org.eclipse.jgit.test/tst/org/eclipse/jgit/internal/storage/file/BatchRefUpdateTest.java - sop/jgit - Git at Google

 /*
  * Copyright (C) 2017 Google Inc.
  * 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.internal.storage.file;

 import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.LOCK_FAILURE;
 import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.OK;
 import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.REJECTED_MISSING_OBJECT;
 import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.REJECTED_NONFASTFORWARD;
 import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.TRANSACTION_ABORTED;
 import static org.eclipse.jgit.lib.ObjectId.zeroId;
 import static org.eclipse.jgit.transport.ReceiveCommand.Type.CREATE;
 import static org.eclipse.jgit.transport.ReceiveCommand.Type.DELETE;
 import static org.eclipse.jgit.transport.ReceiveCommand.Type.UPDATE;
 import static org.eclipse.jgit.transport.ReceiveCommand.Type.UPDATE_NONFASTFORWARD;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;

 import java.io.File;
 import java.io.IOException;
 import java.util.Arrays;
 import java.util.Collection;
 import java.util.LinkedHashMap;
 import java.util.List;
 import java.util.Map;
 import java.util.function.Predicate;

 import org.eclipse.jgit.junit.LocalDiskRepositoryTestCase;
 import org.eclipse.jgit.junit.StrictWorkMonitor;
 import org.eclipse.jgit.junit.TestRepository;
 import org.eclipse.jgit.lib.AnyObjectId;
 import org.eclipse.jgit.lib.BatchRefUpdate;
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.NullProgressMonitor;
 import org.eclipse.jgit.lib.ObjectId;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.RefDatabase;
 import org.eclipse.jgit.lib.Repository;
 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.revwalk.RevWalk;
 import org.eclipse.jgit.transport.ReceiveCommand;
 import org.junit.Before;
 import org.junit.Test;
 import org.junit.runner.RunWith;
 import org.junit.runners.Parameterized;
 import org.junit.runners.Parameterized.Parameter;
 import org.junit.runners.Parameterized.Parameters;

 @RunWith(Parameterized.class)
 public class BatchRefUpdateTest extends LocalDiskRepositoryTestCase {
 	@Parameter
 	public boolean atomic;

 	@Parameters(name = "atomic={0}")
 	public static Collection<Object[]> data() {
 		return Arrays.asList(new Object[][]{ {Boolean.FALSE}, {Boolean.TRUE} });
 	}

 	private Repository diskRepo;
 	private TestRepository<Repository> repo;
 	private RefDirectory refdir;
 	private RevCommit A;
 	private RevCommit B;

 	@Override
 	@Before
 	public void setUp() throws Exception {
 		super.setUp();

 		diskRepo = createBareRepository();
 		refdir = (RefDirectory) diskRepo.getRefDatabase();

 		repo = new TestRepository<>(diskRepo);
 		A = repo.commit().create();
 		B = repo.commit(repo.getRevWalk().parseCommit(A));
 	}

 	@Test
 	public void simpleNoForce() throws IOException {
 		writeLooseRef("refs/heads/master", A);
 		writeLooseRef("refs/heads/masters", B);

 		List<ReceiveCommand> cmds = Arrays.asList(
 				new ReceiveCommand(A, B, "refs/heads/master", UPDATE),
 				new ReceiveCommand(B, A, "refs/heads/masters", UPDATE_NONFASTFORWARD));
 		execute(newBatchUpdate(cmds));

 		if (atomic) {
 			assertResults(cmds, TRANSACTION_ABORTED, REJECTED_NONFASTFORWARD);
 			assertRefs(
 					"refs/heads/master", A,
 					"refs/heads/masters", B);
 		} else {
 			assertResults(cmds, OK, REJECTED_NONFASTFORWARD);
 			assertRefs(
 					"refs/heads/master", B,
 					"refs/heads/masters", B);
 		}
 	}

 	@Test
 	public void simpleForce() throws IOException {
 		writeLooseRef("refs/heads/master", A);
 		writeLooseRef("refs/heads/masters", B);

 		List<ReceiveCommand> cmds = Arrays.asList(
 				new ReceiveCommand(A, B, "refs/heads/master", UPDATE),
 				new ReceiveCommand(B, A, "refs/heads/masters", UPDATE_NONFASTFORWARD));
 		execute(newBatchUpdate(cmds).setAllowNonFastForwards(true));

 		assertResults(cmds, OK, OK);
 		assertRefs(
 				"refs/heads/master", B,
 				"refs/heads/masters", A);
 	}

 	@Test
 	public void nonFastForwardDoesNotDoExpensiveMergeCheck() throws IOException {
 		writeLooseRef("refs/heads/master", B);

 		List<ReceiveCommand> cmds = Arrays.asList(
 				new ReceiveCommand(B, A, "refs/heads/master", UPDATE_NONFASTFORWARD));
 		try (RevWalk rw = new RevWalk(diskRepo) {
 					@Override
 					public boolean isMergedInto(RevCommit base, RevCommit tip) {
 						throw new AssertionError("isMergedInto() should not be called");
 					}
 				}) {
 			newBatchUpdate(cmds)
 					.setAllowNonFastForwards(true)
 					.execute(rw, new StrictWorkMonitor());
 		}

 		assertResults(cmds, OK);
 		assertRefs("refs/heads/master", A);
 	}

 	@Test
 	public void fileDirectoryConflict() throws IOException {
 		writeLooseRef("refs/heads/master", A);
 		writeLooseRef("refs/heads/masters", B);

 		List<ReceiveCommand> cmds = Arrays.asList(
 				new ReceiveCommand(A, B, "refs/heads/master", UPDATE),
 				new ReceiveCommand(zeroId(), A, "refs/heads/master/x", CREATE),
 				new ReceiveCommand(zeroId(), A, "refs/heads", CREATE));
 		execute(newBatchUpdate(cmds).setAllowNonFastForwards(true), false);

 		if (atomic) {
 			// Atomic update sees that master and master/x are conflicting, then marks
 			// the first one in the list as LOCK_FAILURE and aborts the rest.
 			assertResults(cmds,
 					LOCK_FAILURE, TRANSACTION_ABORTED, TRANSACTION_ABORTED);
 			assertRefs(
 					"refs/heads/master", A,
 					"refs/heads/masters", B);
 		} else {
 			// Non-atomic updates are applied in order: master succeeds, then master/x
 			// fails due to conflict.
 			assertResults(cmds, OK, LOCK_FAILURE, LOCK_FAILURE);
 			assertRefs(
 					"refs/heads/master", B,
 					"refs/heads/masters", B);
 		}
 	}

 	@Test
 	public void conflictThanksToDelete() throws IOException {
 		writeLooseRef("refs/heads/master", A);
 		writeLooseRef("refs/heads/masters", B);

 		List<ReceiveCommand> cmds = Arrays.asList(
 				new ReceiveCommand(A, B, "refs/heads/master", UPDATE),
 				new ReceiveCommand(zeroId(), A, "refs/heads/masters/x", CREATE),
 				new ReceiveCommand(B, zeroId(), "refs/heads/masters", DELETE));
 		execute(newBatchUpdate(cmds).setAllowNonFastForwards(true));

 		assertResults(cmds, OK, OK, OK);
 		assertRefs(
 				"refs/heads/master", B,
 				"refs/heads/masters/x", A);
 	}

 	@Test
 	public void updateToMissingObject() throws IOException {
 		writeLooseRef("refs/heads/master", A);

 		ObjectId bad =
 				ObjectId.fromString("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef");
 		List<ReceiveCommand> cmds = Arrays.asList(
 				new ReceiveCommand(A, bad, "refs/heads/master", UPDATE),
 				new ReceiveCommand(zeroId(), B, "refs/heads/foo2", CREATE));
 		execute(newBatchUpdate(cmds).setAllowNonFastForwards(true), false);

 		if (atomic) {
 			assertResults(cmds, REJECTED_MISSING_OBJECT, TRANSACTION_ABORTED);
 			assertRefs("refs/heads/master", A);
 		} else {
 			assertResults(cmds, REJECTED_MISSING_OBJECT, OK);
 			assertRefs(
 					"refs/heads/master", A,
 					"refs/heads/foo2", B);
 		}
 	}

 	@Test
 	public void addMissingObject() throws IOException {
 		writeLooseRef("refs/heads/master", A);

 		ObjectId bad =
 				ObjectId.fromString("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef");
 		List<ReceiveCommand> cmds = Arrays.asList(
 				new ReceiveCommand(A, B, "refs/heads/master", UPDATE),
 				new ReceiveCommand(zeroId(), bad, "refs/heads/foo2", CREATE));
 		execute(newBatchUpdate(cmds).setAllowNonFastForwards(true), false);

 		if (atomic) {
 			assertResults(cmds, TRANSACTION_ABORTED, REJECTED_MISSING_OBJECT);
 			assertRefs("refs/heads/master", A);
 		} else {
 			assertResults(cmds, OK, REJECTED_MISSING_OBJECT);
 			assertRefs("refs/heads/master", B);
 		}
 	}

 	@Test
 	public void oneNonExistentRef() throws IOException {
 		List<ReceiveCommand> cmds = Arrays.asList(
 				new ReceiveCommand(A, B, "refs/heads/foo1", UPDATE),
 				new ReceiveCommand(zeroId(), B, "refs/heads/foo2", CREATE));
 		execute(newBatchUpdate(cmds).setAllowNonFastForwards(true));

 		if (atomic) {
 			assertResults(cmds, LOCK_FAILURE, TRANSACTION_ABORTED);
 			assertRefs();
 		} else {
 			assertResults(cmds, LOCK_FAILURE, OK);
 			assertRefs("refs/heads/foo2", B);
 		}
 	}

 	@Test
 	public void oneRefWrongOldValue() throws IOException {
 		writeLooseRef("refs/heads/master", A);

 		List<ReceiveCommand> cmds = Arrays.asList(
 				new ReceiveCommand(B, B, "refs/heads/master", UPDATE),
 				new ReceiveCommand(zeroId(), B, "refs/heads/foo2", CREATE));
 		execute(newBatchUpdate(cmds).setAllowNonFastForwards(true));

 		if (atomic) {
 			assertResults(cmds, LOCK_FAILURE, TRANSACTION_ABORTED);
 			assertRefs("refs/heads/master", A);
 		} else {
 			assertResults(cmds, LOCK_FAILURE, OK);
 			assertRefs(
 					"refs/heads/master", A,
 					"refs/heads/foo2", B);
 		}
 	}

 	@Test
 	public void nonExistentRef() throws IOException {
 		writeLooseRef("refs/heads/master", A);

 		List<ReceiveCommand> cmds = Arrays.asList(
 				new ReceiveCommand(A, B, "refs/heads/master", UPDATE),
 				new ReceiveCommand(A, zeroId(), "refs/heads/foo2", DELETE));
 		execute(newBatchUpdate(cmds).setAllowNonFastForwards(true));

 		if (atomic) {
 			assertResults(cmds, TRANSACTION_ABORTED, LOCK_FAILURE);
 			assertRefs("refs/heads/master", A);
 		} else {
 			assertResults(cmds, OK, LOCK_FAILURE);
 			assertRefs("refs/heads/master", B);
 		}
 	}

 	private void writeLooseRef(String name, AnyObjectId id) throws IOException {
 		write(new File(diskRepo.getDirectory(), name), id.name() + "\n");
 	}

 	private BatchRefUpdate newBatchUpdate(List<ReceiveCommand> cmds) {
 		BatchRefUpdate u = refdir.newBatchUpdate();
 		if (atomic) {
 			assertTrue(u.isAtomic());
 		} else {
 			u.setAtomic(false);
 		}
 		u.addCommand(cmds);
 		return u;
 	}

 	private void execute(BatchRefUpdate u) throws IOException {
 		execute(u, false);
 	}

 	private void execute(BatchRefUpdate u, boolean strictWork) throws IOException {
 		try (RevWalk rw = new RevWalk(diskRepo)) {
 			u.execute(rw,
 					strictWork ? new StrictWorkMonitor() : NullProgressMonitor.INSTANCE);
 		}
 	}

 	private void assertRefs(Object... args) throws IOException {
 		if (args.length % 2 != 0) {
 			throw new IllegalArgumentException(
 					"expected even number of args: " + Arrays.toString(args));
 		}

 		Map<String, AnyObjectId> expected = new LinkedHashMap<>();
 		for (int i = 0; i < args.length; i += 2) {
 			expected.put((String) args[i], (AnyObjectId) args[i + 1]);
 		}

 		Map<String, Ref> refs = refdir.getRefs(RefDatabase.ALL);
 		Ref actualHead = refs.remove(Constants.HEAD);
 		if (actualHead != null) {
 			String actualLeafName = actualHead.getLeaf().getName();
 			assertEquals(
 					"expected HEAD to point to refs/heads/master, got: " + actualLeafName,
 					"refs/heads/master", actualLeafName);
 			AnyObjectId expectedMaster = expected.get("refs/heads/master");
 			assertNotNull("expected master ref since HEAD exists", expectedMaster);
 			assertEquals(expectedMaster, actualHead.getObjectId());
 		}

 		Map<String, AnyObjectId> actual = new LinkedHashMap<>();
 		refs.forEach((n, r) -> actual.put(n, r.getObjectId()));

 		assertEquals(expected.keySet(), actual.keySet());
 		actual.forEach((n, a) -> assertEquals(n, expected.get(n), a));
 	}

 	enum Result {
 		OK(ReceiveCommand.Result.OK),
 		LOCK_FAILURE(ReceiveCommand.Result.LOCK_FAILURE),
 		REJECTED_NONFASTFORWARD(ReceiveCommand.Result.REJECTED_NONFASTFORWARD),
 		REJECTED_MISSING_OBJECT(ReceiveCommand.Result.REJECTED_MISSING_OBJECT),
 		TRANSACTION_ABORTED(ReceiveCommand::isTransactionAborted);

 		final Predicate<? super ReceiveCommand> p;

 		private Result(Predicate<? super ReceiveCommand> p) {
 			this.p = p;
 		}

 		private Result(ReceiveCommand.Result result) {
 			this(c -> c.getResult() == result);
 		}
 	}

 	private void assertResults(
 			List<ReceiveCommand> cmds, Result... expected) {
 		if (expected.length != cmds.size()) {
 			throw new IllegalArgumentException(
 					"expected " + cmds.size() + " result args");
 		}
 		for (int i = 0; i < cmds.size(); i++) {
 			ReceiveCommand c = cmds.get(i);
 			Result r = expected[i];
 			assertTrue(
 					String.format(
 							"result of command (%d) should be %s: %s %s%s",
 							Integer.valueOf(i), r, c,
 							c.getResult(),
 							c.getMessage() != null ? " (" + c.getMessage() + ")" : ""),
 					r.p.test(c));
 		}
 	}
 }
	/*
	* Copyright (C) 2017 Google Inc.
	* 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.internal.storage.file;

	import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.LOCK_FAILURE;
	import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.OK;
	import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.REJECTED_MISSING_OBJECT;
	import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.REJECTED_NONFASTFORWARD;
	import static org.eclipse.jgit.internal.storage.file.BatchRefUpdateTest.Result.TRANSACTION_ABORTED;
	import static org.eclipse.jgit.lib.ObjectId.zeroId;
	import static org.eclipse.jgit.transport.ReceiveCommand.Type.CREATE;
	import static org.eclipse.jgit.transport.ReceiveCommand.Type.DELETE;
	import static org.eclipse.jgit.transport.ReceiveCommand.Type.UPDATE;
	import static org.eclipse.jgit.transport.ReceiveCommand.Type.UPDATE_NONFASTFORWARD;
	import static org.junit.Assert.assertEquals;
	import static org.junit.Assert.assertNotNull;
	import static org.junit.Assert.assertTrue;

	import java.io.File;
	import java.io.IOException;
	import java.util.Arrays;
	import java.util.Collection;
	import java.util.LinkedHashMap;
	import java.util.List;
	import java.util.Map;
	import java.util.function.Predicate;

	import org.eclipse.jgit.junit.LocalDiskRepositoryTestCase;
	import org.eclipse.jgit.junit.StrictWorkMonitor;
	import org.eclipse.jgit.junit.TestRepository;
	import org.eclipse.jgit.lib.AnyObjectId;
	import org.eclipse.jgit.lib.BatchRefUpdate;
	import org.eclipse.jgit.lib.Constants;
	import org.eclipse.jgit.lib.NullProgressMonitor;
	import org.eclipse.jgit.lib.ObjectId;
	import org.eclipse.jgit.lib.Ref;
	import org.eclipse.jgit.lib.RefDatabase;
	import org.eclipse.jgit.lib.Repository;
	import org.eclipse.jgit.revwalk.RevCommit;
	import org.eclipse.jgit.revwalk.RevWalk;
	import org.eclipse.jgit.transport.ReceiveCommand;
	import org.junit.Before;
	import org.junit.Test;
	import org.junit.runner.RunWith;
	import org.junit.runners.Parameterized;
	import org.junit.runners.Parameterized.Parameter;
	import org.junit.runners.Parameterized.Parameters;

	@RunWith(Parameterized.class)
	public class BatchRefUpdateTest extends LocalDiskRepositoryTestCase {
	@Parameter
	public boolean atomic;

	@Parameters(name = "atomic={0}")
	public static Collection<Object[]> data() {
	return Arrays.asList(new Object[][]{ {Boolean.FALSE}, {Boolean.TRUE} });
	}

	private Repository diskRepo;
	private TestRepository<Repository> repo;
	private RefDirectory refdir;
	private RevCommit A;
	private RevCommit B;

	@Override
	@Before
	public void setUp() throws Exception {
	super.setUp();

	diskRepo = createBareRepository();
	refdir = (RefDirectory) diskRepo.getRefDatabase();

	repo = new TestRepository<>(diskRepo);
	A = repo.commit().create();
	B = repo.commit(repo.getRevWalk().parseCommit(A));
	}

	@Test
	public void simpleNoForce() throws IOException {
	writeLooseRef("refs/heads/master", A);
	writeLooseRef("refs/heads/masters", B);

	List<ReceiveCommand> cmds = Arrays.asList(
	new ReceiveCommand(A, B, "refs/heads/master", UPDATE),
	new ReceiveCommand(B, A, "refs/heads/masters", UPDATE_NONFASTFORWARD));
	execute(newBatchUpdate(cmds));

	if (atomic) {
	assertResults(cmds, TRANSACTION_ABORTED, REJECTED_NONFASTFORWARD);
	assertRefs(
	"refs/heads/master", A,
	"refs/heads/masters", B);
	} else {
	assertResults(cmds, OK, REJECTED_NONFASTFORWARD);
	assertRefs(
	"refs/heads/master", B,
	"refs/heads/masters", B);
	}
	}

	@Test
	public void simpleForce() throws IOException {
	writeLooseRef("refs/heads/master", A);
	writeLooseRef("refs/heads/masters", B);

	List<ReceiveCommand> cmds = Arrays.asList(
	new ReceiveCommand(A, B, "refs/heads/master", UPDATE),
	new ReceiveCommand(B, A, "refs/heads/masters", UPDATE_NONFASTFORWARD));
	execute(newBatchUpdate(cmds).setAllowNonFastForwards(true));

	assertResults(cmds, OK, OK);
	assertRefs(
	"refs/heads/master", B,
	"refs/heads/masters", A);
	}

	@Test
	public void nonFastForwardDoesNotDoExpensiveMergeCheck() throws IOException {
	writeLooseRef("refs/heads/master", B);

	List<ReceiveCommand> cmds = Arrays.asList(
	new ReceiveCommand(B, A, "refs/heads/master", UPDATE_NONFASTFORWARD));
	try (RevWalk rw = new RevWalk(diskRepo) {
	@Override
	public boolean isMergedInto(RevCommit base, RevCommit tip) {
	throw new AssertionError("isMergedInto() should not be called");
	}
	}) {
	newBatchUpdate(cmds)
	.setAllowNonFastForwards(true)
	.execute(rw, new StrictWorkMonitor());
	}

	assertResults(cmds, OK);
	assertRefs("refs/heads/master", A);
	}

	@Test
	public void fileDirectoryConflict() throws IOException {
	writeLooseRef("refs/heads/master", A);
	writeLooseRef("refs/heads/masters", B);

	List<ReceiveCommand> cmds = Arrays.asList(
	new ReceiveCommand(A, B, "refs/heads/master", UPDATE),
	new ReceiveCommand(zeroId(), A, "refs/heads/master/x", CREATE),
	new ReceiveCommand(zeroId(), A, "refs/heads", CREATE));
	execute(newBatchUpdate(cmds).setAllowNonFastForwards(true), false);

	if (atomic) {
	// Atomic update sees that master and master/x are conflicting, then marks
	// the first one in the list as LOCK_FAILURE and aborts the rest.
	assertResults(cmds,
	LOCK_FAILURE, TRANSACTION_ABORTED, TRANSACTION_ABORTED);
	assertRefs(
	"refs/heads/master", A,
	"refs/heads/masters", B);
	} else {
	// Non-atomic updates are applied in order: master succeeds, then master/x
	// fails due to conflict.
	assertResults(cmds, OK, LOCK_FAILURE, LOCK_FAILURE);
	assertRefs(
	"refs/heads/master", B,
	"refs/heads/masters", B);
	}
	}

	@Test
	public void conflictThanksToDelete() throws IOException {
	writeLooseRef("refs/heads/master", A);
	writeLooseRef("refs/heads/masters", B);

	List<ReceiveCommand> cmds = Arrays.asList(
	new ReceiveCommand(A, B, "refs/heads/master", UPDATE),
	new ReceiveCommand(zeroId(), A, "refs/heads/masters/x", CREATE),
	new ReceiveCommand(B, zeroId(), "refs/heads/masters", DELETE));
	execute(newBatchUpdate(cmds).setAllowNonFastForwards(true));

	assertResults(cmds, OK, OK, OK);
	assertRefs(
	"refs/heads/master", B,
	"refs/heads/masters/x", A);
	}

	@Test
	public void updateToMissingObject() throws IOException {
	writeLooseRef("refs/heads/master", A);

	ObjectId bad =
	ObjectId.fromString("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef");
	List<ReceiveCommand> cmds = Arrays.asList(
	new ReceiveCommand(A, bad, "refs/heads/master", UPDATE),
	new ReceiveCommand(zeroId(), B, "refs/heads/foo2", CREATE));
	execute(newBatchUpdate(cmds).setAllowNonFastForwards(true), false);

	if (atomic) {
	assertResults(cmds, REJECTED_MISSING_OBJECT, TRANSACTION_ABORTED);
	assertRefs("refs/heads/master", A);
	} else {
	assertResults(cmds, REJECTED_MISSING_OBJECT, OK);
	assertRefs(
	"refs/heads/master", A,
	"refs/heads/foo2", B);
	}
	}

	@Test
	public void addMissingObject() throws IOException {
	writeLooseRef("refs/heads/master", A);

	ObjectId bad =
	ObjectId.fromString("deadbeefdeadbeefdeadbeefdeadbeefdeadbeef");
	List<ReceiveCommand> cmds = Arrays.asList(
	new ReceiveCommand(A, B, "refs/heads/master", UPDATE),
	new ReceiveCommand(zeroId(), bad, "refs/heads/foo2", CREATE));
	execute(newBatchUpdate(cmds).setAllowNonFastForwards(true), false);

	if (atomic) {
	assertResults(cmds, TRANSACTION_ABORTED, REJECTED_MISSING_OBJECT);
	assertRefs("refs/heads/master", A);
	} else {
	assertResults(cmds, OK, REJECTED_MISSING_OBJECT);
	assertRefs("refs/heads/master", B);
	}
	}

	@Test
	public void oneNonExistentRef() throws IOException {
	List<ReceiveCommand> cmds = Arrays.asList(
	new ReceiveCommand(A, B, "refs/heads/foo1", UPDATE),
	new ReceiveCommand(zeroId(), B, "refs/heads/foo2", CREATE));
	execute(newBatchUpdate(cmds).setAllowNonFastForwards(true));

	if (atomic) {
	assertResults(cmds, LOCK_FAILURE, TRANSACTION_ABORTED);
	assertRefs();
	} else {
	assertResults(cmds, LOCK_FAILURE, OK);
	assertRefs("refs/heads/foo2", B);
	}
	}

	@Test
	public void oneRefWrongOldValue() throws IOException {
	writeLooseRef("refs/heads/master", A);

	List<ReceiveCommand> cmds = Arrays.asList(
	new ReceiveCommand(B, B, "refs/heads/master", UPDATE),
	new ReceiveCommand(zeroId(), B, "refs/heads/foo2", CREATE));
	execute(newBatchUpdate(cmds).setAllowNonFastForwards(true));

	if (atomic) {
	assertResults(cmds, LOCK_FAILURE, TRANSACTION_ABORTED);
	assertRefs("refs/heads/master", A);
	} else {
	assertResults(cmds, LOCK_FAILURE, OK);
	assertRefs(
	"refs/heads/master", A,
	"refs/heads/foo2", B);
	}
	}

	@Test
	public void nonExistentRef() throws IOException {
	writeLooseRef("refs/heads/master", A);

	List<ReceiveCommand> cmds = Arrays.asList(
	new ReceiveCommand(A, B, "refs/heads/master", UPDATE),
	new ReceiveCommand(A, zeroId(), "refs/heads/foo2", DELETE));
	execute(newBatchUpdate(cmds).setAllowNonFastForwards(true));

	if (atomic) {
	assertResults(cmds, TRANSACTION_ABORTED, LOCK_FAILURE);
	assertRefs("refs/heads/master", A);
	} else {
	assertResults(cmds, OK, LOCK_FAILURE);
	assertRefs("refs/heads/master", B);
	}
	}

	private void writeLooseRef(String name, AnyObjectId id) throws IOException {
	write(new File(diskRepo.getDirectory(), name), id.name() + "\n");
	}

	private BatchRefUpdate newBatchUpdate(List<ReceiveCommand> cmds) {
	BatchRefUpdate u = refdir.newBatchUpdate();
	if (atomic) {
	assertTrue(u.isAtomic());
	} else {
	u.setAtomic(false);
	}
	u.addCommand(cmds);
	return u;
	}

	private void execute(BatchRefUpdate u) throws IOException {
	execute(u, false);
	}

	private void execute(BatchRefUpdate u, boolean strictWork) throws IOException {
	try (RevWalk rw = new RevWalk(diskRepo)) {
	u.execute(rw,
	strictWork ? new StrictWorkMonitor() : NullProgressMonitor.INSTANCE);
	}
	}

	private void assertRefs(Object... args) throws IOException {
	if (args.length % 2 != 0) {
	throw new IllegalArgumentException(
	"expected even number of args: " + Arrays.toString(args));
	}

	Map<String, AnyObjectId> expected = new LinkedHashMap<>();
	for (int i = 0; i < args.length; i += 2) {
	expected.put((String) args[i], (AnyObjectId) args[i + 1]);
	}

	Map<String, Ref> refs = refdir.getRefs(RefDatabase.ALL);
	Ref actualHead = refs.remove(Constants.HEAD);
	if (actualHead != null) {
	String actualLeafName = actualHead.getLeaf().getName();
	assertEquals(
	"expected HEAD to point to refs/heads/master, got: " + actualLeafName,
	"refs/heads/master", actualLeafName);
	AnyObjectId expectedMaster = expected.get("refs/heads/master");
	assertNotNull("expected master ref since HEAD exists", expectedMaster);
	assertEquals(expectedMaster, actualHead.getObjectId());
	}

	Map<String, AnyObjectId> actual = new LinkedHashMap<>();
	refs.forEach((n, r) -> actual.put(n, r.getObjectId()));

	assertEquals(expected.keySet(), actual.keySet());
	actual.forEach((n, a) -> assertEquals(n, expected.get(n), a));
	}

	enum Result {
	OK(ReceiveCommand.Result.OK),
	LOCK_FAILURE(ReceiveCommand.Result.LOCK_FAILURE),
	REJECTED_NONFASTFORWARD(ReceiveCommand.Result.REJECTED_NONFASTFORWARD),
	REJECTED_MISSING_OBJECT(ReceiveCommand.Result.REJECTED_MISSING_OBJECT),
	TRANSACTION_ABORTED(ReceiveCommand::isTransactionAborted);

	final Predicate<? super ReceiveCommand> p;

	private Result(Predicate<? super ReceiveCommand> p) {
	this.p = p;
	}

	private Result(ReceiveCommand.Result result) {
	this(c -> c.getResult() == result);
	}
	}

	private void assertResults(
	List<ReceiveCommand> cmds, Result... expected) {
	if (expected.length != cmds.size()) {
	throw new IllegalArgumentException(
	"expected " + cmds.size() + " result args");
	}
	for (int i = 0; i < cmds.size(); i++) {
	ReceiveCommand c = cmds.get(i);
	Result r = expected[i];
	assertTrue(
	String.format(
	"result of command (%d) should be %s: %s %s%s",
	Integer.valueOf(i), r, c,
	c.getResult(),
	c.getMessage() != null ? " (" + c.getMessage() + ")" : ""),
	r.p.test(c));
	}
	}
	}