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

Cabal/Distribution/Backpack/ComponentsGraph.hs

@@ -9,10 +9,11 @@ module Distribution.Backpack.ComponentsGraph (
 
 import Distribution.Package
 import Distribution.PackageDescription as PD hiding (Flag)
+import Distribution.Simple.BuildToolDepends
 import Distribution.Simple.LocalBuildInfo
 import Distribution.Types.ComponentRequestedSpec
 import Distribution.Types.Dependency
-import Distribution.Types.LegacyExeDependency
+import Distribution.Types.ExeDependency
 import Distribution.Types.UnqualComponentName
 import Distribution.Simple.Utils
 import Distribution.Compat.Graph (Node(..))
@@ -55,9 +56,8 @@ 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

@@ -19,13 +19,14 @@ import Distribution.Compat.Prelude hiding ((<>))
 import Distribution.Backpack.Id
 
 import Distribution.Types.Dependency
-import Distribution.Types.LegacyExeDependency
+import Distribution.Types.ExeDependency
 import Distribution.Types.IncludeRenaming
 import Distribution.Types.Mixin
 import Distribution.Types.UnqualComponentName
 import Distribution.Types.ComponentInclude
 import Distribution.Package
 import Distribution.PackageDescription as PD hiding (Flag)
+import Distribution.Simple.BuildToolDepends
 import Distribution.Simple.Setup as Setup
 import Distribution.Simple.LocalBuildInfo
 import Distribution.Version
@@ -169,8 +170,9 @@ 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

@@ -58,8 +58,9 @@ data LinkedComponent
         lc_pkgid :: PackageId,
         -- | Corresponds to 'cc_component'.
         lc_component :: Component,
-        -- | Local @build-tools@ dependencies on executables from the
-        -- same executable.  Corresponds to 'cc_internal_build_tools'.
+        -- | Local @build-tools@ and @build-tool-depends@ dependencies on
+        -- executables from the same package.  Corresponds to
+        -- 'cc_internal_build_tools'.
         lc_internal_build_tools :: [OpenUnitId],
         -- | Is this the public library of a package?  Corresponds to
         -- 'cc_public'.

Cabal/Distribution/PackageDescription/Check.hs

@@ -603,8 +603,7 @@ 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
@@ -59,6 +59,7 @@ import qualified Distribution.ModuleName as ModuleName
 
 import Distribution.Simple.Setup
 import Distribution.Simple.BuildTarget
+import Distribution.Simple.BuildToolDepends
 import Distribution.Simple.PreProcess
 import Distribution.Simple.LocalBuildInfo
 import Distribution.Simple.Program.Types
@@ -77,7 +78,6 @@ 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 )
 
@@ -536,14 +536,10 @@ 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/BuildToolDepends.hs

@@ -77,3 +77,14 @@ getAllToolDependencies pkg bi =
 -- conditions.
 isInternal :: PackageDescription -> ExeDependency -> Bool
 isInternal pkg (ExeDependency n _ _) = n == packageName pkg
+
+
+-- | Get internal "build-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/Simple/Configure.hs

@@ -75,11 +75,13 @@ import Distribution.Types.PackageDescription as PD
 import Distribution.PackageDescription.PrettyPrint
 import Distribution.PackageDescription.Configuration
 import Distribution.PackageDescription.Check hiding (doesFileExist)
+import Distribution.Simple.BuildToolDepends
 import Distribution.Simple.Program
 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
@@ -573,17 +575,11 @@ 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