[Haskell-cafe] cabal-install package precedence with --extra-lib-dirs

[Albert Y. C. Lai]

On 12-02-02 12:12 AM, Scott Lawrence wrote:
> When running cabal install with --extra-lib-dirs=./lib, if a package is
> found both in ~/.cabal/lib and ./lib, cabal seems to favor the
> ~/.cabal/lib one. Is there some way to specify the correct precedence to
> use?

--extra-lib-dirs is for C libs only.

Haskell packages for GHC are not rediscovered every time by scanning 
"lib" directories. They are registered in 2 metadata stores (3 if you 
add an option), and only the metadata stores are consulted. On existence 
of packages, this is final.

The 2 metadata stores also come with a precedence: the "user" store has 
higher priority than the "global" store. On disambiguation of packages, 
this is final.

http://www.vex.net/~trebla/haskell/sicp.xhtml#ident