Re: Announce: Linux-next (Or Andrew's dream :-))

[Roland Dreier <rdreier@cisco.com>]

 > The other is that once somebody says "ok, I *really* need to cause this 
 > breakage, because there's a major bug or we need it for fundamental reason 
 > XYZ", then that person should
 > 
 >  (a) create a base tree with _just_ that fundamental infrastructure change,
 >      and make sure that base branch is so obviously good that there is no 
 >      question about merging it.

I don't disagree with this, but I think I should point out that making
something "obviously good" may be pretty hard.  It's clearly a common
case that the infrastructure change goes through several rounds of
change -- perhaps prompted by exposure in -mm that shows a subtle
issue.  So then if all other maintainers based their trees on this
tree, we're left with two not-so-great alternatives:

 1) merge the original, broken infrastructure change into your
    (Linus's) tree, leaving a known problem for bisecters to trip
    over.

 2) rebase the world.

I don't know if there's really a perfect answer here.  I hope that
tree-wide infrastructure breakage is uncommon enough that we can just
handle these issues "by hand" as they come up.

 - R.