diff --git a/org.eclipse.jgit.test/tst/org/eclipse/jgit/treewalk/filter/InterIndexDiffFilterTest.java b/org.eclipse.jgit.test/tst/org/eclipse/jgit/treewalk/filter/InterIndexDiffFilterTest.java
new file mode 100644
index 0000000..13fe426
--- /dev/null
+++ b/org.eclipse.jgit.test/tst/org/eclipse/jgit/treewalk/filter/InterIndexDiffFilterTest.java
@@ -0,0 +1,199 @@
+/*
+ * Copyright (C) 2013, Robin Rosenberg <robin.rosenberg@dewire.com>
+ * 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.treewalk.filter;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
+
+import java.io.IOException;
+
+import org.eclipse.jgit.dircache.DirCache;
+import org.eclipse.jgit.dircache.DirCacheEditor;
+import org.eclipse.jgit.dircache.DirCacheEntry;
+import org.eclipse.jgit.dircache.DirCacheIterator;
+import org.eclipse.jgit.dircache.DirCacheEditor.PathEdit;
+import org.eclipse.jgit.junit.LocalDiskRepositoryTestCase;
+import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.FileMode;
+import org.eclipse.jgit.lib.ObjectId;
+import org.eclipse.jgit.storage.file.FileRepository;
+import org.eclipse.jgit.treewalk.TreeWalk;
+import org.junit.Before;
+import org.junit.Test;
+
+public class InterIndexDiffFilterTest extends LocalDiskRepositoryTestCase {
+
+	private FileRepository db;
+
+	@Before
+	public void setUp() throws Exception {
+		super.setUp();
+		db = createWorkRepository();
+	}
+
+	@Test
+	public void testEmpty() throws IOException {
+		DirCache dc1 = DirCache.newInCore();
+		DirCache dc2 = DirCache.newInCore();
+		TreeWalk tw = new TreeWalk(db);
+		tw.addTree(new DirCacheIterator(dc1));
+		tw.addTree(new DirCacheIterator(dc2));
+		assertFalse(tw.next());
+	}
+
+	static final class AddEdit extends PathEdit {
+
+		private final ObjectId data;
+
+		private final long length;
+
+		private boolean assumeValid;
+
+		private FileMode type;
+
+		public AddEdit(String entryPath, FileMode type, ObjectId data,
+				long length,
+				boolean assumeValid) {
+			super(entryPath);
+			this.type = type;
+			this.data = data;
+			this.length = length;
+			this.assumeValid = assumeValid;
+		}
+
+		@Override
+		public void apply(DirCacheEntry ent) {
+			ent.setFileMode(type);
+			ent.setLength(length);
+			ent.setObjectId(data);
+			ent.setAssumeValid(assumeValid);
+		}
+	}
+
+	private ObjectId id(String data) {
+		byte[] bytes = data.getBytes();
+		return db.newObjectInserter().idFor(Constants.OBJ_BLOB, bytes);
+	}
+
+	@Test
+	public void testOneOnly() throws IOException {
+		DirCache dc1 = DirCache.newInCore();
+		DirCache dc2 = DirCache.newInCore();
+		DirCacheEditor editor = dc1.editor();
+		editor.add(new AddEdit("a/a", FileMode.REGULAR_FILE, id("a"), 1, false));
+		editor.finish();
+
+		TreeWalk tw = new TreeWalk(db);
+		tw.setRecursive(true);
+		tw.addTree(new DirCacheIterator(dc1));
+		tw.addTree(new DirCacheIterator(dc2));
+		tw.setFilter(InterIndexDiffFilter.INSTANCE);
+		assertTrue(tw.next());
+		assertEquals("a/a", tw.getPathString());
+		assertFalse(tw.next());
+	}
+
+	@Test
+	public void testTwoSame() throws IOException {
+		DirCache dc1 = DirCache.newInCore();
+		DirCache dc2 = DirCache.newInCore();
+		DirCacheEditor ed1 = dc1.editor();
+		ed1.add(new AddEdit("a/a", FileMode.REGULAR_FILE, id("a"), 1, false));
+		ed1.finish();
+		DirCacheEditor ed2 = dc2.editor();
+		ed2.add(new AddEdit("a/a", FileMode.REGULAR_FILE, id("a"), 1, false));
+		ed2.finish();
+
+		TreeWalk tw = new TreeWalk(db);
+		tw.setRecursive(true);
+		tw.addTree(new DirCacheIterator(dc1));
+		tw.addTree(new DirCacheIterator(dc2));
+		tw.setFilter(InterIndexDiffFilter.INSTANCE);
+
+		assertFalse(tw.next());
+	}
+
+	@Test
+	public void testTwoSameDifferByAssumeValid() throws IOException {
+		DirCache dc1 = DirCache.newInCore();
+		DirCache dc2 = DirCache.newInCore();
+		DirCacheEditor ed1 = dc1.editor();
+		ed1.add(new AddEdit("a/a", FileMode.REGULAR_FILE, id("a"), 1, false));
+		ed1.finish();
+		DirCacheEditor ed2 = dc2.editor();
+		ed2.add(new AddEdit("a/a", FileMode.REGULAR_FILE, id("a"), 1, true));
+		ed2.finish();
+
+		TreeWalk tw = new TreeWalk(db);
+		tw.setRecursive(true);
+		tw.addTree(new DirCacheIterator(dc1));
+		tw.addTree(new DirCacheIterator(dc2));
+		tw.setFilter(InterIndexDiffFilter.INSTANCE);
+
+		assertTrue(tw.next());
+		assertEquals("a/a", tw.getPathString());
+		assertFalse(tw.next());
+	}
+
+	@Test
+	public void testTwoSameSameAssumeValidDifferentContent()
+			throws IOException {
+		DirCache dc1 = DirCache.newInCore();
+		DirCache dc2 = DirCache.newInCore();
+		DirCacheEditor ed1 = dc1.editor();
+		ed1.add(new AddEdit("a/a", FileMode.REGULAR_FILE, id("a"), 1, true));
+		ed1.finish();
+		DirCacheEditor ed2 = dc2.editor();
+		ed2.add(new AddEdit("a/a", FileMode.REGULAR_FILE, id("b"), 1, true));
+		ed2.finish();
+
+		TreeWalk tw = new TreeWalk(db);
+		tw.setRecursive(true);
+		tw.addTree(new DirCacheIterator(dc1));
+		tw.addTree(new DirCacheIterator(dc2));
+		tw.setFilter(InterIndexDiffFilter.INSTANCE);
+
+		assertFalse(tw.next());
+	}
+}
diff --git a/org.eclipse.jgit/src/org/eclipse/jgit/treewalk/filter/InterIndexDiffFilter.java b/org.eclipse.jgit/src/org/eclipse/jgit/treewalk/filter/InterIndexDiffFilter.java
new file mode 100644
index 0000000..1719416
--- /dev/null
+++ b/org.eclipse.jgit/src/org/eclipse/jgit/treewalk/filter/InterIndexDiffFilter.java
@@ -0,0 +1,105 @@
+/*
+ * Copyright (C) 2013, Robin Rosenberg <robin.rosenberg@dewire.com>
+ * 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.treewalk.filter;
+
+import org.eclipse.jgit.dircache.DirCacheEntry;
+import org.eclipse.jgit.dircache.DirCacheIterator;
+import org.eclipse.jgit.treewalk.TreeWalk;
+
+/**
+ * A filter for extracting changes between two versions of the dircache. In
+ * addition to what {@link TreeFilter#ANY_DIFF} would do, it also detects
+ * changes that will affect decorations and show up in an attempt to commit.
+ */
+public final class InterIndexDiffFilter extends TreeFilter {
+	private static final int baseTree = 0;
+
+	/**
+	 * Predefined InterIndexDiffFilter for finding changes between two dircaches
+	 */
+	public static final TreeFilter INSTANCE = new InterIndexDiffFilter();
+
+	@Override
+	public boolean include(final TreeWalk walker) {
+		final int n = walker.getTreeCount();
+		if (n == 1) // Assume they meant difference to empty tree.
+			return true;
+
+		final int m = walker.getRawMode(baseTree);
+		for (int i = 1; i < n; i++) {
+			DirCacheIterator baseDirCache = walker.getTree(baseTree,
+					DirCacheIterator.class);
+			DirCacheIterator newDirCache = walker.getTree(i,
+					DirCacheIterator.class);
+			if (baseDirCache != null && newDirCache != null) {
+				DirCacheEntry baseDci = baseDirCache.getDirCacheEntry();
+				DirCacheEntry newDci = newDirCache.getDirCacheEntry();
+				if (baseDci != null && newDci != null) {
+					if (baseDci.isAssumeValid() != newDci.isAssumeValid())
+						return true;
+					if (baseDci.isAssumeValid()) // && newDci.isAssumeValid()
+						return false;
+				}
+			}
+			if (walker.getRawMode(i) != m || !walker.idEqual(i, baseTree))
+				return true;
+		}
+		return false;
+	}
+
+	@Override
+	public boolean shouldBeRecursive() {
+		return false;
+	}
+
+	@Override
+	public TreeFilter clone() {
+		return this;
+	}
+
+	@Override
+	public String toString() {
+		return "INTERINDEX_DIFF"; //$NON-NLS-1$
+	}
+}
\ No newline at end of file