Cannot commit -o file with only file permission change

Bug 345076
Change-Id: Ie64039793ab6ba4748731320399f03301b6282ec
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>

org.eclipse.jgit.test/tst/org/eclipse/jgit/api/CommitAndLogCommandTests.java

 import org.eclipse.jgit.revwalk.RevCommit;
 import org.eclipse.jgit.storage.file.ReflogReader;
 import org.eclipse.jgit.treewalk.TreeWalk;
+import org.eclipse.jgit.util.FS;
 import org.eclipse.jgit.util.FileUtils;
 import org.eclipse.jgit.util.RawParseUtils;
 import org.junit.Test;
 				tw.getObjectId(0).getName());
 	}
 
+	@Test
+	public void testModeChange() throws IOException, NoFilepatternException,
+			NoHeadException, NoMessageException, ConcurrentRefUpdateException,
+			JGitInternalException, WrongRepositoryStateException {
+		Git git = new Git(db);
+
+		// create file
+		File file = new File(db.getWorkTree(), "a.txt");
+		FileUtils.createNewFile(file);
+		PrintWriter writer = new PrintWriter(file);
+		writer.print("content1");
+		writer.close();
+
+		// First commit - a.txt file
+		git.add().addFilepattern("a.txt").call();
+		git.commit().setMessage("commit1").setCommitter(committer).call();
+
+		// pure mode change should be committable
+		FS fs = db.getFS();
+		fs.setExecute(file, true);
+		git.add().addFilepattern("a.txt").call();
+		git.commit().setMessage("mode change").setCommitter(committer).call();
+
+		// pure mode change should be committable with -o option
+		fs.setExecute(file, false);
+		git.add().addFilepattern("a.txt").call();
+		git.commit().setMessage("mode change").setCommitter(committer)
+				.setOnly("a.txt").call();
+	}
+
 	@Test
 	public void testCommitRange() throws NoHeadException, NoMessageException,
 			UnmergedPathException, ConcurrentRefUpdateException,

org.eclipse.jgit/src/org/eclipse/jgit/api/CommitCommand.java

 					// add to temporary in-core index
 					dcBuilder.add(dcEntry);
 
-					if (emptyCommit && (hTree == null || !hTree.idEqual(fTree)))
+					if (emptyCommit
+							&& (hTree == null || !hTree.idEqual(fTree) || hTree
+									.getEntryRawMode() != fTree
+									.getEntryRawMode()))
 						// this is a change
 						emptyCommit = false;
 				} else {