Cabal can handle multiple versions of libraries, but you need to find a consistent set of libraries when building any one executable, since they are all going to be linked together. In this case Cabal has apparently failed to find such a set. You might be able to get this to work with cabal instal gitit --constraint='datetime==0.1', since that version only demands QuickCheck > 1.2, and gitit doesn't specify a datetime version. I haven't tried this though. Happstack-util should probably not depend on QuickCheck at all if the "tests" flag is False -- this appears to be an omission in their Cabal file (http://hackage.haskell.org/packages/archive/happstack-util/0.4.1/happstack-u...). The datetime package doesn't appear to make this a configurable dependency at all... Cheers, Max On 9 February 2010 10:40, Thomas Girod wrote:

Hi there.

I'm trying to reinstall gitit after updating to ghc 6.12 and it's driving me crazy. I hope you will be able to help me troubleshoot this mess ...  I'm starting from scratch again, using cabal. I will post more problems as they appears.

$ cabal install gitit Resolving dependencies... cabal: cannot configure datetime-0.2. It requires QuickCheck ==2.* For the dependency on QuickCheck ==2.* there are these packages: QuickCheck-2.1, QuickCheck-2.1.0.1, QuickCheck-2.1.0.2 and QuickCheck-2.1.0.3. However none of them are available. QuickCheck-2.1 was excluded because happstack-util-0.4.1 requires QuickCheck <2 QuickCheck-2.1.0.1 was excluded because happstack-util-0.4.1 requires QuickCheck <2 QuickCheck-2.1.0.2 was excluded because happstack-util-0.4.1 requires QuickCheck <2 QuickCheck-2.1.0.3 was excluded because happstack-util-0.4.1 requires QuickCheck <2

Can't cabal handle several versions of the same library in parallel ? If not, how can I solve this problem ?

cheers

tom

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