Switch from -this-package-key to -this-unit-id.

A small cosmetic change, but we have to do a bit of work to
actually support it:

    - Cabal submodule update, so that Cabal passes us
      -this-unit-id when we ask for it.  This includes
      a Cabal renaming to be consistent with Unit ID, which
      makes ghc-pkg a bit more scrutable.

    - Build system is updated to use -this-unit-id rather than
      -this-package-key, to avoid deprecation warnings.  Needs
      a version test so I resurrected the old test we had
      (sorry rwbarton!)

    - I've *undeprecated* -package-name, so that we are in the same
      state as GHC 7.10, since the "correct" flag will have only
      entered circulation in GHC 8.0.

    - I removed -package-key.  Since we didn't deprecate -package-id
      I think this should not cause any problems for users; they
      can just change their code to use -package-id.

    - The package database is indexed by UNIT IDs, not component IDs.
      I updated the naming here.

    - I dropped the signatures field from ExposedModule; nothing
      was using it, and instantiatedWith from the package database
      field.

    - ghc-pkg was updated to use unit ID nomenclature, I removed
      the -package-key flags but I decided not to add any new flags
      for now.

Signed-off-by: Edward Z. Yang <ezyang@cs.stanford.edu>

Test Plan: validate

Reviewers: austin, hvr, bgamari

Reviewed By: bgamari

Subscribers: 23Skidoo, thomie, erikd

Differential Revision: https://phabricator.haskell.org/D1780

4 files changed, 40 insertions, 38 deletions

diff --git a/compiler/main/DynFlags.hs b/compiler/main/DynFlags.hs
index d28dd30773..ea0bc53343 100644
--- a/compiler/main/DynFlags.hs
+++ b/compiler/main/DynFlags.hs
@@ -1133,8 +1133,7 @@ isNoLink _      = False
 -- is used.
 data PackageArg =
       PackageArg String    -- ^ @-package@, by 'PackageName'
-    | PackageIdArg String  -- ^ @-package-id@, by 'SourcePackageId'
-    | UnitIdArg String -- ^ @-package-key@, by 'ComponentId'
+    | UnitIdArg String     -- ^ @-package-id@, by 'UnitId'
   deriving (Eq, Show)
 
 -- | Represents the renaming that may be associated with an exposed
@@ -1167,7 +1166,6 @@ data TrustFlag
 -- | Flags for manipulating packages visibility.
 data PackageFlag
   = ExposePackage   String PackageArg ModRenaming -- ^ @-package@, @-package-id@
-                                           -- and @-package-key@
   | HidePackage     String -- ^ @-hide-package@
   deriving (Eq)
 -- NB: equality instance is used by InteractiveUI to test if
@@ -2774,15 +2772,21 @@ package_flags = [
       (NoArg $ do removeUserPkgConf
                   deprecate "Use -no-user-package-db instead")
 
-  , defGhcFlag "package-name"      (HasArg $ \name -> do
+  , defGhcFlag "package-name"       (HasArg $ \name -> do
+                                      upd (setUnitId name))
+                                      -- TODO: Since we JUST deprecated
+                                      -- -this-package-key, let's keep this
+                                      -- undeprecated for another cycle.
+                                      -- Deprecate this eventually.
+                                      -- deprecate "Use -this-unit-id instead")
+  , defGhcFlag "this-package-key"   (HasArg $ \name -> do
                                       upd (setUnitId name)
-                                      deprecate "Use -this-package-key instead")
-  , defGhcFlag "this-package-key"   (hasArg setUnitId)
-  , defFlag "package-id"            (HasArg exposePackageId)
+                                      deprecate "Use -this-unit-id instead")
+  , defGhcFlag "this-unit-id"       (hasArg setUnitId)
   , defFlag "package"               (HasArg exposePackage)
   , defFlag "plugin-package-id"     (HasArg exposePluginPackageId)
   , defFlag "plugin-package"        (HasArg exposePluginPackage)
-  , defFlag "package-key"           (HasArg exposeUnitId)
+  , defFlag "package-id"            (HasArg exposePackageId)
   , defFlag "hide-package"          (HasArg hidePackage)
   , defFlag "hide-all-packages"     (NoArg (setGeneralFlag Opt_HideAllPackages))
   , defFlag "hide-all-plugin-packages" (NoArg (setGeneralFlag Opt_HideAllPluginPackages))
@@ -3860,23 +3864,20 @@ parsePackageFlag flag constr str
              return (orig, orig))
         tok m = m >>= \x -> skipSpaces >> return x
 
-exposePackage, exposePackageId, exposeUnitId, hidePackage,
+exposePackage, exposePackageId, hidePackage,
         exposePluginPackage, exposePluginPackageId,
         ignorePackage,
         trustPackage, distrustPackage :: String -> DynP ()
 exposePackage p = upd (exposePackage' p)
 exposePackageId p =
   upd (\s -> s{ packageFlags =
-    parsePackageFlag "-package-id" PackageIdArg p : packageFlags s })
+    parsePackageFlag "-package-id" UnitIdArg p : packageFlags s })
 exposePluginPackage p =
   upd (\s -> s{ pluginPackageFlags =
     parsePackageFlag "-plugin-package" PackageArg p : pluginPackageFlags s })
 exposePluginPackageId p =
   upd (\s -> s{ pluginPackageFlags =
-    parsePackageFlag "-plugin-package-id" PackageIdArg p : pluginPackageFlags s })
-exposeUnitId p =
-  upd (\s -> s{ packageFlags =
-    parsePackageFlag "-package-key" UnitIdArg p : packageFlags s })
+    parsePackageFlag "-plugin-package-id" UnitIdArg p : pluginPackageFlags s })
 hidePackage p =
   upd (\s -> s{ packageFlags = HidePackage p : packageFlags s })
 ignorePackage p =
@@ -4285,18 +4286,34 @@ compilerInfo dflags
        ("Tables next to code",         cGhcEnableTablesNextToCode),
        ("RTS ways",                    cGhcRTSWays),
        ("RTS expects libdw",           showBool cGhcRtsWithLibdw),
+       -- Whether or not we support @-dynamic-too@
        ("Support dynamic-too",         showBool $ not isWindows),
+       -- Whether or not we support the @-j@ flag with @--make@.
        ("Support parallel --make",     "YES"),
+       -- Whether or not we support "Foo from foo-0.1-XXX:Foo" syntax in
+       -- installed package info.
        ("Support reexported-modules",  "YES"),
+       -- Whether or not we support extended @-package foo (Foo)@ syntax.
        ("Support thinning and renaming package flags", "YES"),
+       -- If true, we require that the 'id' field in installed package info
+       -- match what is passed to the @-this-unit-id@ flag for modules
+       -- built in it
        ("Requires unified installed package IDs", "YES"),
+       -- Whether or not we support the @-this-package-key@ flag.  Prefer
+       -- "Uses unit IDs" over it.
        ("Uses package keys",           "YES"),
+       -- Whether or not we support the @-this-unit-id@ flag
+       ("Uses unit IDs",               "YES"),
+       -- Whether or not GHC compiles libraries as dynamic by default
        ("Dynamic by default",          showBool $ dYNAMIC_BY_DEFAULT dflags),
+       -- Whether or not GHC was compiled using -dynamic
        ("GHC Dynamic",                 showBool dynamicGhc),
+       -- Whether or not GHC was compiled using -prof
        ("GHC Profiled",                showBool rtsIsProfiled),
        ("Leading underscore",          cLeadingUnderscore),
        ("Debug on",                    show debugIsOn),
        ("LibDir",                      topDir dflags),
+       -- The path of the global package database used by GHC
        ("Global Package DB",           systemPackageConfig dflags)
       ]
   where
diff --git a/compiler/main/HscTypes.hs b/compiler/main/HscTypes.hs
index 6b5458ea79..9b4cd65016 100644
--- a/compiler/main/HscTypes.hs
+++ b/compiler/main/HscTypes.hs
@@ -1229,7 +1229,7 @@ The details are a bit tricky though:
    extend the HPT.
 
  * The 'thisPackage' field of DynFlags is *not* set to 'interactive'.
-   It stays as 'main' (or whatever -this-package-key says), and is the
+   It stays as 'main' (or whatever -this-unit-id says), and is the
    package to which :load'ed modules are added to.
 
  * So how do we arrange that declarations at the command prompt get to
@@ -1238,7 +1238,7 @@ The details are a bit tricky though:
    call to initTc in initTcInteractive, which in turn get the module
    from it 'icInteractiveModule' field of the interactive context.
 
-   The 'thisPackage' field stays as 'main' (or whatever -this-package-key says.
+   The 'thisPackage' field stays as 'main' (or whatever -this-unit-id says.
 
  * The main trickiness is that the type environment (tcg_type_env) and
    fixity envt (tcg_fix_env), now contain entities from all the
diff --git a/compiler/main/PackageConfig.hs b/compiler/main/PackageConfig.hs
index 3fdb0af1d3..b19257bcea 100644
--- a/compiler/main/PackageConfig.hs
+++ b/compiler/main/PackageConfig.hs
@@ -20,7 +20,6 @@ module PackageConfig (
         PackageName(..),
         Version(..),
         defaultPackageConfig,
-        componentIdString,
         sourcePackageIdString,
         packageNameString,
         pprPackageConfig,
@@ -41,7 +40,6 @@ import Unique
 -- which is similar to a subset of the InstalledPackageInfo type from Cabal.
 
 type PackageConfig = InstalledPackageInfo
-                       ComponentId
                        SourcePackageId
                        PackageName
                        Module.UnitId
@@ -88,14 +86,11 @@ instance Outputable PackageName where
 -- | Pretty-print an 'ExposedModule' in the same format used by the textual
 -- installed package database.
 pprExposedModule :: (Outputable a, Outputable b) => ExposedModule a b -> SDoc
-pprExposedModule (ExposedModule exposedName exposedReexport exposedSignature) =
+pprExposedModule (ExposedModule exposedName exposedReexport) =
     sep [ ppr exposedName
         , case exposedReexport of
             Just m -> sep [text "from", pprOriginalModule m]
             Nothing -> empty
-        , case exposedSignature of
-            Just m -> sep [text "is", pprOriginalModule m]
-            Nothing -> empty
         ]
 
 -- | Pretty-print an 'OriginalModule' in the same format used by the textual
@@ -107,11 +102,6 @@ pprOriginalModule (OriginalModule originalPackageId originalModuleName) =
 defaultPackageConfig :: PackageConfig
 defaultPackageConfig = emptyInstalledPackageInfo
 
-componentIdString :: PackageConfig -> String
-componentIdString pkg = unpackFS str
-  where
-    ComponentId str = componentId pkg
-
 sourcePackageIdString :: PackageConfig -> String
 sourcePackageIdString pkg = unpackFS str
   where
@@ -127,7 +117,7 @@ pprPackageConfig InstalledPackageInfo {..} =
     vcat [
       field "name"                 (ppr packageName),
       field "version"              (text (showVersion packageVersion)),
-      field "id"                   (ppr componentId),
+      field "id"                   (ppr unitId),
       field "exposed"              (ppr exposed),
       field "exposed-modules"
         (if all isExposedModule exposedModules
@@ -152,7 +142,7 @@ pprPackageConfig InstalledPackageInfo {..} =
     ]
   where
     field name body = text name <> colon <+> nest 4 body
-    isExposedModule (ExposedModule _ Nothing Nothing) = True
+    isExposedModule (ExposedModule _ Nothing) = True
     isExposedModule _ = False
 
 
@@ -163,7 +153,7 @@ pprPackageConfig InstalledPackageInfo {..} =
 -- #package_naming#
 -- Mostly the compiler deals in terms of 'UnitId's, which are md5 hashes
 -- of a package ID, keys of its dependencies, and Cabal flags. You're expected
--- to pass in the unit id in the @-this-package-key@ flag. However, for
+-- to pass in the unit id in the @-this-unit-id@ flag. However, for
 -- wired-in packages like @base@ & @rts@, we don't necessarily know what the
 -- version is, so these are handled specially; see #wired_in_packages#.
 
diff --git a/compiler/main/Packages.hs b/compiler/main/Packages.hs
index cf181046f0..0a8b279374 100644
--- a/compiler/main/Packages.hs
+++ b/compiler/main/Packages.hs
@@ -602,15 +602,11 @@ matchingStr str p
         || str == packageNameString p
 
 matchingId :: String -> PackageConfig -> Bool
-matchingId str p =  str == componentIdString p
-
-matchingKey :: String -> PackageConfig -> Bool
-matchingKey str p = str == unitIdString (packageConfigId p)
+matchingId str p = str == unitIdString (packageConfigId p)
 
 matching :: PackageArg -> PackageConfig -> Bool
 matching (PackageArg str) = matchingStr str
-matching (PackageIdArg str) = matchingId str
-matching (UnitIdArg str) = matchingKey str
+matching (UnitIdArg str)  = matchingId str
 
 sortByVersion :: [PackageConfig] -> [PackageConfig]
 sortByVersion = sortBy (flip (comparing packageVersion))
@@ -1159,8 +1155,7 @@ mkModuleToPkgConfAll dflags pkg_db vis_map =
 
     es :: Bool -> [(ModuleName, Map Module ModuleOrigin)]
     es e = do
-     -- TODO: signature support
-     ExposedModule m exposedReexport _exposedSignature <- exposed_mods
+     ExposedModule m exposedReexport <- exposed_mods
      let (pk', m', pkg', origin') =
           case exposedReexport of
            Nothing -> (pk, m, pkg, fromExposedModules e)