Delta packages

[Sean Fagan]

We have a strong desire to make delta packages -- that is, given version A and version B of a package, to be able to download a package that has only the changes between A and B.

I've written a little program to create this (it currently only has the files that have changed, not binary diffs, although that would I suppose be possible; just harder).

I can, I'm sure, come up with a way to manually extract and update the packages databases; however, I'd prefer to do a lot of that in the package code.  (Among other things, being able to specify what the delta is from would be good; I couldn't see a way to add random key/value pairs to the manifest using the pkg* routines, and while I can add it to the +MANIFEST file I create, that doesn't actually do a whole lot.)

First question:  is anyone working on something like this already?

Second question:  Any objections to it in principal?

Merci beaucoup,

Sean.