* Daniel Trstenjak
Hi Johan,
Cabal is allowed to use any version that fullfills the required bounds. It uses a heuristic the tends to prefer
* installed * newest * other
in that order.
If you want to make sure the newest version is used temporarily you can pass --constraint="foo-1.2.3.4" to cabal install. If you want to make this change more permanent you can set an exact version in a cabal.config file in the same directory as the .cabal file.
So there's no flag to always use the newest one, right?
In my use case it would be a bit cumbersome to first find these libraries and then to list all of them by hand.
The concrete use case is to test your project with the newest available library versions.
You should create a fresh sandbox per build, then. This is both sufficient (nothing is installed => no reason to prefer an older version) and necessary (when in a sandbox, cabal won't let you have two different versions of the library installed). Roman