loadFramework: Output the errors collected in all loading attempts.

With the recent change away from first finding and then loading a
framework, loadFramework had no way of communicating the real reason
why loadDLL failed if it was any reason other than the framework
missing from the file system.  It now collects all loading attempt
errors into a list and concatenates them into a string to return to
the caller.

1 files changed, 8 insertions, 6 deletions

diff --git a/compiler/GHC/Runtime/Linker.hs b/compiler/GHC/Runtime/Linker.hs
index ccbb1791e9..5b7b79c999 100644
--- a/compiler/GHC/Runtime/Linker.hs
+++ b/compiler/GHC/Runtime/Linker.hs
@@ -1705,22 +1705,24 @@ loadFramework hsc_env extraPaths rootname
                                   Left _ -> []
                                   Right dir -> [dir </> "Library/Frameworks"]
               ps = extraPaths ++ homeFrameworkPath ++ defaultFrameworkPaths
-        ; findLoadDLL ps }
+        ; errs <- findLoadDLL ps []
+        ; return $ fmap (intercalate ", ") errs
+        }
    where
      fwk_file = rootname <.> "framework" </> rootname
 
      -- sorry for the hardcoded paths, I hope they won't change anytime soon:
      defaultFrameworkPaths = ["/Library/Frameworks", "/System/Library/Frameworks"]
 
-     findLoadDLL [] =
+     findLoadDLL [] errs =
        -- Tried all our known library paths, but dlopen()
        -- has no built-in paths for frameworks: give up
-       return (Just "not found")
-     findLoadDLL (p:ps) =
+       return $ Just errs
+     findLoadDLL (p:ps) errs =
        do { dll <- loadDLL hsc_env (p </> fwk_file)
           ; case dll of
-              Nothing -> return Nothing
-              Just _  -> findLoadDLL ps
+              Nothing  -> return Nothing
+              Just err -> findLoadDLL ps ((p ++ ": " ++ err):errs)
           }
 
 {- **********************************************************************