[plt-scheme] Version incompatibilities in PLaneT packages

From: Jacob Matthews (jacobm at cs.uchicago.edu)
Date: Tue Mar 21 17:14:02 EST 2006

Carl Eastlund wrote:

>I think this kind of error message will creep up over time; it's
>fundamentally a problem with legacy code, and putting it in early to
>"see how it goes" will result in silently spoiling a lot of old code
>that would otherwise be usable in perpetuity.  Any code in planet that
>links against specific major versions of other code in planet will
>become obsolete as soon as its dependencies update.
There are definitely significant problems with the approach we've taken, 
but there are significant problems with the opposite approach too -- see 
"DLL hell" for example. Fundamentally, we saw that either choice of 
defaults was going to cause both short- and long-term problems for 
_some_ hypothetical group of programs.

Anyway, the solution I had in mind if this ever became a problem was to 
let package authors decide on a case-by-case basis if they want to 
disable this limitation, which it looks like is the same thing you're 


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