[commit: ghc] wip/nfs-locking: Lookup builder in PATH if they are given without path. (4478851)

[git at git.haskell.org]

Repository : ssh://git@git.haskell.org/ghc

On branch  : wip/nfs-locking
Link       : http://ghc.haskell.org/trac/ghc/changeset/44788518cb14c59788fdf320b9ca2d11e11509ca/ghc

>---------------------------------------------------------------

commit 44788518cb14c59788fdf320b9ca2d11e11509ca
Author: Moritz Angermann <moritz.angermann at gmail.com>
Date:   Wed Jan 6 23:22:43 2016 +0800

    Lookup builder in PATH if they are given without path.
    
    `system-gcc` may be given without path (e.g. `clang`), this patch adds lookup using `which`
    for those commands. Also drops calling `fixAbsolutePathOnWindows` on non window hosts.
    Fixes #26


>---------------------------------------------------------------

44788518cb14c59788fdf320b9ca2d11e11509ca
 src/Builder.hs             |  4 +++-
 src/Oracles/WindowsRoot.hs | 11 ++++++++++-
 2 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/src/Builder.hs b/src/Builder.hs
index 5ed9e1d..6e4dba5 100644
--- a/src/Builder.hs
+++ b/src/Builder.hs
@@ -94,7 +94,9 @@ builderPath builder = do
     path <- askConfigWithDefault (builderKey builder) $
             putError $ "\nCannot find path to '" ++ (builderKey builder)
                      ++ "' in configuration files."
-    fixAbsolutePathOnWindows $ if null path then "" else path -<.> exe
+    windows <- windowsHost
+    let path' = if null path then "" else path -<.> exe in
+        (if windows then fixAbsolutePathOnWindows else lookupInPath) path'
 
 getBuilderPath :: Builder -> ReaderT a Action FilePath
 getBuilderPath = lift . builderPath
diff --git a/src/Oracles/WindowsRoot.hs b/src/Oracles/WindowsRoot.hs
index 413f289..195f591 100644
--- a/src/Oracles/WindowsRoot.hs
+++ b/src/Oracles/WindowsRoot.hs
@@ -1,6 +1,6 @@
 {-# LANGUAGE DeriveDataTypeable, GeneralizedNewtypeDeriving #-}
 module Oracles.WindowsRoot (
-    windowsRoot, fixAbsolutePathOnWindows, topDirectory, windowsRootOracle
+    windowsRoot, fixAbsolutePathOnWindows, lookupInPath, topDirectory, windowsRootOracle
     ) where
 
 import Data.Char (isSpace)
@@ -38,6 +38,15 @@ fixAbsolutePathOnWindows path = do
     else
         return path
 
+-- | Lookup a @command@ in @PATH@ environment.
+lookupInPath :: FilePath -> Action FilePath
+lookupInPath command
+    | command /= takeFileName command = return command
+    | otherwise = do
+        Stdout out <- quietly $ cmd ["which", command]
+        let path = dropWhileEnd isSpace out
+        return path
+
 -- Oracle for windowsRoot. This operation requires caching as looking up
 -- the root is slow (at least the current implementation).
 windowsRootOracle :: Rules ()