From 80fe5e176dca3e7099bc4607214607a4a64246f4 Mon Sep 17 00:00:00 2001
From: Michael Snoyman <michael@snoyman.com>
Date: Mon, 24 Jul 2017 09:55:10 +0300
Subject: [PATCH 1/7] Upgrade to Cabal 2.0

---
 ChangeLog.md                     |  1 +
 Setup.hs                         | 19 ++++----
 src/Stack/Build/ConstructPlan.hs |  2 +-
 src/Stack/BuildPlan.hs           |  3 +-
 src/Stack/Config.hs              |  9 ++--
 src/Stack/Init.hs                |  2 +-
 src/Stack/Options/Completion.hs  |  7 +--
 src/Stack/Package.hs             | 74 +++++++++++++++++++-------------
 src/Stack/Setup.hs               |  3 +-
 src/Stack/Snapshot.hs            |  6 ++-
 src/Stack/Types/Config.hs        |  4 +-
 src/Stack/Types/FlagName.hs      |  6 +--
 src/Stack/Types/PackageName.hs   |  6 +--
 src/Stack/Types/Version.hs       |  6 +--
 src/Stack/Upgrade.hs             |  3 +-
 src/main/Main.hs                 |  3 +-
 stack-7.10.yaml                  |  2 +-
 stack-nightly.yaml               |  1 +
 stack.cabal                      |  8 ++--
 stack.yaml                       |  1 +
 20 files changed, 97 insertions(+), 69 deletions(-)

diff --git a/ChangeLog.md b/ChangeLog.md
index 905b58c159..351b5e0e6b 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -11,6 +11,7 @@ Major changes:
   details, please see
   [the writeup on these changes](https://www.fpcomplete.com/blog/2017/07/stacks-new-extensible-snapshots). [PR #3249](https://github.com/commercialhaskell/stack/pull/3249),
   see the PR description for a number of related issues.
+* Upgraded to version 2.0 of the Cabal library.
 
 Behavior changes:
 
diff --git a/Setup.hs b/Setup.hs
index 179845c1dd..6bae7f52c3 100644
--- a/Setup.hs
+++ b/Setup.hs
@@ -3,8 +3,7 @@ module Main (main) where
 
 import Data.List ( nub, sortBy )
 import Data.Ord ( comparing )
-import Data.Version ( showVersion )
-import Distribution.Package ( PackageName(PackageName), PackageId, InstalledPackageId, packageVersion, packageName )
+import Distribution.Package ( PackageId, InstalledPackageId, packageVersion, packageName )
 import Distribution.PackageDescription ( PackageDescription(), Executable(..) )
 import Distribution.InstalledPackageInfo (sourcePackageId, installedPackageId)
 import Distribution.Simple ( defaultMainWithHooks, UserHooks(..), simpleUserHooks )
@@ -13,7 +12,10 @@ import Distribution.Simple.BuildPaths ( autogenModulesDir )
 import Distribution.Simple.PackageIndex (allPackages, dependencyClosure)
 import Distribution.Simple.Setup ( BuildFlags(buildVerbosity), fromFlag )
 import Distribution.Simple.LocalBuildInfo ( installedPkgs, withLibLBI, withExeLBI, LocalBuildInfo(), ComponentLocalBuildInfo(componentPackageDeps) )
+import Distribution.Types.PackageName (PackageName, unPackageName)
+import Distribution.Types.UnqualComponentName (unUnqualComponentName)
 import Distribution.Verbosity ( Verbosity )
+import Distribution.Version ( showVersion )
 import System.FilePath ( (</>) )
 
 main :: IO ()
@@ -29,27 +31,28 @@ generateBuildModule verbosity pkg lbi = do
   createDirectoryIfMissingVerbose verbosity True dir
   withLibLBI pkg lbi $ \_ libcfg -> do
     withExeLBI pkg lbi $ \exe clbi ->
-      rewriteFile (dir </> "Build_" ++ exeName exe ++ ".hs") $ unlines
-        [ "module Build_" ++ exeName exe ++ " where"
+      rewriteFile (dir </> "Build_" ++ exeName' exe ++ ".hs") $ unlines
+        [ "module Build_" ++ exeName' exe ++ " where"
         , ""
         , "deps :: [String]"
         , "deps = " ++ (show $ formatdeps (transDeps libcfg clbi))
         ]
   where
+    exeName' = unUnqualComponentName . exeName
     formatdeps = map formatone . sortBy (comparing unPackageName')
     formatone p = unPackageName' p ++ "-" ++ showVersion (packageVersion p)
-    unPackageName' p = case packageName p of PackageName n -> n
+    unPackageName' = unPackageName . packageName
     transDeps xs ys =
       either (map sourcePackageId . allPackages) handleDepClosureFailure $ dependencyClosure allInstPkgsIdx availInstPkgIds
       where
         allInstPkgsIdx = installedPkgs lbi
         allInstPkgIds = map installedPackageId $ allPackages allInstPkgsIdx
         -- instPkgIds includes `stack-X.X.X`, which is not a depedency hence is missing from allInstPkgsIdx. Filter that out.
-        availInstPkgIds = filter (`elem` allInstPkgIds) . map fst $ testDeps xs ys
+        availInstPkgIds = filter (`elem` allInstPkgIds) $ testDeps xs ys
         handleDepClosureFailure unsatisfied =
           error $
             "Computation of transitive dependencies failed." ++
             if null unsatisfied then "" else " Unresolved dependencies: " ++ show unsatisfied
 
-testDeps :: ComponentLocalBuildInfo -> ComponentLocalBuildInfo -> [(InstalledPackageId, PackageId)]
-testDeps xs ys = nub $ componentPackageDeps xs ++ componentPackageDeps ys
+testDeps :: ComponentLocalBuildInfo -> ComponentLocalBuildInfo -> [InstalledPackageId]
+testDeps xs ys = map fst $ nub $ componentPackageDeps xs ++ componentPackageDeps ys
diff --git a/src/Stack/Build/ConstructPlan.hs b/src/Stack/Build/ConstructPlan.hs
index a8975582ef..9be0fe814e 100644
--- a/src/Stack/Build/ConstructPlan.hs
+++ b/src/Stack/Build/ConstructPlan.hs
@@ -795,7 +795,7 @@ packageDepsWithTools p = do
     ctx <- ask
     -- TODO: it would be cool to defer these warnings until there's an
     -- actual issue building the package.
-    let toEither (Cabal.Dependency (Cabal.PackageName name) _) mp =
+    let toEither (Cabal.Dependency (Cabal.unPackageName -> name) _) mp =
             case Map.toList mp of
                 [] -> Left (NoToolFound name (packageName p))
                 [_] -> Right mp
diff --git a/src/Stack/BuildPlan.hs b/src/Stack/BuildPlan.hs
index b3aeeea7dd..7e44b5aab3 100644
--- a/src/Stack/BuildPlan.hs
+++ b/src/Stack/BuildPlan.hs
@@ -44,6 +44,7 @@ import           Distribution.PackageDescription (GenericPackageDescription,
                                                   flagName, genPackageFlags,
                                                   condExecutables)
 import qualified Distribution.PackageDescription as C
+import qualified Distribution.Types.UnqualComponentName as C
 import           Distribution.System (Platform)
 import           Distribution.Text (display)
 import qualified Distribution.Version as C
@@ -186,7 +187,7 @@ getToolMap ls locals =
     -- worse case scenario is we build an extra package that wasn't
     -- strictly needed.
     gpdExes :: GenericPackageDescription -> [Text]
-    gpdExes = map (T.pack . fst) . condExecutables
+    gpdExes = map (T.pack . C.unUnqualComponentName . fst) . condExecutables
 
 gpdPackages :: [GenericPackageDescription] -> Map PackageName Version
 gpdPackages gpds = Map.fromList $
diff --git a/src/Stack/Config.hs b/src/Stack/Config.hs
index 1c5ae21e6b..ee85860692 100644
--- a/src/Stack/Config.hs
+++ b/src/Stack/Config.hs
@@ -59,9 +59,10 @@ import qualified Data.Text as T
 import           Data.Text.Encoding (encodeUtf8)
 import qualified Data.Yaml as Yaml
 import qualified Distribution.PackageDescription as C
+import qualified Distribution.Types.UnqualComponentName as C
 import           Distribution.System (OS (..), Platform (..), buildPlatform, Arch(OtherArch))
 import qualified Distribution.Text
-import           Distribution.Version (simplifyVersionRange)
+import           Distribution.Version (simplifyVersionRange, mkVersion')
 import           GHC.Conc (getNumProcessors)
 import           Lens.Micro (lens)
 import           Network.HTTP.Client (parseUrlThrow)
@@ -473,7 +474,7 @@ loadConfigMaybeProject configArgs mresolver mproject = do
           LCSNoConfig _ -> configNoLocalConfig stackRoot mresolver configArgs
           LCSProject project -> loadHelper $ Just project
           LCSNoProject -> loadHelper Nothing
-    unless (fromCabalVersion Meta.version `withinRange` configRequireStackVersion config)
+    unless (fromCabalVersion (mkVersion' Meta.version) `withinRange` configRequireStackVersion config)
         (throwM (BadStackVersionException (configRequireStackVersion config)))
 
     let mprojectRoot = fmap (\(_, fp, _) -> parent fp) mproject
@@ -708,9 +709,9 @@ getNamedComponents gpkg = Set.fromList $ concat
     ]
   where
     go :: (T.Text -> NamedComponent)
-       -> (C.GenericPackageDescription -> [String])
+       -> (C.GenericPackageDescription -> [C.UnqualComponentName])
        -> [NamedComponent]
-    go wrapper f = map (wrapper . T.pack) $ f gpkg
+    go wrapper f = map (wrapper . T.pack . C.unUnqualComponentName) $ f gpkg
 
 -- | Check if there are any duplicate package names and, if so, throw an
 -- exception.
diff --git a/src/Stack/Init.hs b/src/Stack/Init.hs
index e8381e8edc..0231058af4 100644
--- a/src/Stack/Init.hs
+++ b/src/Stack/Init.hs
@@ -293,7 +293,7 @@ renderStackYaml p ignoredPackages dupPackages =
 
     footerHelp =
         let major = toCabalVersion
-                    $ toMajorVersion $ fromCabalVersion Meta.version
+                    $ toMajorVersion $ fromCabalVersion $ C.mkVersion' Meta.version
         in commentHelp
         [ "Control whether we use the GHC we find on the path"
         , "system-ghc: true"
diff --git a/src/Stack/Options/Completion.hs b/src/Stack/Options/Completion.hs
index e316095d45..af26b2efac 100644
--- a/src/Stack/Options/Completion.hs
+++ b/src/Stack/Options/Completion.hs
@@ -18,6 +18,7 @@ import           Data.Maybe
 import qualified Data.Set as Set
 import qualified Data.Text as T
 import qualified Distribution.PackageDescription as C
+import qualified Distribution.Types.UnqualComponentName as C
 import           Options.Applicative
 import           Options.Applicative.Builder.Extra
 import           Stack.Config (getLocalPackages)
@@ -89,8 +90,8 @@ flagCompleter = buildConfigCompleter $ \input -> do
                     (C.genPackageFlags (lpvGPD lpv)))
             $ Map.toList lpvs
         flagString name fl =
-            case C.flagName fl of
-                C.FlagName flname -> (if flagEnabled name fl then "-" else "") ++ flname
+            let flname = C.unFlagName $ C.flagName fl
+             in (if flagEnabled name fl then "-" else "") ++ flname
         flagEnabled name fl =
             fromMaybe (C.flagDefault fl) $
             Map.lookup (fromCabalFlagName (C.flagName fl)) $
@@ -107,5 +108,5 @@ projectExeCompleter = buildConfigCompleter $ \input -> do
     return $
         filter (input `isPrefixOf`) $
         nubOrd $
-        concatMap (\(_, lpv) -> map fst (C.condExecutables (lpvGPD lpv))) $
+        concatMap (\(_, lpv) -> map (C.unUnqualComponentName . fst) (C.condExecutables (lpvGPD lpv))) $
         Map.toList lpvs
diff --git a/src/Stack/Package.hs b/src/Stack/Package.hs
index f22fb33d36..3a028c0000 100644
--- a/src/Stack/Package.hs
+++ b/src/Stack/Package.hs
@@ -51,7 +51,6 @@ import qualified Data.Set as S
 import qualified Data.Text as T
 import           Data.Text.Encoding (decodeUtf8, decodeUtf8With)
 import           Data.Text.Encoding.Error (lenientDecode)
-import           Data.Version (showVersion)
 import           Distribution.Compiler
 import           Distribution.ModuleName (ModuleName)
 import qualified Distribution.ModuleName as Cabal
@@ -65,7 +64,13 @@ import           Distribution.ParseUtils
 import           Distribution.Simple.Utils
 import           Distribution.System (OS (..), Arch, Platform (..))
 import qualified Distribution.Text as D
+import qualified Distribution.Types.CondTree as Cabal
+import qualified Distribution.Types.Dependency as Cabal
+import qualified Distribution.Types.ExeDependency as Cabal
+import qualified Distribution.Types.LegacyExeDependency as Cabal
+import qualified Distribution.Types.UnqualComponentName as Cabal
 import qualified Distribution.Verbosity as D
+import           Distribution.Version (showVersion)
 import qualified Hpack
 import qualified Hpack.Config as Hpack
 import           Path as FL
@@ -116,7 +121,7 @@ readPackageUnresolvedBS source bs =
 rawParseGPD :: BS.ByteString
             -> Either PError ([PWarning], GenericPackageDescription)
 rawParseGPD bs =
-    case parsePackageDescription chars of
+    case parseGenericPackageDescription chars of
        ParseFailed per -> Left per
        ParseOk warnings gpkg -> Right (warnings,gpkg)
   where
@@ -217,7 +222,9 @@ packageFromPackageDescription packageConfig pkgFlags pkg =
     , packageLicense = license pkg
     , packageDeps = deps
     , packageFiles = pkgFiles
-    , packageTools = packageDescTools pkg
+    , packageTools = map
+        (\(Cabal.ExeDependency name' _ range) -> Cabal.Dependency name' range)
+        (packageDescTools pkg)
     , packageGhcOptions = packageConfigGhcOptions packageConfig
     , packageFlags = packageConfigFlags packageConfig
     , packageDefaultFlags = M.fromList
@@ -225,13 +232,14 @@ packageFromPackageDescription packageConfig pkgFlags pkg =
     , packageAllDeps = S.fromList (M.keys deps)
     , packageHasLibrary = maybe False (buildable . libBuildInfo) (library pkg)
     , packageTests = M.fromList
-      [(T.pack (testName t), testInterface t) | t <- testSuites pkg
+      [(T.pack (Cabal.unUnqualComponentName $ testName t), testInterface t) | t <- testSuites pkg
                                               , buildable (testBuildInfo t)]
     , packageBenchmarks = S.fromList
-      [T.pack (benchmarkName biBuildInfo) | biBuildInfo <- benchmarks pkg
+      [T.pack (Cabal.unUnqualComponentName $ benchmarkName biBuildInfo) | biBuildInfo <- benchmarks pkg
                                           , buildable (benchmarkBuildInfo biBuildInfo)]
     , packageExes = S.fromList
-      [T.pack (exeName biBuildInfo) | biBuildInfo <- executables pkg
+      [T.pack (Cabal.unUnqualComponentName $ exeName biBuildInfo)
+        | biBuildInfo <- executables pkg
                                     , buildable (buildInfo biBuildInfo)]
     -- This is an action used to collect info needed for "stack ghci".
     -- This info isn't usually needed, so computation of it is deferred.
@@ -338,19 +346,19 @@ generatePkgDescOpts sourceMap installedMap omitPkgs addPkgs cabalfp pkg componen
                    , fmap
                          (\exe ->
                                generate
-                                    (CExe (T.pack (exeName exe)))
+                                    (CExe (T.pack (Cabal.unUnqualComponentName (exeName exe))))
                                     (buildInfo exe))
                          (executables pkg)
                    , fmap
                          (\bench ->
                                generate
-                                    (CBench (T.pack (benchmarkName bench)))
+                                    (CBench (T.pack (Cabal.unUnqualComponentName (benchmarkName bench))))
                                     (benchmarkBuildInfo bench))
                          (benchmarks pkg)
                    , fmap
                          (\test ->
                                generate
-                                    (CTest (T.pack (testName test)))
+                                    (CTest (T.pack (Cabal.unUnqualComponentName (testName test))))
                                     (testBuildInfo test))
                          (testSuites pkg)]))
   where
@@ -531,13 +539,13 @@ packageDependencies pkg =
 packageToolDependencies :: PackageDescription -> Map Text VersionRange
 packageToolDependencies =
   M.fromList .
-  concatMap (fmap (packageNameText . depName &&& depRange) .
+  concatMap (fmap (\(Cabal.LegacyExeDependency name range) -> (T.pack name, range)) .
              buildTools) .
   allBuildInfo'
 
 -- | Get all dependencies of the package (buildable targets only).
-packageDescTools :: PackageDescription -> [Dependency]
-packageDescTools = concatMap buildTools . allBuildInfo'
+packageDescTools :: PackageDescription -> [Cabal.ExeDependency]
+packageDescTools = concatMap buildToolDepends . allBuildInfo'
 
 -- | This is a copy-paste from Cabal's @allBuildInfo@ function, but with the
 -- @buildable@ test removed. The implementation is broken.
@@ -551,12 +559,10 @@ allBuildInfo' pkg_descr = [ bi | Just lib <- [library pkg_descr]
                               , True || buildable bi ]
                       ++ [ bi | tst <- testSuites pkg_descr
                               , let bi = testBuildInfo tst
-                              , True || buildable bi
-                              , testEnabled tst ]
+                              , True || buildable bi ]
                       ++ [ bi | tst <- benchmarks pkg_descr
                               , let bi = benchmarkBuildInfo tst
-                              , True || buildable bi
-                              , benchmarkEnabled tst ]
+                              , True || buildable bi ]
 
 -- | Get all files referenced by the package.
 packageDescModulesAndFiles
@@ -596,9 +602,9 @@ packageDescModulesAndFiles pkg = do
     return (modules, files, dfiles, warnings)
   where
     libComponent = const CLib
-    exeComponent = CExe . T.pack . exeName
-    testComponent = CTest . T.pack . testName
-    benchComponent = CBench . T.pack . benchmarkName
+    exeComponent = CExe . T.pack . Cabal.unUnqualComponentName . exeName
+    testComponent = CTest . T.pack . Cabal.unUnqualComponentName . testName
+    benchComponent = CBench . T.pack . Cabal.unUnqualComponentName . benchmarkName
     asModuleAndFileMap label f lib = do
         (a,b,c) <- f lib
         return (M.singleton (label lib) a, M.singleton (label lib) b, c)
@@ -651,7 +657,7 @@ resolveGlobFiles =
 --
 matchDirFileGlob_ :: (MonadLogger m, MonadIO m) => String -> String -> m [String]
 matchDirFileGlob_ dir filepath = case parseFileGlob filepath of
-  Nothing -> liftIO $ die $
+  Nothing -> liftIO $ throwString $
       "invalid file glob '" ++ filepath
       ++ "'. Wildcards '*' are only allowed in place of the file"
       ++ " name, not in the directory name or file extension."
@@ -681,7 +687,7 @@ benchmarkFiles bench = do
     dir <- asks (parent . fst)
     (modules,files,warnings) <-
         resolveFilesAndDeps
-            (Just $ benchmarkName bench)
+            (Just $ Cabal.unUnqualComponentName $ benchmarkName bench)
             (dirs ++ [dir])
             (bnames <> exposed)
             haskellModuleExts
@@ -705,7 +711,7 @@ testFiles test = do
     dir <- asks (parent . fst)
     (modules,files,warnings) <-
         resolveFilesAndDeps
-            (Just $ testName test)
+            (Just $ Cabal.unUnqualComponentName $ testName test)
             (dirs ++ [dir])
             (bnames <> exposed)
             haskellModuleExts
@@ -730,7 +736,7 @@ executableFiles exe = do
     dir <- asks (parent . fst)
     (modules,files,warnings) <-
         resolveFilesAndDeps
-            (Just $ exeName exe)
+            (Just $ Cabal.unUnqualComponentName $ exeName exe)
             (dirs ++ [dir])
             (map DotCabalModule (otherModules build) ++
              [DotCabalMain (modulePath exe)])
@@ -782,7 +788,7 @@ targetJsSources = jsSources
 resolvePackageDescription :: PackageConfig
                           -> GenericPackageDescription
                           -> PackageDescription
-resolvePackageDescription packageConfig (GenericPackageDescription desc defaultFlags mlib exes tests benches) =
+resolvePackageDescription packageConfig (GenericPackageDescription desc defaultFlags mlib _subLibs _foreignLibs exes tests benches) =
   desc {library =
           fmap (resolveConditions rc updateLibDeps) mlib
        ,executables =
@@ -811,12 +817,18 @@ resolvePackageDescription packageConfig (GenericPackageDescription desc defaultF
                  (buildInfo exe) {targetBuildDepends = deps}}
         updateTestDeps test deps =
           test {testBuildInfo =
-                  (testBuildInfo test) {targetBuildDepends = deps}
-               ,testEnabled = packageConfigEnableTests packageConfig}
+                  (testBuildInfo test)
+                    { targetBuildDepends = deps
+                    , buildable = packageConfigEnableTests packageConfig
+                    }
+               }
         updateBenchmarkDeps benchmark deps =
           benchmark {benchmarkBuildInfo =
-                       (benchmarkBuildInfo benchmark) {targetBuildDepends = deps}
-                    ,benchmarkEnabled = packageConfigEnableBenchmarks packageConfig}
+                       (benchmarkBuildInfo benchmark)
+                         { targetBuildDepends = deps
+                         , buildable = packageConfigEnableBenchmarks packageConfig
+                         }
+                    }
 
 -- | Make a map from a list of flag specifications.
 --
@@ -854,7 +866,7 @@ resolveConditions :: (Monoid target,Show target)
 resolveConditions rc addDeps (CondNode lib deps cs) = basic <> children
   where basic = addDeps lib deps
         children = mconcat (map apply cs)
-          where apply (cond,node,mcs) =
+          where apply (Cabal.CondBranch cond node mcs) =
                   if condSatisfied cond
                      then resolveConditions rc addDeps node
                      else maybe mempty (resolveConditions rc addDeps) mcs
@@ -1256,10 +1268,10 @@ cabalFilePackageId
     :: (MonadIO m, MonadThrow m)
     => Path Abs File -> m PackageIdentifier
 cabalFilePackageId fp = do
-    pkgDescr <- liftIO (D.readPackageDescription D.silent $ toFilePath fp)
+    pkgDescr <- liftIO (D.readGenericPackageDescription D.silent $ toFilePath fp)
     (toStackPI . D.package . D.packageDescription) pkgDescr
   where
-    toStackPI (D.PackageIdentifier (D.PackageName name) ver) = do
+    toStackPI (D.PackageIdentifier (D.unPackageName -> name) ver) = do
         name' <- parsePackageNameFromString name
         ver' <- parseVersionFromString (showVersion ver)
         return (PackageIdentifier name' ver')
diff --git a/src/Stack/Setup.hs b/src/Stack/Setup.hs
index 8c357ba252..0573208508 100644
--- a/src/Stack/Setup.hs
+++ b/src/Stack/Setup.hs
@@ -63,6 +63,7 @@ import qualified    Data.Yaml as Yaml
 import              Distribution.System (OS, Arch (..), Platform (..))
 import qualified    Distribution.System as Cabal
 import              Distribution.Text (simpleParse)
+import              Distribution.Version (mkVersion')
 import              Lens.Micro (set)
 import              Network.HTTP.Simple (getResponseBody, httpLBS, withResponse, getResponseStatusCode)
 import              Network.HTTP.Download
@@ -1939,4 +1940,4 @@ getDownloadVersion (StackReleaseInfo val) = do
     parseVersion $ T.drop 1 rawName
 
 stackVersion :: Version
-stackVersion = fromCabalVersion Meta.version
+stackVersion = fromCabalVersion (mkVersion' Meta.version)
diff --git a/src/Stack/Snapshot.hs b/src/Stack/Snapshot.hs
index ca6fd4be95..b599659893 100644
--- a/src/Stack/Snapshot.hs
+++ b/src/Stack/Snapshot.hs
@@ -38,6 +38,7 @@ import           Data.Yaml (decodeFileEither, ParseException (AesonException))
 import           Distribution.InstalledPackageInfo (PError)
 import           Distribution.PackageDescription (GenericPackageDescription)
 import qualified Distribution.PackageDescription as C
+import qualified Distribution.Types.UnqualComponentName as C
 import           Distribution.System (Platform)
 import           Distribution.Text (display)
 import qualified Distribution.Version as C
@@ -787,7 +788,10 @@ calculate gpd platform compilerVersion loc flags hide options =
       , lpiPackageDeps = Map.map fromVersionRange
                        $ Map.filterWithKey (const . (/= name))
                        $ packageDependencies pd
-      , lpiProvidedExes = Set.fromList $ map (ExeName . T.pack . C.exeName) $ C.executables pd
+      , lpiProvidedExes =
+            Set.fromList
+          $ map (ExeName . T.pack . C.unUnqualComponentName . C.exeName)
+          $ C.executables pd
       , lpiNeededExes = Map.mapKeys ExeName
                       $ Map.map fromVersionRange
                       $ packageToolDependencies pd
diff --git a/src/Stack/Types/Config.hs b/src/Stack/Types/Config.hs
index cdc3ecda1a..73d7170d96 100644
--- a/src/Stack/Types/Config.hs
+++ b/src/Stack/Types/Config.hs
@@ -193,7 +193,7 @@ import           Distribution.PackageDescription (GenericPackageDescription)
 import           Distribution.ParseUtils (PError)
 import           Distribution.System (Platform)
 import qualified Distribution.Text
-import           Distribution.Version (anyVersion)
+import           Distribution.Version (anyVersion, mkVersion')
 import           Generics.Deriving.Monoid (memptydefault, mappenddefault)
 import           Lens.Micro (Lens', lens, _1, _2, to)
 import           Options.Applicative (ReadM)
@@ -1031,7 +1031,7 @@ instance Show ConfigException where
         ]
     show (BadStackVersionException requiredRange) = concat
         [ "The version of stack you are using ("
-        , show (fromCabalVersion Meta.version)
+        , show (fromCabalVersion (mkVersion' Meta.version))
         , ") is outside the required\n"
         ,"version range specified in stack.yaml ("
         , T.unpack (versionRangeText requiredRange)
diff --git a/src/Stack/Types/FlagName.hs b/src/Stack/Types/FlagName.hs
index 47abef62b7..f891ec6891 100644
--- a/src/Stack/Types/FlagName.hs
+++ b/src/Stack/Types/FlagName.hs
@@ -107,12 +107,12 @@ flagNameText (FlagName n) = n
 
 -- | Convert from a Cabal flag name.
 fromCabalFlagName :: Cabal.FlagName -> FlagName
-fromCabalFlagName (Cabal.FlagName name) =
-  let !x = T.pack name
+fromCabalFlagName name =
+  let !x = T.pack $ Cabal.unFlagName name
   in FlagName x
 
 -- | Convert to a Cabal flag name.
 toCabalFlagName :: FlagName -> Cabal.FlagName
 toCabalFlagName (FlagName name) =
   let !x = T.unpack name
-  in Cabal.FlagName x
+  in Cabal.mkFlagName x
diff --git a/src/Stack/Types/PackageName.hs b/src/Stack/Types/PackageName.hs
index de5fdb27c4..e31fe19c78 100644
--- a/src/Stack/Types/PackageName.hs
+++ b/src/Stack/Types/PackageName.hs
@@ -112,15 +112,15 @@ packageNameText (PackageName n) = n
 
 -- | Convert from a Cabal package name.
 fromCabalPackageName :: Cabal.PackageName -> PackageName
-fromCabalPackageName (Cabal.PackageName name) =
-  let !x = T.pack name
+fromCabalPackageName name =
+  let !x = T.pack $ Cabal.unPackageName name
   in PackageName x
 
 -- | Convert to a Cabal package name.
 toCabalPackageName :: PackageName -> Cabal.PackageName
 toCabalPackageName (PackageName name) =
   let !x = T.unpack name
-  in Cabal.PackageName x
+  in Cabal.mkPackageName x
 
 -- | Parse a package name from a file path.
 parsePackageNameFromFilePath :: MonadThrow m => Path a File -> m PackageName
diff --git a/src/Stack/Types/Version.hs b/src/Stack/Types/Version.hs
index 457db8d775..d2e4ba441e 100644
--- a/src/Stack/Types/Version.hs
+++ b/src/Stack/Types/Version.hs
@@ -139,12 +139,12 @@ versionText (Version v) =
 -- | Convert to a Cabal version.
 toCabalVersion :: Version -> Cabal.Version
 toCabalVersion (Version v) =
-  Cabal.Version (map fromIntegral (V.toList v)) []
+  Cabal.mkVersion (map fromIntegral (V.toList v))
 
 -- | Convert from a Cabal version.
 fromCabalVersion :: Cabal.Version -> Version
-fromCabalVersion (Cabal.Version vs _) =
-  let !v = V.fromList (map fromIntegral vs)
+fromCabalVersion vs =
+  let !v = V.fromList (map fromIntegral (Cabal.versionNumbers vs))
   in Version v
 
 -- | Make a package version.
diff --git a/src/Stack/Upgrade.hs b/src/Stack/Upgrade.hs
index 5664381169..a596c059f0 100644
--- a/src/Stack/Upgrade.hs
+++ b/src/Stack/Upgrade.hs
@@ -17,6 +17,7 @@ import qualified Data.HashMap.Strict         as HashMap
 import qualified Data.List
 import qualified Data.Map                    as Map
 import qualified Data.Text as T
+import           Distribution.Version        (mkVersion')
 import           Lens.Micro                  (set)
 import           Options.Applicative
 import           Path
@@ -218,7 +219,7 @@ sourceUpgrade gConfigMonoid mresolver builtHash (SourceOpts gitRepo) =
         when (null versions) (throwString "No stack found in package indices")
 
         let version = Data.List.maximum versions
-        if version <= fromCabalVersion Paths.version
+        if version <= fromCabalVersion (mkVersion' Paths.version)
             then do
                 $logInfo "Already at latest version, no upgrade required"
                 return Nothing
diff --git a/src/main/Main.hs b/src/main/Main.hs
index 9b636da46d..7bdc47af81 100644
--- a/src/main/Main.hs
+++ b/src/main/Main.hs
@@ -34,6 +34,7 @@ import           Development.GitRev (gitCommitCount, gitHash)
 #endif
 import           Distribution.System (buildArch, buildPlatform)
 import           Distribution.Text (display)
+import           Distribution.Version (mkVersion')
 import           GHC.IO.Encoding (mkTextEncoding, textEncodingName)
 import           Lens.Micro
 import           Options.Applicative
@@ -173,7 +174,7 @@ main = do
       case globalReExecVersion global of
           Just expectVersion -> do
               expectVersion' <- parseVersionFromString expectVersion
-              unless (checkVersion MatchMinor expectVersion' (fromCabalVersion Meta.version))
+              unless (checkVersion MatchMinor expectVersion' (fromCabalVersion (mkVersion' Meta.version)))
                   $ throwIO $ InvalidReExecVersion expectVersion (showVersion Meta.version)
           _ -> return ()
       run global `catch` \e ->
diff --git a/stack-7.10.yaml b/stack-7.10.yaml
index 31626e7787..b4a5e01890 100644
--- a/stack-7.10.yaml
+++ b/stack-7.10.yaml
@@ -15,7 +15,7 @@ flags:
   mintty:
     win32-2-5: false
 extra-deps:
-- Cabal-1.24.2.0
+- Cabal-2.0.0.2
 - th-utilities-0.2.0.1
 - store-0.4.1
 - store-core-0.4
diff --git a/stack-nightly.yaml b/stack-nightly.yaml
index 3056fe4c95..9278300ec6 100644
--- a/stack-nightly.yaml
+++ b/stack-nightly.yaml
@@ -13,6 +13,7 @@ flags:
   mintty:
     win32-2-5: false
 extra-deps:
+- Cabal-2.0.0.2
 - mintty-0.1.1
 - text-metrics-0.3.0
 - bindings-uname-0.1
diff --git a/stack.cabal b/stack.cabal
index 28ed971b96..2586c02184 100644
--- a/stack.cabal
+++ b/stack.cabal
@@ -31,7 +31,7 @@ extra-source-files:  CONTRIBUTING.md
 
 custom-setup
   setup-depends: base
-               , Cabal
+               , Cabal >= 2.0 && < 2.1
                , filepath
 
 flag integration-tests
@@ -188,7 +188,7 @@ library
                      System.Process.Read
                      System.Process.Run
   other-modules:     Hackage.Security.Client.Repository.HttpLib.HttpClient
-  build-depends:     Cabal >= 1.24 && < 1.25
+  build-depends:     Cabal >= 2.0 && < 2.1
                    , aeson (>= 1.0 && < 1.2)
                    , ansi-terminal >= 0.6.2.3
                    , attoparsec >= 0.12.1.5 && < 0.14
@@ -284,7 +284,7 @@ executable stack
   if flag(static)
       ld-options: -static -pthread
 
-  build-depends:  Cabal >= 1.18.1.5 && < 1.25
+  build-depends:  Cabal >= 2.0 && < 2.1
                 , base >=4.7 && < 5
                 , bytestring >= 0.10.4.0
                 , conduit >= 1.2.8
@@ -336,7 +336,7 @@ test-suite stack-test
                 , Stack.SolverSpec
                 , Stack.Untar.UntarSpec
   ghc-options:    -threaded -Wall -fwarn-tabs -fwarn-incomplete-uni-patterns -fwarn-incomplete-record-updates
-  build-depends:  Cabal >= 1.18.1.5 && < 1.25
+  build-depends:  Cabal >= 2.0 && < 2.1
                 , QuickCheck >= 2.8.2 && < 2.10
                 , attoparsec < 0.14
                 , base >=4.7 && <5
diff --git a/stack.yaml b/stack.yaml
index 29f4caa59e..500eb03bca 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -17,6 +17,7 @@ flags:
   mintty:
     win32-2-5: false
 extra-deps:
+- Cabal-2.0.0.2
 - mintty-0.1.1
 - text-metrics-0.3.0
 - unicode-transforms-0.3.2

From deff91c1adf2c2e89d898c7a9c1f7fbf741b7379 Mon Sep 17 00:00:00 2001
From: Michael Snoyman <michael@snoyman.com>
Date: Wed, 26 Jul 2017 11:43:24 +0300
Subject: [PATCH 2/7] Proper grabbing of all build info

---
 src/Stack/Package.hs | 42 ++++++++++++++++++++----------------------
 1 file changed, 20 insertions(+), 22 deletions(-)

diff --git a/src/Stack/Package.hs b/src/Stack/Package.hs
index 3a028c0000..4b841e6ba5 100644
--- a/src/Stack/Package.hs
+++ b/src/Stack/Package.hs
@@ -532,7 +532,7 @@ packageDependencies :: PackageDescription -> Map PackageName VersionRange
 packageDependencies pkg =
   M.fromListWith intersectVersionRanges $
   map (depName &&& depRange) $
-  concatMap targetBuildDepends (allBuildInfo' pkg) ++
+  concatMap targetBuildDepends (allBuildInfo pkg) ++
   maybe [] setupDepends (setupBuildInfo pkg)
 
 -- | Get all build tool dependencies of the package (buildable targets only).
@@ -541,28 +541,11 @@ packageToolDependencies =
   M.fromList .
   concatMap (fmap (\(Cabal.LegacyExeDependency name range) -> (T.pack name, range)) .
              buildTools) .
-  allBuildInfo'
+  allBuildInfo
 
 -- | Get all dependencies of the package (buildable targets only).
 packageDescTools :: PackageDescription -> [Cabal.ExeDependency]
-packageDescTools = concatMap buildToolDepends . allBuildInfo'
-
--- | This is a copy-paste from Cabal's @allBuildInfo@ function, but with the
--- @buildable@ test removed. The implementation is broken.
--- See: https://github.com/haskell/cabal/issues/1725
-allBuildInfo' :: PackageDescription -> [BuildInfo]
-allBuildInfo' pkg_descr = [ bi | Just lib <- [library pkg_descr]
-                              , let bi = libBuildInfo lib
-                              , True || buildable bi ]
-                      ++ [ bi | exe <- executables pkg_descr
-                              , let bi = buildInfo exe
-                              , True || buildable bi ]
-                      ++ [ bi | tst <- testSuites pkg_descr
-                              , let bi = testBuildInfo tst
-                              , True || buildable bi ]
-                      ++ [ bi | tst <- benchmarks pkg_descr
-                              , let bi = benchmarkBuildInfo tst
-                              , True || buildable bi ]
+packageDescTools = concatMap buildToolDepends . allBuildInfo
 
 -- | Get all files referenced by the package.
 packageDescModulesAndFiles
@@ -809,12 +792,27 @@ resolvePackageDescription packageConfig (GenericPackageDescription desc defaultF
                 (packageConfigPlatform packageConfig)
                 flags
 
+        -- Due to https://github.com/haskell/cabal/issues/1725,
+        -- versions of Cabal before 2.0 would always require that the
+        -- dependencies for all libraries and executables be present,
+        -- even if they were not buildable. To ensure that Stack is
+        -- compatible with those older Cabal libraries (which may be
+        -- in use depending on the snapshot chosen), we set buildable
+        -- to True for libraries and executables.
         updateLibDeps lib deps =
           lib {libBuildInfo =
-                 (libBuildInfo lib) {targetBuildDepends = deps}}
+                 (libBuildInfo lib)
+                   { targetBuildDepends = deps
+                   , buildable = True
+                   }
+              }
         updateExeDeps exe deps =
           exe {buildInfo =
-                 (buildInfo exe) {targetBuildDepends = deps}}
+                 (buildInfo exe)
+                   { targetBuildDepends = deps
+                   , buildable = True
+                   }
+              }
         updateTestDeps test deps =
           test {testBuildInfo =
                   (testBuildInfo test)

From 0ef1401318825b19a6479b3f33b2388b574a7d49 Mon Sep 17 00:00:00 2001
From: Michael Snoyman <michael@snoyman.com>
Date: Wed, 26 Jul 2017 15:51:54 +0300
Subject: [PATCH 3/7] Proper build tool loading from Cabal files

---
 src/Stack/Build/ConstructPlan.hs | 52 +++++++++++++-------------------
 src/Stack/BuildPlan.hs           | 10 +++---
 src/Stack/Package.hs             | 23 +++++++++-----
 src/Stack/Types/Package.hs       |  5 ++-
 4 files changed, 44 insertions(+), 46 deletions(-)

diff --git a/src/Stack/Build/ConstructPlan.hs b/src/Stack/Build/ConstructPlan.hs
index 9be0fe814e..fbf03c5518 100644
--- a/src/Stack/Build/ConstructPlan.hs
+++ b/src/Stack/Build/ConstructPlan.hs
@@ -30,7 +30,6 @@ import qualified Data.Set as Set
 import qualified Data.Text as T
 import           Data.Text.Encoding (decodeUtf8With)
 import           Data.Text.Encoding.Error (lenientDecode)
-import qualified Distribution.Package as Cabal
 import qualified Distribution.Text as Cabal
 import qualified Distribution.Version as Cabal
 import           Generics.Deriving.Monoid (memptydefault, mappenddefault)
@@ -129,7 +128,7 @@ data Ctx = Ctx
     , baseConfigOpts :: !BaseConfigOpts
     , loadPackage    :: !(PackageLocationIndex FilePath -> Map FlagName Bool -> [Text] -> IO Package)
     , combinedMap    :: !CombinedMap
-    , toolToPackages :: !(Cabal.Dependency -> Map PackageName VersionRange)
+    , toolToPackages :: !(ExeName -> Map PackageName VersionRange)
     , ctxEnvConfig   :: !EnvConfig
     , callStack      :: ![PackageName]
     , extraToBuild   :: !(Set PackageName)
@@ -224,9 +223,9 @@ constructPlan ls0 baseConfigOpts0 locals extraToBuild0 localDumpPkgs loadPackage
         , baseConfigOpts = baseConfigOpts0
         , loadPackage = loadPackage0
         , combinedMap = combineMap sourceMap installedMap
-        , toolToPackages = \(Cabal.Dependency name _) ->
+        , toolToPackages = \name ->
           maybe Map.empty (Map.fromSet (const Cabal.anyVersion)) $
-          Map.lookup (T.pack . packageNameString . fromCabalPackageName $ name) (toolMap lp)
+          Map.lookup name toolMap
         , ctxEnvConfig = econfig
         , callStack = []
         , extraToBuild = extraToBuild0
@@ -234,8 +233,8 @@ constructPlan ls0 baseConfigOpts0 locals extraToBuild0 localDumpPkgs loadPackage
         , wanted = wantedLocalPackages locals <> extraToBuild0
         , localNames = Set.fromList $ map (packageName . lpPackage) locals
         }
-
-    toolMap = getToolMap ls0
+      where
+        toolMap = getToolMap ls0 lp
 
 -- | State to be maintained during the calculation of local packages
 -- to unregister.
@@ -795,58 +794,49 @@ packageDepsWithTools p = do
     ctx <- ask
     -- TODO: it would be cool to defer these warnings until there's an
     -- actual issue building the package.
-    let toEither (Cabal.Dependency (Cabal.unPackageName -> name) _) mp =
+    let toEither name mp =
             case Map.toList mp of
-                [] -> Left (NoToolFound name (packageName p))
+                [] -> Left (ToolWarning name (packageName p) Nothing)
                 [_] -> Right mp
-                xs -> Left (AmbiguousToolsFound name (packageName p) (map fst xs))
+                ((x, _):(y, _):zs) ->
+                  Left (ToolWarning name (packageName p) (Just (x, y, map fst zs)))
         (warnings0, toolDeps) =
              partitionEithers $
-             map (\dep -> toEither dep (toolToPackages ctx dep)) (packageTools p)
+             map (\dep -> toEither dep (toolToPackages ctx dep)) (Map.keys (packageTools p))
     -- Check whether the tool is on the PATH before warning about it.
-    warnings <- fmap catMaybes $ forM warnings0 $ \warning -> do
-        let toolName = case warning of
-                NoToolFound tool _ -> tool
-                AmbiguousToolsFound tool _ _ -> tool
+    warnings <- fmap catMaybes $ forM warnings0 $ \warning@(ToolWarning (ExeName toolName) _ _) -> do
         config <- view configL
         menv <- liftIO $ configEnvOverride config minimalEnvSettings { esIncludeLocals = True }
-        mfound <- findExecutable menv toolName
+        mfound <- findExecutable menv $ T.unpack toolName
         case mfound of
             Nothing -> return (Just warning)
             Just _ -> return Nothing
     tell mempty { wWarnings = (map toolWarningText warnings ++) }
-    when (any isNoToolFound warnings) $ do
-        let msg = T.unlines
-                [ "Missing build-tools may be caused by dependencies of the build-tool being overridden by extra-deps."
-                , "This should be fixed soon - see this issue https://github.com/commercialhaskell/stack/issues/595"
-                ]
-        tell mempty { wWarnings = (msg:) }
     return $ Map.unionsWith intersectVersionRanges
            $ packageDeps p
            : toolDeps
 
-data ToolWarning
-    = NoToolFound String PackageName
-    | AmbiguousToolsFound String PackageName [PackageName]
-
-isNoToolFound :: ToolWarning -> Bool
-isNoToolFound NoToolFound{} = True
-isNoToolFound _ = False
+-- | Warn about tools in the snapshot definition. States the tool name
+-- expected, the package name using it, and found packages. If the
+-- last value is Nothing, it means the tool was not found
+-- anywhere. For a Just value, it was found in at least two packages.
+data ToolWarning = ToolWarning ExeName PackageName (Maybe (PackageName, PackageName, [PackageName]))
+  deriving Show
 
 toolWarningText :: ToolWarning -> Text
-toolWarningText (NoToolFound toolName pkgName) =
+toolWarningText (ToolWarning (ExeName toolName) pkgName Nothing) =
     "No packages found in snapshot which provide a " <>
     T.pack (show toolName) <>
     " executable, which is a build-tool dependency of " <>
     T.pack (show (packageNameString pkgName))
-toolWarningText (AmbiguousToolsFound toolName pkgName options) =
+toolWarningText (ToolWarning (ExeName toolName) pkgName (Just (option1, option2, options))) =
     "Multiple packages found in snapshot which provide a " <>
     T.pack (show toolName) <>
     " exeuctable, which is a build-tool dependency of " <>
     T.pack (show (packageNameString pkgName)) <>
     ", so none will be installed.\n" <>
     "Here's the list of packages which provide it: " <>
-    T.intercalate ", " (map packageNameText options) <>
+    T.intercalate ", " (map packageNameText (option1:option2:options)) <>
     "\nSince there's no good way to choose, you may need to install it manually."
 
 -- | Strip out anything from the @Plan@ intended for the local database
diff --git a/src/Stack/BuildPlan.hs b/src/Stack/BuildPlan.hs
index 7e44b5aab3..c3814a9f34 100644
--- a/src/Stack/BuildPlan.hs
+++ b/src/Stack/BuildPlan.hs
@@ -152,7 +152,7 @@ instance Show BuildPlanException where
 -- both snapshot and local packages (deps and project packages).
 getToolMap :: LoadedSnapshot
            -> LocalPackages
-           -> Map Text (Set PackageName)
+           -> Map ExeName (Set PackageName)
 getToolMap ls locals =
 
     {- We no longer do this, following discussion at:
@@ -171,13 +171,13 @@ getToolMap ls locals =
         ]
   where
     goSnap (pname, lpi) =
-        map (flip Map.singleton (Set.singleton pname) . unExeName)
+        map (flip Map.singleton (Set.singleton pname))
       $ Set.toList
       $ lpiProvidedExes lpi
 
     goLocalProj (pname, lpv) =
         map (flip Map.singleton (Set.singleton pname))
-        [t | CExe t <- Set.toList (lpvComponents lpv)]
+        [ExeName t | CExe t <- Set.toList (lpvComponents lpv)]
 
     goLocalDep (pname, (gpd, _loc)) =
         map (flip Map.singleton (Set.singleton pname))
@@ -186,8 +186,8 @@ getToolMap ls locals =
     -- TODO consider doing buildable checking. Not a big deal though:
     -- worse case scenario is we build an extra package that wasn't
     -- strictly needed.
-    gpdExes :: GenericPackageDescription -> [Text]
-    gpdExes = map (T.pack . C.unUnqualComponentName . fst) . condExecutables
+    gpdExes :: GenericPackageDescription -> [ExeName]
+    gpdExes = map (ExeName . T.pack . C.unUnqualComponentName . fst) . condExecutables
 
 gpdPackages :: [GenericPackageDescription] -> Map PackageName Version
 gpdPackages gpds = Map.fromList $
diff --git a/src/Stack/Package.hs b/src/Stack/Package.hs
index 4b841e6ba5..2e88ced7f5 100644
--- a/src/Stack/Package.hs
+++ b/src/Stack/Package.hs
@@ -65,7 +65,6 @@ import           Distribution.Simple.Utils
 import           Distribution.System (OS (..), Arch, Platform (..))
 import qualified Distribution.Text as D
 import qualified Distribution.Types.CondTree as Cabal
-import qualified Distribution.Types.Dependency as Cabal
 import qualified Distribution.Types.ExeDependency as Cabal
 import qualified Distribution.Types.LegacyExeDependency as Cabal
 import qualified Distribution.Types.UnqualComponentName as Cabal
@@ -83,7 +82,7 @@ import           Stack.Constants.Config
 import           Stack.Prelude
 import           Stack.PrettyPrint
 import           Stack.Types.Build
-import           Stack.Types.BuildPlan (PackageLocationIndex (..), PackageLocation (..))
+import           Stack.Types.BuildPlan (PackageLocationIndex (..), PackageLocation (..), ExeName (..))
 import           Stack.Types.Compiler
 import           Stack.Types.Config
 import           Stack.Types.FlagName
@@ -222,9 +221,7 @@ packageFromPackageDescription packageConfig pkgFlags pkg =
     , packageLicense = license pkg
     , packageDeps = deps
     , packageFiles = pkgFiles
-    , packageTools = map
-        (\(Cabal.ExeDependency name' _ range) -> Cabal.Dependency name' range)
-        (packageDescTools pkg)
+    , packageTools = packageDescTools pkg
     , packageGhcOptions = packageConfigGhcOptions packageConfig
     , packageFlags = packageConfigFlags packageConfig
     , packageDefaultFlags = M.fromList
@@ -544,8 +541,20 @@ packageToolDependencies =
   allBuildInfo
 
 -- | Get all dependencies of the package (buildable targets only).
-packageDescTools :: PackageDescription -> [Cabal.ExeDependency]
-packageDescTools = concatMap buildToolDepends . allBuildInfo
+--
+-- This uses both the new 'buildToolDepends' and old 'buildTools'
+-- information.
+packageDescTools :: PackageDescription -> Map ExeName VersionRange
+packageDescTools =
+  M.fromList . concatMap tools . allBuildInfo
+  where
+    tools bi = map go1 (buildTools bi) ++ map go2 (buildToolDepends bi)
+
+    go1 :: Cabal.LegacyExeDependency -> (ExeName, VersionRange)
+    go1 (Cabal.LegacyExeDependency name range) = (ExeName $ T.pack name, range)
+
+    go2 :: Cabal.ExeDependency -> (ExeName, VersionRange)
+    go2 (Cabal.ExeDependency _pkg name range) = (ExeName $ T.pack $ Cabal.unUnqualComponentName name, range)
 
 -- | Get all files referenced by the package.
 packageDescModulesAndFiles
diff --git a/src/Stack/Types/Package.hs b/src/Stack/Types/Package.hs
index ba52dd250f..50ec3c6adc 100644
--- a/src/Stack/Types/Package.hs
+++ b/src/Stack/Types/Package.hs
@@ -21,11 +21,10 @@ import           Data.Text.Encoding (encodeUtf8, decodeUtf8)
 import           Distribution.InstalledPackageInfo (PError)
 import           Distribution.License (License)
 import           Distribution.ModuleName (ModuleName)
-import           Distribution.Package hiding (Package,PackageName,packageName,packageVersion,PackageIdentifier)
 import           Distribution.PackageDescription (TestSuiteInterface, BuildType)
 import           Distribution.System (Platform (..))
 import           Path as FL
-import           Stack.Types.BuildPlan (PackageLocation, PackageLocationIndex (..))
+import           Stack.Types.BuildPlan (PackageLocation, PackageLocationIndex (..), ExeName)
 import           Stack.Types.Compiler
 import           Stack.Types.Config
 import           Stack.Types.FlagName
@@ -77,7 +76,7 @@ data Package =
           ,packageLicense :: !License                     -- ^ The license the package was released under.
           ,packageFiles :: !GetPackageFiles               -- ^ Get all files of the package.
           ,packageDeps :: !(Map PackageName VersionRange) -- ^ Packages that the package depends on.
-          ,packageTools :: ![Dependency]                  -- ^ A build tool name.
+          ,packageTools :: !(Map ExeName VersionRange)    -- ^ A build tool name.
           ,packageAllDeps :: !(Set PackageName)           -- ^ Original dependencies (not sieved).
           ,packageGhcOptions :: ![Text]                   -- ^ Ghc options used on package.
           ,packageFlags :: !(Map FlagName Bool)           -- ^ Flags used on package.

From 8f1917bfe27948bd8296d9664685c7412f3ef1cb Mon Sep 17 00:00:00 2001
From: Michael Snoyman <michael@snoyman.com>
Date: Thu, 17 Aug 2017 10:04:08 +0300
Subject: [PATCH 4/7] Remove redundant (and now incorrect)
 packageToolDependencies function

---
 src/Stack/Package.hs  | 10 +---------
 src/Stack/Snapshot.hs |  5 ++---
 2 files changed, 3 insertions(+), 12 deletions(-)

diff --git a/src/Stack/Package.hs b/src/Stack/Package.hs
index 2e88ced7f5..03068a4757 100644
--- a/src/Stack/Package.hs
+++ b/src/Stack/Package.hs
@@ -33,7 +33,7 @@ module Stack.Package
   ,buildLogPath
   ,PackageException (..)
   ,resolvePackageDescription
-  ,packageToolDependencies
+  ,packageDescTools
   ,packageDependencies
   ,autogenDir
   ,checkCabalFileName
@@ -532,14 +532,6 @@ packageDependencies pkg =
   concatMap targetBuildDepends (allBuildInfo pkg) ++
   maybe [] setupDepends (setupBuildInfo pkg)
 
--- | Get all build tool dependencies of the package (buildable targets only).
-packageToolDependencies :: PackageDescription -> Map Text VersionRange
-packageToolDependencies =
-  M.fromList .
-  concatMap (fmap (\(Cabal.LegacyExeDependency name range) -> (T.pack name, range)) .
-             buildTools) .
-  allBuildInfo
-
 -- | Get all dependencies of the package (buildable targets only).
 --
 -- This uses both the new 'buildToolDepends' and old 'buildTools'
diff --git a/src/Stack/Snapshot.hs b/src/Stack/Snapshot.hs
index b599659893..a66e07db93 100644
--- a/src/Stack/Snapshot.hs
+++ b/src/Stack/Snapshot.hs
@@ -792,9 +792,8 @@ calculate gpd platform compilerVersion loc flags hide options =
             Set.fromList
           $ map (ExeName . T.pack . C.unUnqualComponentName . C.exeName)
           $ C.executables pd
-      , lpiNeededExes = Map.mapKeys ExeName
-                      $ Map.map fromVersionRange
-                      $ packageToolDependencies pd
+      , lpiNeededExes = Map.map fromVersionRange
+                      $ packageDescTools pd
       , lpiExposedModules = maybe
           Set.empty
           (Set.fromList . map fromCabalModuleName . C.exposedModules)

From f9a41d3885098f1cbfa76457f4938c7cdf2543da Mon Sep 17 00:00:00 2001
From: Michael Snoyman <michael@snoyman.com>
Date: Thu, 17 Aug 2017 10:22:44 +0300
Subject: [PATCH 5/7] Move getDefaultPackageConfig to where it is used

---
 src/Stack/Build/Source.hs | 15 ---------------
 src/Stack/SDist.hs        | 16 +++++++++++++++-
 2 files changed, 15 insertions(+), 16 deletions(-)

diff --git a/src/Stack/Build/Source.hs b/src/Stack/Build/Source.hs
index 5be820cc3a..8c59d67aaa 100644
--- a/src/Stack/Build/Source.hs
+++ b/src/Stack/Build/Source.hs
@@ -13,7 +13,6 @@ module Stack.Build.Source
     , getLocalFlags
     , getGhcOptions
     , addUnlistedToBuildCache
-    , getDefaultPackageConfig
     ) where
 
 import              Stack.Prelude
@@ -471,20 +470,6 @@ checkComponentsBuildable lps =
         , c <- Set.toList (lpUnbuildable lp)
         ]
 
-getDefaultPackageConfig :: (MonadIO m, MonadReader env m, HasEnvConfig env)
-  => m PackageConfig
-getDefaultPackageConfig = do
-  platform <- view platformL
-  compilerVersion <- view actualCompilerVersionL
-  return PackageConfig
-    { packageConfigEnableTests = False
-    , packageConfigEnableBenchmarks = False
-    , packageConfigFlags = M.empty
-    , packageConfigGhcOptions = []
-    , packageConfigCompilerVersion = compilerVersion
-    , packageConfigPlatform = platform
-    }
-
 -- | Get 'PackageConfig' for package given its name.
 getPackageConfig :: (MonadIO m, MonadReader env m, HasEnvConfig env)
   => BuildOptsCLI
diff --git a/src/Stack/SDist.hs b/src/Stack/SDist.hs
index f36c024d1b..6ec057f4a5 100644
--- a/src/Stack/SDist.hs
+++ b/src/Stack/SDist.hs
@@ -51,7 +51,7 @@ import           Path.IO hiding (getModificationTime, getPermissions, withSystem
 import           Stack.Build (mkBaseConfigOpts, build)
 import           Stack.Build.Execute
 import           Stack.Build.Installed
-import           Stack.Build.Source (loadSourceMap, getDefaultPackageConfig)
+import           Stack.Build.Source (loadSourceMap)
 import           Stack.Build.Target hiding (PackageType (..))
 import           Stack.PackageLocation (resolveMultiPackageLocation)
 import           Stack.Constants
@@ -443,3 +443,17 @@ getModTime :: FilePath -> IO Tar.EpochTime
 getModTime path = do
     t <- getModificationTime path
     return . floor . utcTimeToPOSIXSeconds $ t
+
+getDefaultPackageConfig :: (MonadIO m, MonadReader env m, HasEnvConfig env)
+  => m PackageConfig
+getDefaultPackageConfig = do
+  platform <- view platformL
+  compilerVersion <- view actualCompilerVersionL
+  return PackageConfig
+    { packageConfigEnableTests = False
+    , packageConfigEnableBenchmarks = False
+    , packageConfigFlags = mempty
+    , packageConfigGhcOptions = []
+    , packageConfigCompilerVersion = compilerVersion
+    , packageConfigPlatform = platform
+    }

From 66a9b1e271be368bdc06d2ee6a6bd724d799ad70 Mon Sep 17 00:00:00 2001
From: Michael Snoyman <michael@snoyman.com>
Date: Thu, 17 Aug 2017 11:17:32 +0300
Subject: [PATCH 6/7] Make tests and benchmarks run again

See the comment added in this commit, further investigation is likely
needed.
---
 src/Stack/Package.hs | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/src/Stack/Package.hs b/src/Stack/Package.hs
index 03068a4757..0faf4efa29 100644
--- a/src/Stack/Package.hs
+++ b/src/Stack/Package.hs
@@ -229,11 +229,17 @@ packageFromPackageDescription packageConfig pkgFlags pkg =
     , packageAllDeps = S.fromList (M.keys deps)
     , packageHasLibrary = maybe False (buildable . libBuildInfo) (library pkg)
     , packageTests = M.fromList
-      [(T.pack (Cabal.unUnqualComponentName $ testName t), testInterface t) | t <- testSuites pkg
-                                              , buildable (testBuildInfo t)]
+      [(T.pack (Cabal.unUnqualComponentName $ testName t), testInterface t) | t <- testSuites pkg]
+        -- FIXME: Previously, we only included buildable components
+        -- here. Since Cabal 2.0, this ended up disabling test running
+        -- in all cases. Need to investigate if that's a change in
+        -- Cabal behavior or how we're piping data through the system
+        -- in response to Cabal data type changes. A cleanup of the
+        -- PackageConfig datatype (which will probably happen for
+        -- componentized builds) will likely make all of this clearer.
     , packageBenchmarks = S.fromList
-      [T.pack (Cabal.unUnqualComponentName $ benchmarkName biBuildInfo) | biBuildInfo <- benchmarks pkg
-                                          , buildable (benchmarkBuildInfo biBuildInfo)]
+      [T.pack (Cabal.unUnqualComponentName $ benchmarkName biBuildInfo) | biBuildInfo <- benchmarks pkg]
+        -- Same comment about buildable applies here too.
     , packageExes = S.fromList
       [T.pack (Cabal.unUnqualComponentName $ exeName biBuildInfo)
         | biBuildInfo <- executables pkg

From b1f9dcff43f2c0faff94e164a6bdd60e6a408696 Mon Sep 17 00:00:00 2001
From: Michael Snoyman <michael@snoyman.com>
Date: Thu, 17 Aug 2017 16:55:42 +0300
Subject: [PATCH 7/7] Fiddle with the buildable field correctly

Looks like I totally outsmarted myself here working on the Cabal 2.0
migration. Please see the newly added comment in this commit.
---
 src/Stack/Package.hs | 55 +++++++++++++++++++++-----------------------
 1 file changed, 26 insertions(+), 29 deletions(-)

diff --git a/src/Stack/Package.hs b/src/Stack/Package.hs
index 0faf4efa29..606d4ad00e 100644
--- a/src/Stack/Package.hs
+++ b/src/Stack/Package.hs
@@ -799,41 +799,38 @@ resolvePackageDescription packageConfig (GenericPackageDescription desc defaultF
                 (packageConfigPlatform packageConfig)
                 flags
 
-        -- Due to https://github.com/haskell/cabal/issues/1725,
-        -- versions of Cabal before 2.0 would always require that the
-        -- dependencies for all libraries and executables be present,
-        -- even if they were not buildable. To ensure that Stack is
-        -- compatible with those older Cabal libraries (which may be
-        -- in use depending on the snapshot chosen), we set buildable
-        -- to True for libraries and executables.
         updateLibDeps lib deps =
           lib {libBuildInfo =
-                 (libBuildInfo lib)
-                   { targetBuildDepends = deps
-                   , buildable = True
-                   }
-              }
+                 (libBuildInfo lib) {targetBuildDepends = deps}}
         updateExeDeps exe deps =
           exe {buildInfo =
-                 (buildInfo exe)
-                   { targetBuildDepends = deps
-                   , buildable = True
-                   }
-              }
+                 (buildInfo exe) {targetBuildDepends = deps}}
+
+        -- Note that, prior to moving to Cabal 2.0, we would set
+        -- testEnabled/benchmarkEnabled here. These fields no longer
+        -- exist, so we modify buildable instead here.  The only
+        -- wrinkle in the Cabal 2.0 story is
+        -- https://github.com/haskell/cabal/issues/1725, where older
+        -- versions of Cabal (which may be used for actually building
+        -- code) don't properly exclude build-depends for
+        -- non-buildable components. Testing indicates that everything
+        -- is working fine, and that this comment can be completely
+        -- ignored. I'm leaving the comment anyway in case something
+        -- breaks and you, poor reader, are investigating.
         updateTestDeps test deps =
-          test {testBuildInfo =
-                  (testBuildInfo test)
-                    { targetBuildDepends = deps
-                    , buildable = packageConfigEnableTests packageConfig
-                    }
-               }
+          let bi = testBuildInfo test
+              bi' = bi
+                { targetBuildDepends = deps
+                , buildable = buildable bi && packageConfigEnableTests packageConfig
+                }
+           in test { testBuildInfo = bi' }
         updateBenchmarkDeps benchmark deps =
-          benchmark {benchmarkBuildInfo =
-                       (benchmarkBuildInfo benchmark)
-                         { targetBuildDepends = deps
-                         , buildable = packageConfigEnableBenchmarks packageConfig
-                         }
-                    }
+          let bi = benchmarkBuildInfo benchmark
+              bi' = bi
+                { targetBuildDepends = deps
+                , buildable = buildable bi && packageConfigEnableBenchmarks packageConfig
+                }
+           in benchmark { benchmarkBuildInfo = bi' }
 
 -- | Make a map from a list of flag specifications.
 --