[Haskell-cafe] Re: [Haskell] Re: Trying to install binary-0.4

[ChrisK]

Simon Marlow wrote:
 > Ultimately when things settle down
> it might make sense to do this kind of thing, but right now I think an
> easier approach is to just fix packages when dependencies change, and to
> identify sets of mutually-compatible packages (we've talked about doing
> this on Hackage before).
> 
> Cheers,
>     Simon

When coordinating distribution of separately maintained libraries and projects,
the linux distributions do indeed "identify sets of mutually-compatible
packages", quite often including small patchfiles to ensure compilation.

Thus for linux, cabal is a layer below such apt and rpm repositories and
blessing sets of packages would be done at a higher level.

Once cabal is being used to automatically retrieve sets of working packages then
 it is easiest to write cabal to assume that hackage is fixed when dependencies
change.

As a practical matter, it is easy to see how to identify such sets.  Since such
sets must be installed by at least one person, that person's ghc-pkg listing is
already a precise definition of the working set.  All that might need to be done
is to publish such a working set on hackage where cabal (or another tool) can
see it.

Cheers,
  Chris