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

On Wed, Nov 14, 2012 at 1:01 PM, Tobias Müller wrote:

Clark Gaebel wrote:

...

To prevent this, I think the PVP should specify that if dependencies get a major version bump, the package itself should bump its major version (preferably the B field).

No, it has nothing to do with major/minor version bumps. It's just that if you underspecify your dependencies, they may become invalid at some point and you cannot correct them. Overspecified dependencies will always remain correct.

This is required if you want to maintain the property that clients don't break. If A-1.0 dependes on B-1.0.* and C depends on both A-1.0.* and B-1.0.*. Bumping dependency in A on B to B-2.0.* without bumping the major version number of A will cause C to fail to compile as it now depends on both B-1.0.* (directly) and B-2.0.* (though A-1.0). -- Johan