HEADS UP: patches, package versions, and cabal-install

[Simon Marlow]

Claus Reinke wrote:
> If packages are patched without any change in version number,
> bad things can happen if one tries to cabal install additional packages
> onto such a patched ghc.
> 
> At the moment, that seems to be the case for array and containers,
> which were adjusted following the syb split, without changes in version
> number (containers also seems to have gained some exports, foldrWithKey
> and the like, again without version bump). Could this please be fixed?

Yes - the policy should be that we bump version numbers according to the 
PVP as soon as an API change occurs.  However, note that it's not practical 
to do this *every* time an API change occurs, we only need to keep the 
version number correct with respect to released versions of packages, not 
unreleased versions.  This is unlikely to cause a problem, though.

Ian - I think this might be different from the policy we agreed before, but 
I can't remember where (if anywhere) we wrote it down.  The difference is 
that we hadn't considered the possibility of people trying to use cabal 
install with a an unreleased HEAD build before, but I don't think there's a 
good reason why this shouldn't work.

Cheers,
	Simon