Change MungedPackageName to be non-opaque type.

i.e. strict pair of PackageName and LibraryName
the legacy conversion is done via Pretty/Parsec instances.

Change of `Maybe UnqualComponentName` to `LibraryName` caused
a cascade of other changes, but they all seem to be good changes.
In the sense, they made many comments not-so-necessary.

Add Distribution.Types.PackageName.Magic for special package names.

Updates in cabal-install are mostly trivial type error driven changes.
I removed few (deprecated) `Text` instances: `MungedPackageId`,
`MungedPackageName` and `LibraryName`. Turns out only a `Pretty`
part was used, so it was easy to update. Note: `LibraryName`
doesn't have `Pretty` / `Parsec` instances as it's either parsed/printed
as a `ComponentName` or `UnqualComponentName`, never stand alone.

Author: phadej

Cabal/Cabal.cabal

@@ -370,6 +370,7 @@ library
     Distribution.Types.LibraryName
     Distribution.Types.MungedPackageName
     Distribution.Types.PackageName
+    Distribution.Types.PackageName.Magic
     Distribution.Types.PkgconfigName
     Distribution.Types.UnqualComponentName
     Distribution.Types.IncludeRenaming

Cabal/Distribution/Backpack/ComponentsGraph.hs

@@ -73,8 +73,9 @@ mkComponentsGraph enabled pkg_descr =
       where
         bi = componentBuildInfo component
         internalPkgDeps = map (conv . libName) (allLibraries pkg_descr)
-        conv Nothing = packageNameToUnqualComponentName $ packageName pkg_descr
-        conv (Just s) = s
+
+        conv LMainLibName    = packageNameToUnqualComponentName $ packageName pkg_descr
+        conv (LSubLibName s) = s
 
 -- | Given the package description and a 'PackageDescription' (used
 -- to determine if a package name is internal or not), sort the

Cabal/Distribution/Backpack/Configure.hs

@@ -41,6 +41,7 @@ import Distribution.Simple.LocalBuildInfo
 import Distribution.Types.AnnotatedId
 import Distribution.Types.ComponentRequestedSpec
 import Distribution.Types.ComponentInclude
+import Distribution.Types.MungedPackageName
 import Distribution.Verbosity
 import qualified Distribution.Compat.Graph as Graph
 import Distribution.Compat.Graph (Graph, IsNode(..))
@@ -277,7 +278,7 @@ mkLinkedComponentsLocalBuildInfo comp rcs = map go rcs
                     Right instc -> [ (m, OpenModule (DefiniteUnitId uid') m')
                                    | (m, Module uid' m') <- instc_insts instc ]
 
-            compat_name = computeCompatPackageName (packageName rc) (libName lib)
+            compat_name = MungedPackageName (packageName rc) (libName lib)
             compat_key = computeCompatPackageKey comp compat_name (packageVersion rc) this_uid
 
         in LibComponentLocalBuildInfo {

Cabal/Distribution/Backpack/ConfiguredComponent.hs

@@ -315,4 +315,4 @@ fixFakePkgName pkg_descr pn =
   else (pn,                    CLibName LMainLibName            )
   where
     subLibName = packageNameToUnqualComponentName pn
-    internalLibraries = mapMaybe libName (allLibraries pkg_descr)
+    internalLibraries = mapMaybe (libraryNameString . libName) (allLibraries pkg_descr)

Cabal/Distribution/Backpack/Id.hs

@@ -5,7 +5,6 @@
 module Distribution.Backpack.Id(
     computeComponentId,
     computeCompatPackageKey,
-    computeCompatPackageName,
 ) where
 
 import Prelude ()

Cabal/Distribution/Backpack/PreExistingComponent.hs

@@ -46,7 +46,7 @@ ipiToPreExistingComponent :: InstalledPackageInfo -> PreExistingComponent
 ipiToPreExistingComponent ipi =
     PreExistingComponent {
         pc_pkgname = packageName ipi,
-        pc_compname = libraryComponentName $ Installed.sourceLibName ipi,
+        pc_compname = CLibName $ Installed.sourceLibName ipi,
         pc_munged_id = mungedId ipi,
         pc_uid   = Installed.installedUnitId ipi,
         pc_cid   = Installed.installedComponentId ipi,

Cabal/Distribution/Backpack/ReadyComponent.hs

@@ -25,14 +25,15 @@ import Distribution.Types.Component
 import Distribution.Types.ComponentInclude
 import Distribution.Types.ComponentId
 import Distribution.Types.ComponentName
-import Distribution.Types.LibraryName
 import Distribution.Types.PackageId
+import Distribution.Types.PackageName.Magic
 import Distribution.Types.UnitId
 import Distribution.Compat.Graph (IsNode(..))
 import Distribution.Types.Module
 import Distribution.Types.MungedPackageId
 import Distribution.Types.MungedPackageName
 import Distribution.Types.Library
+import Distribution.Types.LibraryName
 
 import Distribution.ModuleName
 import Distribution.Package
@@ -140,8 +141,7 @@ rc_depends rc = ordNub $
         computeCompatPackageId
             (ci_pkgid ci)
             (case ci_cname ci of
-                CLibName LMainLibName -> Nothing
-                CLibName (LSubLibName uqn) -> Just uqn
+                CLibName name -> name
                 _ -> error $ prettyShow (rc_cid rc) ++
                         " depends on non-library " ++ prettyShow (ci_id ci))
 
@@ -275,7 +275,7 @@ toReadyComponents pid_map subst0 comps
                             fmap rc_munged_id (join (Map.lookup dep_uid s)))]
                   where
                     err_pid = MungedPackageId
-                        (mkMungedPackageName "nonexistent-package-this-is-a-cabal-bug")
+                        (MungedPackageName nonExistentPackageThisIsCabalBug LMainLibName)
                         (mkVersion [0])
                 instc = InstantiatedComponent {
                             instc_insts = Map.toList insts,

Cabal/Distribution/InstalledPackageInfo.hs

@@ -52,7 +52,6 @@ import Distribution.FieldGrammar.FieldDescrs
 import Distribution.ModuleName
 import Distribution.Package                  hiding (installedPackageId, installedUnitId)
 import Distribution.Types.ComponentName
-import Distribution.Types.LibraryName
 import Distribution.Utils.Generic            (toUTF8BS)
 
 import qualified Data.Map            as Map
@@ -97,10 +96,7 @@ installedPackageId = installedUnitId
 -- Munging
 
 sourceComponentName :: InstalledPackageInfo -> ComponentName
-sourceComponentName ipi =
-    case sourceLibName ipi of
-        Nothing -> CLibName LMainLibName
-        Just qn -> CLibName $ LSubLibName qn
+sourceComponentName = CLibName . sourceLibName
 
 -- -----------------------------------------------------------------------------
 -- Parsing

Cabal/Distribution/PackageDescription/Check.hs

@@ -54,6 +54,7 @@ import Distribution.System
 import Distribution.Types.ComponentRequestedSpec
 import Distribution.Types.CondTree
 import Distribution.Types.ExeDependency
+import Distribution.Types.LibraryName
 import Distribution.Types.UnqualComponentName
 import Distribution.Utils.Generic                    (isAscii)
 import Distribution.Verbosity
@@ -195,7 +196,7 @@ checkSanity pkg =
       PackageBuildImpossible
         "No executables, libraries, tests, or benchmarks found. Nothing to do."
 
-  , check (any isNothing (map libName $ subLibraries pkg)) $
+  , check (any (== LMainLibName) (map libName $ subLibraries pkg)) $
       PackageBuildImpossible $ "Found one or more unnamed internal libraries. "
         ++ "Only the non-internal library can have the same name as the package."
 
@@ -236,7 +237,7 @@ checkSanity pkg =
     -- The public 'library' gets special dispensation, because it
     -- is common practice to export a library and name the executable
     -- the same as the package.
-    subLibNames = catMaybes . map libName $ subLibraries pkg
+    subLibNames = mapMaybe (libraryNameString . libName) $ subLibraries pkg
     exeNames = map exeName $ executables pkg
     testNames = map testName $ testSuites pkg
     bmNames = map benchmarkName $ benchmarks pkg
@@ -254,10 +255,7 @@ checkLibrary pkg lib =
   -- TODO: This check is bogus if a required-signature was passed through
   , check (null (explicitLibModules lib) && null (reexportedModules lib)) $
       PackageDistSuspiciousWarn $
-           "Library " ++ (case libName lib of
-                            Nothing -> ""
-                            Just n -> prettyShow n
-                            ) ++ "does not expose any modules"
+           showLibraryName (libName lib) ++ " does not expose any modules"
 
     -- check use of signatures sections
   , checkVersion [1,25] (not (null (signatures lib))) $
@@ -589,7 +587,7 @@ checkFields pkg =
       , isNoVersion vr ]
 
     internalLibraries =
-        map (maybe (packageName pkg) (unqualComponentNameToPackageName) . libName)
+        map (maybe (packageName pkg) (unqualComponentNameToPackageName) . libraryNameString . libName)
             (allLibraries pkg)
 
     internalExecutables = map exeName $ executables pkg

Cabal/Distribution/PackageDescription/Configuration.hs

@@ -455,7 +455,7 @@ finalizePD userflags enabled satisfyDep
     (mb_lib, comps) = flattenTaggedTargets targetSet
     mb_lib' = fmap libFillInDefaults mb_lib
     comps' = flip map comps $ \(n,c) -> foldComponent
-      (\l -> CLib   (libFillInDefaults l)   { libName = Just n
+      (\l -> CLib   (libFillInDefaults l)   { libName = LSubLibName n
                                             , libExposed = False })
       (\l -> CFLib  (flibFillInDefaults l)  { foreignLibName = n })
       (\e -> CExe   (exeFillInDefaults e)   { exeName = n })
@@ -541,14 +541,14 @@ flattenPackageDescription
         }
   where
     mlib = f <$> mlib0
-      where f lib = (libFillInDefaults . fst . ignoreConditions $ lib) { libName = Nothing }
+      where f lib = (libFillInDefaults . fst . ignoreConditions $ lib) { libName = LMainLibName }
     sub_libs = flattenLib  <$> sub_libs0
     flibs    = flattenFLib <$> flibs0
     exes     = flattenExe  <$> exes0
     tests    = flattenTst  <$> tests0
     bms      = flattenBm   <$> bms0
     flattenLib (n, t) = libFillInDefaults $ (fst $ ignoreConditions t)
-      { libName = Just n, libExposed = False }
+      { libName = LSubLibName n, libExposed = False }
     flattenFLib (n, t) = flibFillInDefaults $ (fst $ ignoreConditions t)
       { foreignLibName = n }
     flattenExe (n, t) = exeFillInDefaults $ (fst $ ignoreConditions t)