Patch Set 3: Do not submit

(2 inline comments)

Regarding Philipp's question about ANY_DIFF filter... its too difficult within ANY_DIFF filter to find which tree of the N trees is the WorkingTreeIterator and which is the DirCacheIterator... and if they are even related.  They might not be.  Its a valid use case for TreeWalk to compare two working directories to each other by just adding two WorkingTreeIterators to the same TreeWalk.  An application might give us 4 iterators (2 WorkingTreeIterators, 2 DirCacheIterators) and expect us to find the differences, even if they aren't related to each other in any way.

The only sane solution is to have the application configure things for us when they use TreeWalk.  Either by using IndexDiffFilter, and/or by using this new setDirCacheIterator API to let us know which other iterator of the same TreeWalk is associated with the FileTreeIterator.