content: {-# LANGUAGE DeriveGeneric #-}
  {-# LANGUAGE DeriveDataTypeable #-}
  {-# LANGUAGE TypeFamilies #-}
  
  -- | Types used while planning how to build everything in a project.
  --
  -- Primarily this is the 'ElaboratedInstallPlan'.
  --
  module Distribution.Client.ProjectPlanning.Types (
      SolverInstallPlan,
  
      -- * Elaborated install plan types
      ElaboratedInstallPlan,
      ElaboratedConfiguredPackage(..),
  
      elabDistDirParams,
      elabExeDependencyPaths,
      elabLibDependencies,
      elabOrderLibDependencies,
      elabExeDependencies,
      elabOrderExeDependencies,
      elabSetupDependencies,
      elabPkgConfigDependencies,
      elabInplaceDependencyBuildCacheFiles,
      elabRequiresRegistration,
  
      elabPlanPackageName,
      elabConfiguredName,
      elabComponentName,
  
      ElaboratedPackageOrComponent(..),
      ElaboratedComponent(..),
      ElaboratedPackage(..),
      pkgOrderDependencies,
      ElaboratedPlanPackage,
      ElaboratedSharedConfig(..),
      ElaboratedReadyPackage,
      BuildStyle(..),
      CabalFileText,
  
      -- * Build targets
      ComponentTarget(..),
      showComponentTarget,
      showTestComponentTarget,
      showBenchComponentTarget,
      SubComponentTarget(..),
  
      isTestComponentTarget,
  
      -- * Setup script
      SetupScriptStyle(..),
    ) where
  
  import           Distribution.Client.TargetSelector
                     ( SubComponentTarget(..) )
  import           Distribution.Client.PackageHash
  
  import           Distribution.Client.Types
  import qualified Distribution.Client.InstallPlan as InstallPlan
  import           Distribution.Client.InstallPlan
                     ( GenericInstallPlan, GenericPlanPackage(..) )
  import           Distribution.Client.SolverInstallPlan
                     ( SolverInstallPlan )
  import           Distribution.Client.DistDirLayout
  
  import           Distribution.Backpack
  import           Distribution.Backpack.ModuleShape
  
  import           Distribution.Verbosity
  import           Distribution.Text
  import           Distribution.Types.ComponentRequestedSpec
  import           Distribution.Package
                     hiding (InstalledPackageId, installedPackageId)
  import           Distribution.System
  import qualified Distribution.PackageDescription as Cabal
  import           Distribution.InstalledPackageInfo (InstalledPackageInfo)
  import           Distribution.Simple.Compiler
  import qualified Distribution.Simple.BuildTarget as Cabal
  import           Distribution.Simple.Program.Db
  import           Distribution.ModuleName (ModuleName)
  import           Distribution.Simple.LocalBuildInfo (ComponentName(..))
  import qualified Distribution.Simple.InstallDirs as InstallDirs
  import           Distribution.Simple.InstallDirs (PathTemplate)
  import           Distribution.Version
  
  import qualified Distribution.Solver.Types.ComponentDeps as CD
  import           Distribution.Solver.Types.ComponentDeps (ComponentDeps)
  import           Distribution.Solver.Types.OptionalStanza
  import           Distribution.Compat.Graph (IsNode(..))
  import           Distribution.Simple.Utils (ordNub)
  
  import           Data.Map (Map)
  import           Data.Set (Set)
  import qualified Data.ByteString.Lazy as LBS
  import           Distribution.Compat.Binary
  import           GHC.Generics (Generic)
  import qualified Data.Monoid as Mon
  import           Data.Typeable
  import           Control.Monad
  
  
  
  -- | The combination of an elaborated install plan plus a
  -- 'ElaboratedSharedConfig' contains all the details necessary to be able
  -- to execute the plan without having to make further policy decisions.
  --
  -- It does not include dynamic elements such as resources (such as http
  -- connections).
  --
  type ElaboratedInstallPlan
     = GenericInstallPlan InstalledPackageInfo
                          ElaboratedConfiguredPackage
  
  type ElaboratedPlanPackage
     = GenericPlanPackage InstalledPackageInfo
                          ElaboratedConfiguredPackage
  
  -- | User-friendly display string for an 'ElaboratedPlanPackage'.
  elabPlanPackageName :: Verbosity -> ElaboratedPlanPackage -> String
  elabPlanPackageName verbosity (PreExisting ipkg)
      | verbosity <= normal = display (packageName ipkg)
      | otherwise           = display (installedUnitId ipkg)
  elabPlanPackageName verbosity (Configured elab)
      = elabConfiguredName verbosity elab
  elabPlanPackageName verbosity (Installed elab)
      = elabConfiguredName verbosity elab
  
  --TODO: [code cleanup] decide if we really need this, there's not much in it, and in principle
  --      even platform and compiler could be different if we're building things
  --      like a server + client with ghc + ghcjs
  data ElaboratedSharedConfig
     = ElaboratedSharedConfig {
  
         pkgConfigPlatform      :: Platform,
         pkgConfigCompiler      :: Compiler, --TODO: [code cleanup] replace with CompilerInfo
         -- | The programs that the compiler configured (e.g. for GHC, the progs
         -- ghc & ghc-pkg). Once constructed, only the 'configuredPrograms' are
         -- used.
         pkgConfigCompilerProgs :: ProgramDb
       }
    deriving (Show, Generic, Typeable)
    --TODO: [code cleanup] no Eq instance
  
  instance Binary ElaboratedSharedConfig
  
  data ElaboratedConfiguredPackage
     = ElaboratedConfiguredPackage {
         -- | The 'UnitId' which uniquely identifies this item in a build plan
         elabUnitId        :: UnitId,
  
         elabComponentId :: ComponentId,
         elabInstantiatedWith :: Map ModuleName Module,
         elabLinkedInstantiatedWith :: Map ModuleName OpenModule,
  
         -- | This is true if this is an indefinite package, or this is a
         -- package with no signatures.  (Notably, it's not true for instantiated
         -- packages.)  The motivation for this is if you ask to build
         -- @foo-indef@, this probably means that you want to typecheck
         -- it, NOT that you want to rebuild all of the various
         -- instantiations of it.
         elabIsCanonical :: Bool,
  
         -- | The 'PackageId' of the originating package
         elabPkgSourceId    :: PackageId,
  
         -- | Shape of the package/component, for Backpack.
         elabModuleShape    :: ModuleShape,
  
         -- | A total flag assignment for the package.
         -- TODO: Actually this can be per-component if we drop
         -- all flags that don't affect a component.
         elabFlagAssignment   :: Cabal.FlagAssignment,
  
         -- | The original default flag assignment, used only for reporting.
         elabFlagDefaults     :: Cabal.FlagAssignment,
  
         elabPkgDescription :: Cabal.PackageDescription,
  
         -- | Where the package comes from, e.g. tarball, local dir etc. This
         --   is not the same as where it may be unpacked to for the build.
         elabPkgSourceLocation :: PackageLocation (Maybe FilePath),
  
         -- | The hash of the source, e.g. the tarball. We don't have this for
         -- local source dir packages.
         elabPkgSourceHash     :: Maybe PackageSourceHash,
  
         -- | Is this package one of the ones specified by location in the
         -- project file? (As opposed to a dependency, or a named package pulled
         -- in)
         elabLocalToProject         :: Bool,
  
         -- | Are we going to build and install this package to the store, or are
         -- we going to build it and register it locally.
         elabBuildStyle             :: BuildStyle,
  
         -- | Another way of phrasing 'pkgStanzasAvailable'.
         elabEnabledSpec      :: ComponentRequestedSpec,
  
         -- | Which optional stanzas (ie testsuites, benchmarks) can be built.
         -- This means the solver produced a plan that has them available.
         -- This doesn't necessary mean we build them by default.
         elabStanzasAvailable :: Set OptionalStanza,
  
         -- | Which optional stanzas the user explicitly asked to enable or
         -- to disable. This tells us which ones we build by default, and
         -- helps with error messages when the user asks to build something
         -- they explicitly disabled.
         --
         -- TODO: The 'Bool' here should be refined into an ADT with three
         -- cases: NotRequested, ExplicitlyRequested and
         -- ImplicitlyRequested.  A stanza is explicitly requested if
         -- the user asked, for this *specific* package, that the stanza
         -- be enabled; it's implicitly requested if the user asked for
         -- all global packages to have this stanza enabled.  The
         -- difference between an explicit and implicit request is
         -- error reporting behavior: if a user asks for tests to be
         -- enabled for a specific package that doesn't have any tests,
         -- we should warn them about it, but we shouldn't complain
         -- that a user enabled tests globally, and some local packages
         -- just happen not to have any tests.  (But perhaps we should
         -- warn if ALL local packages don't have any tests.)
         elabStanzasRequested :: Map OptionalStanza Bool,
  
         elabSetupPackageDBStack    :: PackageDBStack,
         elabBuildPackageDBStack    :: PackageDBStack,
         elabRegisterPackageDBStack :: PackageDBStack,
  
         elabPkgDescriptionOverride  :: Maybe CabalFileText,
  
         -- TODO: make per-component variants of these flags
         elabVanillaLib           :: Bool,
         elabSharedLib            :: Bool,
         elabDynExe               :: Bool,
         elabGHCiLib              :: Bool,
         elabProfLib              :: Bool,
         elabProfExe              :: Bool,
         elabProfLibDetail        :: ProfDetailLevel,
         elabProfExeDetail        :: ProfDetailLevel,
         elabCoverage             :: Bool,
         elabOptimization         :: OptimisationLevel,
         elabSplitObjs            :: Bool,
         elabStripLibs            :: Bool,
         elabStripExes            :: Bool,
         elabDebugInfo            :: DebugInfoLevel,
         elabVerifyMode           :: Bool,
  
         elabProgramPaths          :: Map String FilePath,
         elabProgramArgs           :: Map String [String],
         elabProgramPathExtra      :: [FilePath],
         elabConfigureScriptArgs   :: [String],
         elabExtraLibDirs          :: [FilePath],
         elabExtraFrameworkDirs    :: [FilePath],
         elabExtraIncludeDirs      :: [FilePath],
         elabProgPrefix            :: Maybe PathTemplate,
         elabProgSuffix            :: Maybe PathTemplate,
  
         elabInstallDirs           :: InstallDirs.InstallDirs FilePath,
  
         elabHaddockHoogle         :: Bool,
         elabHaddockHtml           :: Bool,
         elabHaddockHtmlLocation   :: Maybe String,
         elabHaddockForeignLibs    :: Bool,
         elabHaddockExecutables    :: Bool,
         elabHaddockTestSuites     :: Bool,
         elabHaddockBenchmarks     :: Bool,
         elabHaddockInternal       :: Bool,
         elabHaddockCss            :: Maybe FilePath,
         elabHaddockHscolour       :: Bool,
         elabHaddockHscolourCss    :: Maybe FilePath,
         elabHaddockContents       :: Maybe PathTemplate,
  
         -- Setup.hs related things:
  
         -- | One of four modes for how we build and interact with the Setup.hs
         -- script, based on whether it's a build-type Custom, with or without
         -- explicit deps and the cabal spec version the .cabal file needs.
         elabSetupScriptStyle      :: SetupScriptStyle,
  
         -- | The version of the Cabal command line interface that we are using
         -- for this package. This is typically the version of the Cabal lib
         -- that the Setup.hs is built against.
         elabSetupScriptCliVersion :: Version,
  
         -- Build time related:
         elabBuildTargets          :: [ComponentTarget],
         elabTestTargets           :: [ComponentTarget],
         elabBenchTargets          :: [ComponentTarget],
         elabReplTarget            :: Maybe ComponentTarget,
         elabBuildHaddocks         :: Bool,
  
         --pkgSourceDir ? -- currently passed in later because they can use temp locations
         --pkgBuildDir  ? -- but could in principle still have it here, with optional instr to use temp loc
  
         -- | Component/package specific information
         elabPkgOrComp :: ElaboratedPackageOrComponent
     }
    deriving (Eq, Show, Generic, Typeable)
  
  -- | The package/component contains/is a library and so must be registered
  elabRequiresRegistration :: ElaboratedConfiguredPackage -> Bool
  elabRequiresRegistration elab =
      case elabPkgOrComp elab of
          ElabComponent comp ->
              case compComponentName comp of
                  Just cn -> is_lib cn && build_target
                  _ -> False
          ElabPackage pkg ->
              -- Tricky! Not only do we have to test if the user selected
              -- a library as a build target, we also have to test if
              -- the library was TRANSITIVELY depended upon, since we will
              -- also require a register in this case.
              --
              -- NB: It would have been far nicer to just unconditionally
              -- register in all cases, but some Custom Setups will fall
              -- over if you try to do that, ESPECIALLY if there actually is
              -- a library but they hadn't built it.
              build_target || any (depends_on_lib pkg) (elabBuildTargets elab)
    where
      depends_on_lib pkg (ComponentTarget cn _) =
          not (null (CD.select (== CD.componentNameToComponent cn)
                               (pkgDependsOnSelfLib pkg)))
      build_target =
          if not (null (elabBuildTargets elab))
              then any is_lib_target (elabBuildTargets elab)
              -- Empty build targets mean we build /everything/;
              -- that means we have to look more carefully to see
              -- if there is anything to register
              else Cabal.hasLibs (elabPkgDescription elab)
      -- NB: this means we DO NOT reregister if you just built a
      -- single file
      is_lib_target (ComponentTarget cn WholeComponent) = is_lib cn
      is_lib_target _ = False
      is_lib CLibName = True
      is_lib (CSubLibName _) = True
      is_lib _ = False
  
  instance Package ElaboratedConfiguredPackage where
    packageId = elabPkgSourceId
  
  instance HasConfiguredId ElaboratedConfiguredPackage where
    configuredId elab =
      ConfiguredId (packageId elab) (elabComponentName elab) (elabComponentId elab)
  
  instance HasUnitId ElaboratedConfiguredPackage where
    installedUnitId = elabUnitId
  
  instance IsNode ElaboratedConfiguredPackage where
      type Key ElaboratedConfiguredPackage = UnitId
      nodeKey = elabUnitId
      nodeNeighbors = elabOrderDependencies
  
  instance Binary ElaboratedConfiguredPackage
  
  data ElaboratedPackageOrComponent
      = ElabPackage   ElaboratedPackage
      | ElabComponent ElaboratedComponent
    deriving (Eq, Show, Generic)
  
  instance Binary ElaboratedPackageOrComponent
  
  elabComponentName :: ElaboratedConfiguredPackage -> Maybe ComponentName
  elabComponentName elab =
      case elabPkgOrComp elab of
          ElabPackage _      -> Just CLibName -- there could be more, but default this
          ElabComponent comp -> compComponentName comp
  
  -- | A user-friendly descriptor for an 'ElaboratedConfiguredPackage'.
  elabConfiguredName :: Verbosity -> ElaboratedConfiguredPackage -> String
  elabConfiguredName verbosity elab
      | verbosity <= normal
      = (case elabPkgOrComp elab of
          ElabPackage _ -> ""
          ElabComponent comp ->
              case compComponentName comp of
                  Nothing -> "setup from "
                  Just CLibName -> ""
                  Just cname -> display cname ++ " from ")
        ++ display (packageId elab)
      | otherwise
      = display (elabUnitId elab)
  
  elabDistDirParams :: ElaboratedSharedConfig -> ElaboratedConfiguredPackage -> DistDirParams
  elabDistDirParams shared elab = DistDirParams {
          distParamUnitId = installedUnitId elab,
          distParamComponentId = elabComponentId elab,
          distParamPackageId = elabPkgSourceId elab,
          distParamComponentName = case elabPkgOrComp elab of
              ElabComponent comp -> compComponentName comp
              ElabPackage _ -> Nothing,
          distParamCompilerId = compilerId (pkgConfigCompiler shared),
          distParamPlatform = pkgConfigPlatform shared,
          distParamOptimization = elabOptimization elab
      }
  
  -- | The full set of dependencies which dictate what order we
  -- need to build things in the install plan: "order dependencies"
  -- balls everything together.  This is mostly only useful for
  -- ordering; if you are, for example, trying to compute what
  -- @--dependency@ flags to pass to a Setup script, you need to
  -- use 'elabLibDependencies'.  This method is the same as
  -- 'nodeNeighbors'.
  --
  -- NB: this method DOES include setup deps.
  elabOrderDependencies :: ElaboratedConfiguredPackage -> [UnitId]
  elabOrderDependencies elab =
      case elabPkgOrComp elab of
          -- Important not to have duplicates: otherwise InstallPlan gets
          -- confused.
          ElabPackage pkg    -> ordNub (CD.flatDeps (pkgOrderDependencies pkg))
          ElabComponent comp -> compOrderDependencies comp
  
  -- | Like 'elabOrderDependencies', but only returns dependencies on
  -- libraries.
  elabOrderLibDependencies :: ElaboratedConfiguredPackage -> [UnitId]
  elabOrderLibDependencies elab =
      case elabPkgOrComp elab of
          ElabPackage _      -> map (newSimpleUnitId . confInstId) (elabLibDependencies elab)
          ElabComponent comp -> compOrderLibDependencies comp
  
  -- | The library dependencies (i.e., the libraries we depend on, NOT
  -- the dependencies of the library), NOT including setup dependencies.
  -- These are passed to the @Setup@ script via @--dependency@.
  elabLibDependencies :: ElaboratedConfiguredPackage -> [ConfiguredId]
  elabLibDependencies elab =
      case elabPkgOrComp elab of
          ElabPackage pkg    -> ordNub (CD.nonSetupDeps (pkgLibDependencies pkg))
          ElabComponent comp -> compLibDependencies comp
  
  -- | Like 'elabOrderDependencies', but only returns dependencies on
  -- executables.  (This coincides with 'elabExeDependencies'.)
  elabOrderExeDependencies :: ElaboratedConfiguredPackage -> [UnitId]
  elabOrderExeDependencies =
      map newSimpleUnitId . elabExeDependencies
  
  -- | The executable dependencies (i.e., the executables we depend on);
  -- these are the executables we must add to the PATH before we invoke
  -- the setup script.
  elabExeDependencies :: ElaboratedConfiguredPackage -> [ComponentId]
  elabExeDependencies elab = map confInstId $
      case elabPkgOrComp elab of
          ElabPackage pkg    -> CD.nonSetupDeps (pkgExeDependencies pkg)
          ElabComponent comp -> compExeDependencies comp
  
  -- | This returns the paths of all the executables we depend on; we
  -- must add these paths to PATH before invoking the setup script.
  -- (This is usually what you want, not 'elabExeDependencies', if you
  -- actually want to build something.)
  elabExeDependencyPaths :: ElaboratedConfiguredPackage -> [FilePath]
  elabExeDependencyPaths elab =
      case elabPkgOrComp elab of
          ElabPackage pkg    -> map snd $ CD.nonSetupDeps (pkgExeDependencyPaths pkg)
          ElabComponent comp -> map snd (compExeDependencyPaths comp)
  
  -- | The setup dependencies (the library dependencies of the setup executable;
  -- note that it is not legal for setup scripts to have executable
  -- dependencies at the moment.)
  elabSetupDependencies :: ElaboratedConfiguredPackage -> [ConfiguredId]
  elabSetupDependencies elab =
      case elabPkgOrComp elab of
          ElabPackage pkg -> CD.setupDeps (pkgLibDependencies pkg)
          -- TODO: Custom setups not supported for components yet.  When
          -- they are, need to do this differently
          ElabComponent _ -> []
  
  elabPkgConfigDependencies :: ElaboratedConfiguredPackage -> [(PkgconfigName, Maybe Version)]
  elabPkgConfigDependencies ElaboratedConfiguredPackage { elabPkgOrComp = ElabPackage pkg }
      = pkgPkgConfigDependencies pkg
  elabPkgConfigDependencies ElaboratedConfiguredPackage { elabPkgOrComp = ElabComponent comp }
      = compPkgConfigDependencies comp
  
  -- | The cache files of all our inplace dependencies which,
  -- when updated, require us to rebuild.  See #4202 for
  -- more details.  Essentially, this is a list of filepaths
  -- that, if our dependencies get rebuilt, will themselves
  -- get updated.
  --
  -- Note: the hash of these cache files gets built into
  -- the build cache ourselves, which means that we end
  -- up tracking transitive dependencies!
  --
  -- Note: This tracks the "build" cache file, but not
  -- "registration" or "config" cache files.  Why not?
  -- Arguably we should...
  --
  -- Note: This is a bit of a hack, because it is not really
  -- the hashes of the SOURCES of our (transitive) dependencies
  -- that we should use to decide whether or not to rebuild,
  -- but the output BUILD PRODUCTS.  The strategy we use
  -- here will never work if we want to implement unchanging
  -- rebuilds.
  elabInplaceDependencyBuildCacheFiles
      :: DistDirLayout
      -> ElaboratedSharedConfig
      -> ElaboratedInstallPlan
      -> ElaboratedConfiguredPackage
      -> [FilePath]
  elabInplaceDependencyBuildCacheFiles layout sconf plan root_elab =
      go =<< InstallPlan.directDeps plan (nodeKey root_elab)
    where
      go = InstallPlan.foldPlanPackage (const []) $ \elab -> do
              guard (elabBuildStyle elab == BuildInplaceOnly)
              return $ distPackageCacheFile layout (elabDistDirParams sconf elab) "build"
  
  -- | Some extra metadata associated with an
  -- 'ElaboratedConfiguredPackage' which indicates that the "package"
  -- in question is actually a single component to be built.  Arguably
  -- it would be clearer if there were an ADT which branched into
  -- package work items and component work items, but I've structured
  -- it this way to minimize change to the existing code (which I
  -- don't feel qualified to rewrite.)
  data ElaboratedComponent
     = ElaboratedComponent {
      -- | The name of the component to be built according to the solver
      compSolverName :: CD.Component,
      -- | The name of the component to be built.  Nothing if
      -- it's a setup dep.
      compComponentName :: Maybe ComponentName,
      -- | The *external* library dependencies of this component.  We
      -- pass this to the configure script.
      compLibDependencies :: [ConfiguredId],
      -- | In a component prior to instantiation, this list specifies
      -- the 'OpenUnitId's which, after instantiation, are the
      -- actual dependencies of this package.  Note that this does
      -- NOT include signature packages, which do not turn into real
      -- ordering dependencies when we instantiate.  This is intended to be
      -- a purely temporary field, to carry some information to the
      -- instantiation phase. It's more precise than
      -- 'compLibDependencies', and also stores information about internal
      -- dependencies.
      compLinkedLibDependencies :: [OpenUnitId],
      -- | The executable dependencies of this component (including
      -- internal executables).
      compExeDependencies :: [ConfiguredId],
      -- | The @pkg-config@ dependencies of the component
      compPkgConfigDependencies :: [(PkgconfigName, Maybe Version)],
      -- | The paths all our executable dependencies will be installed
      -- to once they are installed.
      compExeDependencyPaths :: [(ConfiguredId, FilePath)],
      compOrderLibDependencies :: [UnitId]
     }
    deriving (Eq, Show, Generic)
  
  instance Binary ElaboratedComponent
  
  -- | See 'elabOrderDependencies'.
  compOrderDependencies :: ElaboratedComponent -> [UnitId]
  compOrderDependencies comp =
      compOrderLibDependencies comp
   ++ compOrderExeDependencies comp
  
  -- | See 'elabOrderExeDependencies'.
  compOrderExeDependencies :: ElaboratedComponent -> [UnitId]
  compOrderExeDependencies = map (newSimpleUnitId . confInstId) . compExeDependencies
  
  data ElaboratedPackage
     = ElaboratedPackage {
         pkgInstalledId :: InstalledPackageId,
  
         -- | The exact dependencies (on other plan packages)
         --
         pkgLibDependencies :: ComponentDeps [ConfiguredId],
  
         -- | Components which depend (transitively) on an internally
         -- defined library.  These are used by 'elabRequiresRegistration',
         -- to determine if a user-requested build is going to need
         -- a library registration
         --
         pkgDependsOnSelfLib :: ComponentDeps [()],
  
         -- | Dependencies on executable packages.
         --
         pkgExeDependencies :: ComponentDeps [ConfiguredId],
  
         -- | Paths where executable dependencies live.
         --
         pkgExeDependencyPaths :: ComponentDeps [(ConfiguredId, FilePath)],
  
         -- | Dependencies on @pkg-config@ packages.
         -- NB: this is NOT per-component (although it could be)
         -- because Cabal library does not track per-component
         -- pkg-config depends; it always does them all at once.
         --
         pkgPkgConfigDependencies :: [(PkgconfigName, Maybe Version)],
  
         -- | Which optional stanzas (ie testsuites, benchmarks) will actually
         -- be enabled during the package configure step.
         pkgStanzasEnabled :: Set OptionalStanza
       }
    deriving (Eq, Show, Generic)
  
  instance Binary ElaboratedPackage
  
  -- | See 'elabOrderDependencies'.  This gives the unflattened version,
  -- which can be useful in some circumstances.
  pkgOrderDependencies :: ElaboratedPackage -> ComponentDeps [UnitId]
  pkgOrderDependencies pkg =
      fmap (map (newSimpleUnitId . confInstId)) (pkgLibDependencies pkg) `Mon.mappend`
      fmap (map (newSimpleUnitId . confInstId)) (pkgExeDependencies pkg)
  
  -- | This is used in the install plan to indicate how the package will be
  -- built.
  --
  data BuildStyle =
      -- | The classic approach where the package is built, then the files
      -- installed into some location and the result registered in a package db.
      --
      -- If the package came from a tarball then it's built in a temp dir and
      -- the results discarded.
      BuildAndInstall
  
      -- | The package is built, but the files are not installed anywhere,
      -- rather the build dir is kept and the package is registered inplace.
      --
      -- Such packages can still subsequently be installed.
      --
      -- Typically 'BuildAndInstall' packages will only depend on other
      -- 'BuildAndInstall' style packages and not on 'BuildInplaceOnly' ones.
      --
    | BuildInplaceOnly
    deriving (Eq, Show, Generic)
  
  instance Binary BuildStyle
  
  type CabalFileText = LBS.ByteString
  
  type ElaboratedReadyPackage = GenericReadyPackage ElaboratedConfiguredPackage
  
  
  ---------------------------
  -- Build targets
  --
  
  -- | Specific targets within a package or component to act on e.g. to build,
  -- haddock or open a repl.
  --
  data ComponentTarget = ComponentTarget ComponentName SubComponentTarget
    deriving (Eq, Ord, Show, Generic)
  
  instance Binary ComponentTarget
  
  -- | Unambiguously render a 'ComponentTarget', e.g., to pass
  -- to a Cabal Setup script.
  showComponentTarget :: PackageId -> ComponentTarget -> String
  showComponentTarget pkgid =
      Cabal.showBuildTarget pkgid . toBuildTarget
    where
      toBuildTarget :: ComponentTarget -> Cabal.BuildTarget
      toBuildTarget (ComponentTarget cname subtarget) =
        case subtarget of
          WholeComponent     -> Cabal.BuildTargetComponent cname
          ModuleTarget mname -> Cabal.BuildTargetModule    cname mname
          FileTarget   fname -> Cabal.BuildTargetFile      cname fname
  
  showTestComponentTarget :: PackageId -> ComponentTarget -> Maybe String
  showTestComponentTarget _ (ComponentTarget (CTestName n) _) = Just $ display n
  showTestComponentTarget _ _ = Nothing
  
  isTestComponentTarget :: ComponentTarget -> Bool
  isTestComponentTarget (ComponentTarget (CTestName _) _) = True
  isTestComponentTarget _                                 = False
  
  showBenchComponentTarget :: PackageId -> ComponentTarget -> Maybe String
  showBenchComponentTarget _ (ComponentTarget (CBenchName n) _) = Just $ display n
  showBenchComponentTarget _ _ = Nothing
  
  ---------------------------
  -- Setup.hs script policy
  --
  
  -- | There are four major cases for Setup.hs handling:
  --
  --  1. @build-type@ Custom with a @custom-setup@ section
  --  2. @build-type@ Custom without a @custom-setup@ section
  --  3. @build-type@ not Custom with @cabal-version >  $our-cabal-version@
  --  4. @build-type@ not Custom with @cabal-version <= $our-cabal-version@
  --
  -- It's also worth noting that packages specifying @cabal-version: >= 1.23@
  -- or later that have @build-type@ Custom will always have a @custom-setup@
  -- section. Therefore in case 2, the specified @cabal-version@ will always be
  -- less than 1.23.
  --
  -- In cases 1 and 2 we obviously have to build an external Setup.hs script,
  -- while in case 4 we can use the internal library API. In case 3 we also have
  -- to build an external Setup.hs script because the package needs a later
  -- Cabal lib version than we can support internally.
  --
  data SetupScriptStyle = SetupCustomExplicitDeps
                        | SetupCustomImplicitDeps
                        | SetupNonCustomExternalLib
                        | SetupNonCustomInternalLib
    deriving (Eq, Show, Generic, Typeable)
  
  instance Binary SetupScriptStyle
  