On 10 December 2005 23:27, Robert Dockins wrote:

I just want to mention that these kind of changes represent represent a VERY big problem.

I agree, this is indeed a big problem. I've mentioned it before, albeit only briefly, and we didn't reach a conclusion. As you say, Cabal solves (for some value of solve) the versioning problem for everything except the Setup.lhs script itself. In the Setup.lhs script we have absolutely no way to request a particular version of the Cabal library, and even if you have the right version installed, it might not be the one used by default, so you're screwed ("runghc -package Cabal-1.0 Setup.lhs" doesn't work, and even if it did this would be a poor solution). The cabal-version field is only a partial solution - it doesn't help if the Cabal API changes such that your Setup.lhs script breaks. I support doing some explicit interface versioning along the lines of EternalCompatibiliyInTheory, but only for Cabal. It's extra work, but it's necessary if we want to be taken seriously. Cheers, Simon