I found that a simple “stack install …” worked perfectly, as an alternative to “cabal install ...". Stack seems to have honored all the “cabal …” things I did in setting up my sandbox, including all my “cabal sandbox —add-source …” commands (5 in all). And, of course, it used the back-rev’d version of ghc I configured it (i.e. - stack) for.

On Sep 2, 2015, at 8:59 PM, Michael Snoyman <michael@snoyman.com> wrote:

On Thu, Sep 3, 2015 at 3:37 AM, David Banas <capn.freako@gmail.com> wrote:
Hi all,

How do I direct cabal to use an alternative (i.e. - not my system’s default) version of ghc, which I’ve installed, via stack?

I tried this:

stack exec cabal install ...

but got this:

cabal: Use of GHC's environment variable GHC_PACKAGE_PATH is incompatible with
Cabal. Use the flag --package-db to specify a package database (it can be used
multiple times).

Thanks,
-db

_______________________________________________
Haskell-Cafe mailing list
Haskell-Cafe@haskell.org
http://mail.haskell.org/cgi-bin/mailman/listinfo/haskell-cafe

We have a flag to working better with cabal, you can try:

stack exec --no-ghc-package-path -- cabal install

I'm under the impression that there are changes planned to cabal (possibly already implemented but not released) that will allow it to function nicely with the GHC_PACKAGE_PATH environment variable, but I'm uncertain if that's true.

Michael