Fix git-describe tie-breakers

Correct behaviour as git 1.7.1.1 is to resolve tie-breakers to choose
the most recent tag.

https://github.com/git/git/blob/master/Documentation/RelNotes/1.7.1.1.txt:
* "git describe" did not tie-break tags that point at the same commit
   correctly; newer ones are preferred by paying attention to the
   tagger date now.

Bug: 538610
Change-Id: Ib0b2a301997bb7f75935baf7005473f4de952a64
Signed-off-by: Håvard Wall <haavardw@gmail.com>

1 files changed, 40 insertions, 15 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
index 79da2da7ea..a2d8e89699 100644
--- a/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/DescribeCommandTest.java
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/api/DescribeCommandTest.java
@@ -44,6 +44,7 @@ package org.eclipse.jgit.api;
 
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 
 import java.io.File;
@@ -134,24 +135,48 @@ public class DescribeCommandTest extends RepositoryTestCase {
 	public void testDescribeMultiMatch() throws Exception {
 		ObjectId c1 = modify("aaa");
 		tag("v1.0.0");
+		tick();
+		tag("v1.0.1");
+		tick();
+		tag("v1.1.0");
+		tick();
 		tag("v1.1.1");
 		ObjectId c2 = modify("bbb");
 
-		// Ensure that if we're interested in any tags, we get the first match as per Git behaviour
-		assertEquals("v1.0.0", describe(c1));
-		assertEquals("v1.0.0-1-g3747db3", describe(c2));
-
-		// Ensure that if we're only interested in one of multiple tags, we get the right match
-		assertEquals("v1.0.0", describe(c1, "v1.0*"));
-		assertEquals("v1.1.1", describe(c1, "v1.1*"));
-		assertEquals("v1.0.0-1-g3747db3", describe(c2, "v1.0*"));
-		assertEquals("v1.1.1-1-g3747db3", describe(c2, "v1.1*"));
-
-		// Ensure that ordering of match precedence is preserved as per Git behaviour
-		assertEquals("v1.0.0", describe(c1, "v1.0*", "v1.1*"));
-		assertEquals("v1.1.1", describe(c1, "v1.1*", "v1.0*"));
-		assertEquals("v1.0.0-1-g3747db3", describe(c2, "v1.0*", "v1.1*"));
-		assertEquals("v1.1.1-1-g3747db3", describe(c2, "v1.1*", "v1.0*"));
+		// Ensure that if we're interested in any tags, we get the most recent tag
+		// as per Git behaviour since 1.7.1.1
+		if (useAnnotatedTags) {
+			assertEquals("v1.1.1", describe(c1));
+			assertEquals("v1.1.1-1-gb89dead", describe(c2));
+
+			// Ensure that if we're only interested in one of multiple tags, we get the right match
+			assertEquals("v1.0.1", describe(c1, "v1.0*"));
+			assertEquals("v1.1.1", describe(c1, "v1.1*"));
+			assertEquals("v1.0.1-1-gb89dead", describe(c2, "v1.0*"));
+			assertEquals("v1.1.1-1-gb89dead", describe(c2, "v1.1*"));
+
+			// Ensure that ordering of match precedence is preserved as per Git behaviour
+			assertEquals("v1.0.1", describe(c1, "v1.0*", "v1.1*"));
+			assertEquals("v1.1.1", describe(c1, "v1.1*", "v1.0*"));
+			assertEquals("v1.0.1-1-gb89dead", describe(c2, "v1.0*", "v1.1*"));
+			assertEquals("v1.1.1-1-gb89dead", describe(c2, "v1.1*", "v1.0*"));
+		} else {
+			// no timestamps so no guarantees on which tag is chosen
+			assertNotNull(describe(c1));
+			assertNotNull(describe(c2));
+
+			assertNotNull(describe(c1, "v1.0*"));
+			assertNotNull(describe(c1, "v1.1*"));
+			assertNotNull(describe(c2, "v1.0*"));
+			assertNotNull(describe(c2, "v1.1*"));
+
+			// Ensure that ordering of match precedence is preserved as per Git behaviour
+			assertNotNull(describe(c1, "v1.0*", "v1.1*"));
+			assertNotNull(describe(c1, "v1.1*", "v1.0*"));
+			assertNotNull(describe(c2, "v1.0*", "v1.1*"));
+			assertNotNull(describe(c2, "v1.1*", "v1.0*"));
+
+		}
 	}
 
 	/**