Added the git-describe implementation

CQ: 7609
Bug: 339246
Change-Id: I689bc0578ce3a430b9800ad84122e221c69829f4
Signed-off-by: Kohsuke Kawaguchi <kk@kohsuke.org>
Also-By: Robin Stocker<robin@nibor.org>
Also-By: Matthias Sohn <matthias.sohn@sap.com>
Also-By: Christian Halstrick <christian.halstrick@sap.com>

1 files changed, 242 insertions, 0 deletions

diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/DescribeCommandTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/DescribeCommandTest.java
new file mode 100644
index 0000000000..88f6108926
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/DescribeCommandTest.java
@@ -0,0 +1,242 @@
+/*
+ * Copyright (C) 2013, CloudBees, 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 org.eclipse.jgit.api.errors.GitAPIException;
+import org.eclipse.jgit.junit.RepositoryTestCase;
+import org.eclipse.jgit.lib.ObjectId;
+import org.junit.Test;
+
+import java.io.File;
+import java.io.FileWriter;
+import java.io.IOException;
+
+import static org.junit.Assert.*;
+
+public class DescribeCommandTest extends RepositoryTestCase {
+
+	private Git git;
+
+	@Override
+	public void setUp() throws Exception {
+		super.setUp();
+		git = new Git(db);
+	}
+
+	@Test(expected = IllegalArgumentException.class)
+	public void noTargetSet() throws Exception {
+		git.describe().call();
+	}
+
+	@Test
+	public void testDescribe() throws Exception {
+		ObjectId c1 = modify("aaa");
+
+		ObjectId c2 = modify("bbb");
+		tag("t1");
+
+		ObjectId c3 = modify("ccc");
+		tag("t2");
+
+		ObjectId c4 = modify("ddd");
+
+		assertNull(describe(c1));
+		assertEquals("t1", describe(c2));
+		assertEquals("t2", describe(c3));
+
+		assertNameStartsWith(c4, "3e563c5");
+		// the value verified with git-describe(1)
+		assertEquals("t2-1-g3e563c5", describe(c4));
+	}
+
+	/**
+	 * Make sure it finds a tag when not all ancestries include a tag.
+	 *
+	 * <pre>
+	 * c1 -+-> T  -
+	 *     |       |
+	 *     +-> c3 -+-> c4
+	 * </pre>
+	 *
+	 * @throws Exception
+	 */
+	@Test
+	public void testDescribeBranch() throws Exception {
+		ObjectId c1 = modify("aaa");
+
+		ObjectId c2 = modify("bbb");
+		tag("t");
+
+		branch("b", c1);
+
+		ObjectId c3 = modify("ccc");
+
+		ObjectId c4 = merge(c2);
+
+		assertNameStartsWith(c4, "119892b");
+		assertEquals("t-2-g119892b", describe(c4)); // 2 commits: c4 and c3
+		assertNull(describe(c3));
+	}
+
+	private void branch(String name, ObjectId base) throws GitAPIException {
+		git.checkout().setCreateBranch(true).setName(name)
+				.setStartPoint(base.name()).call();
+	}
+
+	/**
+	 * When t2 dominates t1, it's clearly preferable to describe by using t2.
+	 *
+	 * <pre>
+	 * t1 -+-> t2  -
+	 *     |       |
+	 *     +-> c3 -+-> c4
+	 * </pre>
+	 *
+	 * @throws Exception
+	 */
+	@Test
+	public void t1DominatesT2() throws Exception {
+		ObjectId c1 = modify("aaa");
+		tag("t1");
+
+		ObjectId c2 = modify("bbb");
+		tag("t2");
+
+		branch("b", c1);
+
+		ObjectId c3 = modify("ccc");
+
+		ObjectId c4 = merge(c2);
+
+		assertNameStartsWith(c4, "119892b");
+		assertEquals("t2-2-g119892b", describe(c4)); // 2 commits: c4 and c3
+
+		assertNameStartsWith(c3, "0244e7f");
+		assertEquals("t1-1-g0244e7f", describe(c3));
+	}
+
+	/**
+	 * When t1 is nearer than t2, t2 should be found
+	 *
+	 * <pre>
+	 * c1 -+-> c2 -> t1 -+
+	 *     |             |
+	 *     +-> t2 -> c3 -+-> c4
+	 * </pre>
+	 *
+	 * @throws Exception
+	 */
+	@Test
+	public void t1nearerT2() throws Exception {
+		ObjectId c1 = modify("aaa");
+		modify("bbb");
+		ObjectId t1 = modify("ccc");
+		tag("t1");
+
+		branch("b", c1);
+		modify("ddd");
+		tag("t2");
+		modify("eee");
+		ObjectId c4 = merge(t1);
+
+		assertNameStartsWith(c4, "bb389a4");
+		assertEquals("t1-3-gbb389a4", describe(c4));
+	}
+
+	/**
+	 * When t1 and t2 have same depth native git seems to add the depths of both
+	 * paths
+	 *
+	 * <pre>
+	 * c1 -+-> t1 -> c2 -+
+	 *     |             |
+	 *     +-> t2 -> c3 -+-> c4
+	 * </pre>
+	 *
+	 * @throws Exception
+	 */
+	@Test
+	public void t1sameDepthT2() throws Exception {
+		ObjectId c1 = modify("aaa");
+		modify("bbb");
+		tag("t1");
+		ObjectId c2 = modify("ccc");
+
+		branch("b", c1);
+		modify("ddd");
+		tag("t2");
+		modify("eee");
+		ObjectId c4 = merge(c2);
+
+		assertNameStartsWith(c4, "bb389a4");
+		assertEquals("t2-4-gbb389a4", describe(c4));
+	}
+
+	private ObjectId merge(ObjectId c2) throws GitAPIException {
+		return git.merge().include(c2).call().getNewHead();
+	}
+
+	private ObjectId modify(String content) throws Exception {
+		File a = new File(db.getWorkTree(), "a.txt");
+		touch(a, content);
+		return git.commit().setAll(true).setMessage(content).call().getId();
+	}
+
+	private void tag(String tag) throws GitAPIException {
+		git.tag().setName(tag).setMessage(tag).call();
+	}
+
+	private static void touch(File f, String contents) throws Exception {
+		FileWriter w = new FileWriter(f);
+		w.write(contents);
+		w.close();
+	}
+
+	private String describe(ObjectId c1) throws GitAPIException, IOException {
+		return git.describe().setTarget(c1).call();
+	}
+
+	private static void assertNameStartsWith(ObjectId c4, String prefix) {
+		assertTrue(c4.name(), c4.name().startsWith(prefix));
+	}
+}