Merge branch 'stable-4.9' into stable-4.10

* stable-4.9:
  BatchRefUpdate: repro racy atomic update, and fix it
  Delete unused FileTreeIteratorWithTimeControl
  Fix RacyGitTests#testRacyGitDetection
  Change RacyGitTests to create a racy git situation in a stable way
  Silence API warnings

Change-Id: Id5bf44645655fca40ad22bb1f1ad20a7c2e8f6db
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

3 files changed, 69 insertions, 203 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/BatchRefUpdateTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/BatchRefUpdateTest.java
index 3c4b8cf4bc..2ac4a846ea 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/BatchRefUpdateTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/BatchRefUpdateTest.java
@@ -43,6 +43,7 @@
 
 package org.eclipse.jgit.internal.storage.file;
 
+import static java.nio.charset.StandardCharsets.UTF_8;
 import static java.util.concurrent.TimeUnit.NANOSECONDS;
 import static java.util.concurrent.TimeUnit.SECONDS;
 import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.LOCK_FAILURE;
@@ -64,6 +65,7 @@ import static org.junit.Assume.assumeTrue;
 
 import java.io.File;
 import java.io.IOException;
+import java.nio.file.Files;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.Collections;
@@ -162,6 +164,33 @@ public class BatchRefUpdateTest extends LocalDiskRepositoryTestCase {
 	}
 
 	@Test
+	public void packedRefsFileIsSorted() throws IOException {
+		assumeTrue(atomic);
+
+		for (int i = 0; i < 2; i++) {
+			BatchRefUpdate bu = diskRepo.getRefDatabase().newBatchUpdate();
+			String b1  = String.format("refs/heads/a%d",i);
+			String b2  = String.format("refs/heads/b%d",i);
+			bu.setAtomic(atomic);
+			ReceiveCommand c1 = new ReceiveCommand(ObjectId.zeroId(), A, b1);
+			ReceiveCommand c2 = new ReceiveCommand(ObjectId.zeroId(), B, b2);
+			bu.addCommand(c1, c2);
+			try (RevWalk rw = new RevWalk(diskRepo)) {
+				bu.execute(rw, NullProgressMonitor.INSTANCE);
+			}
+			assertEquals(c1.getResult(), ReceiveCommand.Result.OK);
+			assertEquals(c2.getResult(), ReceiveCommand.Result.OK);
+		}
+
+		File packed = new File(diskRepo.getDirectory(), "packed-refs");
+		String packedStr = new String(Files.readAllBytes(packed.toPath()), UTF_8);
+
+		int a2 = packedStr.indexOf("refs/heads/a1");
+		int b1 = packedStr.indexOf("refs/heads/b0");
+		assertTrue(a2 <  b1);
+	}
+
+	@Test
 	public void simpleNoForce() throws IOException {
 		writeLooseRef("refs/heads/master", A);
 		writeLooseRef("refs/heads/masters", B);
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RacyGitTests.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RacyGitTests.java
index 9236b4e821..552b7a1e99 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RacyGitTests.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/lib/RacyGitTests.java
@@ -42,93 +42,25 @@
  */
 package org.eclipse.jgit.lib;
 
-import static java.lang.Long.valueOf;
 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.util.TreeSet;
 
 import org.eclipse.jgit.api.Git;
+import org.eclipse.jgit.dircache.DirCache;
 import org.eclipse.jgit.junit.RepositoryTestCase;
 import org.eclipse.jgit.treewalk.FileTreeIterator;
-import org.eclipse.jgit.treewalk.FileTreeIteratorWithTimeControl;
-import org.eclipse.jgit.treewalk.NameConflictTreeWalk;
-import org.eclipse.jgit.util.FileUtils;
+import org.eclipse.jgit.treewalk.WorkingTreeOptions;
 import org.junit.Test;
 
 public class RacyGitTests extends RepositoryTestCase {
-	@Test
-	public void testIterator() throws IllegalStateException, IOException,
-			InterruptedException {
-		TreeSet<Long> modTimes = new TreeSet<>();
-		File lastFile = null;
-		for (int i = 0; i < 10; i++) {
-			lastFile = new File(db.getWorkTree(), "0." + i);
-			FileUtils.createNewFile(lastFile);
-			if (i == 5)
-				fsTick(lastFile);
-		}
-		modTimes.add(valueOf(fsTick(lastFile)));
-		for (int i = 0; i < 10; i++) {
-			lastFile = new File(db.getWorkTree(), "1." + i);
-			FileUtils.createNewFile(lastFile);
-		}
-		modTimes.add(valueOf(fsTick(lastFile)));
-		for (int i = 0; i < 10; i++) {
-			lastFile = new File(db.getWorkTree(), "2." + i);
-			FileUtils.createNewFile(lastFile);
-			if (i % 4 == 0)
-				fsTick(lastFile);
-		}
-		FileTreeIteratorWithTimeControl fileIt = new FileTreeIteratorWithTimeControl(
-				db, modTimes);
-		try (NameConflictTreeWalk tw = new NameConflictTreeWalk(db)) {
-			tw.addTree(fileIt);
-			tw.setRecursive(true);
-			FileTreeIterator t;
-			long t0 = 0;
-			for (int i = 0; i < 10; i++) {
-				assertTrue(tw.next());
-				t = tw.getTree(0, FileTreeIterator.class);
-				if (i == 0) {
-					t0 = t.getEntryLastModified();
-				} else {
-					assertEquals(t0, t.getEntryLastModified());
-				}
-			}
-			long t1 = 0;
-			for (int i = 0; i < 10; i++) {
-				assertTrue(tw.next());
-				t = tw.getTree(0, FileTreeIterator.class);
-				if (i == 0) {
-					t1 = t.getEntryLastModified();
-					assertTrue(t1 > t0);
-				} else {
-					assertEquals(t1, t.getEntryLastModified());
-				}
-			}
-			long t2 = 0;
-			for (int i = 0; i < 10; i++) {
-				assertTrue(tw.next());
-				t = tw.getTree(0, FileTreeIterator.class);
-				if (i == 0) {
-					t2 = t.getEntryLastModified();
-					assertTrue(t2 > t1);
-				} else {
-					assertEquals(t2, t.getEntryLastModified());
-				}
-			}
-		}
-	}
 
 	@Test
 	public void testRacyGitDetection() throws Exception {
-		TreeSet<Long> modTimes = new TreeSet<>();
-		File lastFile;
-
 		// Reset to force creation of index file
 		try (Git git = new Git(db)) {
 			git.reset().call();
@@ -136,45 +68,59 @@ public class RacyGitTests extends RepositoryTestCase {
 
 		// wait to ensure that modtimes of the file doesn't match last index
 		// file modtime
-		modTimes.add(valueOf(fsTick(db.getIndexFile())));
+		fsTick(db.getIndexFile());
 
 		// create two files
-		addToWorkDir("a", "a");
-		lastFile = addToWorkDir("b", "b");
+		File a = writeToWorkDir("a", "a");
+		File b = writeToWorkDir("b", "b");
+		assertTrue(a.setLastModified(b.lastModified()));
+		assertTrue(b.setLastModified(b.lastModified()));
 
 		// wait to ensure that file-modTimes and therefore index entry modTime
 		// doesn't match the modtime of index-file after next persistance
-		modTimes.add(valueOf(fsTick(lastFile)));
+		fsTick(b);
 
 		// now add both files to the index. No racy git expected
-		resetIndex(new FileTreeIteratorWithTimeControl(db, modTimes));
+		resetIndex(new FileTreeIterator(db));
 
 		assertEquals(
-				"[a, mode:100644, time:t0, length:1, content:a]" +
-				"[b, mode:100644, time:t0, length:1, content:b]",
+				"[a, mode:100644, time:t0, length:1, content:a]"
+						+ "[b, mode:100644, time:t0, length:1, content:b]",
 				indexState(SMUDGE | MOD_TIME | LENGTH | CONTENT));
 
-		// Remember the last modTime of index file. All modifications times of
-		// further modification are translated to this value so it looks that
-		// files have been modified in the same time slot as the index file
-		modTimes.add(Long.valueOf(db.getIndexFile().lastModified()));
+		// wait to ensure the file 'a' is updated at t1.
+		fsTick(db.getIndexFile());
 
-		// modify one file
-		addToWorkDir("a", "a2");
-		// now update the index the index. 'a' has to be racily clean -- because
-		// it's modification time is exactly the same as the previous index file
-		// mod time.
-		resetIndex(new FileTreeIteratorWithTimeControl(db, modTimes));
+		// 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");
+		long newLastModified = updatedA.lastModified() + 100;
+		assertTrue(updatedA.setLastModified(newLastModified));
+		resetIndex(new FileTreeIterator(db));
+		assertTrue(db.getIndexFile().setLastModified(newLastModified));
 
-		db.readDirCache();
-		// although racily clean a should not be reported as being dirty
+		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));
+				"[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 addToWorkDir(String path, String content) throws IOException {
+	private File writeToWorkDir(String path, String content) throws IOException {
 		File f = new File(db.getWorkTree(), path);
 		FileOutputStream fos = new FileOutputStream(f);
 		try {
diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/treewalk/FileTreeIteratorWithTimeControl.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/treewalk/FileTreeIteratorWithTimeControl.java
deleted file mode 100644
index 717a2f3b2c..0000000000
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/treewalk/FileTreeIteratorWithTimeControl.java
+++ /dev/null
@@ -1,109 +0,0 @@
-/*
- * Copyright (C) 2010, Christian Halstrick <christian.halstrick@sap.com>
- * and other copyright owners as documented in the project's IP log.
- *
- * This program and the accompanying materials are made available
- * under the terms of the Eclipse Distribution License v1.0 which
- * accompanies this distribution, is reproduced below, and is
- * available at http://www.eclipse.org/org/documents/edl-v10.php
- *
- * All rights reserved.
- *
- * Redistribution and use in source and binary forms, with or
- * without modification, are permitted provided that the following
- * conditions are met:
- *
- * - Redistributions of source code must retain the above copyright
- *   notice, this list of conditions and the following disclaimer.
- *
- * - Redistributions in binary form must reproduce the above
- *   copyright notice, this list of conditions and the following
- *   disclaimer in the documentation and/or other materials provided
- *   with the distribution.
- *
- * - Neither the name of the Eclipse Foundation, Inc. nor the
- *   names of its contributors may be used to endorse or promote
- *   products derived from this software without specific prior
- *   written permission.
- *
- * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
- * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
- * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
- * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
- * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
- * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
- * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
- * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
- * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
- * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
- * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
- * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
- */
-package org.eclipse.jgit.treewalk;
-
-import java.io.File;
-import java.util.SortedSet;
-import java.util.TreeSet;
-
-import org.eclipse.jgit.lib.Config;
-import org.eclipse.jgit.lib.ObjectReader;
-import org.eclipse.jgit.lib.Repository;
-import org.eclipse.jgit.util.FS;
-
-/**
- * A {@link FileTreeIterator} used in tests which allows to specify explicitly
- * what will be returned by {@link #getEntryLastModified()}. This allows to
- * write tests where certain files have to have the same modification time.
- * <p>
- * This iterator is configured by a list of strictly increasing long values
- * t(0), t(1), ..., t(n). For each file with a modification between t(x) and
- * t(x+1) [ t(x) &lt;= time &lt; t(x+1) ] this iterator will report t(x). For
- * files with a modification time smaller t(0) a modification time of 0 is
- * returned. For files with a modification time greater or equal t(n) t(n) will
- * be returned.
- * <p>
- * This class was written especially to test racy-git problems
- */
-public class FileTreeIteratorWithTimeControl extends FileTreeIterator {
-	private TreeSet<Long> modTimes;
-
-	public FileTreeIteratorWithTimeControl(FileTreeIterator p, Repository repo,
-			TreeSet<Long> modTimes) {
-		super(p, repo.getWorkTree(), repo.getFS());
-		this.modTimes = modTimes;
-	}
-
-	public FileTreeIteratorWithTimeControl(FileTreeIterator p, File f, FS fs,
-			TreeSet<Long> modTimes) {
-		super(p, f, fs);
-		this.modTimes = modTimes;
-	}
-
-	public FileTreeIteratorWithTimeControl(Repository repo,
-			TreeSet<Long> modTimes) {
-		super(repo);
-		this.modTimes = modTimes;
-	}
-
-	public FileTreeIteratorWithTimeControl(File f, FS fs,
-			TreeSet<Long> modTimes) {
-		super(f, fs, new Config().get(WorkingTreeOptions.KEY));
-		this.modTimes = modTimes;
-	}
-
-	@Override
-	public AbstractTreeIterator createSubtreeIterator(final ObjectReader reader) {
-		return new FileTreeIteratorWithTimeControl(this,
-				((FileEntry) current()).getFile(), fs, modTimes);
-	}
-
-	@Override
-	public long getEntryLastModified() {
-		if (modTimes == null)
-			return 0;
-		Long cutOff = Long.valueOf(super.getEntryLastModified() + 1);
-		SortedSet<Long> head = modTimes.headSet(cutOff);
-		return head.isEmpty() ? 0 : head.last().longValue();
-	}
-}