[Haskell-cafe] hackage version scheme survey

[Duncan Coutts]

On Sat, 2009-05-23 at 19:57 -0500, brian at lorf.org wrote:
> On Saturday, 23.05.09 at 17:26, Don Stewart wrote:
> > http://haskell.org/haskellwiki/Package_versioning_policy  ?
> 
> That helps a lot. I should have found that. But putting the policy on a
> web page doesn't seem to be working; there are a lot of non-compliant
> packages. I guess I'm surprised thah 'cabal check' doesn't complain
> about it and HDB doesn't reject them.

We cannot force maintainers to follow the PVP, however we do have a plan
to encourage adoption. The key is to get maintainers to opt-in. For
packages that opt-in we will enforce it.

Following the PVP is extra work for a maintainer so there need to be two
sides to the bargain. The benefit to maintainers that we can enforce
that all newly uploaded hackage packages that depend on their
PVP-following package do actually specify an upper version bound. This
benefits the maintainer because it lets them release new versions
knowing that they are not breaking dependent packages.

The bargain on the other side is that it's a benefit to you as a package
author if you can rely on the proper versioning of the packages you
depend on. In return however you must actually make proper use of that
by specifying appropriate upper bounds (and the tools should be able to
give helpful suggestions).

However, like most of our grand plans, there's nobody actually working
on implementing them at the moment. The key part of this plan is the PVP
checker tool.

Duncan