| /* |
| * Copyright (C) 2010, Christian Halstrick <christian.halstrick@sap.com> and others |
| * |
| * This program and the accompanying materials are made available under the |
| * terms of the Eclipse Distribution License v. 1.0 which is available at |
| * https://www.eclipse.org/org/documents/edl-v10.php. |
| * |
| * SPDX-License-Identifier: BSD-3-Clause |
| */ |
| package org.eclipse.jgit.lib; |
| |
| import static java.nio.charset.StandardCharsets.UTF_8; |
| import static org.junit.Assert.assertEquals; |
| import static org.junit.Assert.assertFalse; |
| import static org.junit.Assert.assertTrue; |
| |
| import java.io.File; |
| import java.io.FileOutputStream; |
| import java.io.IOException; |
| import java.time.Instant; |
| |
| import org.eclipse.jgit.api.Git; |
| import org.eclipse.jgit.dircache.DirCache; |
| import org.eclipse.jgit.junit.RepositoryTestCase; |
| import org.eclipse.jgit.junit.time.TimeUtil; |
| import org.eclipse.jgit.treewalk.FileTreeIterator; |
| import org.eclipse.jgit.treewalk.WorkingTreeOptions; |
| import org.eclipse.jgit.util.FS; |
| import org.junit.Test; |
| |
| public class RacyGitTests extends RepositoryTestCase { |
| |
| /** |
| * This test is inherently flaky in nature since using clocks in a computer |
| * to determine file modifications in a filesystem from Java is difficult |
| * and depends on many factors and we can't test all combinations |
| * |
| * If this test fails on your computer, don't worry but let us know if you |
| * are willing to provide details which may help to further improve handling |
| * of the racy git problem in JGit. |
| * |
| * Despite not being completely reproducible this test is still useful to |
| * detect regressions when running this test repeatedly on the same |
| * OS/filesystem/Java version (which we do on the CI used to build JGit). |
| * |
| * @see "https://git-scm.com/docs/racy-git" |
| * @see "https://www.youtube.com/watch?v=m44cAozuLNI" |
| */ |
| @Test |
| public void testRacyGitDetection() throws Exception { |
| // Reset to force creation of index file |
| try (Git git = new Git(db)) { |
| git.reset().call(); |
| } |
| |
| // wait to ensure that modtimes of the file doesn't match last index |
| // file modtime |
| fsTick(db.getIndexFile()); |
| |
| // create two files |
| File a = writeToWorkDir("a", "a"); |
| File b = writeToWorkDir("b", "b"); |
| TimeUtil.setLastModifiedOf(a.toPath(), b.toPath()); |
| TimeUtil.setLastModifiedOf(b.toPath(), b.toPath()); |
| |
| // wait to ensure that file-modTimes and therefore index entry modTime |
| // doesn't match the modtime of index-file after next persistance |
| fsTick(b); |
| |
| // now add both files to the index. No racy git expected |
| resetIndex(new FileTreeIterator(db)); |
| |
| assertEquals( |
| "[a, mode:100644, time:t0, length:1, content:a]" |
| + "[b, mode:100644, time:t0, length:1, content:b]", |
| indexState(SMUDGE | MOD_TIME | LENGTH | CONTENT)); |
| |
| // wait to ensure the file 'a' is updated at t1. |
| fsTick(db.getIndexFile()); |
| |
| // Create a racy git situation. This is a situation that the index is |
| // updated and then a file is modified within the same tick of the |
| // filesystem timestamp resolution. By changing the index file |
| // artificially, we create a fake racy situation. |
| File updatedA = writeToWorkDir("a", "a2"); |
| Instant newLastModified = TimeUtil |
| .setLastModifiedWithOffset(updatedA.toPath(), 100L); |
| resetIndex(new FileTreeIterator(db)); |
| FS.DETECTED.setLastModified(db.getIndexFile().toPath(), |
| newLastModified); |
| |
| DirCache dc = db.readDirCache(); |
| // check index state: although racily clean a should not be reported as |
| // being dirty since we forcefully reset the index to match the working |
| // tree |
| assertEquals( |
| "[a, mode:100644, time:t1, smudged, length:0, content:a2]" |
| + "[b, mode:100644, time:t0, length:1, content:b]", |
| indexState(SMUDGE | MOD_TIME | LENGTH | CONTENT)); |
| |
| // compare state of files in working tree with index to check that |
| // FileTreeIterator.isModified() works as expected |
| FileTreeIterator f = new FileTreeIterator(db.getWorkTree(), db.getFS(), |
| db.getConfig().get(WorkingTreeOptions.KEY)); |
| assertTrue(f.findFile("a")); |
| try (ObjectReader reader = db.newObjectReader()) { |
| assertFalse(f.isModified(dc.getEntry("a"), false, reader)); |
| } |
| } |
| |
| private File writeToWorkDir(String path, String content) throws IOException { |
| File f = new File(db.getWorkTree(), path); |
| try (FileOutputStream fos = new FileOutputStream(f)) { |
| fos.write(content.getBytes(UTF_8)); |
| return f; |
| } |
| } |
| } |