stack ghci weird behaviour with ghc installed via ghcformacosx

[jhedev]

I'm on OS X 10.9.5 and ghc-7.8.4 is installed using ghcformacosx.

I have the following problem:

$ which ghc
/Applications/ghc-7.8.4.app/Contents/bin/ghc
$ ghc --interactive
GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
λ>
$ stack -v ghci
...
2015-06-23 18:52:01.203545: [debug] Run process: /Applications/ghc-7.8.4.app/Contents/bin/ghc --interactive @(stack-0.1.0.0:Stack.Exec src/Stack/Exec.hs:41:5)
GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... <command line>: can't load .so/.DLL for: libHSghc-prim-0.3.1.0.dylib (dlopen(libHSghc-prim-0.3.1.0.dylib, 9): image not found)
$ /Applications/ghc-7.8.4.app/Contents/bin/ghc --interactive
GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
λ>

As you can see I can run the ghc manually and it works as expected but running it via stack I get the error.
If I remove ghc from the $PATH and run stack setup first to download and install ghc, everything works fine:

$ which ghc
ghc not found
$ stack -v ghci
...
2015-06-23 19:00:14.401176: [debug] Run process: /Users/joel/.stack/programs/x86_64-osx/ghc-7.8.4/bin/ghc --interactive @(stack-0.1.0.0:Stack.Exec src/Stack/Exec.hs:41:5)
GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
λ>

I'm not sure if this is a bug or something specific to my environment.

EDIT: stack version is:

$ stack --version
Version 0.1.0.0, Git revision c2e5af39679439921570552e3e722f6819f4f4bf

[vijaykiran]

Looks like I've the same problem, I tried setting DYLD_PATH, but still won't work.

[chrisdone]

I don't know anything about OS X development, but perhaps we can compare:

$ env

with

$ stack exec env

And see what's different? Please paste to https://gist.github.com/.

[jhedev]

I started a bash using env -i to have a minimal environment, and I can still reproduce. See here.

[vijaykiran]

Here's something interesting:

➜  ~  GHC_PACKAGE_PATH=/Applications/ghc-7.8.4.app/Contents/lib/ghc-7.8.4/package.conf.d/ ghci
GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... <command line>: can't load .so/.DLL for: libHSghc-prim-0.3.1.0.dylib (dlopen(libHSghc-prim-0.3.1.0.dylib, 9): image not found)
➜  ~  ghci
GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Prelude>
Leaving GHCi.
➜  ~

stac exec env has

GHC_PACKAGE_PATH=/Users/vijaykiran/tmp/stacker/.stack-work/install/x86_64-osx/lts-2.15/7.8.4/pkgdb/:/Users/vijaykiran/.stack/snapshots/x86_64-osx/lts-2.15/7.8.4/pkgdb/:/Applications/ghc-7.8.4.app/Contents/lib/ghc-7.8.4/package.conf.d/

[jhedev]

Yep, same here.

[jhedev]

Another observation:

$ GHC_PACKAGE_PATH=/Applications/ghc-7.8.4.app/Contents/lib/ghc-7.8.4/package.conf.d/ ghci
GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... <command line>: can't load .so/.DLL for: libHSghc-prim-0.3.1.0.dylib (dlopen(libHSghc-prim-0.3.1.0.dylib, 9): image not found)

vs.

$ GHC_PACKAGE_PATH=/Applications/ghc-7.8.4.app/Contents/lib/ghc-7.8.4/package.conf.d ghci
GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
λ>
Leaving GHCi.

Looks like the trailing slash has to be removed in every entry of $GHC_PACKAGE_PATH to make it work?

[snoyberg]

That's very interesting/weird, but should be trivial to implement.

[snoyberg]

Could you try with latest master and see if that resolves it?

[vijaykiran]

Works! Thanks @snoyberg

➜  stacker  /Users/vijaykiran/tmp/stack/.stack-work/install/x86_64-osx/lts-2.9/7.8.4/bin/stack --version
Version 0.1.0.0, Git revision 8dddd963f95be160e7b5232cbc2ca3498c3ea3eb
➜  stacker  /Users/vijaykiran/tmp/stack/.stack-work/install/x86_64-osx/lts-2.9/7.8.4/bin/stack ghci
Configuring GHCi with the following packages: new-template
GHCi, version 7.8.4: http://www.haskell.org/ghc/  :? for help
Loading package ghc-prim ... linking ... done.
Loading package integer-gmp ... linking ... done.
Loading package base ... linking ... done.
Loading package new-template-0.1.0.0 ... linking ... done.
[1 of 1] Compiling Lib              ( /Users/vijaykiran/tmp/stacker/src/Lib.hs, interpreted )
Ok, modules loaded: Lib.
*Lib>

[snoyberg]

I hardly did anything, thanks to you guys for diagnosing the problem with the trailing slash.