#601: cabal setup doesn't respect --prefix ----------------------------+----------------------------------------------- Reporter: zooko | Owner: Type: defect | Status: new Priority: normal | Milestone: Component: Cabal library | Version: 1.6.0.1 Severity: normal | Resolution: Keywords: | Difficulty: unknown Ghcversion: | Platform: ----------------------------+----------------------------------------------- Comment (by duncan): Replying to [comment:2 zooko]:
So, it appears to me that if the user specifies {{{--prefix}}} then that should dictate the location of the package database as well as the other files.
This is not possible if you want the installation to work by default. For packages to be used by ghc they must be registered in a package database. There are two default package databases and their location is independent of the prefix used for installing package files. As Saizan says, you can install into a non-default package database and your packages will not be available by default. Instead you will have to use eg: {{{ ghci -package-conf /usr/local/stow/Cabal/var/lib/package.conf }}} Generally people do not actually want that as default behaviour. Hence the default (depending on the --global / --user flag) is to use one of the standard package databases. Supposing there were no global package database then you'd still need some other mechanism to register where packages are, eg Java uses the CLASSPATH etc. Making a persistent change to that requires some similar change to a file that is not inside the selected prefix. Perhaps we can at least make things a bit clearer, eg by checking up-front if we are likely to be able to modify the target package db and giving a more helpful error message. Any other suggestions for what we can improve here, otherwise we should close this ticket. -- Ticket URL: http://hackage.haskell.org/trac/hackage/ticket/601#comment:3 Hackage http://haskell.org/cabal/ Hackage: Cabal and related projects