HsUnix.h not available to Stack for builds.

[seanparsons]

Most of the history around this is in here: commercialhaskell/stack-ide#96

Installing libghc-unix-dev (on Ubuntu) apparently fixes this, but that pulls in a particular version of GHC with all the usual hilarity that brings. It would appear if someone wants Stack to be totally in control of everything GHC related this should be another element it controls.

[borsboom]

In my attempt to reproduce this on Ubuntu 14.04/trusty, I had a slightly different experience.

    In file included from Posix.hsc:60:0:
    /home/vagrant/.stack/programs/x86_64-linux/ghc-7.10.2/lib/ghc-7.10.2/unix_A3WgcI5QiHK4PDo4jSYdwQ/include/HsUnix.h:79:25: fatal error: bsd/libutil.h: No such file or directory
     #include <bsd/libutil.h>
                             ^

So it's finding the HsUtil.h that's included with the unix package, but HsUtil.h can't find bsd/libutil.h. That file is included in libbsd-dev (at least on Trusty) and running

sudo apt-get install -y libbsd-dev

fixed the build. Since that's an external dependency, it's not something Stack has control over (unless you use the Nix or Docker integration, of course).

Note that installing libghc-unix-dev, as mentioned in commercialhaskell/stack-ide#96, ends up installing libbsd-dev as well, and I think it's likely that rather than installing the system GHC is what actually fixes the problem for people. Also, there was a recently fixed bug that probably masked the error message I saw above (and would have caused the "Could not resolve" error to appear instead, as referenced in commercialhaskell/stack-ide#96).

Please confirm whether installing just libbsd-dev fixes it for your case as well.

[seanparsons]

Ah, interesting, I will check that later.

[seanparsons]

Confirmed, it's libbsd-dev that fixes the problem!

[seanparsons]

I don't understand why I didn't get the error listed by @borsboom above, just this semi-cryptic message:

ide-backend-0.10.0: copy/register
PCould not resolve file /home/sean/workspace/stack-ide/ide-backend/ide-backend-server/In file included from Posix.hsc
rogress: %

[borsboom]

@seanparsons: see #1561 (comment). Should be fixed in the git master version of Stack.

[seanparsons]

Works for me.