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)

Cabal/Distribution/PackageDescription/FieldGrammar.hs

@@ -123,7 +123,7 @@ packageDescriptionFieldGrammar = PackageDescription
 
 libraryFieldGrammar
     :: (FieldGrammar g, Applicative (g Library), Applicative (g BuildInfo))
-    => Maybe UnqualComponentName
+    => LibraryName
     -> g Library Library
 libraryFieldGrammar n = Library n
     <$> monoidalFieldAla  "exposed-modules"    (alaList' VCat MQuoted) L.exposedModules
@@ -134,16 +134,16 @@ libraryFieldGrammar n = Library n
     <*> visibilityField
     <*> blurFieldGrammar L.libBuildInfo buildInfoFieldGrammar
   where
-    visibilityField
+    visibilityField = case n of
         -- nameless/"main" libraries are public
-        | isNothing n = pure LibraryVisibilityPublic
+        LMainLibName -> pure LibraryVisibilityPublic
         -- named libraries have the field
-        | otherwise   =
+        LSubLibName _ ->
             optionalFieldDef "visibility" L.libVisibility LibraryVisibilityPrivate
             ^^^ availableSince CabalSpecV3_0 LibraryVisibilityPrivate
 
-{-# SPECIALIZE libraryFieldGrammar :: Maybe UnqualComponentName -> ParsecFieldGrammar' Library #-}
-{-# SPECIALIZE libraryFieldGrammar :: Maybe UnqualComponentName -> PrettyFieldGrammar' Library #-}
+{-# SPECIALIZE libraryFieldGrammar :: LibraryName -> ParsecFieldGrammar' Library #-}
+{-# SPECIALIZE libraryFieldGrammar :: LibraryName -> PrettyFieldGrammar' Library #-}
 
 -------------------------------------------------------------------------------
 -- Foreign library

Cabal/Distribution/PackageDescription/Parsec.hs

@@ -267,16 +267,18 @@ goSections specVer = traverse_ process
                 "Multiple main libraries; have you forgotten to specify a name for an internal library?"
 
             commonStanzas <- use stateCommonStanzas
-            lib <- lift $ parseCondTree' (libraryFieldGrammar Nothing) (libraryFromBuildInfo Nothing) commonStanzas fields
-
+            let name'' = LMainLibName
+            lib <- lift $ parseCondTree' (libraryFieldGrammar name'') (libraryFromBuildInfo name'') commonStanzas fields
+            --
+            -- TODO check that not set
             stateGpd . L.condLibrary ?= lib
 
         -- Sublibraries
         -- TODO: check cabal-version
         | name == "library" = do
             commonStanzas <- use stateCommonStanzas
             name' <- parseUnqualComponentName pos args
-            let name'' = Just name'
+            let name'' = LSubLibName name'
             lib   <- lift $ parseCondTree' (libraryFieldGrammar name'') (libraryFromBuildInfo name'') commonStanzas fields
             -- TODO check duplicate name here?
             stateGpd . L.condSubLibraries %= snoc (name', lib)
@@ -545,10 +547,12 @@ type CondTreeBuildInfo = CondTree ConfVar [Dependency] BuildInfo
 class L.HasBuildInfo a => FromBuildInfo a where
     fromBuildInfo' :: BuildInfo -> a
 
-libraryFromBuildInfo :: Maybe UnqualComponentName -> BuildInfo -> Library
+libraryFromBuildInfo :: LibraryName -> BuildInfo -> Library
 libraryFromBuildInfo n bi = emptyLibrary
     { libName       = n
-    , libVisibility = if isNothing n then LibraryVisibilityPublic else LibraryVisibilityPrivate
+    , libVisibility = case n of
+        LMainLibName  -> LibraryVisibilityPublic
+        LSubLibName _ -> LibraryVisibilityPrivate
     , libBuildInfo  = bi
     }
 
@@ -726,7 +730,7 @@ data Syntax = OldSyntax | NewSyntax
 
 -- TODO:
 libFieldNames :: [FieldName]
-libFieldNames = fieldGrammarKnownFieldList (libraryFieldGrammar Nothing)
+libFieldNames = fieldGrammarKnownFieldList (libraryFieldGrammar LMainLibName)
 
 -------------------------------------------------------------------------------
 -- Suplementary build information

Cabal/Distribution/PackageDescription/PrettyPrint.hs

@@ -34,6 +34,7 @@ import Prelude ()
 import Distribution.Types.CondTree
 import Distribution.Types.Dependency
 import Distribution.Types.ForeignLib          (ForeignLib (foreignLibName))
+import Distribution.Types.LibraryName
 import Distribution.Types.UnqualComponentName
 
 import Distribution.PackageDescription
@@ -133,12 +134,12 @@ ppCondTree2 grammar = go
 ppCondLibrary :: Maybe (CondTree ConfVar [Dependency] Library) -> [PrettyField]
 ppCondLibrary Nothing = mempty
 ppCondLibrary (Just condTree) = pure $ PrettySection "library" [] $
-    ppCondTree2 (libraryFieldGrammar Nothing) condTree
+    ppCondTree2 (libraryFieldGrammar LMainLibName) condTree
 
 ppCondSubLibraries :: [(UnqualComponentName, CondTree ConfVar [Dependency] Library)] -> [PrettyField]
 ppCondSubLibraries libs =
     [ PrettySection "library" [pretty n]
-    $ ppCondTree2 (libraryFieldGrammar $ Just n) condTree
+    $ ppCondTree2 (libraryFieldGrammar $ LSubLibName n) condTree
     | (n, condTree) <- libs
     ]
 
@@ -216,7 +217,7 @@ pdToGpd pd = GenericPackageDescription
     -- We set CondTree's [Dependency] to an empty list, as it
     -- is not pretty printed anyway.
     mkCondTree  x = CondNode x [] []
-    mkCondTreeL l = (fromMaybe (mkUnqualComponentName "") (libName l), CondNode l [] [])
+    mkCondTreeL l = (fromMaybe (mkUnqualComponentName "") (libraryNameString (libName l)), CondNode l [] [])
 
     mkCondTree'
         :: (a -> UnqualComponentName)

Cabal/Distribution/Simple/Build.hs

@@ -454,7 +454,7 @@ testSuiteLibV09AsLibAndExe pkg_descr
   where
     bi  = testBuildInfo test
     lib = Library {
-            libName = Nothing,
+            libName = LMainLibName,
             exposedModules = [ m ],
             reexportedModules = [],
             signatures = [],
@@ -465,7 +465,8 @@ 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 (Just (testName test))
+    -- Note: we do make internal library from the test!
+    compat_name = MungedPackageName pkg_name (LSubLibName (testName test))
     compat_key = computeCompatPackageKey (compiler lbi) compat_name pkg_ver (componentUnitId clbi)
     libClbi = LibComponentLocalBuildInfo
                 { componentPackageDeps = componentPackageDeps clbi
@@ -483,7 +484,7 @@ testSuiteLibV09AsLibAndExe pkg_descr
                 , componentExposedModules = [IPI.ExposedModule m Nothing]
                 }
     pkg = pkg_descr {
-            package      = (package pkg_descr) { pkgName = mkPackageName $ unMungedPackageName compat_name }
+            package      = (package pkg_descr) { pkgName = mkPackageName $ prettyShow compat_name }
           , executables  = []
           , testSuites   = []
           , subLibraries = [lib]
@@ -505,7 +506,7 @@ testSuiteLibV09AsLibAndExe pkg_descr
     -- | The stub executable needs a new 'ComponentLocalBuildInfo'
     -- that exposes the relevant test suite library.
     deps = (IPI.installedUnitId ipi, mungedId ipi)
-         : (filter (\(_, x) -> let name = unMungedPackageName $ mungedName x
+         : (filter (\(_, x) -> let name = prettyShow $ mungedName x
                                in name == "Cabal" || name == "base")
                    (componentPackageDeps clbi))
     exeClbi = ExeComponentLocalBuildInfo {

Cabal/Distribution/Simple/Build/Macros.hs

@@ -82,13 +82,11 @@ generate pkg_descr lbi clbi =
   generateComponentIdMacro lbi clbi ++
   generateCurrentPackageVersion pkg_descr
  where
-  getPid (_, MungedPackageId mpn v) =
-    PackageIdentifier pn v
-   where
-    -- NB: Drop the component name! We're just reporting package versions.
+  getPid (_, MungedPackageId (MungedPackageName pn _) v) =
+    -- NB: Drop the library name! We're just reporting package versions.
     -- This would have to be revisited if you are allowed to depend
     -- on different versions of the same package
-    pn = fst (decodeCompatPackageName mpn)
+    PackageIdentifier pn v
 
 -- | Helper function that generates just the @VERSION_pkg@ and @MIN_VERSION_pkg@
 -- macros for a list of package ids (usually used with the specific deps of