Refactor UnitId to be an abstract newtype around String.

The primary consequence is that we can't assume that we
have a ComponentId when we have a UnitId in hand.  Most
of the time, this just means we have to pass around
ComponentId explicitly.  No problem.
Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Cabal/Distribution/Backpack.hs

@@ -13,7 +13,6 @@
 module Distribution.Backpack (
     -- * OpenUnitId
     OpenUnitId(..),
-    openUnitIdComponentId,
     openUnitIdFreeHoles,
     mkOpenUnitId,
 
@@ -117,11 +116,6 @@ instance Text OpenUnitId where
                        parseOpenModuleSubst
             return (IndefFullUnitId cid insts)
 
--- | Get the 'ComponentId' of an 'OpenUnitId'.
-openUnitIdComponentId :: OpenUnitId -> ComponentId
-openUnitIdComponentId (IndefFullUnitId cid _) = cid
-openUnitIdComponentId (DefiniteUnitId def_uid) = unitIdComponentId (unDefUnitId def_uid)
-
 -- | Get the set of holes ('ModuleVar') embedded in a 'UnitId'.
 openUnitIdFreeHoles :: OpenUnitId -> Set ModuleName
 openUnitIdFreeHoles (IndefFullUnitId _ insts) = openModuleSubstFreeHoles insts
@@ -129,11 +123,11 @@ openUnitIdFreeHoles _ = Set.empty
 
 -- | Safe constructor from a UnitId.  The only way to do this safely
 -- is if the instantiation is provided.
-mkOpenUnitId :: UnitId -> OpenModuleSubst -> OpenUnitId
-mkOpenUnitId uid insts =
+mkOpenUnitId :: UnitId -> ComponentId -> OpenModuleSubst -> OpenUnitId
+mkOpenUnitId uid cid insts =
     if Set.null (openModuleSubstFreeHoles insts)
         then DefiniteUnitId (unsafeMkDefUnitId uid) -- invariant holds!
-        else IndefFullUnitId (unitIdComponentId uid) insts
+        else IndefFullUnitId cid insts
 
 -----------------------------------------------------------------------
 -- DefUnitId
@@ -142,7 +136,9 @@ mkOpenUnitId uid insts =
 -- with no holes.
 mkDefUnitId :: ComponentId -> Map ModuleName Module -> DefUnitId
 mkDefUnitId cid insts =
-    unsafeMkDefUnitId (UnitId cid (hashModuleSubst insts)) -- impose invariant!
+    unsafeMkDefUnitId (mkUnitId
+        (unComponentId cid ++ maybe "" ("+"++) (hashModuleSubst insts)))
+        -- impose invariant!
 
 -----------------------------------------------------------------------
 -- OpenModule

Cabal/Distribution/Backpack/Configure.hs

@@ -107,14 +107,12 @@ configureComponentLocalBuildInfos
              (vcat (map dispLinkedComponent graph2))
 
     let pid_map = Map.fromList $
-            [ (pc_cid pkg, pc_pkgid pkg)
+            [ (pc_uid pkg, pc_pkgid pkg)
             | pkg <- prePkgDeps] ++
-            [ (Installed.installedComponentId pkg, Installed.sourcePackageId pkg)
+            [ (Installed.installedUnitId pkg, Installed.sourcePackageId pkg)
             | (_, Module uid _) <- instantiate_with
             , Just pkg <- [PackageIndex.lookupUnitId
-                                installedPackageSet (unDefUnitId uid)] ] ++
-            [ (lc_cid lc, lc_pkgid lc)
-            | lc <- graph2 ]
+                                installedPackageSet (unDefUnitId uid)] ]
         subst = Map.fromList instantiate_with
         graph3 = toReadyComponents pid_map subst graph2
         graph4 = Graph.revTopSort (Graph.fromList graph3)
@@ -251,10 +249,7 @@ mkLinkedComponentsLocalBuildInfo comp rcs = map go rcs
               = Installed.ExposedModule modname'
                   (Just (OpenModule (DefiniteUnitId uid) modname))
             convOpenModuleExport (modname', modu@(OpenModule uid modname))
-              -- TODO: This isn't a good enough test if we have mutual
-              -- recursion (but maybe we'll get saved by the module name
-              -- check regardless.)
-              | openUnitIdComponentId uid == this_cid
+              | uid == this_open_uid
               , modname' == modname
               = Installed.ExposedModule modname' Nothing
               | otherwise
@@ -276,6 +271,7 @@ mkLinkedComponentsLocalBuildInfo comp rcs = map go rcs
         in LibComponentLocalBuildInfo {
           componentPackageDeps = cpds,
           componentUnitId = this_uid,
+          componentComponentId = this_cid,
           componentInstantiatedWith = insts,
           componentIsIndefinite_ = is_indefinite,
           componentLocalName = cname,
@@ -290,6 +286,7 @@ mkLinkedComponentsLocalBuildInfo comp rcs = map go rcs
       CExe _ ->
         ExeComponentLocalBuildInfo {
           componentUnitId = this_uid,
+          componentComponentId = this_cid,
           componentLocalName = cname,
           componentPackageDeps = cpds,
           componentExeDeps = map unDefUnitId $ rc_internal_build_tools rc,
@@ -299,6 +296,7 @@ mkLinkedComponentsLocalBuildInfo comp rcs = map go rcs
       CTest _ ->
         TestComponentLocalBuildInfo {
           componentUnitId = this_uid,
+          componentComponentId = this_cid,
           componentLocalName = cname,
           componentPackageDeps = cpds,
           componentExeDeps = map unDefUnitId $ rc_internal_build_tools rc,
@@ -308,6 +306,7 @@ mkLinkedComponentsLocalBuildInfo comp rcs = map go rcs
       CBench _ ->
         BenchComponentLocalBuildInfo {
           componentUnitId = this_uid,
+          componentComponentId = this_cid,
           componentLocalName = cname,
           componentPackageDeps = cpds,
           componentExeDeps = map unDefUnitId $ rc_internal_build_tools rc,
@@ -315,8 +314,9 @@ mkLinkedComponentsLocalBuildInfo comp rcs = map go rcs
           componentIncludes = includes
         }
      where
-      this_uid = rc_uid rc
-      this_cid = unitIdComponentId this_uid
+      this_uid      = rc_uid rc
+      this_open_uid = rc_open_uid rc
+      this_cid      = rc_cid rc
       cname = componentName (rc_component rc)
       cpds = rc_depends rc
       is_indefinite =

Cabal/Distribution/Backpack/Id.hs

@@ -94,23 +94,16 @@ computeComponentId mb_ipid mb_cid pid cname mb_details =
 -- When we have the public library, the compat-pkg-name is just the
 -- package-name, no surprises there!
 --
-computeCompatPackageName :: PackageName -> ComponentName -> Maybe UnitId -> PackageName
+computeCompatPackageName :: PackageName -> ComponentName -> PackageName
 -- First handle the cases where we can just use the original 'PackageName'.
 -- This is for the PRIMARY library, and it is non-Backpack, or the
 -- indefinite package for us.
-computeCompatPackageName pkg_name CLibName Nothing = pkg_name
-computeCompatPackageName pkg_name CLibName (Just (UnitId _ Nothing))
-    = pkg_name
--- OK, we have to z-encode
-computeCompatPackageName pkg_name cname mb_uid
+computeCompatPackageName pkg_name CLibName = pkg_name
+computeCompatPackageName pkg_name cname
     = mkPackageName $ "z-" ++ zdashcode (display pkg_name)
                  ++ (case componentNameString cname of
                         Just cname_str -> "-z-" ++ zdashcode cname_str
                         Nothing -> "")
-                 ++ (case mb_uid of
-                        Just (UnitId _ (Just hash))
-                            -> "-z-" ++ hash
-                        _ -> "")
 
 zdashcode :: String -> String
 zdashcode s = go s (Nothing :: Maybe Int) []
@@ -173,11 +166,11 @@ computeCompatPackageKey
     -> Version
     -> UnitId
     -> String
-computeCompatPackageKey comp pkg_name pkg_version (UnitId cid Nothing)
+computeCompatPackageKey comp pkg_name pkg_version uid
     | not (packageKeySupported comp) =
         display pkg_name ++ "-" ++ display pkg_version
     | not (unifiedIPIDRequired comp) =
-        let str = unComponentId cid
+        let str = unUnitId uid -- assume no Backpack support
             mb_verbatim_key
                 = case simpleParse str :: Maybe PackageId of
                     -- Something like 'foo-0.1', use it verbatim.
@@ -192,6 +185,4 @@ computeCompatPackageKey comp pkg_name pkg_version (UnitId cid Nothing)
                         else Nothing
             rehashed_key = hashToBase62 str
         in fromMaybe rehashed_key (mb_verbatim_key `mplus` mb_truncated_key)
-    | otherwise = unComponentId cid
-computeCompatPackageKey _comp _pkg_name _pkg_version uid@UnitId{}
-    = display uid
+    | otherwise = display uid

Cabal/Distribution/Backpack/LinkedComponent.hs

@@ -3,7 +3,6 @@
 -- | See <https://github.com/ezyang/ghc-proposals/blob/backpack/proposals/0000-backpack.rst>
 module Distribution.Backpack.LinkedComponent (
     LinkedComponent(..),
-    lc_cid,
     toLinkedComponent,
     toLinkedComponents,
     dispLinkedComponent,
@@ -47,6 +46,7 @@ import Text.PrettyPrint
 data LinkedComponent
     = LinkedComponent {
         lc_uid :: OpenUnitId,
+        lc_cid :: ComponentId,
         lc_pkgid :: PackageId,
         lc_insts :: [(ModuleName, OpenModule)],
         lc_component :: Component,
@@ -60,9 +60,6 @@ data LinkedComponent
         lc_depends :: [(OpenUnitId, PackageId)]
       }
 
-lc_cid :: LinkedComponent -> ComponentId
-lc_cid = openUnitIdComponentId . lc_uid
-
 dispLinkedComponent :: LinkedComponent -> Doc
 dispLinkedComponent lc =
     hang (text "unit" <+> disp (lc_uid lc)) 4 $
@@ -238,6 +235,7 @@ toLinkedComponent verbosity db this_pid pkg_map ConfiguredComponent {
 
     return $ LinkedComponent {
                 lc_uid = this_uid,
+                lc_cid = this_cid,
                 lc_insts = insts,
                 lc_pkgid = pkgid,
                 lc_component = component,

Cabal/Distribution/Backpack/PreExistingComponent.hs

 -- | See <https://github.com/ezyang/ghc-proposals/blob/backpack/proposals/0000-backpack.rst>
 module Distribution.Backpack.PreExistingComponent (
     PreExistingComponent(..),
-    pc_cid,
     ipiToPreExistingComponent,
 ) where
 
@@ -27,14 +26,11 @@ data PreExistingComponent
         pc_pkgname :: PackageName,
         pc_pkgid :: PackageId,
         pc_uid   :: UnitId,
+        pc_cid   :: ComponentId,
         pc_open_uid :: OpenUnitId,
         pc_shape :: ModuleShape
     }
 
--- | The 'ComponentId' of a 'PreExistingComponent'.
-pc_cid :: PreExistingComponent -> ComponentId
-pc_cid pc = unitIdComponentId (pc_uid pc)
-
 -- | Convert an 'InstalledPackageInfo' into a 'PreExistingComponent',
 -- which was brought into scope under the 'PackageName' (important for
 -- a package qualified reference.)
@@ -44,6 +40,7 @@ ipiToPreExistingComponent (pn, ipi) =
         pc_pkgname = pn,
         pc_pkgid = Installed.sourcePackageId ipi,
         pc_uid   = Installed.installedUnitId ipi,
+        pc_cid   = Installed.installedComponentId ipi,
         pc_open_uid =
             IndefFullUnitId (Installed.installedComponentId ipi)
                             (Map.fromList (Installed.instantiatedWith ipi)),

Cabal/Distribution/Backpack/ReadyComponent.hs

@@ -35,6 +35,7 @@ import Control.Monad
 import Text.PrettyPrint
 import qualified Data.Map as Map
 
+import Distribution.Version
 import Distribution.Text
 
 -- | An instantiated component is simply a linked component which
@@ -62,6 +63,8 @@ data IndefiniteComponent
 data ReadyComponent
     = ReadyComponent {
         rc_uid          :: UnitId,
+        rc_open_uid     :: OpenUnitId,
+        rc_cid          :: ComponentId,
         rc_pkgid        :: PackageId,
         rc_component    :: Component,
         -- build-tools don't participate in mix-in linking.
@@ -85,18 +88,19 @@ instance IsNode ReadyComponent where
     nodeKey = rc_uid
     nodeNeighbors rc =
       (case rc_i rc of
-        Right _ | UnitId cid (Just _)
-                    <- rc_uid rc -> [newSimpleUnitId cid]
+        Right inst | [] <- instc_insts inst
+                   -> []
+                   | otherwise
+                   -> [newSimpleUnitId (rc_cid rc)]
         _ -> []) ++
       ordNub (map fst (rc_depends rc))
 
 rc_compat_name :: ReadyComponent -> PackageName
 rc_compat_name ReadyComponent{
         rc_pkgid = PackageIdentifier pkg_name _,
-        rc_component = component,
-        rc_uid = uid
+        rc_component = component
     }
-    = computeCompatPackageName pkg_name (componentName component) (Just uid)
+    = computeCompatPackageName pkg_name (componentName component)
 
 rc_compat_key :: ReadyComponent -> Compiler -> String
 rc_compat_key rc@ReadyComponent {
@@ -158,7 +162,7 @@ instance Monad InstM where
 -- instantiated components are given 'HashedUnitId'.
 --
 toReadyComponents
-    :: Map ComponentId PackageId
+    :: Map UnitId PackageId
     -> Map ModuleName Module -- subst for the public component
     -> [LinkedComponent]
     -> [ReadyComponent]
@@ -198,12 +202,19 @@ toReadyComponents pid_map subst0 comps
                 x' <- substUnitId insts x
                 return (x', y)
             build_tools <- mapM (substUnitId insts) (lc_internal_build_tools lc)
+            s <- InstM $ \s -> (s, s)
             let getDep (Module dep_def_uid _)
                     | let dep_uid = unDefUnitId dep_def_uid
-                    , Just pid <- Map.lookup (unitIdComponentId dep_uid) pid_map
                     -- Lose DefUnitId invariant for rc_depends
-                    = [(dep_uid, pid)]
-                getDep _ = []
+                    = [(dep_uid,
+                          fromMaybe err_pid $
+                            Map.lookup dep_uid pid_map A.<|>
+                            fmap rc_pkgid (join (Map.lookup dep_uid s)))]
+                  where
+                    err_pid =
+                      PackageIdentifier
+                        (mkPackageName "nonexistent-package-this-is-a-cabal-bug")
+                        (mkVersion [0])
                 instc = InstantiatedComponent {
                             instc_insts = Map.toList insts,
                             instc_provides = provides,
@@ -211,6 +222,8 @@ toReadyComponents pid_map subst0 comps
                         }
             return $ Just ReadyComponent {
                     rc_uid          = uid,
+                    rc_open_uid     = DefiniteUnitId (unsafeMkDefUnitId uid),
+                    rc_cid          = lc_cid lc,
                     rc_pkgid        = lc_pkgid lc,
                     rc_component    = lc_component lc,
                     rc_internal_build_tools = build_tools,
@@ -263,7 +276,9 @@ toReadyComponents pid_map subst0 comps
                         indefc_includes = lc_includes lc
                     }
             return $ Just ReadyComponent {
-                    rc_uid = uid,
+                    rc_uid          = uid,
+                    rc_open_uid     = lc_uid lc,
+                    rc_cid = lc_cid lc,
                     rc_pkgid        = lc_pkgid lc,
                     rc_component    = lc_component lc,
                     rc_internal_build_tools = build_tools,

Cabal/Distribution/InstalledPackageInfo.hs

@@ -29,8 +29,8 @@
 
 module Distribution.InstalledPackageInfo (
         InstalledPackageInfo(..),
-        installedComponentId,
         installedPackageId,
+        installedComponentId,
         requiredSignatures,
         installedOpenUnitId,
         ExposedModule(..),
@@ -72,6 +72,7 @@ data InstalledPackageInfo
         -- these parts are exactly the same as PackageDescription
         sourcePackageId   :: PackageId,
         installedUnitId   :: UnitId,
+        installedComponentId_ :: ComponentId,
         -- INVARIANT: if this package is definite, OpenModule's
         -- OpenUnitId directly records UnitId.  If it is
         -- indefinite, OpenModule is always an OpenModuleVar
@@ -118,6 +119,12 @@ data InstalledPackageInfo
     }
     deriving (Eq, Generic, Read, Show)
 
+installedComponentId :: InstalledPackageInfo -> ComponentId
+installedComponentId ipi =
+    case unComponentId (installedComponentId_ ipi) of
+        "" -> mkComponentId (unUnitId (installedUnitId ipi))
+        _  -> installedComponentId_ ipi
+
 -- | Get the indefinite unit identity representing this package.
 -- This IS NOT guaranteed to give you a substitution; for
 -- instantiated packages you will get @DefiniteUnitId (installedUnitId ipi)@.
@@ -125,16 +132,13 @@ data InstalledPackageInfo
 -- an @OpenUnitId@ with the appropriate 'OpenModuleSubst'.
 installedOpenUnitId :: InstalledPackageInfo -> OpenUnitId
 installedOpenUnitId ipi
-    = mkOpenUnitId (installedUnitId ipi) (Map.fromList (instantiatedWith ipi))
+    = mkOpenUnitId (installedUnitId ipi) (installedComponentId ipi) (Map.fromList (instantiatedWith ipi))
 
 -- | Returns the set of module names which need to be filled for
 -- an indefinite package, or the empty set if the package is definite.
 requiredSignatures :: InstalledPackageInfo -> Set ModuleName
 requiredSignatures ipi = openModuleSubstFreeHoles (Map.fromList (instantiatedWith ipi))
 
-installedComponentId :: InstalledPackageInfo -> ComponentId
-installedComponentId ipi = unitIdComponentId (installedUnitId ipi)
-
 {-# DEPRECATED installedPackageId "Use installedUnitId instead" #-}
 -- | Backwards compatibility with Cabal pre-1.24.
 -- This type synonym is slightly awful because in cabal-install
@@ -164,6 +168,7 @@ emptyInstalledPackageInfo
    = InstalledPackageInfo {
         sourcePackageId   = PackageIdentifier (mkPackageName "") nullVersion,
         installedUnitId   = mkUnitId "",
+        installedComponentId_ = mkComponentId "",
         instantiatedWith  = [],
         compatPackageKey  = "",
         license           = UnspecifiedLicense,

Cabal/Distribution/Package.hs

@@ -24,11 +24,10 @@ module Distribution.Package (
 
         -- * Package keys/installed package IDs (used for linker symbols)
         ComponentId, unComponentId, mkComponentId,
-        UnitId(..),
+        UnitId, unUnitId, mkUnitId,
         DefUnitId,
         unsafeMkDefUnitId,
         unDefUnitId,
-        mkUnitId,
         newSimpleUnitId,
         mkLegacyUnitId,
         getHSLibraryName,
@@ -248,28 +247,20 @@ getHSLibraryName uid = "HS" ++ display uid
 -- "Distribution.Backpack.FullUnitId" for a mechanism for expanding an
 -- instantiated 'UnitId' to retrieve its mapping.
 --
-data UnitId
-    = UnitId {
-        unitIdComponentId :: ComponentId,
-        unitIdHash        :: Maybe String
-    }
-  deriving (Generic, Read, Show, Eq, Ord, Typeable, Data)
+newtype UnitId = UnitId String
+  deriving (Generic, Read, Show, Eq, Ord, Typeable, Data, NFData)
 
 instance Binary UnitId
 
-instance NFData UnitId where
-    rnf (UnitId cid str) = rnf cid `seq` rnf str
-
 instance Text UnitId where
-    disp (UnitId cid Nothing)     = disp cid
-    disp (UnitId cid (Just hash)) = disp cid <<>> text "+" <<>> text hash
-    parse = parseUnitId <++ parseSimpleUnitId
-      where
-        parseUnitId = do cid <- parse
-                         _ <- Parse.char '+'
-                         hash <- Parse.munch1 isAlphaNum
-                         return (UnitId cid (Just hash))
-        parseSimpleUnitId = fmap newSimpleUnitId parse
+    disp (UnitId str)     = text str
+    parse = UnitId `fmap` Parse.munch1 (\c -> isAlphaNum c || c `elem` "-_.+")
+
+unUnitId :: UnitId -> String
+unUnitId (UnitId str) = str
+
+mkUnitId :: String -> UnitId
+mkUnitId str = UnitId str
 
 -- | A 'UnitId' for a definite package.  The 'DefUnitId' invariant says
 -- that a 'UnitId' identified this way is definite; i.e., it has no
@@ -285,15 +276,7 @@ unsafeMkDefUnitId = DefUnitId
 -- | Create a unit identity with no associated hash directly
 -- from a 'ComponentId'.
 newSimpleUnitId :: ComponentId -> UnitId
-newSimpleUnitId cid =
-    UnitId {
-        unitIdComponentId = cid,
-        unitIdHash = Nothing
-    }
-
--- | Makes a simple-style UnitId from a string.
-mkUnitId :: String -> UnitId
-mkUnitId = newSimpleUnitId . mkComponentId
+newSimpleUnitId cid = UnitId (unComponentId cid)
 
 -- | Make an old-style UnitId from a package identifier
 mkLegacyUnitId :: PackageId -> UnitId

Cabal/Distribution/Simple/Build.hs

@@ -424,7 +424,7 @@ testSuiteLibV09AsLibAndExe pkg_descr
     -- This is, like, the one place where we use a CTestName for a library.
     -- Should NOT use library name, since that could conflict!
     PackageIdentifier pkg_name pkg_ver = package pkg_descr
-    compat_name = computeCompatPackageName pkg_name (CTestName (testName test)) (Just (componentUnitId clbi))
+    compat_name = computeCompatPackageName pkg_name (CTestName (testName test))
     compat_key = computeCompatPackageKey (compiler lbi) compat_name pkg_ver (componentUnitId clbi)
     libClbi = LibComponentLocalBuildInfo
                 { componentPackageDeps = componentPackageDeps clbi
@@ -435,6 +435,7 @@ testSuiteLibV09AsLibAndExe pkg_descr
                 , componentIsPublic = False
                 , componentIncludes = componentIncludes clbi
                 , componentUnitId = componentUnitId clbi
+                , componentComponentId = componentComponentId clbi
                 , componentInstantiatedWith = []
                 , componentCompatPackageName = compat_name
                 , componentCompatPackageKey = compat_key
@@ -470,6 +471,7 @@ testSuiteLibV09AsLibAndExe pkg_descr
                 -- TODO: this is a hack, but as long as this is unique
                 -- (doesn't clobber something) we won't run into trouble
                 componentUnitId = mkUnitId (stubName test),
+                componentComponentId = mkComponentId (stubName test),
                 componentInternalDeps = [componentUnitId clbi],
                 componentExeDeps = [],
                 componentLocalName = CExeName (stubName test),
@@ -497,6 +499,7 @@ benchmarkExeV10asExe bm@Benchmark { benchmarkInterface = BenchmarkExeV10 _ f }
           }
     exeClbi = ExeComponentLocalBuildInfo {
                 componentUnitId = componentUnitId clbi,
+                componentComponentId = componentComponentId clbi,
                 componentLocalName = CExeName (benchmarkName bm),
                 componentInternalDeps = componentInternalDeps clbi,
                 componentExeDeps = componentExeDeps clbi,

Cabal/Distribution/Simple/Configure.hs

@@ -1182,15 +1182,14 @@ selectDependency pkgid internalIndex installedIndex requiredDepsMap
         []   -> Left  $
                   case is_internal of
                     Just cname -> DependencyMissingInternal dep_pkgname
-                                    (computeCompatPackageName
-                                     (packageName pkgid) cname Nothing)
+                                    (computeCompatPackageName (packageName pkgid) cname)
                     Nothing -> DependencyNotExists dep_pkgname
         pkgs -> Right $ ExternalDependency dep $
                 case last pkgs of
                   (_ver, pkginstances) -> head pkginstances
      where
       dep' | Just cname <- is_internal
-           = Dependency (computeCompatPackageName (packageName pkgid) cname Nothing) vr
+           = Dependency (computeCompatPackageName (packageName pkgid) cname) vr
            | otherwise = dep
     -- NB: here computeCompatPackageName we want to pick up the INDEFINITE ones
     -- which is why we pass 'Nothing' as 'UnitId'

Cabal/Distribution/Simple/GHC.hs

@@ -737,11 +737,10 @@ buildOrReplLib forRepl verbosity numJobs pkg_descr lbi lib clbi = do
                       -> toFlag pk
                     _ -> mempty,
                 ghcOptThisComponentId = case clbi of
-                    LibComponentLocalBuildInfo { componentUnitId = lib_uid
-                                               , componentInstantiatedWith = insts } ->
+                    LibComponentLocalBuildInfo { componentInstantiatedWith = insts } ->
                         if null insts
                             then mempty
-                            else toFlag (unitIdComponentId lib_uid)
+                            else toFlag (componentComponentId clbi)
                     _ -> mempty,
                 ghcOptInstantiatedWith = case clbi of
                     LibComponentLocalBuildInfo { componentInstantiatedWith = insts }

Cabal/Distribution/Simple/GHC/IPI642.hs

@@ -19,6 +19,7 @@ import Distribution.Compat.Prelude
 import qualified Distribution.InstalledPackageInfo as Current
 import qualified Distribution.Package as Current hiding (installedUnitId)
 import Distribution.Simple.GHC.IPIConvert
+import Distribution.Text
 
 -- | This is the InstalledPackageInfo type used by ghc-6.4.2 and later.
 --
@@ -69,6 +70,7 @@ toCurrent ipi@InstalledPackageInfo{} =
   in Current.InstalledPackageInfo {
     Current.sourcePackageId    = pid,
     Current.installedUnitId    = Current.mkLegacyUnitId pid,
+    Current.installedComponentId_ = Current.mkComponentId (display pid),
     Current.instantiatedWith   = [],
     Current.compatPackageKey   = "",
     Current.abiHash            = Current.mkAbiHash "", -- bogus but old GHCs don't care.

Cabal/Distribution/Simple/GHC/Internal.hs

@@ -290,11 +290,11 @@ componentGhcOptions verbosity lbi bi clbi odir =
           -> toFlag pk
         _ -> mempty,
       ghcOptThisComponentId = case clbi of
-          LibComponentLocalBuildInfo { componentUnitId = uid
+          LibComponentLocalBuildInfo { componentComponentId = cid
                                      , componentInstantiatedWith = insts } ->
               if null insts
                   then mempty
-                  else toFlag (unitIdComponentId uid)
+                  else toFlag cid
           _ -> mempty,
       ghcOptInstantiatedWith = case clbi of
         LibComponentLocalBuildInfo { componentInstantiatedWith = insts }

Cabal/Distribution/Simple/LocalBuildInfo.hs

@@ -33,7 +33,6 @@ module Distribution.Simple.LocalBuildInfo (
         showComponentName,
         componentNameString,
         ComponentLocalBuildInfo(..),
-        componentComponentId,
         componentBuildDir,
         foldComponent,
         componentName,
@@ -106,12 +105,14 @@ componentBuildDir :: LocalBuildInfo -> ComponentLocalBuildInfo -> FilePath
 componentBuildDir lbi clbi
     = buildDir lbi </>
         case componentLocalName clbi of
-            CLibName      -> case unitIdHash (componentUnitId clbi) of
-                               Just hash -> hash
-                               Nothing   -> ""
-            CSubLibName s -> case unitIdHash (componentUnitId clbi) of
-                               Just hash -> s ++ "-" ++ hash
-                               Nothing   -> s
+            CLibName      ->
+                if display (componentUnitId clbi) == display (componentComponentId clbi)
+                    then ""
+                    else display (componentUnitId clbi)
+            CSubLibName s ->
+                if display (componentUnitId clbi) == display (componentComponentId clbi)
+                    then s
+                    else display (componentUnitId clbi)
             CExeName s   -> s
             CTestName s  -> s
             CBenchName s -> s

Cabal/Distribution/Simple/Program/HcPkg.hs

@@ -315,11 +315,12 @@ mungePackagePaths pkgroot pkginfo =
 -- field, so if it is missing then we fill it as the source package ID.
 setUnitId :: InstalledPackageInfo -> InstalledPackageInfo
 setUnitId pkginfo@InstalledPackageInfo {
-                        installedUnitId = UnitId cid _,
+                        installedUnitId = uid,
                         sourcePackageId = pkgid
-                      } | cid == mkComponentId ""
+                      } | unUnitId uid == ""
                     = pkginfo {
-                        installedUnitId = mkLegacyUnitId pkgid
+                        installedUnitId = mkLegacyUnitId pkgid,
+                        installedComponentId_ = mkComponentId (display pkgid)
                       }
 setUnitId pkginfo = pkginfo
 

Cabal/Distribution/Simple/Register.hs

@@ -389,6 +389,7 @@ generalInstalledPackageInfo adjustRelIncDirs pkg abi_hash lib lbi clbi installDi
                                 pkgName = componentCompatPackageName clbi
                              },
     IPI.installedUnitId    = componentUnitId clbi,
+    IPI.installedComponentId_ = componentComponentId clbi,
     IPI.instantiatedWith   = componentInstantiatedWith clbi,
     IPI.compatPackageKey   = componentCompatPackageKey clbi,
     IPI.license            = license     pkg,

Cabal/Distribution/Types/ComponentLocalBuildInfo.hs

@@ -4,7 +4,6 @@
 module Distribution.Types.ComponentLocalBuildInfo (
   ComponentLocalBuildInfo(..),
   componentIsIndefinite,
-  componentComponentId,
   ) where
 
 import Prelude ()
@@ -29,6 +28,8 @@ data ComponentLocalBuildInfo
     -- PackageDescription.  NB: eventually, this will NOT uniquely