Initialize 'pathLen' field also for empty directories

Bug: 445363
Change-Id: Ia8428af84fb61ba0d572374a19e8e8c55b138a63
Signed-off-by: Andrey Loskutov <loskutov@gmx.de>

org.eclipse.jgit.test/tst/org/eclipse/jgit/treewalk/FileTreeIteratorTest.java

@@ -144,6 +144,43 @@ public class FileTreeIteratorTest extends RepositoryTestCase {
 		assertTrue(fti.eof());
 	}
 
+	@Test
+	public void testEmptyIteratorOnEmptyDirectory() throws Exception {
+		String nonExistingFileName = "not-existing-file";
+		final File r = new File(trash, nonExistingFileName);
+		assertFalse(r.exists());
+		FileUtils.mkdir(r);
+
+		final FileTreeIterator parent = new FileTreeIterator(db);
+
+		while (!parent.getEntryPathString().equals(nonExistingFileName))
+			parent.next(1);
+
+		final FileTreeIterator childIter = new FileTreeIterator(parent, r,
+				db.getFS());
+		assertTrue(childIter.first());
+		assertTrue(childIter.eof());
+
+		String parentPath = parent.getEntryPathString();
+		assertEquals(nonExistingFileName, parentPath);
+
+		// must be "not-existing-file/", but getEntryPathString() was broken by
+		// 445363 too
+		String childPath = childIter.getEntryPathString();
+
+		// in bug 445363 the iterator wrote garbage to the parent "path" field
+		EmptyTreeIterator e = childIter.createEmptyTreeIterator();
+		assertNotNull(e);
+
+		// check if parent path is not overridden by empty iterator (bug 445363)
+		// due bug 445363 this was "/ot-existing-file" instead of
+		// "not-existing-file"
+		assertEquals(parentPath, parent.getEntryPathString());
+		assertEquals(parentPath + "/", childPath);
+		assertEquals(parentPath + "/", childIter.getEntryPathString());
+		assertEquals(childPath + "/", e.getEntryPathString());
+	}
+
 	@Test
 	public void testSimpleIterate() throws Exception {
 		final FileTreeIterator top = new FileTreeIterator(trash, db.getFS(),

org.eclipse.jgit/src/org/eclipse/jgit/treewalk/WorkingTreeIterator.java

@@ -668,6 +668,8 @@ public abstract class WorkingTreeIterator extends AbstractTreeIterator {
 		ptr = 0;
 		if (!eof())
 			parseEntry();
+		else if (pathLen == 0) // see bug 445363
+			pathLen = pathOffset;
 	}
 
 	/**