Fix package shadowing order (#4072)

[ghc-hetmet.git] / compiler / main / Packages.lhs

diff --git a/compiler/main/Packages.lhs b/compiler/main/Packages.lhs
index 4b14462..06cd573 100644 (file)
--- a/compiler/main/Packages.lhs
+++ b/compiler/main/Packages.lhs
@@ -60,6 +60,7 @@ import System.Directory
 import System.FilePath
 import Control.Monad
 import Data.List as List
+import qualified Data.Set as Set
 
 -- ---------------------------------------------------------------------------
 -- The Package state
@@ -193,7 +194,7 @@ readPackageConfigs dflags = do
                     -- the we tack on the system paths.
 
    pkgs <- mapM (readPackageConfig dflags)
-                (reverse pkgconfs ++ reverse (extraPkgConfs dflags))
+                (pkgconfs ++ reverse (extraPkgConfs dflags))
                 -- later packages shadow earlier ones.  extraPkgConfs
                 -- is in the opposite order to the flags on the
                 -- command line.
@@ -219,7 +220,7 @@ getSystemPackageConfigs dflags = do
       if exist then return [pkgconf] else return []
     `catchIO` (\_ -> return [])
 
-   return (user_pkgconf ++ [system_pkgconf])
+   return (system_pkgconf : user_pkgconf)
 
 readPackageConfig :: DynFlags -> FilePath -> IO [PackageConfig]
 readPackageConfig dflags conf_file = do
@@ -557,11 +558,12 @@ shadowPackages pkgs preferred
  where
  check (shadowed,pkgmap) pkg
       | Just oldpkg <- lookupUFM pkgmap (packageConfigId pkg)
-      = let
-          ipid_new = installedPackageId pkg
-          ipid_old = installedPackageId oldpkg
-        in
-        if ipid_old `elem` preferred
+      , let
+            ipid_new = installedPackageId pkg
+            ipid_old = installedPackageId oldpkg
+        --
+      , ipid_old /= ipid_new
+      = if ipid_old `elem` preferred
            then ( (ipid_new, ShadowedBy ipid_old) : shadowed, pkgmap )
            else ( (ipid_old, ShadowedBy ipid_new) : shadowed, pkgmap' )
       | otherwise
@@ -655,6 +657,22 @@ mkPackageState dflags pkgs0 preload0 this_package = do
   let
       flags = reverse (packageFlags dflags)
 
+      -- pkgs0 with duplicate packages filtered out.  This is
+      -- important: it is possible for a package in the global package
+      -- DB to have the same IPID as a package in the user DB, and
+      -- we want the latter to take precedence.  This is not the same
+      -- as shadowing (below), since in this case the two packages
+      -- have the same ABI and are interchangeable.
+      --
+      -- #4072: note that we must retain the ordering of the list here
+      -- so that shadowing behaves as expected when we apply it later.
+      pkgs0_unique = snd $ foldr del (Set.empty,[]) pkgs0
+          where del p (s,ps)
+                  | pid `Set.member` s = (s,ps)
+                  | otherwise          = (Set.insert pid s, p:ps)
+                  where pid = installedPackageId p
+          -- XXX this is just a variant of nub
+
       ipid_map = listToFM [ (installedPackageId p, p) | p <- pkgs0 ]
 
       ipid_selected = depClosure ipid_map [ InstalledPackageId i
@@ -664,11 +682,11 @@ mkPackageState dflags pkgs0 preload0 this_package = do
       is_ignore IgnorePackage{} = True
       is_ignore _ = False
 
-      shadowed = shadowPackages pkgs0 ipid_selected
+      shadowed = shadowPackages pkgs0_unique ipid_selected
 
-      ignored  = ignorePackages ignore_flags pkgs0
+      ignored  = ignorePackages ignore_flags pkgs0_unique
 
-      pkgs0' = filter (not . (`elemFM` (plusFM shadowed ignored)) . installedPackageId) pkgs0
+      pkgs0' = filter (not . (`elemFM` (plusFM shadowed ignored)) . installedPackageId) pkgs0_unique
       broken   = findBroken pkgs0'
       unusable = shadowed `plusFM` ignored `plusFM` broken
 
@@ -678,7 +696,7 @@ mkPackageState dflags pkgs0 preload0 this_package = do
   -- Modify the package database according to the command-line flags
   -- (-package, -hide-package, -ignore-package, -hide-all-packages).
   --
-  pkgs1 <- foldM (applyPackageFlag unusable) pkgs0 other_flags
+  pkgs1 <- foldM (applyPackageFlag unusable) pkgs0_unique other_flags
   let pkgs2 = filter (not . (`elemFM` unusable) . installedPackageId) pkgs1
 
   -- Here we build up a set of the packages mentioned in -package
@@ -807,9 +825,9 @@ packageHsLibs dflags p = map (mkDynName . addSuffix) (hsLibraries p)
         -- the name of a shared library is libHSfoo-ghc<version>.so
         -- we leave out the _dyn, because it is superfluous
 
-        -- debug RTS includes support for -ticky and -eventlog
+        -- debug RTS includes support for -eventlog
         ways2 | WayDebug `elem` map wayName ways1 
-              = filter ((`notElem` [WayTicky,WayEventLog]) . wayName) ways1
+              = filter ((/= WayEventLog) . wayName) ways1
               | otherwise
               = ways1