<Project, Repository> gitRoots = new HashMap<>();
+	Map<File, Repository> gitRoots = new HashMap<>();
 	Table<Repository, String, ObjectId> rootTreeShaCache = HashBasedTable.create();
 	Map<Project, ObjectId> subtreeShaCache = new HashMap<>();
 
@@ -147,25 +146,14 @@ private static boolean worktreeIsCleanCheckout(TreeWalk treeWalk) {
 	 * We cache the Repository for every Project in {@code gitRoots}, and use dynamic programming to populate it.
 	 */
 	protected Repository repositoryFor(Project project) throws IOException {
-		Repository repo = gitRoots.get(project);
+		File projectGitDir = GitWorkarounds.getDotGitDir(getDir(project));
+		if (projectGitDir == null || !RepositoryCache.FileKey.isGitRepository(projectGitDir, FS.DETECTED)) {
+			throw new IllegalArgumentException("Cannot find git repository in any parent directory");
+		}
+		Repository repo = gitRoots.get(projectGitDir);
 		if (repo == null) {
-			if (isGitRoot(getDir(project))) {
-				repo = createRepo(getDir(project));
-			} else {
-				Project parentProj = getParent(project);
-				if (parentProj == null) {
-					repo = traverseParentsUntil(getDir(project).getParentFile(), null);
-					if (repo == null) {
-						throw new IllegalArgumentException("Cannot find git repository in any parent directory");
-					}
-				} else {
-					repo = traverseParentsUntil(getDir(project).getParentFile(), getDir(parentProj));
-					if (repo == null) {
-						repo = repositoryFor(parentProj);
-					}
-				}
-			}
-			gitRoots.put(project, repo);
+			repo = FileRepositoryBuilder.create(projectGitDir);
+			gitRoots.put(projectGitDir, repo);
 		}
 		return repo;
 	}
@@ -174,26 +162,6 @@ protected Repository repositoryFor(Project project) throws IOException {
 
 	protected abstract @Nullable Project getParent(Project project);
 
-	private static @Nullable Repository traverseParentsUntil(File startWith, @Nullable File file) throws IOException {
-		while (startWith != null && !Objects.equals(startWith, file)) {
-			if (isGitRoot(startWith)) {
-				return createRepo(startWith);
-			} else {
-				startWith = startWith.getParentFile();
-			}
-		}
-		return null;
-	}
-
-	private static boolean isGitRoot(File dir) {
-		File dotGit = GitWorkarounds.getDotGitDir(dir);
-		return dotGit != null && RepositoryCache.FileKey.isGitRepository(dotGit, FS.DETECTED);
-	}
-
-	static Repository createRepo(File dir) throws IOException {
-		return FileRepositoryBuilder.create(GitWorkarounds.getDotGitDir(dir));
-	}
-
 	/**
 	 * Fast way to return treeSha of the given ref against the git repository which stores the given project.
 	 * Because of parallel project evaluation, there may be races here, so we synchronize on ourselves.  However, this method

plugin-gradle/CHANGES.md

@@ -3,6 +3,8 @@
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `3.27.0`).
 
 ## [Unreleased]
+### Fixed
+* Improve memory usage when using git ratchet ([#1426](https://github.com/diffplug/spotless/pull/1426))
 
 ## [6.12.0] - 2022-11-24
 ### Added

plugin-maven/CHANGES.md

@@ -3,13 +3,16 @@
 We adhere to the [keepachangelog](https://keepachangelog.com/en/1.0.0/) format (starting after version `1.27.0`).
 
 ## [Unreleased]
+### Fixed
+* Improve memory usage when using git ratchet ([#1426](https://github.com/diffplug/spotless/pull/1426))
 
 ## [2.28.0] - 2022-11-24
 ### Added
 * `importOrder` now support groups of imports without blank lines ([#1401](https://github.com/diffplug/spotless/pull/1401))
 ### Fixed
 * Don't treat `@Value` as a type annotation [#1367](https://github.com/diffplug/spotless/pull/1367)
 * Support `ktlint_disabled_rules` in `ktlint` 0.47.x [#1378](https://github.com/diffplug/spotless/pull/1378)
+* Share git repositories across projects when using ratchet ([#1426](https://github.com/diffplug/spotless/pull/1426))
 ### Changes
 * Bump default `ktfmt` version to latest `0.40` -> `0.41` ([#1340](https://github.com/diffplug/spotless/pull/1340))
 * Bump default `scalafmt` version to latest `3.5.9` -> `3.6.1` ([#1373](https://github.com/diffplug/spotless/pull/1373))