From ef84d1201ab8f8ead17ef7dd2d7ee33b3ed1ad27 Mon Sep 17 00:00:00 2001
From: Michael Snoyman <michael@snoyman.com>
Date: Fri, 4 Apr 2014 08:21:17 +0300
Subject: [PATCH] Output build.log on error

---
 Stackage/Build.hs | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/Stackage/Build.hs b/Stackage/Build.hs
index 35944615..d8f26e31 100644
--- a/Stackage/Build.hs
+++ b/Stackage/Build.hs
@@ -19,6 +19,7 @@ import           System.IO                  (BufferMode (NoBuffering),
 import qualified System.IO.UTF8
 import           System.Process             (rawSystem, runProcess,
                                              waitForProcess)
+import qualified Data.ByteString.Lazy.Char8 as L8
 
 defaultBuildSettings :: Maybe Int -- ^ argument to -j
                      -> GhcMajorVersion
@@ -105,6 +106,7 @@ build settings' bp = do
     ec <- waitForProcess ph
     unless (ec == ExitSuccess) $ do
         putStrLn "Build failed, please see build.log"
+        L8.readFile "build.log" >>= L8.putStr
         exitWith ec
 
     putStrLn "Build completed successfully, checking for module name conflicts"