On Fri, Apr 29, 2011 at 3:05 PM, Daniil Elovkov
Hello list
I have an idea on versioning of Haskell packages and a small question about release model of Haskell Platform. Since the latter is shorter let's start with it.
So, what is the release model of Haskell Platform? Is it released every N months and frozen at that point? Or some intermediate package/compiler updates can make the new version to appear out of schedule?
Now, about package versioning. Haskell packages are flourishing and evolving at a high speed. Packages depend on other package and they evolve asynchronously. In result it is easy to end up in need of multiple versions of the same package in one program or maybe stumble upon other conflicts/problems. I'm expressing myself a little vaguely because I don't have a good example in my head right now.
However, the idea is to maintain not just multi-digit version names that don't carry any semantics except that 1.1.3 is later than 1.1.2, but also somehow describe compatibility between versions.
This way, even if the package A has jumped from 1.0 to 1.5 and the dependent package B has been stagnant all this time (and B depends on A 1.0), if we have information that 1.5 is compatible with 1.0, then we can safely use A 1.5 while building B. Or we could use whatever version of A is found in the system as long as its compatible with A 1.0 that B depends on.
I think the PVP (Package Versioning Policy) covers a lot of what you're discussing, but I may misunderstand: http://www.haskell.org/haskellwiki/Package_versioning_policy We *do* still have some trouble maintaining / enforcing the PVP in general, and there are a few things that it doesn't cover (I don't believe exception behavior is covered, for example, although I'd argue that throwing more exceptions than a previous version introduces a substantial API change. Anyhow, that's a different rant. ;). Finer granularity would be great -- if it can be done autonomously. I think that raising awareness of the PVP and refining the tools to check for necessary version bumps would be a great step in the right direction. --Rogan