Implement "tool-depends" in Cabal, and legacy "build-tools" via desugar

Cabal/Distribution/Backpack/ComponentsGraph.hs

@@ -12,10 +12,12 @@ import Distribution.PackageDescription as PD hiding (Flag)
 import Distribution.Simple.LocalBuildInfo
 import Distribution.Types.ComponentRequestedSpec
 import Distribution.Types.Dependency
+import Distribution.Types.ExeDependency
 import Distribution.Types.LegacyExeDependency
 import Distribution.Types.UnqualComponentName
 import Distribution.Simple.Utils
 import Distribution.Compat.Graph (Node(..))
+import Distribution.FooBar
 import qualified Distribution.Compat.Graph as Graph
 
 import Distribution.Text
@@ -55,9 +57,8 @@ toComponentsGraph enabled pkg_descr =
     -- The dependencies for the given component
     componentDeps component =
          [ CExeName toolname
-         | LegacyExeDependency name _ <- buildTools bi
-         , let toolname = mkUnqualComponentName name
-         , toolname `elem` map exeName (executables pkg_descr) ]
+         | (ExeDependency _ toolname _)
+            <- getAllInternalToolDependencies pkg_descr bi ]
 
       ++ [ if pkgname == packageName pkg_descr
            then CLibName

Cabal/Distribution/Backpack/ConfiguredComponent.hs

@@ -19,6 +19,7 @@ import Distribution.Compat.Prelude hiding ((<>))
 import Distribution.Backpack.Id
 
 import Distribution.Types.Dependency
+import Distribution.Types.ExeDependency
 import Distribution.Types.LegacyExeDependency
 import Distribution.Types.IncludeRenaming
 import Distribution.Types.Mixin
@@ -28,6 +29,7 @@ import Distribution.PackageDescription as PD hiding (Flag)
 import Distribution.Simple.Setup as Setup
 import Distribution.Simple.LocalBuildInfo
 import Distribution.Version
+import Distribution.FooBar
 
 import qualified Data.Set as Set
 import qualified Data.Map as Map
@@ -143,8 +145,9 @@ toConfiguredComponent pkg_descr this_cid
         | otherwise
         = Map.toList external_lib_map
     exe_deps = [ cid
-               | LegacyExeDependency name _ <- buildTools bi
-               , Just cid <- [ Map.lookup (mkUnqualComponentName name) exe_map ] ]
+               | (ExeDependency _ toolName _)
+                 <- getAllInternalToolDependencies pkg_descr bi
+               , Just cid <- [ Map.lookup toolName exe_map ] ]
 
 -- | Also computes the 'ComponentId', and sets cc_public if necessary.
 -- This is Cabal-only; cabal-install won't use this.

Cabal/Distribution/Backpack/LinkedComponent.hs

@@ -51,7 +51,7 @@ data LinkedComponent
         lc_insts :: [(ModuleName, OpenModule)],
         lc_component :: Component,
         lc_shape :: ModuleShape,
-        -- | Local buildTools dependencies
+        -- | Local "build-tools" and "tool-depends" dependencies
         lc_internal_build_tools :: [OpenUnitId],
         lc_public :: Bool,
         lc_includes :: [(OpenUnitId, ModuleRenaming)],

Cabal/Distribution/FooBar.hs

@@ -57,3 +57,14 @@ getAllToolDependencies pkg bi =
 -- conditions.
 isInternal :: PackageDescription -> ExeDependency -> Bool
 isInternal pkg (ExeDependency n _ _) = n == packageName pkg
+
+
+-- | Get internal "tool-depends", along with internal "build-tools"
+--
+-- This is a tiny function, but used in a number of places. The same
+-- restrictions that apply to `isInternal` also apply to this function.
+getAllInternalToolDependencies :: PackageDescription
+                               -> BuildInfo
+                               -> [ExeDependency]
+getAllInternalToolDependencies pkg bi =
+  filter (isInternal pkg) $ getAllToolDependencies pkg bi

Cabal/Distribution/PackageDescription/Check.hs

@@ -602,8 +602,7 @@ checkFields pkg =
     internalExeDeps =
       [ dep
       | bi <- allBuildInfo pkg
-      , dep <- getAllToolDependencies pkg bi
-      , isInternal pkg dep
+      , dep <- getAllInternalToolDependencies pkg bi
       ]
 
     depInternalLibraryWithExtraVersion =

Cabal/Distribution/Simple/Build.hs

@@ -30,7 +30,7 @@ import Prelude ()
 import Distribution.Compat.Prelude
 
 import Distribution.Types.Dependency
-import Distribution.Types.LegacyExeDependency
+import Distribution.Types.ExeDependency
 import Distribution.Types.LocalBuildInfo
 import Distribution.Types.TargetInfo
 import Distribution.Types.ComponentRequestedSpec
@@ -72,12 +72,12 @@ import Distribution.Simple.Utils
 import Distribution.System
 import Distribution.Text
 import Distribution.Verbosity
+import Distribution.FooBar
 
 import Distribution.Compat.Graph (IsNode(..))
 
 import Control.Monad
 import qualified Data.Set as Set
-import Data.List ( intersect )
 import System.FilePath ( (</>), (<.>), takeDirectory )
 import System.Directory ( getCurrentDirectory )
 
@@ -534,14 +534,10 @@ addInternalBuildTools pkg lbi bi progs =
     foldr updateProgram progs internalBuildTools
   where
     internalBuildTools =
-      [ simpleConfiguredProgram toolName (FoundOnSystem toolLocation)
-      | toolName <- toolNames
-      , let toolLocation = buildDir lbi </> toolName </> toolName <.> exeExtension ]
-    toolNames = intersect buildToolNames internalExeNames
-    internalExeNames = map (unUnqualComponentName . exeName) (executables pkg)
-    buildToolNames   = map buildToolName (buildTools bi)
-      where
-        buildToolName (LegacyExeDependency pname _) = pname
+      [ simpleConfiguredProgram toolName' (FoundOnSystem toolLocation)
+      | ExeDependency _ toolName _ <- getAllInternalToolDependencies pkg bi
+      , let toolName' = unUnqualComponentName toolName
+      , let toolLocation = buildDir lbi </> toolName' </> toolName' <.> exeExtension ]
 
 
 -- TODO: build separate libs in separate dirs so that we can build

Cabal/Distribution/Simple/Configure.hs

@@ -80,6 +80,7 @@ import Distribution.Simple.Setup as Setup
 import Distribution.Simple.BuildTarget
 import Distribution.Simple.LocalBuildInfo
 import Distribution.Types.Dependency
+import Distribution.Types.ExeDependency
 import Distribution.Types.LegacyExeDependency
 import Distribution.Types.PkgconfigDependency
 import Distribution.Types.LocalBuildInfo
@@ -99,6 +100,7 @@ import Distribution.Backpack.Configure
 import Distribution.Backpack.PreExistingComponent
 import Distribution.Backpack.ConfiguredComponent (newPackageDepsBehaviour)
 import Distribution.Backpack.Id
+import Distribution.FooBar
 import Distribution.Utils.LogProgress
 
 import qualified Distribution.Simple.GHC   as GHC
@@ -566,17 +568,11 @@ configure (pkg_descr0', pbi) cfg = do
     --
     -- TODO: Factor this into a helper package.
     let requiredBuildTools =
-          [ buildTool
-          | let exeNames = map (unUnqualComponentName . exeName) (executables pkg_descr)
-          , bi <- enabledBuildInfos pkg_descr enabled
-          , buildTool@(LegacyExeDependency toolPName reqVer)
-            <- buildTools bi
-          , let isInternal =
-                    toolPName `elem` exeNames
-                    -- we assume all internal build-tools are
-                    -- versioned with the package:
-                 && packageVersion pkg_descr `withinRange` reqVer
-          , not isInternal ]
+          [ LegacyExeDependency (unUnqualComponentName eName) versionRange
+          | bi <- enabledBuildInfos pkg_descr enabled
+          , buildTool@(ExeDependency _ eName versionRange)
+            <- getAllToolDependencies pkg_descr bi
+          , not $ isInternal pkg_descr buildTool ]
 
     programDb' <-
           configureAllKnownPrograms (lessVerbose verbosity) programDb