Hello,
When I install cabal-dev and cab first and then re-install everything with cab instead of cabal the issue with re-installing already installed packages described above disappears and only an "unknown symbol" message related to the correctly found installed cairo package remains. So is there an error in package database handling somewhere or changed semantics in cabal | ghc-pkg | (even) pkg-config flags I missed?
"cab" is just a wrapper for "cabal" and "cabal-dev" for installation. So, I have no idea about what's going on. Please try "cab install <package> -n" to see what will happen before typing "cab install <package>". If you find the word "reinstall", you should not install the package because the installation operation will break your package environment. You can analyze package dependency with: cab deps <package> -r cab revdeps <package> -r cab list -r Adding the "-a" option displays global packages also. I recommend to use a sandbox when you try to resolve a dependency problem. --Kazu