[commit: ghc] wip/nfs-locking: Report an error if an executable is not found, unify paths. (05e7242)

[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/05e7242655e0b8d5657c487e2ed2f392dd520429/ghc

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

commit 05e7242655e0b8d5657c487e2ed2f392dd520429
Author: Andrey Mokhov <andrey.mokhov at gmail.com>
Date:   Wed Feb 10 11:27:03 2016 +0000

    Report an error if an executable is not found, unify paths.


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

05e7242655e0b8d5657c487e2ed2f392dd520429
 src/Oracles/LookupInPath.hs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/src/Oracles/LookupInPath.hs b/src/Oracles/LookupInPath.hs
index 6bf2bba..2f6e713 100644
--- a/src/Oracles/LookupInPath.hs
+++ b/src/Oracles/LookupInPath.hs
@@ -18,8 +18,10 @@ lookupInPathOracle :: Rules ()
 lookupInPathOracle = do
     answer <- newCache $ \query -> do
         maybePath <- liftIO $ findExecutable query
-        let path = fromMaybe query maybePath
-        putOracle $ "Lookup executable '" ++ query ++ "': " ++ path
+        path <- case maybePath of
+            Just value -> return $ unifyPath value
+            Nothing    -> putError $ "Cannot find executable '" ++ query ++ "'."
+        putOracle $ "Executable found: " ++ query ++ " => " ++ path
         return path
     _ <- addOracle $ \(LookupInPath query) -> answer query
     return ()