On Tue, Jun 8, 2010 at 7:06 PM, Ivan Lazar Miljenovic
I recall having a discussion with either you or someone else from the happstack team about why it isn't applicable there, but the QuickCheck problem can be solved in the general case by having its dependency be a compile-time-only option which is disabled by default.
Not really. Cabal likes to recompile things, and it won't remember that I compiled another library with quickcheck enabled. So if library B depends on library A with quickcheck enabled, it may still happen that after I install library A with quickcheck enabled, cabal will decide to recompile A again when building library B, and it will build A without quickcheck, causing B to fail...
However, this is definitely a major problem with parsec, HaXml, etc. and probably what I consider the main argument _against_ keeping the same name for fgl, though this can occur with packages even with a relatively minor API change (e.g. haskell-src-exts going from 1.6 to 1.7; the API change was minor but until all package maintainers upgraded their packages to work with 1.7 there would be some inconsistencies).
Right. Minor dependencies have the same issue. The only difference is that it is generally less work for maintainers to update their code. So maybe it happens faster/more often. But, we still run into that issue with happstack as well. We have fixed it by sending patches upstream. Since they are small patches it is usually easy to get them created and applied than something like HaXml 1.13 -> 1.19. - jeremy