[Haskell-cafe] How to determine correct dependency versions for a library?

Ganesh Sittampalam ganesh at earth.li
Sat Nov 17 21:25:47 CET 2012

On 09/11/2012 18:35, Clark Gaebel wrote:
> I think we just use dependencies different things. This is a problem
> inherent in cabal.
> When I (and others) specify a dependency, I'm saying "My package will
> work with these packages. I promise."
> When you (and others) specify a dependency, you're saying "If you use a
> version outside of these bounds, my package will break. I promise."
> They're similar, but subtly different. There are merits to both of these
> strategies, and it's unfortunate that this isn't specified in the PVP [1].

I always understood that the policy was the former, i.e. allowing a
version means you positively expect it to work. Otherwise, why does the
PVP insist on upper bounds? You can't in general know that the package
will break with a version that doesn't exist yet.

As this thread and others show, there is of course a substantial set of
people that would prefer the policy to be the latter.



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