[plt-scheme] Re: On PLaneT packages and compatible upgrades

On 5/9/06, Jacob Matthews <jacobm at cs.uchicago.edu> wrote:
> pedro pinto wrote:
>
> > For me, its clear that package users should  be able to use minor
> > version to specify exactly which package they want.
>
> Yes, they should be able to and they have been able to since PLaneT has
> existed.

Unfortunately, this only solves part of the problem.  If A imports B,
and specifies B version 2.0, and B imports C and specifies C version
1.4 or greater, than A has done all it can to achieve stability but
will still break if something goes wrong with an upgrade of C.  It
only works if all of your transitive imports obey the "precise version
imports only" rule.

It has to be turtles all the way down.

--
Carl Eastlund
"Cynical, but technically correct."