patch applied (cabal-install): Disable cabal upgrade and add cabal install --upgrade-dependencies

[Duncan Coutts]

On Tue, 2010-06-01 at 16:48 +0200, Peter Robinson wrote:
> On 31 May 2010 15:18, Duncan Coutts <duncan.coutts at googlemail.com> wrote:
> > Mon May 31 06:03:06 PDT 2010  Duncan Coutts <duncan at haskell.org>
> >  * Disable cabal upgrade and add cabal install --upgrade-dependencies
> >  cabal upgrade now gives an error message telling people to use install
> > or, if they know what they're doing, install --upgrade-dependencies
> 
> How about also adding a reference to 'cabal install world'? I think that's the
> behaviour most people actually want when running upgrade (at least I do :) ).

Yes, I was thinking about that. I think we need a little more work
before the world feature is recommended to the masses.

http://hackage.haskell.org/trac/hackage/ticket/695

As you point out, we would really need to start tracking programs.

The other thing I'm not yet convinced about is keeping just the flags in
the world file. I suspect we'll need more eventually and should perhaps
plan the format with that in mind. Also currently we do not properly
assign flags to individual packages, that's not the fault of the world
feature, it's a problem elsewhere in cabal-install.

Don't get me wrong, the world feature is definitely what we need (and
works well for distros) but generally I think we need more experience of
how it works in practise. I suspect one of the first things we'll find
is that the dep resolver runs into problems when trying to install
world. While it could find install plans for each package individually
it might not be able to find a plan for all the world packages
simultaneously. We may need some significant improvements in the solver
and we might have to do things like treating the flags etc as
suggestions rather than hard "all or nothing" constraints.

Duncan