[Nix-dev] Building an old GHC for a new Cabal...

[Jason Dusek]

  I managed to build GHC 6.12 in Nix on Ubuntu after some help
  in an earlier discussion on this list. Now, my old Cabal
  (built through Nix) complains about an invalid package format;
  this is to be expected if it shells out to `ghc-pkg' to read
  the package list.

  When I try to rebuild Cabal, it tries to build it against GHC
  6.10 instead of 6.12:

    :;  nix-env --install cabal-install-0.8.0
    warning: there are multiple derivations named
`cabal-install-0.8.0'; using the first one
    replacing old `cabal-install-0.6.2'
    installing `cabal-install-0.8.0'
    the following derivations will be built:
      /nix/store/48s13mpj6rqvaf3gq3mag8wmbx571kdl-haskell-zlib-ghc6.10.4-0.5.2.0.drv
      /nix/store/5qhafcrc10a66xg6aayd862fag6jkvk4-cabal-install-0.8.0.tar.gz.drv
      /nix/store/al2b217ah6hbs89dpj3wkmw968vvd4y8-zlib-0.5.2.0.tar.gz.drv
      /nix/store/h84yfpg550c8kqiv08pvajdlkijj1ls5-cabal-install-0.8.0.drv
    the following paths will be downloaded/copied (3.32 MiB):
      /nix/store/cb84zvm4n5290w185j3xazhkz89fa9wx-haskell-network-ghc6.10.4-2.2.1.7
      /nix/store/mxyc0q4r8xyfx995qlrfwr5kx05x8z7p-haskell-HTTP-ghc6.10.4-4000.0.9
      /nix/store/qr4hwvbrbpvfx3r9c596grdf3sssbk6f-curl-7.19.7
      /nix/store/s60nzmp97k010vxp6hi9j3dbc4pz939w-openssl-0.9.8n

  I do have GHC 6.10 still installed; but why does it not build
  against the new GHC? Should I delete the `.drv' files? Perhaps
  these cache something about which GHC to build against?

--
Jason Dusek
Linux User #510144 | http://counter.li.org/