Status of adding "overlay repositories" to standard Mercurial?

[Larry Hastings]

Brendan Cully wrote a very interesting patch for Mercurial, adding 
"overlay repositories":
    http://hg.kublai.com/mercurial/patches/overlay
If I understand it correctly, when you clone a repository you can tell 
it to leave all the old revisions in the parent, and the clone will 
contain only the metadata of those revisions--it won't copy the data 
proper.  The "overlay" branch acts just like any other branch, except 
that it must access the parent whenever it needs file data from an 
"overlay" revision.  (I assume revisions later pulled from the parent 
are also "overlay" revisions, though I'm not sure.)

I think it's a swell idea, and it might help sell hg at a site I know 
of.  They were concerned about how much disk space N branches x N 
developers would take up on their network share--after all, what shared 
network filesystem is not perpetually almost-full?  "Overlay 
repositories" would greatly ease this concern.

Any chance this is going in to an official Mercurial release?

Cheers,


/larry/