wither the Platform

[Duncan Coutts]

On Sun, 2015-03-22 at 10:52 +0100, Herbert Valerio Riedel wrote:

> My biggest complaint about the current HP is that it pollutes the global
> package database with additional packages which leak into `cabal
> sandbox`es. This causes `cabal sandbox` to provide quite different
> sandbox environments for HP environments compared to a non-HP
> environment without those additional packages pre-installed.
> 
> Currently GHC/Cabal knows about a global package db and a user package
> db (the user pkg db is is what gets replaced/shadowed by cabal
> sandboxes). Maybe we need a 3rd package db sitting between the global
> and the user package db that interacts better with cabal sandboxes?

I think this is a good idea.

As far as I can see there's no conflict between the advocates of mini
and maxi installers (as aimed at new users) except for this behaviour of
new sandboxes.

All we need to do is make "cabal sandbox init" start with a minimal
package set, rather than taking the global package db.

It's true that the ghc/platform installers could help with this, e.g. by
shipping an environment file (a new 7.10 feature) that lists all the
core packages, and cabal-install could use this as a basis for new
sandboxes.

Duncan