Don't check lastModified, length on folders for submodules

The metadata comparison of submodules is not reliable because of the
last modified timestamp and directory length.

Bug: 498759
Change-Id: If5db69ef3868e475ac477d3e8a7750b268799b0c

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

@@ -268,7 +268,9 @@ public abstract class WorkingTreeIterator extends AbstractTreeIterator {
 							DirCacheIterator.class);
 			if (i != null) {
 				DirCacheEntry ent = i.getDirCacheEntry();
-				if (ent != null && compareMetadata(ent) == MetadataDiff.EQUAL) {
+				if (ent != null && compareMetadata(ent) == MetadataDiff.EQUAL
+						&& ((ent.getFileMode().getBits()
+								& FileMode.TYPE_MASK) != FileMode.TYPE_GITLINK)) {
 					contentIdOffset = i.idOffset();
 					contentIdFromPtr = ptr;
 					return contentId = i.idBuffer();
@@ -843,10 +845,15 @@ public abstract class WorkingTreeIterator extends AbstractTreeIterator {
 		if (entry.isUpdateNeeded())
 			return MetadataDiff.DIFFER_BY_METADATA;
 
-		if (!entry.isSmudged() && entry.getLength() != (int) getEntryLength())
+		if (isModeDifferent(entry.getRawMode()))
 			return MetadataDiff.DIFFER_BY_METADATA;
 
-		if (isModeDifferent(entry.getRawMode()))
+		// Don't check for length or lastmodified on folders
+		int type = mode & FileMode.TYPE_MASK;
+		if (type == FileMode.TYPE_TREE || type == FileMode.TYPE_GITLINK)
+			return MetadataDiff.EQUAL;
+
+		if (!entry.isSmudged() && entry.getLength() != (int) getEntryLength())
 			return MetadataDiff.DIFFER_BY_METADATA;
 
 		// Git under windows only stores seconds so we round the timestamp
@@ -915,6 +922,9 @@ public abstract class WorkingTreeIterator extends AbstractTreeIterator {
 			// Lets do a content check
 			return contentCheck(entry, reader);
 		case EQUAL:
+			if (mode == FileMode.SYMLINK.getBits()) {
+				return contentCheck(entry, reader);
+			}
 			return false;
 		case DIFFER_BY_METADATA:
 			if (mode == FileMode.SYMLINK.getBits())