Add command support for dropping a stashed commit

This extracts the logic for writing to the reflog from
RefDirectory into a new ReflogWriter class.  This class
creates a public API for writing reflog entries similar
to ReflogReader for reading reflog entries.

The new command supports rewriting the stash's log to remove
a configured entry followed by updating the stash ref to
the value at the bottom of the newly written log.

Change-Id: Icfcbc70e838666769a742a94196eb8dc9c7efcc7
Signed-off-by: Chris Aniszczyk <zx@twitter.com>

1 files changed, 298 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/StashDropCommandTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/StashDropCommandTest.java
new file mode 100644
index 0000000000..b60af64a82
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/StashDropCommandTest.java
@@ -0,0 +1,298 @@
+/*
+ * Copyright (C) 2012, GitHub 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.api;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotNull;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.fail;
+
+import java.io.File;
+import java.util.List;
+
+import org.eclipse.jgit.api.errors.JGitInternalException;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.lib.Ref;
+import org.eclipse.jgit.lib.RepositoryTestCase;
+import org.eclipse.jgit.revwalk.RevCommit;
+import org.eclipse.jgit.storage.file.ReflogEntry;
+import org.eclipse.jgit.storage.file.ReflogReader;
+import org.junit.Before;
+import org.junit.Test;
+
+/**
+ * Unit tests of {@link StashCreateCommand}
+ */
+public class StashDropCommandTest extends RepositoryTestCase {
+
+	private RevCommit head;
+
+	private Git git;
+
+	private File committedFile;
+
+	@Before
+	public void setUp() throws Exception {
+		super.setUp();
+		git = Git.wrap(db);
+		committedFile = writeTrashFile("file.txt", "content");
+		git.add().addFilepattern("file.txt").call();
+		head = git.commit().setMessage("add file").call();
+		assertNotNull(head);
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void dropNegativeRef() {
+		git.stashDrop().setStashRef(-1);
+	}
+
+	@Test
+	public void dropWithNoStashedCommits() throws Exception {
+		assertNull(git.stashDrop().call());
+	}
+
+	@Test
+	public void dropWithInvalidLogIndex() throws Exception {
+		write(committedFile, "content2");
+		Ref stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNull(stashRef);
+		RevCommit stashed = git.stashCreate().call();
+		assertNotNull(stashed);
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertEquals(stashed, git.getRepository().getRef(Constants.R_STASH)
+				.getObjectId());
+		try {
+			assertNull(git.stashDrop().setStashRef(100).call());
+			fail("Exception not thrown");
+		} catch (JGitInternalException e) {
+			assertNotNull(e.getMessage());
+			assertTrue(e.getMessage().length() > 0);
+		}
+	}
+
+	@Test
+	public void dropSingleStashedCommit() throws Exception {
+		write(committedFile, "content2");
+		Ref stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNull(stashRef);
+		RevCommit stashed = git.stashCreate().call();
+		assertNotNull(stashed);
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertEquals(stashed, git.getRepository().getRef(Constants.R_STASH)
+				.getObjectId());
+		assertNull(git.stashDrop().call());
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNull(stashRef);
+
+		ReflogReader reader = new ReflogReader(git.getRepository(),
+				Constants.R_STASH);
+		assertTrue(reader.getReverseEntries().isEmpty());
+	}
+
+	@Test
+	public void dropAll() throws Exception {
+		write(committedFile, "content2");
+		Ref stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNull(stashRef);
+		RevCommit firstStash = git.stashCreate().call();
+		assertNotNull(firstStash);
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(firstStash, git.getRepository().getRef(Constants.R_STASH)
+				.getObjectId());
+
+		write(committedFile, "content3");
+		RevCommit secondStash = git.stashCreate().call();
+		assertNotNull(secondStash);
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(secondStash, git.getRepository().getRef(Constants.R_STASH)
+				.getObjectId());
+
+		assertNull(git.stashDrop().setAll(true).call());
+		assertNull(git.getRepository().getRef(Constants.R_STASH));
+
+		ReflogReader reader = new ReflogReader(git.getRepository(),
+				Constants.R_STASH);
+		assertTrue(reader.getReverseEntries().isEmpty());
+	}
+
+	@Test
+	public void dropFirstStashedCommit() throws Exception {
+		write(committedFile, "content2");
+		Ref stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNull(stashRef);
+		RevCommit firstStash = git.stashCreate().call();
+		assertNotNull(firstStash);
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(firstStash, git.getRepository().getRef(Constants.R_STASH)
+				.getObjectId());
+
+		write(committedFile, "content3");
+		RevCommit secondStash = git.stashCreate().call();
+		assertNotNull(secondStash);
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(secondStash, git.getRepository().getRef(Constants.R_STASH)
+				.getObjectId());
+
+		assertEquals(firstStash, git.stashDrop().call());
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(firstStash, stashRef.getObjectId());
+
+		ReflogReader reader = new ReflogReader(git.getRepository(),
+				Constants.R_STASH);
+		List<ReflogEntry> entries = reader.getReverseEntries();
+		assertEquals(1, entries.size());
+		assertEquals(ObjectId.zeroId(), entries.get(0).getOldId());
+		assertEquals(firstStash, entries.get(0).getNewId());
+		assertTrue(entries.get(0).getComment().length() > 0);
+	}
+
+	@Test
+	public void dropMiddleStashCommit() throws Exception {
+		write(committedFile, "content2");
+		Ref stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNull(stashRef);
+		RevCommit firstStash = git.stashCreate().call();
+		assertNotNull(firstStash);
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(firstStash, git.getRepository().getRef(Constants.R_STASH)
+				.getObjectId());
+
+		write(committedFile, "content3");
+		RevCommit secondStash = git.stashCreate().call();
+		assertNotNull(secondStash);
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(secondStash, git.getRepository().getRef(Constants.R_STASH)
+				.getObjectId());
+
+		write(committedFile, "content4");
+		RevCommit thirdStash = git.stashCreate().call();
+		assertNotNull(thirdStash);
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(thirdStash, git.getRepository().getRef(Constants.R_STASH)
+				.getObjectId());
+
+		assertEquals(thirdStash, git.stashDrop().setStashRef(1).call());
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(thirdStash, stashRef.getObjectId());
+
+		ReflogReader reader = new ReflogReader(git.getRepository(),
+				Constants.R_STASH);
+		List<ReflogEntry> entries = reader.getReverseEntries();
+		assertEquals(2, entries.size());
+		assertEquals(ObjectId.zeroId(), entries.get(1).getOldId());
+		assertEquals(firstStash, entries.get(1).getNewId());
+		assertTrue(entries.get(1).getComment().length() > 0);
+		assertEquals(entries.get(0).getOldId(), entries.get(1).getNewId());
+		assertEquals(thirdStash, entries.get(0).getNewId());
+		assertTrue(entries.get(0).getComment().length() > 0);
+	}
+
+	@Test
+	public void dropBoundaryStashedCommits() throws Exception {
+		write(committedFile, "content2");
+		Ref stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNull(stashRef);
+		RevCommit firstStash = git.stashCreate().call();
+		assertNotNull(firstStash);
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(firstStash, git.getRepository().getRef(Constants.R_STASH)
+				.getObjectId());
+
+		write(committedFile, "content3");
+		RevCommit secondStash = git.stashCreate().call();
+		assertNotNull(secondStash);
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(secondStash, git.getRepository().getRef(Constants.R_STASH)
+				.getObjectId());
+
+		write(committedFile, "content4");
+		RevCommit thirdStash = git.stashCreate().call();
+		assertNotNull(thirdStash);
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(thirdStash, git.getRepository().getRef(Constants.R_STASH)
+				.getObjectId());
+
+		write(committedFile, "content5");
+		RevCommit fourthStash = git.stashCreate().call();
+		assertNotNull(fourthStash);
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(fourthStash, git.getRepository().getRef(Constants.R_STASH)
+				.getObjectId());
+
+		assertEquals(thirdStash, git.stashDrop().call());
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(thirdStash, stashRef.getObjectId());
+
+		assertEquals(thirdStash, git.stashDrop().setStashRef(2).call());
+		stashRef = git.getRepository().getRef(Constants.R_STASH);
+		assertNotNull(stashRef);
+		assertEquals(thirdStash, stashRef.getObjectId());
+
+		ReflogReader reader = new ReflogReader(git.getRepository(),
+				Constants.R_STASH);
+		List<ReflogEntry> entries = reader.getReverseEntries();
+		assertEquals(2, entries.size());
+		assertEquals(ObjectId.zeroId(), entries.get(1).getOldId());
+		assertEquals(secondStash, entries.get(1).getNewId());
+		assertTrue(entries.get(1).getComment().length() > 0);
+		assertEquals(entries.get(0).getOldId(), entries.get(1).getNewId());
+		assertEquals(thirdStash, entries.get(0).getNewId());
+		assertTrue(entries.get(0).getComment().length() > 0);
+	}
+}