[GSoC2018] [FREEZED on 2018-08-14] Add support for multiple public libraries in a single package

Cabal/Cabal.cabal

@@ -343,6 +343,7 @@ library
     Distribution.Types.ModuleReexport
     Distribution.Types.ModuleRenaming
     Distribution.Types.ComponentName
+    Distribution.Types.LibraryName
     Distribution.Types.MungedPackageName
     Distribution.Types.PackageName
     Distribution.Types.PkgconfigName
@@ -367,6 +368,7 @@ library
     Distribution.Types.Version
     Distribution.Types.VersionRange
     Distribution.Types.VersionInterval
+    Distribution.Types.GivenComponent
     Distribution.Utils.Generic
     Distribution.Utils.NubList
     Distribution.Utils.ShortText

Cabal/Distribution/Backpack/ComponentsGraph.hs

@@ -65,10 +65,11 @@ mkComponentsGraph enabled pkg_descr =
     componentDeps component =
       (CExeName <$> getAllInternalToolDependencies pkg_descr bi)
 
+      --TODO check this
       ++ [ if pkgname == packageName pkg_descr
-           then CLibName
-           else CSubLibName toolname
-         | Dependency pkgname _ <- targetBuildDepends bi
+           then CLibName LMainLibName
+           else CLibName (LSubLibName toolname)
+         | Dependency pkgname _ _ <- targetBuildDepends bi
          , let toolname = packageNameToUnqualComponentName pkgname
          , toolname `elem` internalPkgDeps ]
       where

Cabal/Distribution/Backpack/ConfiguredComponent.hs

@@ -30,6 +30,7 @@ import Distribution.Types.PackageId
 import Distribution.Types.PackageName
 import Distribution.Types.Mixin
 import Distribution.Types.ComponentName
+import Distribution.Types.LibraryName
 import Distribution.Types.UnqualComponentName
 import Distribution.Types.ComponentInclude
 import Distribution.Package
@@ -150,7 +151,7 @@ mkConfiguredComponent pkg_descr this_cid lib_deps exe_deps component = do
     bi = componentBuildInfo component
     deps_map = Map.fromList [ ((packageName dep, ann_cname dep), dep)
                             | dep <- lib_deps ]
-    is_public = componentName component == CLibName
+    is_public = componentName component == CLibName LMainLibName
 
 type ConfiguredComponentMap =
         Map PackageName (Map ComponentName (AnnotatedId ComponentId))
@@ -165,16 +166,41 @@ toConfiguredComponent
 toConfiguredComponent pkg_descr this_cid lib_dep_map exe_dep_map component = do
     lib_deps <-
         if newPackageDepsBehaviour pkg_descr
-            then forM (targetBuildDepends bi) $ \(Dependency name _) -> do
+            then fmap concat $ forM (targetBuildDepends bi) $ \(Dependency name _ sublibs) -> do
                     let (pn, cn) = fixFakePkgName pkg_descr name
-                    value <- case Map.lookup cn =<< Map.lookup pn lib_dep_map of
+                    pkg <- case Map.lookup pn lib_dep_map of
+                        Nothing ->
+                            dieProgress $
+                                text "Dependency on unbuildable" <+>
+                                text "package" <+> disp pn
+                        Just p -> return p
+                    mainLibraryComponent <-
+                      if sublibs /= Set.singleton LMainLibName
+                      then pure Nothing
+                      -- No sublibraries were specified, so we may be in the
+                      -- legacy case where the package name is used as library
+                      -- name
+                      else Just <$>
+                        case Map.lookup cn pkg of
                         Nothing ->
                             dieProgress $
                                 text "Dependency on unbuildable (i.e. 'buildable: False')" <+>
                                 text (showComponentName cn) <+>
                                 text "from" <+> disp pn
                         Just v -> return v
-                    return value
+                    subLibrariesComponents <- forM (Set.toList sublibs) $ \lib ->
+                        let comp = CLibName lib in
+                        case Map.lookup (CLibName $ LSubLibName $ packageNameToUnqualComponentName name) pkg
+                         <|> Map.lookup comp pkg
+                        of
+                            Nothing ->
+                                dieProgress $
+                                    text "Dependency on unbuildable" <+>
+                                    text (showLibraryName lib) <+>
+                                    text "from" <+> disp pn
+                                    <+> text "available:" <+> text (show pkg)
+                            Just v -> return v
+                    return (maybeToList mainLibraryComponent ++ subLibrariesComponents)
             else return old_style_lib_deps
     mkConfiguredComponent
        pkg_descr this_cid
@@ -192,7 +218,7 @@ toConfiguredComponent pkg_descr this_cid lib_dep_map exe_dep_map component = do
                          | (pn, comp_map) <- Map.toList lib_dep_map
                          , pn /= packageName pkg_descr
                          , (cn, e) <- Map.toList comp_map
-                         , cn == CLibName ]
+                         , cn == CLibName LMainLibName ]
     -- We have to nub here, because 'getAllToolDependencies' may return
     -- duplicates (see #4986).  (NB: This is not needed for lib_deps,
     -- since those elaborate into includes, for which there explicitly
@@ -296,8 +322,8 @@ newPackageDepsBehaviour pkg =
 fixFakePkgName :: PackageDescription -> PackageName -> (PackageName, ComponentName)
 fixFakePkgName pkg_descr pn =
   if subLibName `elem` internalLibraries
-  then (packageName pkg_descr, CSubLibName subLibName)
-  else (pn,                    CLibName)
+  then (packageName pkg_descr, CLibName (LSubLibName subLibName))
+  else (pn,                    CLibName LMainLibName            )
   where
     subLibName = packageNameToUnqualComponentName pn
     internalLibraries = mapMaybe libName (allLibraries pkg_descr)

Cabal/Distribution/Backpack/ModuleScope.hs

@@ -23,6 +23,7 @@ import Distribution.ModuleName
 import Distribution.Types.IncludeRenaming
 import Distribution.Types.PackageName
 import Distribution.Types.ComponentName
+import Distribution.Types.LibraryName
 
 import Distribution.Backpack
 import Distribution.Backpack.ModSubst
@@ -113,8 +114,8 @@ dispComponent pn cn =
     -- should be clear enough.  To do source syntax, we'd
     -- need to know what the package we're linking is.
     case cn of
-        CLibName -> disp pn
-        CSubLibName ucn -> disp pn <<>> colon <<>> disp ucn
+        CLibName LMainLibName -> disp pn
+        CLibName (LSubLibName ucn) -> disp pn <<>> colon <<>> disp ucn
         -- Case below shouldn't happen
         _ -> disp pn <+> parens (disp cn)
 

Cabal/Distribution/Backpack/ReadyComponent.hs

@@ -25,6 +25,7 @@ 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.UnitId
 import Distribution.Compat.Graph (IsNode(..))
@@ -139,8 +140,8 @@ rc_depends rc = ordNub $
         computeCompatPackageId
             (ci_pkgid ci)
             (case ci_cname ci of
-                CLibName -> Nothing
-                CSubLibName uqn -> Just uqn
+                CLibName LMainLibName -> Nothing
+                CLibName (LSubLibName uqn) -> Just uqn
                 _ -> error $ display (rc_cid rc) ++
                         " depends on non-library " ++ display (ci_id ci))
 

Cabal/Distribution/Backpack/UnifyM.hs

@@ -441,8 +441,8 @@ ci_msg ci
     pn = pkgName (ci_pkgid ci)
     pp_pn =
         case ci_cname ci of
-            CLibName -> disp pn
-            CSubLibName cn -> disp pn <<>> colon <<>> disp cn
+            CLibName LMainLibName -> disp pn
+            CLibName (LSubLibName cn) -> disp pn <<>> colon <<>> disp cn
             -- Shouldn't happen
             cn -> disp pn <+> parens (disp cn)
 

Cabal/Distribution/InstalledPackageInfo.hs

@@ -54,6 +54,7 @@ import Distribution.ModuleName
 import Distribution.Package                  hiding (installedPackageId, installedUnitId)
 import Distribution.ParseUtils
 import Distribution.Types.ComponentName
+import Distribution.Types.LibraryName
 import Distribution.Utils.Generic            (toUTF8BS)
 
 import qualified Data.Map                        as Map
@@ -104,8 +105,8 @@ installedPackageId = installedUnitId
 sourceComponentName :: InstalledPackageInfo -> ComponentName
 sourceComponentName ipi =
     case sourceLibName ipi of
-        Nothing -> CLibName
-        Just qn -> CSubLibName qn
+        Nothing -> CLibName LMainLibName
+        Just qn -> CLibName $ LSubLibName qn
 
 -- -----------------------------------------------------------------------------
 -- Parsing

Cabal/Distribution/PackageDescription.hs

@@ -86,6 +86,7 @@ module Distribution.PackageDescription (
         allBuildDepends,
         enabledBuildDepends,
         ComponentName(..),
+        LibraryName(..),
         defaultLibName,
         HookedBuildInfo,
         emptyHookedBuildInfo,
@@ -135,5 +136,6 @@ import Distribution.Types.CondTree
 import Distribution.Types.Condition
 import Distribution.Types.PackageDescription
 import Distribution.Types.ComponentName
+import Distribution.Types.LibraryName
 import Distribution.Types.HookedBuildInfo
 import Distribution.Types.SourceRepo

Cabal/Distribution/PackageDescription/Check.hs

@@ -585,7 +585,7 @@ checkFields pkg =
              , name `elem` map display knownLanguages ]
 
     testedWithImpossibleRanges =
-      [ Dependency (mkPackageName (display compiler)) vr
+      [ Dependency (mkPackageName (display compiler)) vr Set.empty
       | (compiler, vr) <- testedWith pkg
       , isNoVersion vr ]
 
@@ -598,7 +598,7 @@ checkFields pkg =
     internalLibDeps =
       [ dep
       | bi <- allBuildInfo pkg
-      , dep@(Dependency name _) <- targetBuildDepends bi
+      , dep@(Dependency name _ _) <- targetBuildDepends bi
       , name `elem` internalLibraries
       ]
 
@@ -611,14 +611,14 @@ checkFields pkg =
 
     depInternalLibraryWithExtraVersion =
       [ dep
-      | dep@(Dependency _ versionRange) <- internalLibDeps
+      | dep@(Dependency _ versionRange _) <- internalLibDeps
       , not $ isAnyVersion versionRange
       , packageVersion pkg `withinRange` versionRange
       ]
 
     depInternalLibraryWithImpossibleVersion =
       [ dep
-      | dep@(Dependency _ versionRange) <- internalLibDeps
+      | dep@(Dependency _ versionRange _) <- internalLibDeps
       , not $ packageVersion pkg `withinRange` versionRange
       ]
 
@@ -1243,8 +1243,8 @@ checkCabalVersion pkg =
         ++ ". To use this new syntax the package need to specify at least "
         ++ "'cabal-version: >= 1.6'. Alternatively, if broader compatibility "
         ++ "is important then use: " ++ commaSep
-           [ display (Dependency name (eliminateWildcardSyntax versionRange))
-           | Dependency name versionRange <- depsUsingWildcardSyntax ]
+           [ display (Dependency name (eliminateWildcardSyntax versionRange) Set.empty)
+           | Dependency name versionRange _ <- depsUsingWildcardSyntax ]
 
     -- check use of "build-depends: foo ^>= 1.2.3" syntax
   , checkVersion [2,0] (not (null depsUsingMajorBoundSyntax)) $
@@ -1255,8 +1255,8 @@ checkCabalVersion pkg =
         ++ ". To use this new syntax the package need to specify at least "
         ++ "'cabal-version: 2.0'. Alternatively, if broader compatibility "
         ++ "is important then use: " ++ commaSep
-           [ display (Dependency name (eliminateMajorBoundSyntax versionRange))
-           | Dependency name versionRange <- depsUsingMajorBoundSyntax ]
+           [ display (Dependency name (eliminateMajorBoundSyntax versionRange) Set.empty)
+           | Dependency name versionRange _ <- depsUsingMajorBoundSyntax ]
 
   , checkVersion [2,1] (any (not . null)
                         (concatMap buildInfoField
@@ -1292,8 +1292,8 @@ checkCabalVersion pkg =
         ++ ". To use this new syntax the package need to specify at least "
         ++ "'cabal-version: >= 1.6'. Alternatively, if broader compatibility "
         ++ "is important then use: " ++ commaSep
-           [ display (Dependency name (eliminateWildcardSyntax versionRange))
-           | Dependency name versionRange <- testedWithUsingWildcardSyntax ]
+           [ display (Dependency name (eliminateWildcardSyntax versionRange) Set.empty)
+           | Dependency name versionRange _ <- testedWithUsingWildcardSyntax ]
 
     -- check use of "source-repository" section
   , checkVersion [1,6] (not (null (sourceRepos pkg))) $
@@ -1367,11 +1367,11 @@ checkCabalVersion pkg =
     buildInfoField field         = map field (allBuildInfo pkg)
 
     versionRangeExpressions =
-        [ dep | dep@(Dependency _ vr) <- allBuildDepends pkg
+        [ dep | dep@(Dependency _ vr _) <- allBuildDepends pkg
               , usesNewVersionRangeSyntax vr ]
 
     testedWithVersionRangeExpressions =
-        [ Dependency (mkPackageName (display compiler)) vr
+        [ Dependency (mkPackageName (display compiler)) vr Set.empty
         | (compiler, vr) <- testedWith pkg
         , usesNewVersionRangeSyntax vr ]
 
@@ -1395,16 +1395,16 @@ checkCabalVersion pkg =
         alg (VersionRangeParensF _) = 3
         alg _ = 1 :: Int
 
-    depsUsingWildcardSyntax = [ dep | dep@(Dependency _ vr) <- allBuildDepends pkg
+    depsUsingWildcardSyntax = [ dep | dep@(Dependency _ vr _) <- allBuildDepends pkg
                                     , usesWildcardSyntax vr ]
 
-    depsUsingMajorBoundSyntax = [ dep | dep@(Dependency _ vr) <- allBuildDepends pkg
+    depsUsingMajorBoundSyntax = [ dep | dep@(Dependency _ vr _) <- allBuildDepends pkg
                                       , usesMajorBoundSyntax vr ]
 
     usesBackpackIncludes = any (not . null . mixins) (allBuildInfo pkg)
 
     testedWithUsingWildcardSyntax =
-      [ Dependency (mkPackageName (display compiler)) vr
+      [ Dependency (mkPackageName (display compiler)) vr Set.empty
       | (compiler, vr) <- testedWith pkg
       , usesWildcardSyntax vr ]
 
@@ -1493,8 +1493,8 @@ checkCabalVersion pkg =
     allModuleNamesAutogen = concatMap autogenModules (allBuildInfo pkg)
 
 displayRawDependency :: Dependency -> String
-displayRawDependency (Dependency pkg vr) =
-  display pkg ++ " " ++ display vr
+displayRawDependency (Dependency pkg vr cs) =
+  display pkg ++ " " ++ display vr ++ " " ++ (unwords . fmap display . Set.toList $ cs) --MAYBE maybe drop cs entirely
 
 
 -- ------------------------------------------------------------
@@ -1545,7 +1545,7 @@ checkPackageVersions pkg =
           foldr intersectVersionRanges anyVersion baseDeps
         where
           baseDeps =
-            [ vr | Dependency pname vr <- allBuildDepends pkg'
+            [ vr | Dependency pname vr _ <- allBuildDepends pkg'
                  , pname == mkPackageName "base" ]
 
       -- Just in case finalizePD fails for any reason,

Cabal/Distribution/PackageDescription/Configuration.hs

@@ -65,6 +65,8 @@ import Distribution.Types.DependencyMap
 
 import qualified Data.Map.Strict as Map.Strict
 import qualified Data.Map.Lazy   as Map
+import Data.Set ( Set )
+import qualified Data.Set as Set
 import Data.Tree ( Tree(Node) )
 
 ------------------------------------------------------------------------------
@@ -229,7 +231,7 @@ resolveWithFlags dom enabled os arch impl constrs trees checkDeps =
     mp (Left xs)   (Left ys)   =
         let union = Map.foldrWithKey (Map.Strict.insertWith combine)
                     (unDepMapUnion xs) (unDepMapUnion ys)
-            combine x y = simplifyVersionRange $ unionVersionRanges x y
+            combine x y = (\(vr, cs) -> (simplifyVersionRange vr,cs)) $ unionVersionRangesAndIntersectionLibraries x y
         in union `seq` Left (DepMapUnion union)
 
     -- `mzero'
@@ -307,14 +309,22 @@ extractConditions f gpkg =
 
 
 -- | A map of dependencies that combines version ranges using 'unionVersionRanges'.
-newtype DepMapUnion = DepMapUnion { unDepMapUnion :: Map PackageName VersionRange }
+newtype DepMapUnion = DepMapUnion { unDepMapUnion :: Map PackageName (VersionRange, Set LibraryName) }
+
+-- TODO is this right? an union of versions should correspond to an intersection
+-- of the components, but I'll have to check how this module actually works
+unionVersionRangesAndIntersectionLibraries :: (VersionRange, Set LibraryName)
+                                           -> (VersionRange, Set LibraryName)
+                                           -> (VersionRange, Set LibraryName)
+unionVersionRangesAndIntersectionLibraries (vra, csa) (vrb, csb) =
+  (unionVersionRanges vra vrb, Set.intersection csa csb)
 
 toDepMapUnion :: [Dependency] -> DepMapUnion
 toDepMapUnion ds =
-  DepMapUnion $ Map.fromListWith unionVersionRanges [ (p,vr) | Dependency p vr <- ds ]
+  DepMapUnion $ Map.fromListWith unionVersionRangesAndIntersectionLibraries [ (p,(vr,cs)) | Dependency p vr cs <- ds ]
 
 fromDepMapUnion :: DepMapUnion -> [Dependency]
-fromDepMapUnion m = [ Dependency p vr | (p,vr) <- Map.toList (unDepMapUnion m) ]
+fromDepMapUnion m = [ Dependency p vr cs | (p,(vr,cs)) <- Map.toList (unDepMapUnion m) ]
 
 freeVars :: CondTree ConfVar c a  -> [FlagName]
 freeVars t = [ f | Flag f <- freeVars' t ]
@@ -344,12 +354,14 @@ overallDependencies enabled (TargetSet targets) = mconcat depss
     -- UGH. The embedded componentName in the 'Component's here is
     -- BLANK.  I don't know whose fault this is but I'll use the tag
     -- instead. -- ezyang
-    removeDisabledSections (Lib _)     = componentNameRequested enabled CLibName
+    removeDisabledSections (Lib _)     = componentNameRequested
+                                           enabled
+                                           (CLibName LMainLibName)
     removeDisabledSections (SubComp t c)
         -- Do NOT use componentName
         = componentNameRequested enabled
         $ case c of
-            CLib  _ -> CSubLibName t
+            CLib  _ -> CLibName (LSubLibName t)
             CFLib _ -> CFLibName   t
             CExe  _ -> CExeName    t
             CTest _ -> CTestName   t

Cabal/Distribution/Simple/Build.hs

@@ -470,7 +470,7 @@ testSuiteLibV09AsLibAndExe pkg_descr
                 , componentInternalDeps = componentInternalDeps clbi
                 , componentIsIndefinite_ = False
                 , componentExeDeps = componentExeDeps clbi
-                , componentLocalName = CSubLibName (testName test)
+                , componentLocalName = CLibName $ LSubLibName $ testName test
                 , componentIsPublic = False
                 , componentIncludes = componentIncludes clbi
                 , componentUnitId = componentUnitId clbi