Add a --quick switch to 'ghcup run'

Also fixes #360, because we resolve all tags/versions now
by default.

CHANGELOG.md

@@ -1,5 +1,13 @@
 # Revision history for ghcup
 
+## 0.1.17.8 -- XXXX-XX-XX
+
+* Re-enable upgrade functionality for all configurations wrt [#250](https://gitlab.haskell.org/haskell/ghcup-hs/-/merge_requests/250)
+
+## 0.1.17.7 -- 2022-04-21
+
+* Fix `ghcup run` on windows wrt [#345](https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/345)
+
 ## 0.1.17.6 -- 2022-03-18
 
 * Vastly improve shell completions wrt [#242](https://gitlab.haskell.org/haskell/ghcup-hs/-/merge_requests/242)

app/ghcup/BrickMain.hs

@@ -437,6 +437,7 @@ install' _ (_, ListResult {..}) = do
               , TarDirDoesNotExist
               , FileAlreadyExistsError
               , ProcessError
+              , GHCupShadowed
               ]
 
   run (do
@@ -452,7 +453,7 @@ install' _ (_, ListResult {..}) = do
           liftE $ installCabalBin lVer Nothing False $> (vi, dirs, ce)
         GHCup -> do
           let vi = snd <$> getLatest dls GHCup
-          liftE $ upgradeGHCup Nothing False $> (vi, dirs, ce)
+          liftE $ upgradeGHCup Nothing False False $> (vi, dirs, ce)
         HLS   -> do
           let vi = getVersionInfo lVer HLS dls
           liftE $ installHLSBin lVer Nothing False $> (vi, dirs, ce)

app/ghcup/GHCup/OptParse.hs

@@ -96,7 +96,7 @@ data Command
   | Config ConfigCommand
   | Whereis WhereisOptions WhereisCommand
 #ifndef DISABLE_UPGRADE
-  | Upgrade UpgradeOpts Bool
+  | Upgrade UpgradeOpts Bool Bool
 #endif
   | ToolRequirements ToolReqOpts
   | ChangeLog ChangeLogOptions
@@ -222,18 +222,18 @@ com =
            (info (List <$> listOpts <**> helper)
                  (progDesc "Show available GHCs and other tools")
            )
-#ifndef DISABLE_UPGRADE
       <> command
            "upgrade"
            (info
              (    (Upgrade <$> upgradeOptsP <*> switch
                     (short 'f' <> long "force" <> help "Force update")
+                    <*> switch
+                    (long "fail-if-shadowed" <> help "Fails after upgrading if the upgraded ghcup binary is shadowed by something else in PATH (useful for CI)")
                   )
              <**> helper
              )
              (progDesc "Upgrade ghcup")
            )
-#endif
       <> command
            "compile"
            (   Compile

app/ghcup/GHCup/OptParse/Compile.hs

@@ -283,7 +283,7 @@ hlsCompileOpts =
           (short 'g' <> long "git-ref" <> metavar "GIT_REFERENCE" <> help
             "The git commit/branch/ref to build from"
           ) <*>
-          optional (option str (short 'r' <> long "repository" <> metavar "GIT_REPOSITORY" <> help "The git repository to build from (defaults to GHC upstream)"
+          optional (option str (short 'r' <> long "repository" <> metavar "GIT_REPOSITORY" <> help "The git repository to build from (defaults to HLS upstream)"
             <> completer (gitFileUri ["https://github.com/haskell/haskell-language-server.git"])
           ))
           )))

app/ghcup/GHCup/OptParse/Run.hs

@@ -61,6 +61,7 @@ data RunOptions = RunOptions
   , runHLSVer     :: Maybe ToolVersion
   , runStackVer   :: Maybe ToolVersion
   , runBinDir     :: Maybe FilePath
+  , runQuick      :: Bool
   , runCOMMAND    :: [String]
   }
 
@@ -70,8 +71,8 @@ data RunOptions = RunOptions
     --[ Parsers ]--
     ---------------
 
-          
-    
+
+
 runOpts :: Parser RunOptions
 runOpts =
   RunOptions
@@ -121,6 +122,8 @@ runOpts =
            <> completer (bashCompleter "directory")
            )
           )
+    <*> switch
+          (short 'q' <> long "quick" <> help "Avoid any expensive work (such as downloads, version/tag resolution etc.). Disables --install.")
     <*> many (argument str (metavar "COMMAND" <> help "The command to run, with arguments (use longopts --). If omitted, just prints the created bin/ dir to stdout and exits."))
           
 
@@ -219,29 +222,15 @@ run :: forall m.
    -> (ReaderT LeanAppState m () -> m ())
    -> m ExitCode
 run RunOptions{..} runAppState leanAppstate runLogger = do
-   r <- if or (fmap (maybe False isToolTag) [runGHCVer, runCabalVer, runHLSVer, runStackVer]) || runInstTool'
+   r <- if not runQuick
         then runRUN runAppState $ do
          toolchain <- liftE resolveToolchainFull
-         tmp <- case runBinDir of
-           Just bindir -> do
-             liftIO $ createDirRecursive' bindir
-             liftIO $ canonicalizePath bindir
-           Nothing -> do
-             d <- liftIO $ predictableTmpDir toolchain
-             liftIO $ createDirRecursive' d
-             liftIO $ canonicalizePath d
+         tmp <- liftIO $ createTmpDir toolchain
          liftE $ installToolChainFull toolchain tmp
          pure tmp
         else runLeanRUN leanAppstate $ do
          toolchain <- resolveToolchain
-         tmp <- case runBinDir of
-           Just bindir -> do
-             liftIO $ createDirRecursive' bindir
-             liftIO $ canonicalizePath bindir
-           Nothing -> do
-             d <- liftIO $ predictableTmpDir toolchain
-             liftIO $ createDirRecursive' d
-             liftIO $ canonicalizePath d
+         tmp <- liftIO $ createTmpDir toolchain
          liftE $ installToolChain toolchain tmp
          pure tmp
    case r of
@@ -269,9 +258,16 @@ run RunOptions{..} runAppState leanAppstate runLogger = do
 
   where
 
-   isToolTag :: ToolVersion -> Bool
-   isToolTag (ToolTag _) = True
-   isToolTag _           = False
+   createTmpDir :: Toolchain -> IO FilePath
+   createTmpDir toolchain =
+     case runBinDir of
+           Just bindir -> do
+             createDirRecursive' bindir
+             canonicalizePath bindir
+           Nothing -> do
+             d <- predictableTmpDir toolchain
+             createDirRecursive' d
+             canonicalizePath d
 
    -- TODO: doesn't work for cross
    resolveToolchainFull :: ( MonadFail m

app/ghcup/GHCup/OptParse/Upgrade.hs

@@ -59,15 +59,16 @@ data UpgradeOpts = UpgradeInplace
     --[ Parsers ]--
     ---------------
 
-          
+
 upgradeOptsP :: Parser UpgradeOpts
 upgradeOptsP =
   flag'
       UpgradeInplace
       (short 'i' <> long "inplace" <> help
-        "Upgrade ghcup in-place (wherever it's at)"
+        "Upgrade ghcup in-place"
       )
-    <|> (   UpgradeAt
+    <|>
+      (   UpgradeAt
         <$> option
               str
               (short 't' <> long "target" <> metavar "TARGET_DIR" <> help
@@ -92,6 +93,7 @@ type UpgradeEffects = '[ DigestError
                        , FileDoesNotExistError
                        , CopyError
                        , DownloadFailed
+                       , GHCupShadowed
                        ]
 
 
@@ -120,18 +122,19 @@ upgrade :: ( Monad m
            )
         => UpgradeOpts
         -> Bool
+        -> Bool
         -> Dirs
         -> (forall a. ReaderT AppState m (VEither UpgradeEffects a) -> m (VEither UpgradeEffects a))
         -> (ReaderT LeanAppState m () -> m ())
         -> m ExitCode
-upgrade uOpts force' Dirs{..} runAppState runLogger = do
+upgrade uOpts force' fatal Dirs{..} runAppState runLogger = do
   target <- case uOpts of
     UpgradeInplace  -> Just <$> liftIO getExecutablePath
     (UpgradeAt p)   -> pure $ Just p
     UpgradeGHCupDir -> pure (Just (binDir </> "ghcup" <> exeExt))
 
   runUpgrade runAppState (do
-    v' <- liftE $ upgradeGHCup target force'
+    v' <- liftE $ upgradeGHCup target force' fatal
     GHCupInfo { _ghcupDownloads = dls } <- lift getGHCupInfo
     pure (v', dls)
     ) >>= \case

app/ghcup/Main.hs

@@ -141,9 +141,7 @@ main = do
         )
   let listCommands = infoOption
         ("install set rm install-cabal list"
-#ifndef DISABLE_UPGRADE
           <> " upgrade"
-#endif
           <> " compile debug-info tool-requirements changelog"
         )
         (  long "list-commands"
@@ -245,14 +243,10 @@ Report bugs at <https://gitlab.haskell.org/haskell/ghcup-hs/issues>|]
                              alreadyInstalling' <- alreadyInstalling optCommand newTool
                              when (not alreadyInstalling') $
                                case t of
-#ifdef DISABLE_UPGRADE
-                                 GHCup -> pure ()
-#else
                                  GHCup -> runLogger $
                                             logWarn ("New GHCup version available: "
                                               <> prettyVer l
                                               <> ". To upgrade, run 'ghcup upgrade'")
-#endif
                                  _ -> runLogger $
                                         logWarn ("New "
                                           <> T.pack (prettyShow t)
@@ -296,26 +290,24 @@ Report bugs at <https://gitlab.haskell.org/haskell/ghcup-hs/issues>|]
               s' <- appState
               liftIO $ brickMain s' >> pure ExitSuccess
 #endif
-            Install installCommand   -> install installCommand settings appState runLogger
-            InstallCabalLegacy iopts -> install (Left (InstallCabal iopts)) settings appState runLogger
-            Set setCommand           -> set setCommand runAppState runLeanAppState runLogger
-            UnSet unsetCommand       -> unset unsetCommand runLeanAppState runLogger
-            List lo                  -> list lo no_color runAppState
-            Rm rmCommand             -> rm rmCommand runAppState runLogger
-            DInfo                    -> dinfo runAppState runLogger
-            Compile compileCommand   -> compile compileCommand settings dirs runAppState runLogger
-            Config configCommand     -> config configCommand settings keybindings runLogger
+            Install installCommand     -> install installCommand settings appState runLogger
+            InstallCabalLegacy iopts   -> install (Left (InstallCabal iopts)) settings appState runLogger
+            Set setCommand             -> set setCommand runAppState runLeanAppState runLogger
+            UnSet unsetCommand         -> unset unsetCommand runLeanAppState runLogger
+            List lo                    -> list lo no_color runAppState
+            Rm rmCommand               -> rm rmCommand runAppState runLogger
+            DInfo                      -> dinfo runAppState runLogger
+            Compile compileCommand     -> compile compileCommand settings dirs runAppState runLogger
+            Config configCommand       -> config configCommand settings keybindings runLogger
             Whereis whereisOptions
-                    whereisCommand   -> whereis whereisCommand whereisOptions runAppState leanAppstate runLogger
-#ifndef DISABLE_UPGRADE
-            Upgrade uOpts force'     -> upgrade uOpts force' dirs runAppState runLogger
-#endif
-            ToolRequirements topts   -> toolRequirements topts runAppState runLogger
-            ChangeLog changelogOpts  -> changelog changelogOpts runAppState runLogger
-            Nuke                     -> nuke appState runLogger
-            Prefetch pfCom           -> prefetch pfCom runAppState runLogger
-            GC gcOpts                -> gc gcOpts runAppState runLogger
-            Run runCommand           -> run runCommand appState leanAppstate runLogger
+                    whereisCommand     -> whereis whereisCommand whereisOptions runAppState leanAppstate runLogger
+            Upgrade uOpts force' fatal -> upgrade uOpts force' fatal dirs runAppState runLogger
+            ToolRequirements topts     -> toolRequirements topts runAppState runLogger
+            ChangeLog changelogOpts    -> changelog changelogOpts runAppState runLogger
+            Nuke                       -> nuke appState runLogger
+            Prefetch pfCom             -> prefetch pfCom runAppState runLogger
+            GC gcOpts                  -> gc gcOpts runAppState runLogger
+            Run runCommand             -> run runCommand appState leanAppstate runLogger
 
           case res of
             ExitSuccess        -> pure ()
@@ -353,9 +345,7 @@ Report bugs at <https://gitlab.haskell.org/haskell/ghcup-hs/issues>|]
     (HLS, ver)   = cmp' HLS (Just $ ToolVersion (mkTVer over)) ver
   alreadyInstalling (Compile (CompileHLS HLSCompileOptions{ targetHLS = Left tver }))
     (HLS, ver)   = cmp' HLS (Just $ ToolVersion (mkTVer tver)) ver
-#ifndef DISABLE_UPGRADE
-  alreadyInstalling (Upgrade _ _) (GHCup, _) = pure True
-#endif
+  alreadyInstalling (Upgrade _ _ _) (GHCup, _) = pure True
   alreadyInstalling _ _ = pure False
 
   cmp' :: ( HasLog env

docs/guide.md

@@ -57,6 +57,13 @@ as e.g. `/etc/bash_completion.d/ghcup` (depending on distro)
 and make sure your bashrc sources the startup script
 (`/usr/share/bash-completion/bash_completion` on some distros).
 
+## Portability
+
+`ghcup` is very portable. There are a few exceptions though:
+
+1. `ghcup tui` is only available on non-windows platforms
+2. legacy subcommands `ghcup install` (without a tool identifier) and `ghcup install-cabal` may be removed in the future
+
 # Configuration
 
 A configuration file can be put in `~/.ghcup/config.yaml`. The default config file

docs/install.md

@@ -105,7 +105,8 @@ GHCup supports the following tools, which are also known as the **Haskell Toolch
 <table>
 <thead><tr><th>HLS Version</th><th>Tags</th></tr></thead>
 <tbody>
-<tr><td>1.6.1.0</td><td><span style="color:blue">latest</span>, <span style="color:green">recommended</span></td></tr>
+<tr><td>1.7.0.0</td><td><span style="color:blue">latest</span>, <span style="color:green">recommended</span></td></tr>
+<tr><td>1.6.1.0</td><td></td></tr>
 <tr><td>1.6.0.0</td><td></td></tr>
 <tr><td>1.5.1</td><td></td></tr>
 <tr><td>1.5.0</td><td></td></tr>

docs/steps.md

@@ -16,6 +16,8 @@ The Glorious Glasgow Haskell Compilation System, version 8.10.7
 If this fails, consult [the Getting started page](../install) for information on
 how to install Haskell on your computer.
 
+This guide is partly based on [Gil Mizrahi's blog](https://gilmi.me/blog/post/2021/08/14/hs-core-tools).
+
 ## Compiling programs with ghc
 
 Running `ghc` invokes the Glasgow Haskell Compiler (GHC), and can be used to
@@ -326,6 +328,7 @@ see the [Cabal user guide](https://cabal.readthedocs.io/en/stable/getting-starte
 <a href="https://hackage.haskell.org/" class="btn btn-primary" role="button">Discover Haskell packages</a>
 <a href="https://hackage.haskell.org/package/base" class="btn btn-primary" role="button">The standard library</a>
 <a href="https://haskell-language-server.readthedocs.io/en/stable/installation.html" class="btn btn-primary" role="button">Editor setup with HLS</a>
+<a href="https://play-haskell.tomsmeding.com/play" class="btn btn-primary" role="button">Online playground</a>
 </div>
 
 ## How to learn Haskell proper

ghcup.cabal

@@ -1,6 +1,6 @@
 cabal-version:      3.0
 name:               ghcup
-version:            0.1.17.6
+version:            0.1.17.7
 license:            LGPL-3.0-only
 license-file:       LICENSE
 copyright:          Julian Ospald 2020
@@ -48,13 +48,6 @@ flag no-exe
   default:     False
   manual:      True
 
-flag disable-upgrade
-  description:
-    Disable upgrade functionality. This is mainly to support brew packagers.
-
-  default:     False
-  manual:      True
-
 library
   exposed-modules:
     GHCup
@@ -204,6 +197,7 @@ executable ghcup
     GHCup.OptParse.Set
     GHCup.OptParse.ToolRequirements
     GHCup.OptParse.UnSet
+    GHCup.OptParse.Upgrade
     GHCup.OptParse.Whereis
 
   hs-source-dirs:     app/ghcup
@@ -277,11 +271,6 @@ executable ghcup
   if flag(no-exe)
     buildable: False
 
-  if flag(disable-upgrade)
-    cpp-options: -DDISABLE_UPGRADE
-
-  else
-    other-modules: GHCup.OptParse.Upgrade
 
 test-suite ghcup-test
   type:               exitcode-stdio-1.0

lib/GHCup.hs

@@ -2587,6 +2587,7 @@ upgradeGHCup :: ( MonadMask m
              => Maybe FilePath    -- ^ full file destination to write ghcup into
              -> Bool              -- ^ whether to force update regardless
                                   --   of currently installed version
+             -> Bool              -- ^ whether to throw an error if ghcup is shadowed
              -> Excepts
                   '[ CopyError
                    , DigestError
@@ -2595,15 +2596,16 @@ upgradeGHCup :: ( MonadMask m
                    , DownloadFailed
                    , NoDownload
                    , NoUpdate
+                   , GHCupShadowed
                    ]
                   m
                   Version
-upgradeGHCup mtarget force' = do
+upgradeGHCup mtarget force' fatal = do
   Dirs {..} <- lift getDirs
   GHCupInfo { _ghcupDownloads = dls } <- lift getGHCupInfo
 
   lift $ logInfo "Upgrading GHCup..."
-  let latestVer = fromJust $ fst <$> getLatest dls GHCup
+  let latestVer = fst (fromJust (getLatest dls GHCup))
   (Just ghcupPVPVer) <- pure $ pvpToVersion ghcUpVer ""
   when (not force' && (latestVer <= ghcupPVPVer)) $ throwE NoUpdate
   dli   <- liftE $ getDownloadInfo GHCup latestVer
@@ -2625,15 +2627,18 @@ upgradeGHCup mtarget force' = do
     lift $ logWarn $ T.pack (takeFileName destFile) <> " is not in PATH! You have to add it in order to use ghcup."
   liftIO (isShadowed destFile) >>= \case
     Nothing -> pure ()
-    Just pa -> lift $ logWarn $ "ghcup is shadowed by "
-      <> T.pack pa
-      <> ". The upgrade will not be in effect, unless you remove "
-      <> T.pack pa
-      <> " or make sure "
-      <> T.pack destDir
-      <> " comes before "
-      <> T.pack (takeFileName pa)
-      <> " in PATH."
+    Just pa
+      | fatal -> throwE (GHCupShadowed pa destFile latestVer)
+      | otherwise ->
+        lift $ logWarn $ "ghcup is shadowed by "
+          <> T.pack pa
+          <> ". The upgrade will not be in effect, unless you remove "
+          <> T.pack pa
+          <> " or make sure "
+          <> T.pack destDir
+          <> " comes before "
+          <> T.pack (takeDirectory pa)
+          <> " in PATH."
 
   pure latestVer
 

lib/GHCup/Errors.hs

@@ -27,6 +27,7 @@ import           Data.CaseInsensitive           ( CI )
 import           Data.Text                      ( Text )
 import           Data.Versions
 import           Haskus.Utils.Variant
+import           System.FilePath
 import           Text.PrettyPrint               hiding ( (<>) )
 import           Text.PrettyPrint.HughesPJClass hiding ( (<>) )
 import           URI.ByteString
@@ -291,6 +292,24 @@ instance Pretty HadrianNotFound where
   pPrint HadrianNotFound =
     text "Could not find Hadrian build files. Does this GHC version support Hadrian builds?"
 
+data GHCupShadowed = GHCupShadowed
+                       FilePath  -- shadow binary
+                       FilePath  -- upgraded binary
+                       Version   -- upgraded version
+  deriving Show
+
+instance Pretty GHCupShadowed where
+  pPrint (GHCupShadowed sh up _) =
+    text ("ghcup is shadowed by "
+         <> sh
+         <> ". The upgrade will not be in effect, unless you remove "
+         <> sh
+         <> " or make sure "
+         <> takeDirectory up
+         <> " comes before "
+         <> takeDirectory sh
+         <> " in PATH."
+         )
 
     -------------------------
     --[ High-level errors ]--

lib/GHCup/Utils.hs

@@ -317,10 +317,10 @@ ghcSet mtarget = do
            MP.setInput rest
            pure x
          )
-        <* pathSep
+        <* MP.some pathSep
         <* MP.takeRest
         <* MP.eof
-    ghcSubPath = pathSep <* MP.chunk "ghc" *> pathSep
+    ghcSubPath = MP.some pathSep <* MP.chunk "ghc" *> MP.some pathSep
 
 -- | Get all installed GHCs by reading ~/.ghcup/ghc/<dir>.
 -- If a dir cannot be parsed, returns left.
@@ -398,10 +398,10 @@ cabalSet = do
   cabalParse = MP.chunk "cabal-" *> version'
   -- parses any path component ending with path separator,
   -- e.g. "foo/"
-  stripPathComponet = parseUntil1 pathSep *> pathSep
+  stripPathComponet = parseUntil1 pathSep *> MP.some pathSep
   -- parses an absolute path up until the last path separator,
   -- e.g. "/bar/baz/foo" -> "/bar/baz/", leaving "foo"
-  stripAbsolutePath = pathSep *> MP.many (MP.try stripPathComponet)
+  stripAbsolutePath = MP.some pathSep *> MP.many (MP.try stripPathComponet)
   -- parses a relative path up until the last path separator,
   -- e.g. "bar/baz/foo" -> "bar/baz/", leaving "foo"
   stripRelativePath = MP.many (MP.try stripPathComponet)
@@ -492,10 +492,10 @@ stackSet = do
     cabalParse = MP.chunk "stack-" *> version'
     -- parses any path component ending with path separator,
     -- e.g. "foo/"
-    stripPathComponet = parseUntil1 pathSep *> pathSep
+    stripPathComponet = parseUntil1 pathSep *> MP.some pathSep
     -- parses an absolute path up until the last path separator,
     -- e.g. "/bar/baz/foo" -> "/bar/baz/", leaving "foo"
-    stripAbsolutePath = pathSep *> MP.many (MP.try stripPathComponet)
+    stripAbsolutePath = MP.some pathSep *> MP.many (MP.try stripPathComponet)
     -- parses a relative path up until the last path separator,
     -- e.g. "bar/baz/foo" -> "bar/baz/", leaving "foo"
     stripRelativePath = MP.many (MP.try stripPathComponet)
@@ -543,10 +543,10 @@ hlsSet = do
     cabalParse = MP.chunk "haskell-language-server-wrapper-" *> version'
     -- parses any path component ending with path separator,
     -- e.g. "foo/"
-    stripPathComponet = parseUntil1 pathSep *> pathSep
+    stripPathComponet = parseUntil1 pathSep *> MP.some pathSep
     -- parses an absolute path up until the last path separator,
     -- e.g. "/bar/baz/foo" -> "/bar/baz/", leaving "foo"
-    stripAbsolutePath = pathSep *> MP.many (MP.try stripPathComponet)
+    stripAbsolutePath = MP.some pathSep *> MP.many (MP.try stripPathComponet)
     -- parses a relative path up until the last path separator,
     -- e.g. "bar/baz/foo" -> "bar/baz/", leaving "foo"
     stripRelativePath = MP.many (MP.try stripPathComponet)

scripts/bootstrap/bootstrap-haskell

@@ -16,6 +16,7 @@
 #   * BOOTSTRAP_HASKELL_INSTALL_HLS - whether to install latest hls
 #   * BOOTSTRAP_HASKELL_ADJUST_BASHRC - whether to adjust PATH in bashrc (prepend)
 #   * BOOTSTRAP_HASKELL_ADJUST_CABAL_CONFIG - whether to adjust mingw paths in cabal.config on windows
+#   * GHCUP_BASE_URL - the base url for ghcup binary download (use this to overwrite https://downloads.haskell.org/~ghcup with a mirror)
 
 # License: LGPL-3.0
 
@@ -25,8 +26,8 @@
 
 plat="$(uname -s)"
 arch=$(uname -m)
-ghver="0.1.17.6"
-base_url="https://downloads.haskell.org/~ghcup"
+ghver="0.1.17.7"
+: "${GHCUP_BASE_URL:=https://downloads.haskell.org/~ghcup}"
 
 export GHCUP_SKIP_UPDATE_CHECK=yes
 
@@ -235,26 +236,26 @@ download_ghcup() {
 					# we could be in a 32bit docker container, in which
 					# case uname doesn't give us what we want
 					if [ "$(getconf LONG_BIT)" = "32" ] ; then
-						_url=${base_url}/${ghver}/i386-linux-ghcup-${ghver}
+						_url=${GHCUP_BASE_URL}/${ghver}/i386-linux-ghcup-${ghver}
 					elif [ "$(getconf LONG_BIT)" = "64" ] ; then
-						_url=${base_url}/${ghver}/x86_64-linux-ghcup-${ghver}
+						_url=${GHCUP_BASE_URL}/${ghver}/x86_64-linux-ghcup-${ghver}
 					else
 						die "Unknown long bit size: $(getconf LONG_BIT)"
 					fi
 					;;
 				i*86)
-					_url=${base_url}/${ghver}/i386-linux-ghcup-${ghver}
+					_url=${GHCUP_BASE_URL}/${ghver}/i386-linux-ghcup-${ghver}
 					;;
 				armv7*|*armv8l*)
-					_url=${base_url}/${ghver}/armv7-linux-ghcup-${ghver}
+					_url=${GHCUP_BASE_URL}/${ghver}/armv7-linux-ghcup-${ghver}
 					;;
 				aarch64|arm64)
 					# we could be in a 32bit docker container, in which
 					# case uname doesn't give us what we want
 					if [ "$(getconf LONG_BIT)" = "32" ] ; then
-						_url=${base_url}/${ghver}/armv7-linux-ghcup-${ghver}
+						_url=${GHCUP_BASE_URL}/${ghver}/armv7-linux-ghcup-${ghver}
 					elif [ "$(getconf LONG_BIT)" = "64" ] ; then
-						_url=${base_url}/${ghver}/aarch64-linux-ghcup-${ghver}
+						_url=${GHCUP_BASE_URL}/${ghver}/aarch64-linux-ghcup-${ghver}
 					else
 						die "Unknown long bit size: $(getconf LONG_BIT)"
 					fi
@@ -281,15 +282,15 @@ download_ghcup() {
 				*) die "Unknown architecture: ${arch}"
 					;;
 			esac
-			_url=${base_url}/${ghver}/x86_64-freebsd${freebsd_ver}-ghcup-${ghver}
+			_url=${GHCUP_BASE_URL}/${ghver}/x86_64-freebsd${freebsd_ver}-ghcup-${ghver}
             ;;
         "Darwin"|"darwin")
 			case "${arch}" in
 				x86_64|amd64)
-					_url=${base_url}/${ghver}/x86_64-apple-darwin-ghcup-${ghver}
+					_url=${GHCUP_BASE_URL}/${ghver}/x86_64-apple-darwin-ghcup-${ghver}
 					;;
 				aarch64|arm64|armv8l)
-					_url=${base_url}/${ghver}/aarch64-apple-darwin-ghcup-${ghver}
+					_url=${GHCUP_BASE_URL}/${ghver}/aarch64-apple-darwin-ghcup-${ghver}
 					;;
 				i*86)
 					die "i386 currently not supported!"
@@ -301,7 +302,7 @@ download_ghcup() {
         MSYS*|MINGW*)
 			case "${arch}" in
 				x86_64|amd64)
-					_url=${base_url}/${ghver}/x86_64-mingw64-ghcup-${ghver}.exe
+					_url=${GHCUP_BASE_URL}/${ghver}/x86_64-mingw64-ghcup-${ghver}.exe
 					;;
 				*) die "Unknown architecture: ${arch}"
 					;;

scripts/bootstrap/bootstrap-haskell.ps1

@@ -239,7 +239,27 @@ if ($Silent -and !($InstallDir)) {
   }
 } else {
   while ($true) {
-    Print-Msg -color Magenta -msg ('Where to install to (this should be a short Path, preferably a Drive like ''C:\''){1}Press enter to accept the default [{0}]:' -f $defaultGhcupBasePrefix, "`n")
+	Print-Msg -color Magenta -msg (@'
+Welcome to Haskell!
+
+This script will download and install the following programs:
+  * ghcup - The Haskell toolchain installer
+  * ghc   - The Glasgow Haskell Compiler
+  * msys2 - A linux-style toolchain environment required for many operations
+  * cabal - The Cabal build tool for managing Haskell software
+  * stack - (optional) A cross-platform program for developing Haskell projects
+  * hls   - (optional) A language server for developers to integrate with their editor/IDE
+
+Please note that ANTIVIRUS may interfere with the installation. If you experience problems, consider
+disabling it temporarily.
+
+Where to install to (this should be a short Path, preferably a Drive like 'C:\')?
+If you accept this path, binaries will be installed into '{0}ghcup\bin' and msys2 into '{0}ghcup\msys64'.
+Press enter to accept the default [{0}]:
+
+'@ -f $defaultGhcupBasePrefix)
+
+
     $basePrefixPrompt = Read-Host
     $GhcupBasePrefix = ($defaultGhcupBasePrefix,$basePrefixPrompt)[[bool]$basePrefixPrompt]
     if (!($GhcupBasePrefix.EndsWith('\'))) {

stack.yaml

@@ -1,4 +1,4 @@
-resolver: lts-18.27
+resolver: lts-18.28
 
 packages:
   - .