On 8 December 2012 03:12, Albert Y. C. Lai
I do not understand the conflict. First you have GHC, and it comes with bytestring-0.9.2. Then one of two things happen, but I can't see a conflict either way:
* You request A, but A should be fine with the existing bytestring-0.9.2. Then you request B, but B should be fine with the existing A you have, and indifferent about bytestring.
When you install A, you may not know that you'll need to depend on a lower version of bytestring later on. Cabal will pick the highest version available (0.10 if present). If a program you install later on depends on A (needs bytestring-0.10) and ghc (needs bytestring-0.9), you'll have a conflict. Using cabal-dev seems like a good approach. Just yesterday I was able to install hoodle without problems (even though installing it with cabal would have broken many packages). The fact that you can unpack any package, fix the problems, add its path as source and install when other packages depend on it saved me a lot of time already.