[cdv-devel] tree merging

I'm trying to understand how cdv-merge applies to tree rearrangement
merging.
  
Say we have a standard criss-cross merge case, where some file's name
is the conflict:
    A
   / \
  P   Y
  |\ /|
  | X |
  |/ \|
  Q   Z
The file is named "foo" in A, "bar" in P and Q, and "baz" in Y and Z.
We, of course, want to merge Q and Z.

Q and Z have different values, so we get a first-order conflict, and
look to see if we can resolve it.  Q's last-changed rev is P, and P is
an ancestor of Z, so Q wants to lose; likewise, Z's last-changed rev
is Y, and Y is an ancestor of Q, so Z wants to lose -- basically, this
is a classic ambiguous clean merge.  Unlike ambig cleans found in text
merging, though, it doesn't seem like we've been sloppy about identity
-- there's a single atomic-valued cell being merged here, no questions
of identity at all...

What does codeville do in this case?  Or perhaps I should ask what
codeville _should_ do in this case? :-)

Why?

How do you think about these sorts of issues, and are there other
similar ones you know of?

Cheers,
-- Nathaniel

-- 
"Of course, the entire effort is to put oneself
 Outside the ordinary range
 Of what are called statistics."
  -- Stephan Spender