#369: Version ranges should be simplified before printing ----------------------------+----------------------------------------------- Reporter: nominolo | Owner: Type: defect | Status: new Priority: normal | Milestone: Cabal-1.8 Component: Cabal library | Version: HEAD Severity: minor | Resolution: Keywords: | Difficulty: very easy (<1 hour) Ghcversion: | Platform: ----------------------------+----------------------------------------------- Changes (by duncan): * difficulty: normal => very easy (<1 hour) * ghcversion: 6.9 => * milestone: => Cabal-1.8 Comment: Sometimes these are quite entertainingly long. For example with happstack- server: {{{ cabal: Unresolved dependencies: base >=3&&<4, base >=3&&<4, base >=3&&<4, base >=3&&<4, base >=3&&<4, base >=3&&<4, base >=3&&<4, base >=3&&<4, base >=3&&<4 }}} No, really. :-) With the new version intervals adt we've got a function: {{{ simplifyVersionRange :: VersionRange -> VersionRange }}} which should make this stuff easy. Just take the intersection of version constraints per-package and simplify and print. A slightly more sophisticated approach would be to check that taking intersections does not end up with an empty range, ie that the constraints are necessarily unsatisfiable irrespective of potential available packages. The intervals adt also makes this check easy and efficient. -- Ticket URL: http://hackage.haskell.org/trac/hackage/ticket/369#comment:3 Hackage http://haskell.org/cabal/ Hackage: Cabal and related projects