Platform policy question: API compatability in minor releases

[Duncan Coutts]

On Sun, 2009-05-10 at 09:11 +0200, Heinrich Apfelmus wrote:
> Duncan Coutts wrote:
> > So by arguing for new features in minor releases we're saying we should
> > have a 4-6 week cycle. New library features every 6 weeks.
> > 
> > Now perhaps 12 months is too long (I think it is). Perhaps 6 months is
> > too long even (though many other groups have settled on 6 months). But
> > surely 6 weeks is far too short. That means essentially no
> > synchronisation effect at all.
> > 
> > If the majority opinion is that 6 months is too long to wait for new
> > features, then how about 4 months, or even 3? Do people see the point
> > I'm trying to make about the value of synchronisation?
> 
> Can the Haskell Platform be uninstalled / upgraded seamlessly?

This depends on the packaging for each OS.

The Windows installer will install a new ghc and set of packages without
disturbing existing installations. The source based installer will do
the same (though it has no builtin uninstall facility). Not sure yet
about OSX.

> I think it's a key technical requirement for shorter release cycles that
> installing a new release does not break due to any old ones that were
> installed previously.

It is possible in principle though many distro packaging systems only
allow one version of a package at once.

I think distros would prefer the slightly longer release cycle. They
already deal with many projects that work on 6 month cycles. However
they could probably cope with 4 months. They cope with the Linux
kernel's 3 month cycle, though they often skip some major releases.

Duncan