planning for ghc-6.10.1 and hackage

Duncan Coutts duncan.coutts at
Fri Oct 3 12:54:12 EDT 2008

On Fri, 2008-10-03 at 14:27 +0100, Claus Reinke wrote: 
> > Perhaps we could even go as far as saying "base >= 3.0" is equivalent to 
> > "base == 3.0.*".  i.e. if you don't supply an upper bound, then we'll give 
> > you a conservative one.  I wonder how much stuff would break if we did that.
> All open-ended dependencies are lies.. 


> Well, actually they are optimistic approximations (some programs will
> work with base 3 or base 4), and closed dependency ranges are
> pessimistic approximations (few programs need all of base 3). The
> problem is that there is no definite interface spec.


Don and I are rather of the opinion that we need to look much more
carefully at the package system. We're basically operating without the
reassuring assistance of the type checker.

There are some practical things we can do to make the current system
work considerably better though. If we get the platform packages to opt
into the package versioning policy and get cabal/hackage to warn about
upwardly open version ranges then that'd go a long way to making things
better. We should also write a tool using the ghc-api to compare apis of
different versions of packages to inform people of changes and enforce
the versioning policy for packages that have opted in.

Having those interface specs around might also help a more robust
package composition consistency checker or solver.


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