error: package id couldn't be found

[donnut]

Installed stack on Arch Linus. cabal and ghc are installed using nix. Running stack build in an empty directory gives the output:

No .cabal file found in directory /home/donnut/dev/haskell/test/
Writing default config file to: /home/donnut/dev/haskell/test/stack.yaml
After installing Cabal, the package id couldn't be found (via ghc-pkg describe Cabal). This shouldn't  happen, please report as a bug

I tried stack build --system-ghc, with the same result.
Running stack ghc outputs:

ghc: can't find a package database at /nix/store/dhwpkyhh5fc7093695n3bi022zfdrp3q-haskell-aeson-ghc7.8.4-0.8.0.2-shared/lib/ghc-7.8.4/package.conf.d/aeson-0.8.0.2.installedconf/

Is nix the problem here? Is it correct to say that I don't need nix anymore to use different versions of ghc?

[bitemyapp]

@donnut if you're on Nix I wouldn't recommend attempting to use the system ghc and instead let stack use its own GHC if possible. Much of the benefit of Nix+Haskell is in caching/managing package dependencies, but if you're using Stack you're using Stackage/LTS snapshots anyway.

[snoyberg]

Fairly certain nix is the issue, what do you get when you run:

ghc-pkg list Cabal

Since stack uses the Cabal library to do the building, it requires it to be already present.

Also, can you try with --no-system-ghc?

If this turns out to be the issue, it would be good to get this documented in the Wiki's FAQ page.

[donnut]

ghc-pkg list Cabal issues a long list:
/home/donnut/.nix-profile/bin/../lib/ghc-7.8.4/package.conf.d/aeson-0.8.0.2.installedconf
...

and stack build --no-system-ghc did oke, but when I try stack ghc it outputs:

GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
ghc: can't find a package database at /nix/store/dhwpkyhh5fc7...

[snoyberg]

You'd need to use --no-system-ghc for all commands, otherwise it will keep reverting back to the nix-installed one. Perhaps we should have a config options about whether to use the system GHC.

[snoyberg]

If you're building stack from master, you can now add system-ghc: false to ~/.stack/stack.yaml to get the desired behavior. Modifying your PATH to not include GHC will also work.

[snoyberg]

@donnut Should we consider this issue resolved?

[donnut]

Yes, it works when I keep using `--no-system-ghc.
Thanks!