simonmarhaskell:
Several good points have been raised in this thread, and while I might not agree with everything, I think we can all agree on the goal: things shouldn't break so often.
So rather than keep replying to individual points, I'd like to make some concrete proposals so we can make progress.
1. Document the version numbering policy.
We should have done this earlier, but we didn't. The proposed policy, for the sake of completeness is: x.y where:
x changes ==> API changed x constant but y changes ==> API extended only x and y constant ==> API is identical
further sub-versions may be added after the x.y, their meaning is package-defined. Ordering on versions is lexicographic, given multiple versions that satisfy a dependency Cabal will pick the latest.
2. Precise dependencies.
As suggested by various people in this thread: we change the convention so that dependencies must specify a single x.y API version, or a range of versions with an upper bound. Cabal or Hackage can refuse to accept packages that don't follow this convention (perhaps Hackage is a better place to enforce it, and Cabal should just warn, I'm not sure).
I agree. >= 1.0 isn't viable in the long term. Rather, a specific list, or bounded range of tested versions seems likely to be more robust. -- Don