Dependencies/backwards compatibility in Hackage

[Isaac Jones]

The way I propose to solve this version incompatibility problem in the
short term is to use the "testing" hackage repository to collect
packages that are known to work together.  For instance, we could put
haxml 1.17 in and only allow things that compile with that version.
unstable can still have stuff that only compiles w/ 1.13, but if an
author wants their tool to be in "testing", then they have to fix it
up to be compatible.  (Or we might decide that 1.13 is a better
version to have in testing.)

This will encouarage people to update their packages with a collection
of dependencies that are somewhat "blessed", even if that blessing is
a little arbitrary.

We can ourselves modify packages so that their version dependency is
more accurate than upstream knows them to be :)


peace,

  isaac