From 8fd5cba63213736e8720799a57afab32c8ef544b Mon Sep 17 00:00:00 2001
From: Samuel Pilz <samuel.pilz@posteo.net>
Date: Tue, 9 Apr 2019 00:54:16 +0200
Subject: [PATCH 01/13] improve consistency in the install.hs script

---
 install.hs | 192 +++++++++++++++++++++++++----------------------------
 1 file changed, 91 insertions(+), 101 deletions(-)

diff --git a/install.hs b/install.hs
index 6484b5ce4..81f35cbf0 100755
--- a/install.hs
+++ b/install.hs
@@ -4,11 +4,17 @@
   --resolver nightly-2018-12-15
   --package shake
   --package directory
+  --package extra
 -}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE TupleSections #-}
 import           Development.Shake
 import           Development.Shake.Command
 import           Development.Shake.FilePath
 import           Control.Monad
+import           Control.Monad.IO.Class
+import           Control.Monad.Extra (unlessM, mapMaybeM)
+import           Data.Maybe (isJust)
 import           System.Directory               ( findExecutable )
 import           System.Environment             ( getProgName
                                                 , unsetEnv
@@ -19,6 +25,7 @@ import           System.Info                    ( os
 
 import           Data.List                      ( dropWhileEnd
                                                 , intersperse
+                                                , intercalate
                                                 )
 import           Data.Char                      ( isSpace )
 
@@ -57,7 +64,7 @@ main = do
     want ["short-help"]
     -- general purpose targets
     phony "submodules" updateSubmodules
-    phony "cabal"      (getStackGhcPath mostRecentHieVersion >>= installCabal)
+    phony "cabal"      installCabal
     phony "short-help" shortHelpMessage
     phony "all"        shortHelpMessage
     phony "help"       helpMessage
@@ -72,11 +79,9 @@ main = do
                  )
       liftIO $ putStrLn $ embedInStars msg
 
-
     -- stack specific targets
     phony "build"      (need (reverse $ map ("hie-" ++) hieVersions))
-    phony "build-all"  (need ["build-docs", "build"])
-    phony "build-docs" (need (reverse $ map ("build-doc-" ++) hieVersions))
+    phony "build-all"  (need ["build-doc", "build"])
     phony "test" $ do
       need ["submodules"]
       need ["cabal"]
@@ -84,14 +89,11 @@ main = do
 
     phony "build-copy-compiler-tool" $ forM_ hieVersions buildCopyCompilerTool
 
-    phony "stack-build-doc" stackBuildDoc
-    forM_
-      hieVersions
-      (\version -> phony ("build-doc-" ++ version) $ do
+    phony "build-doc" $ do
         need ["submodules"]
-        need ["cabal"]
-        need ["stack-build-doc"]
-      )
+        stackBuildDoc
+
+    -- main targets for building hie with `stack`
     forM_
       hieVersions
       (\version -> phony ("hie-" ++ version) $ do
@@ -103,22 +105,17 @@ main = do
 
     -- cabal specific targets
     phony "cabal-build"      (need (map ("cabal-hie-" ++) ghcVersions))
-    phony "cabal-build-all"  (need ["cabal-build-docs", "cabal-build"])
-    phony "cabal-build-docs" (need (map ("cabal-build-doc-" ++) ghcVersions))
+    phony "cabal-build-all"  (need ["cabal-build-doc", "cabal-build"])
+    phony "cabal-build-doc" $ do
+        need ["submodules"]
+        need ["cabal"]
+        cabalBuildDoc
 
     phony "cabal-test" $ do
       need ["submodules"]
       need ["cabal"]
       forM_ ghcVersions cabalTest
 
-    phony "cabal-doc" cabalBuildDoc
-    forM_
-      hieVersions
-      (\version -> phony ("cabal-build-doc-" ++ version) $ do
-        need ["submodules"]
-        need ["cabal"]
-        need ["cabal-doc"]
-      )
     forM_
       hieVersions
       (\version -> phony ("cabal-hie-" ++ version) $ do
@@ -145,6 +142,7 @@ buildIcuMacosFix version = execStackWithYaml_
   , "--extra-include-dirs=/usr/local/opt/icu4c/include"
   ]
 
+-- |update the submodules that the project is in the state as required by the `stack.yaml` files
 updateSubmodules :: Action ()
 updateSubmodules = do
   command_ [] "git" ["submodule", "sync", "--recursive"]
@@ -157,9 +155,8 @@ validateCabalNewInstallIsSupported = when (os `elem` ["mingw32", "win32"]) $ do
 
 configureCabal :: VersionNumber -> Action ()
 configureCabal versionNumber = do
-  ghcPath' <- liftIO $ getGhcPath versionNumber
-  ghcPath  <- case ghcPath' of
-    Nothing -> do
+  ghcPath <- getGhcPath versionNumber >>= \case
+    Nothing -> do -- TODO: this is better written using a monad-transformer
       liftIO $ putStrLn $ embedInStars (ghcVersionNotFound versionNumber)
       error (ghcVersionNotFound versionNumber)
     Just p -> return p
@@ -167,14 +164,12 @@ configureCabal versionNumber = do
     ["new-configure", "-w", ghcPath, "--write-ghc-environment-files=never"]
 
 findInstalledGhcs :: IO [(VersionNumber, GhcPath)]
-findInstalledGhcs = foldM
-  (\found version -> do
-    path <- getGhcPath version
-    case path of
-      Nothing -> return found
-      Just p  -> return $ (version, p) : found
+findInstalledGhcs = mapMaybeM
+  (\version -> do
+    getGhcPath version >>= \case
+      Nothing -> return Nothing
+      Just p  -> return $ Just (version, p)
   )
-  []
   hieVersions
 
 cabalBuildHie :: VersionNumber -> Action ()
@@ -198,36 +193,30 @@ cabalInstallHie versionNumber = do
             (localBin </> "hie-" ++ dropExtension versionNumber <.> exe)
 
 cabalBuildDoc :: Action ()
-cabalBuildDoc = generateHoogleDatabase $ do 
-  localBin <- getLocalBin
-  execCabal_ ["new-install", "--symlink-bindir=" ++ localBin, "hoogle"]
+cabalBuildDoc = do
+  execCabal_ ["new-build", "hoogle", "generate"]
   execCabal_ ["new-exec", "hoogle", "generate"]
 
-generateHoogleDatabase :: Action () -> Action ()
-generateHoogleDatabase installIfNecessary = do
-  mayHoogle <- liftIO $ findExecutable "hoogle"
-  case mayHoogle of
-    Nothing -> installIfNecessary
-    Just hoogle -> command_ [] "hoogle" ["generate"]
-
-
 cabalTest :: VersionNumber -> Action ()
 cabalTest versionNumber = do
   configureCabal versionNumber
   execCabal_ ["new-test"]
 
-installCabal :: GhcPath -> Action ()
-installCabal ghc = do
-  execStack_ ["install", "--stack-yaml=shake.yaml", "cabal-install"]
+installCabal :: Action ()
+installCabal = do
+  -- install `cabal-install` if not already installed
+  unlessM (existsExecutable "cabal") $ do
+    execStack_ ["install", "--stack-yaml=shake.yaml", "cabal-install"]
   execCabal_ ["update"]
+  ghc <- getStackGhcPath mostRecentHieVersion
   execCabal_ ["install", "Cabal-2.4.1.0", "--with-compiler=" ++ ghc]
 
 stackBuildHie :: VersionNumber -> Action ()
 stackBuildHie versionNumber = do
-  execStackWithYaml_ versionNumber ["install", "happy"]
   execStackWithYaml_ versionNumber ["build"]
     `actionOnException` liftIO (putStrLn stackBuildFailMsg)
 
+-- | copy the built binaries into the localBinDir
 stackInstallHie :: VersionNumber -> Action ()
 stackInstallHie versionNumber = do
   execStackWithYaml_ versionNumber ["install"]
@@ -247,10 +236,11 @@ stackTest :: VersionNumber -> Action ()
 stackTest versionNumber = execStackWithYaml_ versionNumber ["test"]
 
 stackBuildDoc :: Action ()
-stackBuildDoc = generateHoogleDatabase $ do
-  execStack_ ["--stack-yaml=shake.yaml", "install", "hoogle"]
+stackBuildDoc = do
+  execStack_ ["--stack-yaml=shake.yaml", "build", "hoogle"]
   execStack_ ["--stack-yaml=shake.yaml", "exec", "hoogle", "generate"]
 
+-- | short help message is printed by default
 shortHelpMessage :: Action ()
 shortHelpMessage = do
   let out = liftIO . putStrLn
@@ -275,25 +265,19 @@ shortHelpMessage = do
         ++ allVersionMessage hieVersions
         ++ ")"
       )
-    , ( "build-all"
-      , "Builds hie and hoogle databases for all supported GHC versions"
-      )
+    , stackBuildAllTarget
     , stackHieTarget mostRecentHieVersion
-    , stackBuildDocTarget mostRecentHieVersion
+    , stackBuildDocTarget
     , stackHieTarget "8.4.4"
-    , stackBuildDocTarget "8.4.4"
     , emptyTarget
     , ( "cabal-ghcs"
       , "Show all GHC versions that can be installed via `cabal-build` and `cabal-build-all`."
       )
-    , ("cabal-build", "Builds hie with cabal with all installed GHCs.")
-    , ( "cabal-build-all"
-      , "Builds hie and hoogle databases for all installed GHC versions with cabal"
-      )
+    , cabalBuildTarget
+    , cabalBuildAllTarget
     , cabalHieTarget mostRecentHieVersion
-    , cabalBuildDocTarget mostRecentHieVersion
+    , cabalBuildDocTarget
     , cabalHieTarget "8.4.4"
-    , cabalBuildDocTarget "8.4.4"
     ]
 
 
@@ -315,13 +299,13 @@ helpMessage = do
   -- All targets the shake file supports
   targets :: [(String, String)]
   targets =
-    generalTargets
-      ++ [emptyTarget]
-      ++ stackTargets
-      ++ [emptyTarget]
-      ++ cabalTargets
-      ++ [emptyTarget]
-      ++ macosTargets
+    intercalate
+      [emptyTarget]
+      [ generalTargets
+      , stackTargets
+      , cabalTargets
+      , macosTargets
+      ]
 
   -- All targets with their respective help message.
   generalTargets =
@@ -339,39 +323,29 @@ helpMessage = do
       ++ allVersionMessage hieVersions
       ++ ")"
       )
-      , ( "build-all"
-        , "Builds hie and hoogle databases for all supported GHC versions"
-        )
-      , ( "build-docs"
-        , "Builds the Hoogle database for all supported GHC versions"
-        )
+      , stackBuildAllTarget
+      , stackBuildDocTarget
       , ("test", "Runs hie tests with stack")
       ]
       ++ map stackHieTarget      hieVersions
-      ++ map stackBuildDocTarget hieVersions
 
   cabalTargets =
     [ ( "cabal-ghcs"
       , "Show all GHC versions that can be installed via `cabal-build` and `cabal-build-all`."
       )
-      , ("cabal-build", "Builds hie with cabal with all installed GHCs.")
-      , ( "cabal-build-all"
-        , "Builds hie and hoogle databases for all installed GHC versions with cabal"
-        )
-      , ( "cabal-build-docs"
-        , "Builds the Hoogle database for all installed GHC versions with cabal"
-        )
+      , cabalBuildTarget
+      , cabalBuildAllTarget
+      , cabalBuildDocTarget
       , ("cabal-test", "Runs hie tests with cabal")
       ]
       ++ map cabalHieTarget      hieVersions
-      ++ map cabalBuildDocTarget hieVersions
 
 -- | Empty target. Purpose is to introduce a newline between the targets
 emptyTarget :: (String, String)
 emptyTarget = ("", "")
 
 -- |Number of spaces the target name including whitespace should have.
--- At least twenty, maybe more if target names are long. At most length of the longest target plus five.
+-- At least twenty, maybe more if target names are long and at least the length of the longest target plus five.
 space :: [(String, String)] -> Int
 space phonyTargets = maximum (20 : map ((+ 5) . length . fst) phonyTargets)
 
@@ -395,20 +369,32 @@ cabalHieTarget version =
   , "Builds hie for GHC version " ++ version ++ " only with cabal new-build"
   )
 
-stackBuildDocTarget :: VersionNumber -> (String, String)
-stackBuildDocTarget version =
-  ( "build-doc-" ++ version
-  , "Builds the Hoogle database for GHC version "
-    ++ version
-    ++ " only with stack"
+stackBuildDocTarget :: (String, String)
+stackBuildDocTarget =
+  ( "build-doc"
+  , "Builds the Hoogle database"
+  )
+
+stackBuildAllTarget :: (String, String)
+stackBuildAllTarget =
+  ( "build-all"
+  , "Builds hie for all supported GHC versions and the hoogle database"
+  )
+
+cabalBuildTarget :: (String, String)
+cabalBuildTarget =
+  ("cabal-build", "Builds hie with cabal with all installed GHCs.")
+
+cabalBuildDocTarget :: (String, String)
+cabalBuildDocTarget =
+  ( "cabal-build-doc"
+  , "Builds the Hoogle database with cabal"
   )
 
-cabalBuildDocTarget :: VersionNumber -> (String, String)
-cabalBuildDocTarget version =
-  ( "cabal-build-doc-" ++ version
-  , "Builds the Hoogle database for GHC version "
-    ++ version
-    ++ " only with cabal"
+cabalBuildAllTarget :: (String, String)
+cabalBuildAllTarget =
+  ( "cabal-build-all"
+  , "Builds hie for all installed GHC versions and the hoogle database with cabal"
   )
 
 -- | Creates a message of the form "a, b, c and d", where a,b,c,d are GHC versions.
@@ -422,6 +408,9 @@ allVersionMessage wordList = case wordList of
         lastVersion = last msg
     in  concat $ (init $ init msg) ++ [" and ", lastVersion]
 
+
+-- TODO: more sophisticated interface to stack and cabal
+
 execStackWithYaml_ :: VersionNumber -> [String] -> Action ()
 execStackWithYaml_ versionNumber args = do
   let stackFile = "stack-" ++ versionNumber ++ ".yaml"
@@ -441,6 +430,9 @@ execStack_ = command_ [] "stack"
 execCabal_ :: [String] -> Action ()
 execCabal_ = command_ [] "cabal"
 
+existsExecutable :: MonadIO m => String -> m Bool
+existsExecutable executable = liftIO $ isJust <$> findExecutable executable
+
 -- |Get the path to the GHC compiler executable linked to the local `stack-$GHCVER.yaml`.
 -- Equal to the command `stack path --stack-yaml $stack-yaml --compiler-exe`.
 -- This might install a GHC if it is not already installed, thus, might fail if stack fails to install the GHC.
@@ -453,14 +445,12 @@ getStackGhcPath ghcVersion = do
 -- If no such GHC can be found, Nothing is returned.
 -- First, it is checked whether there is a GHC with the name `ghc-$VersionNumber`.
 -- If this yields no result, it is checked, whether the numeric-version of the `ghc`
--- command fits to the desired version. 
-getGhcPath :: VersionNumber -> IO (Maybe GhcPath)
-getGhcPath ghcVersion = do
-  pathMay <- findExecutable ("ghc-" ++ ghcVersion)
-  case pathMay of
+-- command fits to the desired version.
+getGhcPath :: MonadIO m => VersionNumber -> m (Maybe GhcPath)
+getGhcPath ghcVersion = liftIO $ do
+  findExecutable ("ghc-" ++ ghcVersion) >>= \case
     Nothing -> do
-      noPrefixPathMay <- findExecutable "ghc"
-      case noPrefixPathMay of
+      findExecutable "ghc" >>= \case
         Nothing -> return Nothing
         Just p  -> do
           Stdout version <- cmd p ["--numeric-version"] :: IO (Stdout String)

From e0fb0a6c5394c037f2cdaaf18c60d1cc916a8a51 Mon Sep 17 00:00:00 2001
From: Samuel Pilz <samuel.pilz@posteo.net>
Date: Tue, 9 Apr 2019 12:01:08 +0200
Subject: [PATCH 02/13] include @fendor's comments

---
 install.hs | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/install.hs b/install.hs
index 81f35cbf0..260b798b2 100755
--- a/install.hs
+++ b/install.hs
@@ -156,7 +156,7 @@ validateCabalNewInstallIsSupported = when (os `elem` ["mingw32", "win32"]) $ do
 configureCabal :: VersionNumber -> Action ()
 configureCabal versionNumber = do
   ghcPath <- getGhcPath versionNumber >>= \case
-    Nothing -> do -- TODO: this is better written using a monad-transformer
+    Nothing -> do
       liftIO $ putStrLn $ embedInStars (ghcVersionNotFound versionNumber)
       error (ghcVersionNotFound versionNumber)
     Just p -> return p
@@ -170,7 +170,7 @@ findInstalledGhcs = mapMaybeM
       Nothing -> return Nothing
       Just p  -> return $ Just (version, p)
   )
-  hieVersions
+  (reverse hieVersions)
 
 cabalBuildHie :: VersionNumber -> Action ()
 cabalBuildHie versionNumber = do
@@ -345,7 +345,7 @@ emptyTarget :: (String, String)
 emptyTarget = ("", "")
 
 -- |Number of spaces the target name including whitespace should have.
--- At least twenty, maybe more if target names are long and at least the length of the longest target plus five.
+-- At least twenty, maybe more if target names are long. At most the length of the longest target plus five.
 space :: [(String, String)] -> Int
 space phonyTargets = maximum (20 : map ((+ 5) . length . fst) phonyTargets)
 

From aa5ea40bc3862fdfc0f585b160d44107508c06aa Mon Sep 17 00:00:00 2001
From: Samuel Pilz <samuel.pilz@posteo.net>
Date: Tue, 9 Apr 2019 14:16:18 +0200
Subject: [PATCH 03/13] check version of existing cabal before using that

---
 install.hs | 113 +++++++++++++++++++++++++++++++----------------------
 1 file changed, 66 insertions(+), 47 deletions(-)

diff --git a/install.hs b/install.hs
index 260b798b2..061c31830 100755
--- a/install.hs
+++ b/install.hs
@@ -12,22 +12,31 @@ import           Development.Shake
 import           Development.Shake.Command
 import           Development.Shake.FilePath
 import           Control.Monad
+import           Control.Monad
 import           Control.Monad.IO.Class
-import           Control.Monad.Extra (unlessM, mapMaybeM)
-import           Data.Maybe (isJust)
-import           System.Directory               ( findExecutable )
-import           System.Environment             ( getProgName
-                                                , unsetEnv
-                                                )
-import           System.Info                    ( os
-                                                , arch
-                                                )
-
-import           Data.List                      ( dropWhileEnd
-                                                , intersperse
-                                                , intercalate
-                                                )
-import           Data.Char                      ( isSpace )
+import           Control.Monad.Extra                      ( unlessM
+                                                          , mapMaybeM
+                                                          )
+import           Data.Maybe                               ( isJust )
+import           System.Directory                         ( findExecutable )
+import           System.Environment                       ( getProgName
+                                                          , unsetEnv
+                                                          )
+import           System.Info                              ( os
+                                                          , arch
+                                                          )
+
+import           Data.Maybe                               ( isNothing )
+import           Data.List                                ( dropWhileEnd
+                                                          , intersperse
+                                                          , intercalate
+                                                          )
+import           Data.Char                                ( isSpace )
+import           Data.Version                             ( parseVersion
+                                                          , makeVersion
+                                                          )
+import           Data.Function                            ( (&) )
+import           Text.ParserCombinators.ReadP             ( readP_to_S )
 
 type VersionNumber = String
 type GhcPath = String
@@ -80,8 +89,8 @@ main = do
       liftIO $ putStrLn $ embedInStars msg
 
     -- stack specific targets
-    phony "build"      (need (reverse $ map ("hie-" ++) hieVersions))
-    phony "build-all"  (need ["build-doc", "build"])
+    phony "build"     (need (reverse $ map ("hie-" ++) hieVersions))
+    phony "build-all" (need ["build-doc", "build"])
     phony "test" $ do
       need ["submodules"]
       need ["cabal"]
@@ -90,8 +99,8 @@ main = do
     phony "build-copy-compiler-tool" $ forM_ hieVersions buildCopyCompilerTool
 
     phony "build-doc" $ do
-        need ["submodules"]
-        stackBuildDoc
+      need ["submodules"]
+      stackBuildDoc
 
     -- main targets for building hie with `stack`
     forM_
@@ -104,12 +113,12 @@ main = do
       )
 
     -- cabal specific targets
-    phony "cabal-build"      (need (map ("cabal-hie-" ++) ghcVersions))
-    phony "cabal-build-all"  (need ["cabal-build-doc", "cabal-build"])
+    phony "cabal-build"     (need (map ("cabal-hie-" ++) ghcVersions))
+    phony "cabal-build-all" (need ["cabal-build-doc", "cabal-build"])
     phony "cabal-build-doc" $ do
-        need ["submodules"]
-        need ["cabal"]
-        cabalBuildDoc
+      need ["submodules"]
+      need ["cabal"]
+      cabalBuildDoc
 
     phony "cabal-test" $ do
       need ["submodules"]
@@ -149,7 +158,7 @@ updateSubmodules = do
   command_ [] "git" ["submodule", "update", "--init", "--recursive"]
 
 validateCabalNewInstallIsSupported :: Action ()
-validateCabalNewInstallIsSupported = when (os `elem` ["mingw32", "win32"]) $ do
+validateCabalNewInstallIsSupported = when isWindowsSystem $ do
   liftIO $ putStrLn $ embedInStars cabalInstallNotSuported
   error cabalInstallNotSuported
 
@@ -165,10 +174,9 @@ configureCabal versionNumber = do
 
 findInstalledGhcs :: IO [(VersionNumber, GhcPath)]
 findInstalledGhcs = mapMaybeM
-  (\version -> do
-    getGhcPath version >>= \case
-      Nothing -> return Nothing
-      Just p  -> return $ Just (version, p)
+  (\version -> getGhcPath version >>= \case
+    Nothing -> return Nothing
+    Just p  -> return $ Just (version, p)
   )
   (reverse hieVersions)
 
@@ -204,8 +212,22 @@ cabalTest versionNumber = do
 
 installCabal :: Action ()
 installCabal = do
+  -- try to find existing `cabal` executable with appropriate version
+  cabalExe <- liftIO (findExecutable "cabal") >>= \case
+    Nothing       -> return Nothing
+    Just cabalExe -> do
+      Stdout cabalVersion <- execCabal ["--numeric-version"]
+      let (parsedVersion, "") : _ =
+            cabalVersion & trim & readP_to_S parseVersion & filter
+              (("" ==) . snd)
+
+      return $ if parsedVersion >= makeVersion [2, 4, 1, 0]
+        then Just cabalExe
+        else Nothing
+
+
   -- install `cabal-install` if not already installed
-  unlessM (existsExecutable "cabal") $ do
+  when (isNothing cabalExe) $
     execStack_ ["install", "--stack-yaml=shake.yaml", "cabal-install"]
   execCabal_ ["update"]
   ghc <- getStackGhcPath mostRecentHieVersion
@@ -298,14 +320,9 @@ helpMessage = do
   spaces = space targets
   -- All targets the shake file supports
   targets :: [(String, String)]
-  targets =
-    intercalate
-      [emptyTarget]
-      [ generalTargets
-      , stackTargets
-      , cabalTargets
-      , macosTargets
-      ]
+  targets = intercalate
+    [emptyTarget]
+    [generalTargets, stackTargets, cabalTargets, macosTargets]
 
   -- All targets with their respective help message.
   generalTargets =
@@ -327,7 +344,7 @@ helpMessage = do
       , stackBuildDocTarget
       , ("test", "Runs hie tests with stack")
       ]
-      ++ map stackHieTarget      hieVersions
+      ++ map stackHieTarget hieVersions
 
   cabalTargets =
     [ ( "cabal-ghcs"
@@ -338,7 +355,7 @@ helpMessage = do
       , cabalBuildDocTarget
       , ("cabal-test", "Runs hie tests with cabal")
       ]
-      ++ map cabalHieTarget      hieVersions
+      ++ map cabalHieTarget hieVersions
 
 -- | Empty target. Purpose is to introduce a newline between the targets
 emptyTarget :: (String, String)
@@ -370,10 +387,7 @@ cabalHieTarget version =
   )
 
 stackBuildDocTarget :: (String, String)
-stackBuildDocTarget =
-  ( "build-doc"
-  , "Builds the Hoogle database"
-  )
+stackBuildDocTarget = ("build-doc", "Builds the Hoogle database")
 
 stackBuildAllTarget :: (String, String)
 stackBuildAllTarget =
@@ -387,9 +401,7 @@ cabalBuildTarget =
 
 cabalBuildDocTarget :: (String, String)
 cabalBuildDocTarget =
-  ( "cabal-build-doc"
-  , "Builds the Hoogle database with cabal"
-  )
+  ("cabal-build-doc", "Builds the Hoogle database with cabal")
 
 cabalBuildAllTarget :: (String, String)
 cabalBuildAllTarget =
@@ -427,12 +439,19 @@ execStack = command [] "stack"
 execStack_ :: [String] -> Action ()
 execStack_ = command_ [] "stack"
 
+execCabal :: CmdResult r => [String] -> Action r
+execCabal = command [] "cabal"
+
 execCabal_ :: [String] -> Action ()
 execCabal_ = command_ [] "cabal"
 
 existsExecutable :: MonadIO m => String -> m Bool
 existsExecutable executable = liftIO $ isJust <$> findExecutable executable
 
+-- |Check if the current system is windows
+isWindowsSystem :: Bool
+isWindowsSystem = os `elem` ["mingw32", "win32"]
+
 -- |Get the path to the GHC compiler executable linked to the local `stack-$GHCVER.yaml`.
 -- Equal to the command `stack path --stack-yaml $stack-yaml --compiler-exe`.
 -- This might install a GHC if it is not already installed, thus, might fail if stack fails to install the GHC.

From 36b0f998f56088c88f5ca9f8b47191cf5423fb6c Mon Sep 17 00:00:00 2001
From: Samuel Pilz <samuel.pilz@posteo.net>
Date: Sat, 13 Apr 2019 15:47:48 +0200
Subject: [PATCH 04/13] implement check for `stack` version

---
 install.hs | 36 ++++++++++++++++++++++++++++--------
 1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/install.hs b/install.hs
index 061c31830..c8c46e481 100755
--- a/install.hs
+++ b/install.hs
@@ -72,11 +72,12 @@ main = do
   shakeArgs shakeOptions { shakeFiles = "_build" } $ do
     want ["short-help"]
     -- general purpose targets
-    phony "submodules" updateSubmodules
-    phony "cabal"      installCabal
-    phony "short-help" shortHelpMessage
-    phony "all"        shortHelpMessage
-    phony "help"       helpMessage
+    phony "submodules"  updateSubmodules
+    phony "cabal"       installCabal
+    phony "short-help"  shortHelpMessage
+    phony "all"         shortHelpMessage
+    phony "help"        helpMessage
+    phony "check-stack" checkStack
 
     phony "cabal-ghcs" $ do
       let
@@ -93,6 +94,7 @@ main = do
     phony "build-all" (need ["build-doc", "build"])
     phony "test" $ do
       need ["submodules"]
+      need ["check-stack"]
       need ["cabal"]
       forM_ hieVersions stackTest
 
@@ -100,6 +102,7 @@ main = do
 
     phony "build-doc" $ do
       need ["submodules"]
+      need ["check-stack"]
       stackBuildDoc
 
     -- main targets for building hie with `stack`
@@ -107,6 +110,7 @@ main = do
       hieVersions
       (\version -> phony ("hie-" ++ version) $ do
         need ["submodules"]
+        need ["check-stack"]
         need ["cabal"]
         stackBuildHie version
         stackInstallHie version
@@ -224,8 +228,6 @@ installCabal = do
       return $ if parsedVersion >= makeVersion [2, 4, 1, 0]
         then Just cabalExe
         else Nothing
-
-
   -- install `cabal-install` if not already installed
   when (isNothing cabalExe) $
     execStack_ ["install", "--stack-yaml=shake.yaml", "cabal-install"]
@@ -233,8 +235,20 @@ installCabal = do
   ghc <- getStackGhcPath mostRecentHieVersion
   execCabal_ ["install", "Cabal-2.4.1.0", "--with-compiler=" ++ ghc]
 
+
+checkStack :: Action ()
+checkStack = do
+  Stdout stackVersion <- execStack ["--numeric-version"]
+  let (parsedVersion, "") : _ =
+        stackVersion & trim & readP_to_S parseVersion & filter
+          (("" ==) . snd)
+  unless (parsedVersion >= makeVersion [1, 9, 3]) $ do
+    liftIO $ putStrLn $ embedInStars stackExeIsOld
+    error stackExeIsOld
+
+
 stackBuildHie :: VersionNumber -> Action ()
-stackBuildHie versionNumber = do
+stackBuildHie versionNumber =
   execStackWithYaml_ versionNumber ["build"]
     `actionOnException` liftIO (putStrLn stackBuildFailMsg)
 
@@ -529,3 +543,9 @@ cabalInstallNotSuported =
     ++ "Unfortunately, `cabal new-install` is currently not supported on windows.\n"
     ++ "Please use one of the stack-based targets.\n\n"
     ++ "If this system has been falsely identified, please open an issue at:\n\thttps://github.com/haskell/haskell-ide-engine\n"
+
+-- | Error message when a windows system tries to install HIE via `cabal new-install`
+stackExeIsOld :: String
+stackExeIsOld =
+  "You The `stack` executable is outdated.\n"
+    ++ "Please run `stack upgrade` to upgrade you stack installation"

From 0d2e6fac25e2623fab2f5eb8faa962f938dd5330 Mon Sep 17 00:00:00 2001
From: Samuel Pilz <samuel.pilz@posteo.net>
Date: Sat, 13 Apr 2019 16:08:04 +0200
Subject: [PATCH 05/13] use the compiler from shake to install Cabal

---
 install.hs | 7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/install.hs b/install.hs
index c8c46e481..18ec2a0e0 100755
--- a/install.hs
+++ b/install.hs
@@ -232,7 +232,7 @@ installCabal = do
   when (isNothing cabalExe) $
     execStack_ ["install", "--stack-yaml=shake.yaml", "cabal-install"]
   execCabal_ ["update"]
-  ghc <- getStackGhcPath mostRecentHieVersion
+  ghc <- getStackGhcPathShake
   execCabal_ ["install", "Cabal-2.4.1.0", "--with-compiler=" ++ ghc]
 
 
@@ -474,6 +474,11 @@ getStackGhcPath ghcVersion = do
   Stdout ghc <- execStackWithYaml ghcVersion ["path", "--compiler-exe"]
   return $ trim ghc
 
+getStackGhcPathShake :: Action GhcPath
+getStackGhcPathShake = do
+  Stdout ghc <- execStack ["--stack-yaml=shake.yaml", "path", "--compiler-exe"]
+  return $ trim ghc
+
 -- |Get the path to a GHC that has the version specified by `VersionNumber`
 -- If no such GHC can be found, Nothing is returned.
 -- First, it is checked whether there is a GHC with the name `ghc-$VersionNumber`.

From cadcfe50e729335a5cc0cff80408ff9b53e3463d Mon Sep 17 00:00:00 2001
From: Samuel Pilz <samuel.pilz@posteo.net>
Date: Sat, 13 Apr 2019 17:32:53 +0200
Subject: [PATCH 06/13] change helper functions to always use shake-yaml or
 specific ghc-based yaml

---
 install.hs | 92 ++++++++++++++++++++++++++++++------------------------
 1 file changed, 51 insertions(+), 41 deletions(-)

diff --git a/install.hs b/install.hs
index 18ec2a0e0..7c71ecba3 100755
--- a/install.hs
+++ b/install.hs
@@ -1,7 +1,7 @@
 #!/usr/bin/env stack
 {- stack
-  script
-  --resolver nightly-2018-12-15
+  runghc
+  --stack-yaml=shake.yaml
   --package shake
   --package directory
   --package extra
@@ -147,7 +147,7 @@ main = do
 
 
 buildIcuMacosFix :: VersionNumber -> Action ()
-buildIcuMacosFix version = execStackWithYaml_
+buildIcuMacosFix version = execStackWithGhc_
   version
   [ "build"
   , "text-icu"
@@ -163,15 +163,15 @@ updateSubmodules = do
 
 validateCabalNewInstallIsSupported :: Action ()
 validateCabalNewInstallIsSupported = when isWindowsSystem $ do
-  liftIO $ putStrLn $ embedInStars cabalInstallNotSuported
-  error cabalInstallNotSuported
+  liftIO $ putStrLn $ embedInStars cabalInstallNotSuportedFailMsg
+  error cabalInstallNotSuportedFailMsg
 
 configureCabal :: VersionNumber -> Action ()
 configureCabal versionNumber = do
   ghcPath <- getGhcPath versionNumber >>= \case
     Nothing -> do
-      liftIO $ putStrLn $ embedInStars (ghcVersionNotFound versionNumber)
-      error (ghcVersionNotFound versionNumber)
+      liftIO $ putStrLn $ embedInStars (ghcVersionNotFoundFailMsg versionNumber)
+      error (ghcVersionNotFoundFailMsg versionNumber)
     Just p -> return p
   execCabal_
     ["new-configure", "-w", ghcPath, "--write-ghc-environment-files=never"]
@@ -230,7 +230,7 @@ installCabal = do
         else Nothing
   -- install `cabal-install` if not already installed
   when (isNothing cabalExe) $
-    execStack_ ["install", "--stack-yaml=shake.yaml", "cabal-install"]
+    execStackShake_ ["install", "cabal-install"]
   execCabal_ ["update"]
   ghc <- getStackGhcPathShake
   execCabal_ ["install", "Cabal-2.4.1.0", "--with-compiler=" ++ ghc]
@@ -238,24 +238,24 @@ installCabal = do
 
 checkStack :: Action ()
 checkStack = do
-  Stdout stackVersion <- execStack ["--numeric-version"]
+  Stdout stackVersion <- execStackShake ["--numeric-version"]
   let (parsedVersion, "") : _ =
         stackVersion & trim & readP_to_S parseVersion & filter
           (("" ==) . snd)
   unless (parsedVersion >= makeVersion [1, 9, 3]) $ do
-    liftIO $ putStrLn $ embedInStars stackExeIsOld
-    error stackExeIsOld
+    liftIO $ putStrLn $ embedInStars stackExeIsOldFailMsg
+    error stackExeIsOldFailMsg
 
 
 stackBuildHie :: VersionNumber -> Action ()
 stackBuildHie versionNumber =
-  execStackWithYaml_ versionNumber ["build"]
+  execStackWithGhc_ versionNumber ["build"]
     `actionOnException` liftIO (putStrLn stackBuildFailMsg)
 
 -- | copy the built binaries into the localBinDir
 stackInstallHie :: VersionNumber -> Action ()
 stackInstallHie versionNumber = do
-  execStackWithYaml_ versionNumber ["install"]
+  execStackWithGhc_ versionNumber ["install"]
   localBinDir      <- getLocalBin
   localInstallRoot <- getLocalInstallRoot versionNumber
   let hie = "hie" <.> exe
@@ -266,15 +266,15 @@ stackInstallHie versionNumber = do
 
 buildCopyCompilerTool :: VersionNumber -> Action ()
 buildCopyCompilerTool versionNumber =
-  execStackWithYaml_ versionNumber ["build", "--copy-compiler-tool"]
+  execStackWithGhc_ versionNumber ["build", "--copy-compiler-tool"]
 
 stackTest :: VersionNumber -> Action ()
-stackTest versionNumber = execStackWithYaml_ versionNumber ["test"]
+stackTest versionNumber = execStackWithGhc_ versionNumber ["test"]
 
 stackBuildDoc :: Action ()
 stackBuildDoc = do
-  execStack_ ["--stack-yaml=shake.yaml", "build", "hoogle"]
-  execStack_ ["--stack-yaml=shake.yaml", "exec", "hoogle", "generate"]
+  execStackShake_ ["build", "hoogle"]
+  execStackShake_ ["exec", "hoogle", "generate"]
 
 -- | short help message is printed by default
 shortHelpMessage :: Action ()
@@ -435,26 +435,33 @@ allVersionMessage wordList = case wordList of
     in  concat $ (init $ init msg) ++ [" and ", lastVersion]
 
 
--- TODO: more sophisticated interface to stack and cabal
+-- RUN EXECUTABLES
 
-execStackWithYaml_ :: VersionNumber -> [String] -> Action ()
-execStackWithYaml_ versionNumber args = do
+-- |Execute a stack command for a specified ghc, discarding the output
+execStackWithGhc_ :: VersionNumber -> [String] -> Action ()
+execStackWithGhc_ versionNumber args = do
   let stackFile = "stack-" ++ versionNumber ++ ".yaml"
   command_ [] "stack" (("--stack-yaml=" ++ stackFile) : args)
 
-execStackWithYaml :: CmdResult r => VersionNumber -> [String] -> Action r
-execStackWithYaml versionNumber args = do
+-- |Execute a stack command for a specified ghc
+execStackWithGhc :: CmdResult r => VersionNumber -> [String] -> Action r
+execStackWithGhc versionNumber args = do
   let stackFile = "stack-" ++ versionNumber ++ ".yaml"
   command [] "stack" (("--stack-yaml=" ++ stackFile) : args)
 
-execStack :: CmdResult r => [String] -> Action r
-execStack = command [] "stack"
+-- |Execute a stack command with the same resolver as the build script
+execStackShake :: CmdResult r => [String] -> Action r
+execStackShake args =
+  command [] "stack" ("--stack-yaml=shake.yaml" : args)
 
-execStack_ :: [String] -> Action ()
-execStack_ = command_ [] "stack"
+-- |Execute a stack command with the same resolver as the build script, discarding the output
+execStackShake_ :: [String] -> Action ()
+execStackShake_ args =
+  command_ [] "stack" ("--stack-yaml=shake.yaml" : args)
 
 execCabal :: CmdResult r => [String] -> Action r
-execCabal = command [] "cabal"
+execCabal =
+  command [] "cabal"
 
 execCabal_ :: [String] -> Action ()
 execCabal_ = command_ [] "cabal"
@@ -462,6 +469,9 @@ execCabal_ = command_ [] "cabal"
 existsExecutable :: MonadIO m => String -> m Bool
 existsExecutable executable = liftIO $ isJust <$> findExecutable executable
 
+
+-- QUERY ENVIRONMENT
+
 -- |Check if the current system is windows
 isWindowsSystem :: Bool
 isWindowsSystem = os `elem` ["mingw32", "win32"]
@@ -471,12 +481,12 @@ isWindowsSystem = os `elem` ["mingw32", "win32"]
 -- This might install a GHC if it is not already installed, thus, might fail if stack fails to install the GHC.
 getStackGhcPath :: VersionNumber -> Action GhcPath
 getStackGhcPath ghcVersion = do
-  Stdout ghc <- execStackWithYaml ghcVersion ["path", "--compiler-exe"]
+  Stdout ghc <- execStackWithGhc ghcVersion ["path", "--compiler-exe"]
   return $ trim ghc
 
 getStackGhcPathShake :: Action GhcPath
 getStackGhcPathShake = do
-  Stdout ghc <- execStack ["--stack-yaml=shake.yaml", "path", "--compiler-exe"]
+  Stdout ghc <- execStackShake ["path", "--compiler-exe"]
   return $ trim ghc
 
 -- |Get the path to a GHC that has the version specified by `VersionNumber`
@@ -485,7 +495,7 @@ getStackGhcPathShake = do
 -- If this yields no result, it is checked, whether the numeric-version of the `ghc`
 -- command fits to the desired version.
 getGhcPath :: MonadIO m => VersionNumber -> m (Maybe GhcPath)
-getGhcPath ghcVersion = liftIO $ do
+getGhcPath ghcVersion = liftIO $
   findExecutable ("ghc-" ++ ghcVersion) >>= \case
     Nothing -> do
       findExecutable "ghc" >>= \case
@@ -500,7 +510,7 @@ getGhcPath ghcVersion = liftIO $ do
 -- Equal to the command `stack path --local-install-root`
 getLocalInstallRoot :: VersionNumber -> Action FilePath
 getLocalInstallRoot hieVersion = do
-  Stdout localInstallRoot' <- execStackWithYaml
+  Stdout localInstallRoot' <- execStackWithGhc
     hieVersion
     ["path", "--local-install-root"]
   return $ trim localInstallRoot'
@@ -509,8 +519,8 @@ getLocalInstallRoot hieVersion = do
 -- Equal to the command `stack path --local-bin`
 getLocalBin :: Action FilePath
 getLocalBin = do
-  Stdout stackLocalDir' <- execStack
-    ["path", "--stack-yaml=shake.yaml", "--local-bin"]
+  Stdout stackLocalDir' <- execStackShake
+    ["path", "--local-bin"]
   return $ trim stackLocalDir'
 
 -- |Trim the end of a string
@@ -534,23 +544,23 @@ stackBuildFailMsg =
     ++ "\thttps://github.com/haskell/haskell-ide-engine"
 
 -- |No suitable ghc version has been found. Show a message.
-ghcVersionNotFound :: VersionNumber -> String
-ghcVersionNotFound versionNumber =
+ghcVersionNotFoundFailMsg :: VersionNumber -> String
+ghcVersionNotFoundFailMsg versionNumber =
   "No GHC with version "
     <> versionNumber
     <> " has been found.\n"
     <> "Either install a fitting GHC, use the stack targets or modify the PATH variable accordingly."
 
 -- | Error message when a windows system tries to install HIE via `cabal new-install`
-cabalInstallNotSuported :: String
-cabalInstallNotSuported =
+cabalInstallNotSuportedFailMsg :: String
+cabalInstallNotSuportedFailMsg =
   "This system has been identified as a windows system.\n"
     ++ "Unfortunately, `cabal new-install` is currently not supported on windows.\n"
     ++ "Please use one of the stack-based targets.\n\n"
     ++ "If this system has been falsely identified, please open an issue at:\n\thttps://github.com/haskell/haskell-ide-engine\n"
 
 -- | Error message when a windows system tries to install HIE via `cabal new-install`
-stackExeIsOld :: String
-stackExeIsOld =
-  "You The `stack` executable is outdated.\n"
-    ++ "Please run `stack upgrade` to upgrade you stack installation"
+stackExeIsOldFailMsg :: String
+stackExeIsOldFailMsg =
+  "The `stack` executable is outdated.\n"
+    ++ "Please run `stack upgrade` to upgrade your stack installation"

From 7a974297cea02f4ae8734a25bfd57e4b7e33b369 Mon Sep 17 00:00:00 2001
From: Samuel Pilz <samuel.pilz@posteo.net>
Date: Sat, 13 Apr 2019 17:42:12 +0200
Subject: [PATCH 07/13] document that cabal new-build will work on windows in
 next release

---
 install.hs | 1 +
 1 file changed, 1 insertion(+)

diff --git a/install.hs b/install.hs
index 7c71ecba3..082834b1b 100755
--- a/install.hs
+++ b/install.hs
@@ -161,6 +161,7 @@ updateSubmodules = do
   command_ [] "git" ["submodule", "sync", "--recursive"]
   command_ [] "git" ["submodule", "update", "--init", "--recursive"]
 
+-- TODO: this restriction will be gone in the next release of cabal
 validateCabalNewInstallIsSupported :: Action ()
 validateCabalNewInstallIsSupported = when isWindowsSystem $ do
   liftIO $ putStrLn $ embedInStars cabalInstallNotSuportedFailMsg

From a7bb6e987a22f04a921b17e6da7bb143b35b2463 Mon Sep 17 00:00:00 2001
From: Samuel Pilz <samuel.pilz@posteo.net>
Date: Tue, 16 Apr 2019 12:51:11 +0200
Subject: [PATCH 08/13] fix documentation comments

---
 install.hs | 38 +++++++++++++++++++-------------------
 1 file changed, 19 insertions(+), 19 deletions(-)

diff --git a/install.hs b/install.hs
index 082834b1b..34f708089 100755
--- a/install.hs
+++ b/install.hs
@@ -41,7 +41,7 @@ import           Text.ParserCombinators.ReadP             ( readP_to_S )
 type VersionNumber = String
 type GhcPath = String
 
--- |Defines all different hie versions that are buildable.
+-- | Defines all different hie versions that are buildable.
 -- If they are edited, make sure to maintain the order of the versions.
 hieVersions :: [VersionNumber]
 hieVersions =
@@ -56,7 +56,7 @@ hieVersions =
   , "8.6.4"
   ]
 
--- |Most recent version of hie.
+-- | Most recent version of hie.
 -- Shown in the more concise help message.
 mostRecentHieVersion :: VersionNumber
 mostRecentHieVersion = last hieVersions
@@ -155,7 +155,7 @@ buildIcuMacosFix version = execStackWithGhc_
   , "--extra-include-dirs=/usr/local/opt/icu4c/include"
   ]
 
--- |update the submodules that the project is in the state as required by the `stack.yaml` files
+-- | update the submodules that the project is in the state as required by the `stack.yaml` files
 updateSubmodules :: Action ()
 updateSubmodules = do
   command_ [] "git" ["submodule", "sync", "--recursive"]
@@ -376,25 +376,25 @@ helpMessage = do
 emptyTarget :: (String, String)
 emptyTarget = ("", "")
 
--- |Number of spaces the target name including whitespace should have.
+-- | Number of spaces the target name including whitespace should have.
 -- At least twenty, maybe more if target names are long. At most the length of the longest target plus five.
 space :: [(String, String)] -> Int
 space phonyTargets = maximum (20 : map ((+ 5) . length . fst) phonyTargets)
 
--- |Show a target.
+-- | Show a target.
 -- Concatenates the target with its help message and inserts whitespace between them.
 showTarget :: Int -> (String, String) -> String
 showTarget spaces (target, msg) =
   target ++ replicate (spaces - length target) ' ' ++ msg
 
--- |Target for a specific ghc version
+-- | Target for a specific ghc version
 stackHieTarget :: String -> (String, String)
 stackHieTarget version =
   ( "hie-" ++ version
   , "Builds hie for GHC version " ++ version ++ " only with stack"
   )
 
--- |Target for a specific ghc version
+-- | Target for a specific ghc version
 cabalHieTarget :: String -> (String, String)
 cabalHieTarget version =
   ( "cabal-hie-" ++ version
@@ -438,24 +438,24 @@ allVersionMessage wordList = case wordList of
 
 -- RUN EXECUTABLES
 
--- |Execute a stack command for a specified ghc, discarding the output
+-- | Execute a stack command for a specified ghc, discarding the output
 execStackWithGhc_ :: VersionNumber -> [String] -> Action ()
 execStackWithGhc_ versionNumber args = do
   let stackFile = "stack-" ++ versionNumber ++ ".yaml"
   command_ [] "stack" (("--stack-yaml=" ++ stackFile) : args)
 
--- |Execute a stack command for a specified ghc
+-- | Execute a stack command for a specified ghc
 execStackWithGhc :: CmdResult r => VersionNumber -> [String] -> Action r
 execStackWithGhc versionNumber args = do
   let stackFile = "stack-" ++ versionNumber ++ ".yaml"
   command [] "stack" (("--stack-yaml=" ++ stackFile) : args)
 
--- |Execute a stack command with the same resolver as the build script
+-- | Execute a stack command with the same resolver as the build script
 execStackShake :: CmdResult r => [String] -> Action r
 execStackShake args =
   command [] "stack" ("--stack-yaml=shake.yaml" : args)
 
--- |Execute a stack command with the same resolver as the build script, discarding the output
+-- | Execute a stack command with the same resolver as the build script, discarding the output
 execStackShake_ :: [String] -> Action ()
 execStackShake_ args =
   command_ [] "stack" ("--stack-yaml=shake.yaml" : args)
@@ -477,7 +477,7 @@ existsExecutable executable = liftIO $ isJust <$> findExecutable executable
 isWindowsSystem :: Bool
 isWindowsSystem = os `elem` ["mingw32", "win32"]
 
--- |Get the path to the GHC compiler executable linked to the local `stack-$GHCVER.yaml`.
+-- | Get the path to the GHC compiler executable linked to the local `stack-$GHCVER.yaml`.
 -- Equal to the command `stack path --stack-yaml $stack-yaml --compiler-exe`.
 -- This might install a GHC if it is not already installed, thus, might fail if stack fails to install the GHC.
 getStackGhcPath :: VersionNumber -> Action GhcPath
@@ -490,7 +490,7 @@ getStackGhcPathShake = do
   Stdout ghc <- execStackShake ["path", "--compiler-exe"]
   return $ trim ghc
 
--- |Get the path to a GHC that has the version specified by `VersionNumber`
+-- | Get the path to a GHC that has the version specified by `VersionNumber`
 -- If no such GHC can be found, Nothing is returned.
 -- First, it is checked whether there is a GHC with the name `ghc-$VersionNumber`.
 -- If this yields no result, it is checked, whether the numeric-version of the `ghc`
@@ -506,7 +506,7 @@ getGhcPath ghcVersion = liftIO $
           if ghcVersion == trim version then return $ Just p else return Nothing
     p -> return p
 
--- |Read the local install root of the stack project specified by the VersionNumber
+-- | Read the local install root of the stack project specified by the VersionNumber
 -- Returns the filepath of the local install root.
 -- Equal to the command `stack path --local-install-root`
 getLocalInstallRoot :: VersionNumber -> Action FilePath
@@ -516,7 +516,7 @@ getLocalInstallRoot hieVersion = do
     ["path", "--local-install-root"]
   return $ trim localInstallRoot'
 
--- |Get the local binary path of stack.
+-- | Get the local binary path of stack.
 -- Equal to the command `stack path --local-bin`
 getLocalBin :: Action FilePath
 getLocalBin = do
@@ -524,11 +524,11 @@ getLocalBin = do
     ["path", "--local-bin"]
   return $ trim stackLocalDir'
 
--- |Trim the end of a string
+-- | Trim the end of a string
 trim :: String -> String
 trim = dropWhileEnd isSpace
 
--- |Embed a string within two lines of stars to improve perceivability and, thus, readability.
+-- | Embed a string within two lines of stars to improve perceivability and, thus, readability.
 embedInStars :: String -> String
 embedInStars str =
   let starsLine
@@ -544,7 +544,7 @@ stackBuildFailMsg =
     ++ "If this does not work, open an issue at \n"
     ++ "\thttps://github.com/haskell/haskell-ide-engine"
 
--- |No suitable ghc version has been found. Show a message.
+-- | No suitable ghc version has been found. Show a message.
 ghcVersionNotFoundFailMsg :: VersionNumber -> String
 ghcVersionNotFoundFailMsg versionNumber =
   "No GHC with version "
@@ -560,7 +560,7 @@ cabalInstallNotSuportedFailMsg =
     ++ "Please use one of the stack-based targets.\n\n"
     ++ "If this system has been falsely identified, please open an issue at:\n\thttps://github.com/haskell/haskell-ide-engine\n"
 
--- | Error message when a windows system tries to install HIE via `cabal new-install`
+-- | Error message when the `stack` binary is an older version
 stackExeIsOldFailMsg :: String
 stackExeIsOldFailMsg =
   "The `stack` executable is outdated.\n"

From 1fffd94b333606ed757a271fe9c77370c3ab4cb8 Mon Sep 17 00:00:00 2001
From: Samuel Pilz <samuel.pilz@posteo.net>
Date: Tue, 16 Apr 2019 12:57:01 +0200
Subject: [PATCH 09/13] add current stack version to error about too old stack
 version

---
 install.hs | 9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

diff --git a/install.hs b/install.hs
index 34f708089..f96c14e7b 100755
--- a/install.hs
+++ b/install.hs
@@ -244,8 +244,8 @@ checkStack = do
         stackVersion & trim & readP_to_S parseVersion & filter
           (("" ==) . snd)
   unless (parsedVersion >= makeVersion [1, 9, 3]) $ do
-    liftIO $ putStrLn $ embedInStars stackExeIsOldFailMsg
-    error stackExeIsOldFailMsg
+    liftIO $ putStrLn $ embedInStars $ stackExeIsOldFailMsg stackVersion
+    error $ stackExeIsOldFailMsg stackVersion
 
 
 stackBuildHie :: VersionNumber -> Action ()
@@ -561,7 +561,8 @@ cabalInstallNotSuportedFailMsg =
     ++ "If this system has been falsely identified, please open an issue at:\n\thttps://github.com/haskell/haskell-ide-engine\n"
 
 -- | Error message when the `stack` binary is an older version
-stackExeIsOldFailMsg :: String
-stackExeIsOldFailMsg =
+stackExeIsOldFailMsg :: String -> String
+stackExeIsOldFailMsg stackVersion =
   "The `stack` executable is outdated.\n"
+    ++ "found version is `" ++ stackVersion ++ "`.\n"
     ++ "Please run `stack upgrade` to upgrade your stack installation"

From 5b0d0de7348907a9382c1f3f1c820de8858925f7 Mon Sep 17 00:00:00 2001
From: Samuel Pilz <samuel.pilz@posteo.net>
Date: Tue, 16 Apr 2019 17:47:30 +0200
Subject: [PATCH 10/13] add required stack version to error message

---
 install.hs | 11 ++++++++---
 1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/install.hs b/install.hs
index f96c14e7b..c614d009a 100755
--- a/install.hs
+++ b/install.hs
@@ -34,6 +34,7 @@ import           Data.List                                ( dropWhileEnd
 import           Data.Char                                ( isSpace )
 import           Data.Version                             ( parseVersion
                                                           , makeVersion
+                                                          , showVersion
                                                           )
 import           Data.Function                            ( (&) )
 import           Text.ParserCombinators.ReadP             ( readP_to_S )
@@ -243,9 +244,9 @@ checkStack = do
   let (parsedVersion, "") : _ =
         stackVersion & trim & readP_to_S parseVersion & filter
           (("" ==) . snd)
-  unless (parsedVersion >= makeVersion [1, 9, 3]) $ do
-    liftIO $ putStrLn $ embedInStars $ stackExeIsOldFailMsg stackVersion
-    error $ stackExeIsOldFailMsg stackVersion
+  unless (parsedVersion >= makeVersion requiredStackVersion) $ do
+    liftIO $ putStrLn $ embedInStars $ stackExeIsOldFailMsg $ trim stackVersion
+    error $ stackExeIsOldFailMsg $ trim stackVersion
 
 
 stackBuildHie :: VersionNumber -> Action ()
@@ -565,4 +566,8 @@ stackExeIsOldFailMsg :: String -> String
 stackExeIsOldFailMsg stackVersion =
   "The `stack` executable is outdated.\n"
     ++ "found version is `" ++ stackVersion ++ "`.\n"
+    ++ "required version is `" ++ showVersion (makeVersion requiredStackVersion) ++ "`.\n"
     ++ "Please run `stack upgrade` to upgrade your stack installation"
+
+requiredStackVersion :: [Int]
+requiredStackVersion = [1, 9, 3]

From c28a4bec1909a1f8851020039394bb420a25cfe9 Mon Sep 17 00:00:00 2001
From: Samuel Pilz <samuel.pilz@posteo.net>
Date: Thu, 18 Apr 2019 00:38:44 +0200
Subject: [PATCH 11/13] correct the readme to match the new docs targets in
 install.hs

---
 README.md | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/README.md b/README.md
index f53458261..ebb74018b 100644
--- a/README.md
+++ b/README.md
@@ -153,7 +153,7 @@ then it means you have the command in PATH.
 
 On Linux you will need install a couple of extra libraries (for Unicode ([ICU](http://site.icu-project.org/)) and [NCURSES](https://www.gnu.org/software/ncurses/)):
 
-**Debian/Ubuntu**: 
+**Debian/Ubuntu**:
 
 ```bash
 sudo apt install libicu-dev libtinfo-dev libgmp-dev
@@ -194,7 +194,7 @@ Available commands can be seen with:
 stack ./install.hs help
 ```
 
-Remember, this will take time to download a Stackage-LTS and an appropriate GHC. However, afterwards all commands should work as expected. 
+Remember, this will take time to download a Stackage-LTS and an appropriate GHC. However, afterwards all commands should work as expected.
 
 ##### Install specific GHC Version
 
@@ -202,14 +202,14 @@ Install **Nightly** (and hoogle docs):
 
 ```bash
 stack ./install.hs hie-8.6.4
-stack ./install.hs build-doc-8.6.4
+stack ./install.hs build-docs
 ```
 
 Install **LTS** (and hoogle docs):
 
 ```bash
 stack ./install.hs hie-8.4.4
-stack ./install.hs build-doc-8.4.4
+stack ./install.hs build-docs
 ```
 
 The Haskell IDE Engine can also be built with `cabal new-build` instead of `stack build`.
@@ -237,7 +237,7 @@ If your desired ghc has been found, you use it to install Haskell IDE Engine.
 
 ```bash
 stack install.hs cabal-hie-8.4.4
-stack install.hs cabal-build-doc-8.4.4
+stack install.hs cabal-build-docs
 ```
 
 To install HIE for all GHC versions that are present on your system, use:
@@ -589,11 +589,11 @@ These builds have a dependency on [homebrew](https://brew.sh)'s `gmp` library. I
 
 ### cannot satisfy -package-id \<package\>
 
-#### Is \<package\> base-x? 
+#### Is \<package\> base-x?
 Make sure that you are running the correct version of hie for your version of ghc, or check out hie-wrapper.
 
 #### Is there a hash (#) after \<package\>?
 Delete any `.ghc.environment*` files in your project root and try again. (At the time of writing, cabal new-style projects are not supported with ghc-mod)
 
 #### Otherwise
-Try running `cabal update`. 
+Try running `cabal update`.

From e03b5e5ae4a0cbe95f91b157df359eade24427f2 Mon Sep 17 00:00:00 2001
From: Samuel Pilz <samuel.pilz@posteo.net>
Date: Thu, 18 Apr 2019 14:21:24 +0200
Subject: [PATCH 12/13] dynamically load hie-versions and exclude `8.6.3` for
 windows

---
 install.hs | 89 +++++++++++++++++++++++++++++++++---------------------
 1 file changed, 54 insertions(+), 35 deletions(-)

diff --git a/install.hs b/install.hs
index c614d009a..ede8c65a5 100755
--- a/install.hs
+++ b/install.hs
@@ -18,7 +18,9 @@ import           Control.Monad.Extra                      ( unlessM
                                                           , mapMaybeM
                                                           )
 import           Data.Maybe                               ( isJust )
-import           System.Directory                         ( findExecutable )
+import           System.Directory                         ( findExecutable
+                                                          , listDirectory
+                                                          )
 import           System.Environment                       ( getProgName
                                                           , unsetEnv
                                                           )
@@ -26,11 +28,14 @@ import           System.Info                              ( os
                                                           , arch
                                                           )
 
-import           Data.Maybe                               ( isNothing )
+import           Data.Maybe                               ( isNothing
+                                                          , mapMaybe
+                                                          )
 import           Data.List                                ( dropWhileEnd
                                                           , intersperse
                                                           , intercalate
                                                           )
+import qualified Data.Text as T
 import           Data.Char                                ( isSpace )
 import           Data.Version                             ( parseVersion
                                                           , makeVersion
@@ -43,24 +48,27 @@ type VersionNumber = String
 type GhcPath = String
 
 -- | Defines all different hie versions that are buildable.
--- If they are edited, make sure to maintain the order of the versions.
-hieVersions :: [VersionNumber]
-hieVersions =
-  [ "8.2.1"
-  , "8.2.2"
-  , "8.4.2"
-  , "8.4.3"
-  , "8.4.4"
-  , "8.6.1"
-  , "8.6.2"
-  , "8.6.3"
-  , "8.6.4"
-  ]
+--
+-- The current directory is scanned for `stack-*.yaml` files.
+-- On windows, `8.6.3` is excluded as this version of ghc does not work there
+getHieVersions :: MonadIO m => m [VersionNumber]
+getHieVersions = do
+  let stackYamlPrefix = T.pack "stack-"
+  let stackYamlSuffix = T.pack ".yaml"
+  files <- liftIO $ listDirectory "."
+  let hieVersions = files
+        & map T.pack
+        & mapMaybe
+          (T.stripPrefix stackYamlPrefix >=> T.stripSuffix stackYamlSuffix)
+        & map T.unpack
+        -- the following line excludes `8.6.3` on windows systems
+        & filter (\p -> not isWindowsSystem || p /= "8.6.3")
+  return hieVersions
 
 -- | Most recent version of hie.
 -- Shown in the more concise help message.
-mostRecentHieVersion :: VersionNumber
-mostRecentHieVersion = last hieVersions
+mostRecentHieVersion :: MonadIO m => m VersionNumber
+mostRecentHieVersion = last <$> getHieVersions
 
 main :: IO ()
 main = do
@@ -70,6 +78,8 @@ main = do
   ghcPaths <- findInstalledGhcs
   let ghcVersions = map fst ghcPaths
 
+  hieVersions <- getHieVersions
+
   shakeArgs shakeOptions { shakeFiles = "_build" } $ do
     want ["short-help"]
     -- general purpose targets
@@ -179,12 +189,14 @@ configureCabal versionNumber = do
     ["new-configure", "-w", ghcPath, "--write-ghc-environment-files=never"]
 
 findInstalledGhcs :: IO [(VersionNumber, GhcPath)]
-findInstalledGhcs = mapMaybeM
-  (\version -> getGhcPath version >>= \case
-    Nothing -> return Nothing
-    Just p  -> return $ Just (version, p)
-  )
-  (reverse hieVersions)
+findInstalledGhcs = do
+  hieVersions <- getHieVersions :: IO [VersionNumber]
+  mapMaybeM
+    (\version -> getGhcPath version >>= \case
+      Nothing -> return Nothing
+      Just p  -> return $ Just (version, p)
+    )
+    (reverse hieVersions)
 
 cabalBuildHie :: VersionNumber -> Action ()
 cabalBuildHie versionNumber = do
@@ -281,6 +293,7 @@ stackBuildDoc = do
 -- | short help message is printed by default
 shortHelpMessage :: Action ()
 shortHelpMessage = do
+  hieVersions <- getHieVersions
   let out = liftIO . putStrLn
   scriptName <- liftIO getProgName
   out ""
@@ -288,14 +301,14 @@ shortHelpMessage = do
   out' ("stack " <> scriptName <> " <target>")
   out ""
   out "Targets:"
-  mapM_ (out' . showTarget spaces) targets
+  mapM_ (out' . showTarget (spaces hieVersions)) (targets hieVersions)
   out ""
  where
   out    = liftIO . putStrLn
   out'   = out . ("    " ++)
 
-  spaces = space targets
-  targets =
+  spaces hieVersions = space (targets hieVersions)
+  targets hieVersions =
     [ ("help", "Show help message including all targets")
     , emptyTarget
     , ( "build"
@@ -304,7 +317,7 @@ shortHelpMessage = do
         ++ ")"
       )
     , stackBuildAllTarget
-    , stackHieTarget mostRecentHieVersion
+    -- , stackHieTarget mostRecentHieVersion
     , stackBuildDocTarget
     , stackHieTarget "8.4.4"
     , emptyTarget
@@ -313,7 +326,7 @@ shortHelpMessage = do
       )
     , cabalBuildTarget
     , cabalBuildAllTarget
-    , cabalHieTarget mostRecentHieVersion
+    -- , cabalHieTarget mostRecentHieVersion
     , cabalBuildDocTarget
     , cabalHieTarget "8.4.4"
     ]
@@ -321,24 +334,30 @@ shortHelpMessage = do
 
 helpMessage :: Action ()
 helpMessage = do
+
+  hieVersions <- getHieVersions
   scriptName <- liftIO getProgName
   out ""
   out "Usage:"
   out' ("stack " <> scriptName <> " <target>")
   out ""
   out "Targets:"
-  mapM_ (out' . showTarget spaces) targets
+  mapM_ (out' . showTarget (spaces hieVersions)) (targets hieVersions)
   out ""
  where
   out    = liftIO . putStrLn
   out'   = out . ("    " ++)
 
-  spaces = space targets
+  spaces hieVersions = space (targets hieVersions)
   -- All targets the shake file supports
-  targets :: [(String, String)]
-  targets = intercalate
+  targets :: [VersionNumber] -> [(String, String)]
+  targets hieVersions = intercalate
     [emptyTarget]
-    [generalTargets, stackTargets, cabalTargets, macosTargets]
+    [ generalTargets
+    , stackTargets hieVersions
+    , cabalTargets hieVersions
+    , macosTargets
+    ]
 
   -- All targets with their respective help message.
   generalTargets =
@@ -350,7 +369,7 @@ helpMessage = do
 
   macosTargets = [("icu-macos-fix", "Fixes icu related problems in MacOS")]
 
-  stackTargets =
+  stackTargets hieVersions =
     [ ( "build"
       , "Builds hie for all supported GHC versions ("
       ++ allVersionMessage hieVersions
@@ -362,7 +381,7 @@ helpMessage = do
       ]
       ++ map stackHieTarget hieVersions
 
-  cabalTargets =
+  cabalTargets hieVersions =
     [ ( "cabal-ghcs"
       , "Show all GHC versions that can be installed via `cabal-build` and `cabal-build-all`."
       )

From b51def0ddcefdcf6a618dbe6503c43c2a0241e6a Mon Sep 17 00:00:00 2001
From: Samuel Pilz <samuel.pilz@posteo.net>
Date: Sun, 21 Apr 2019 00:07:08 +0200
Subject: [PATCH 13/13] sort the found supported ghc-versions

---
 install.hs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/install.hs b/install.hs
index ede8c65a5..9ed87fe4e 100755
--- a/install.hs
+++ b/install.hs
@@ -34,6 +34,7 @@ import           Data.Maybe                               ( isNothing
 import           Data.List                                ( dropWhileEnd
                                                           , intersperse
                                                           , intercalate
+                                                          , sort
                                                           )
 import qualified Data.Text as T
 import           Data.Char                                ( isSpace )
@@ -63,6 +64,7 @@ getHieVersions = do
         & map T.unpack
         -- the following line excludes `8.6.3` on windows systems
         & filter (\p -> not isWindowsSystem || p /= "8.6.3")
+        & sort
   return hieVersions
 
 -- | Most recent version of hie.
@@ -319,7 +321,7 @@ shortHelpMessage = do
     , stackBuildAllTarget
     -- , stackHieTarget mostRecentHieVersion
     , stackBuildDocTarget
-    , stackHieTarget "8.4.4"
+    , stackHieTarget (last hieVersions)
     , emptyTarget
     , ( "cabal-ghcs"
       , "Show all GHC versions that can be installed via `cabal-build` and `cabal-build-all`."
@@ -328,7 +330,7 @@ shortHelpMessage = do
     , cabalBuildAllTarget
     -- , cabalHieTarget mostRecentHieVersion
     , cabalBuildDocTarget
-    , cabalHieTarget "8.4.4"
+    , cabalHieTarget (last hieVersions)
     ]