ghc 7.8.2 with --devel

[glehmann]

ghc 7.8 uses clang internally. clang is used to build the ghc 7.8 on mavericks
64 bit, and gcc is used on older OS and 32 bit builds. Also advise to use
cabal-install in the caveat.

[MikeMcQuaid]

Hmm, seems potentially weird. Can clang not be used to build too?

[glehmann]

no, because a binary ghc 7.8 is required to booststrap the build, and it is available to download only for mavericks 64 bit

[MikeMcQuaid]

Cheers for doing this!

[Josh-Tilles]

By the way, when I built GHC 7.8.2 on my machine (Mavericks) with the --tests flag, I got the following outcome:

Unexpected results from:
TEST="T8958 T8256 T3064 T4801 T6048"

OVERALL SUMMARY for test run started at Wed May  7 17:26:50 2014 EDT
 0:08:11 spent to go through
    3639 total tests, which gave rise to
   14083 test cases, of which
   10738 were skipped

      43 had missing libraries
    3261 expected passes
      36 expected failures

       0 caused framework failures
       0 unexpected passes
       5 unexpected failures

Unexpected failures:
   codeGen/should_run    T8256 [exit code non-0] (normal)
   perf/compiler         T3064 [stat not good enough] (normal)
   perf/compiler         T4801 [stat not good enough] (normal)
   perf/compiler         T6048 [stat not good enough] (optasm)
   roles/should_compile  T8958 [stderr mismatch] (normal)

(I don't know whether that's alarming or not.)

In addition, I was able to build pandoc and shellcheck from source with GHC 7.8.2. Both formulae also passed brew test.

Caveat: I used my version of the formula because glehmann's didn't yet exist.

[Josh-Tilles]

Heads up: GHC 7.8.2 will fail to build cabal-install from source. For details, check out:

• cabal haddock fails on cabal-1.20 tree
• Emergency workaround for GHC 7.8.1 on OSX
• Haddock fails with "Module defined in multiple files"

The workaround could be as simple as adding --no-doc to the cabal-install.rb line system "sh", "bootstrap.sh". Or perhaps when GHC 7.8 gets moved out of --devel, we can simultaneously change the cabal-install formula to use a wrapper script that injects --ghc-options=-optP-P.

[adamv]

Given issues with 7.8.x at large, is it OK to merge this as a devel version now, or is there more work to do first?

[MikeMcQuaid]

@adamv 👍