Re: [PATCH 2/2] Add keyword unexpansion support to convert.c

On Tue, 17 Apr 2007, Andy Parkins wrote:

Adding expansion is harder, as I have no clue which calls to make to find
even the most basic information about an object; but I thought I'd get
feedback before I expend that effort.

Adding expansion is not just "harder". It's basically impossible to do 
with any kind of performance.

Think "git checkout newbranch".

And think what we do about files (and whole subdirectories!) that haven't 
even changed. And finally, think about how important that optimization is 
in an SCM like git that supports branches.

I think you'll find that keyword expansion simply isn't acceptable.

But hey, you didn't believe me, so I'm happy you are trying to write the 
patches. Either you'll prove me wrong, or you'll realize just *how* broken 
the feature is.

(Yeah, "unexpansion" is easy. It's easy for all the same reasons CRLF is 
easy: it has no state!)

			Linus