Document and handle '--force' option better

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

.gitlab-ci.yml

@@ -134,6 +134,7 @@ variables:
   extends:
     - .test_ghcup_version
     - .debian
+    - .root_cleanup
   before_script:
     - ./.gitlab/before_script/linux/install_deps.sh
 
@@ -141,6 +142,7 @@ variables:
   extends:
     - .test_ghcup_version
     - .alpine:32bit
+    - .root_cleanup
   before_script:
     - ./.gitlab/before_script/linux/alpine/install_deps.sh
 
@@ -148,6 +150,7 @@ variables:
   extends:
     - .test_ghcup_version
     - .linux:armv7
+    - .root_cleanup
   before_script:
     - ./.gitlab/before_script/linux/install_deps.sh
 
@@ -155,6 +158,7 @@ variables:
   extends:
     - .test_ghcup_version
     - .linux:aarch64
+    - .root_cleanup
   before_script:
     - ./.gitlab/before_script/linux/install_deps.sh
 

.gitlab/script/ghcup_version.sh

@@ -100,7 +100,7 @@ eghcup set ghc ${GHC_VERSION}
 eghcup install cabal ${CABAL_VERSION}
 [ `$(eghcup whereis cabal ${CABAL_VERSION}) --numeric-version` = "${CABAL_VERSION}" ]
 eghcup unset cabal
-"$GHCUP_BIN"/cabal --version && exit || echo yes
+"$GHCUP_BIN"/cabal --version && exit 1 || echo yes
 eghcup set cabal ${CABAL_VERSION}
 [ `$(eghcup whereis cabal ${CABAL_VERSION}) --numeric-version` = "${CABAL_VERSION}" ]
 [ `eghcup run --cabal ${CABAL_VERSION} -- cabal --numeric-version` = "${CABAL_VERSION}" ]
@@ -170,7 +170,7 @@ else
 	eghcup set ${GHC_VERSION}
 	[ "$(ghc --numeric-version)" = "${ghc_ver}" ]
 	eghcup unset ghc
-    "$GHCUP_BIN"/ghc --numeric-version && exit || echo yes
+    "$GHCUP_BIN"/ghc --numeric-version && exit 1 || echo yes
 	eghcup set ${GHC_VERSION}
 	eghcup --offline rm 8.10.3
 	[ "$(ghc --numeric-version)" = "${ghc_ver}" ]
@@ -189,12 +189,12 @@ else
 			eghcup install hls
 			haskell-language-server-wrapper --version
 			eghcup unset hls
-			"$GHCUP_BIN"/haskell-language-server-wrapper --version && exit || echo yes
+			"$GHCUP_BIN"/haskell-language-server-wrapper --version && exit 1 || echo yes
 
 			eghcup install stack
 			stack --version
-			eghcup unset hls
+			eghcup unset stack
-			"$GHCUP_BIN"/stack --version && exit || echo yes
+			"$GHCUP_BIN"/stack --version && exit 1 || echo yes
 		fi
 	fi
 fi
@@ -217,6 +217,8 @@ if [ "${OS}" = "LINUX" ] ; then
 	fi
 fi
 
+eghcup gc -c
+
 sha_sum() {
 	if [ "${OS}" = "FREEBSD" ] ; then
 		sha256 "$@"
@@ -264,6 +266,19 @@ if [ "${ARCH}" = "64" ] ; then
 		eghcup install hls -i "$(pwd)/isolated" 1.3.0
 		[ "$(isolated/haskell-language-server-wrapper --numeric-version)" = "1.3.0" ] ||
 			[ "$(isolated/haskell-language-server-wrapper --numeric-version)" = "1.3.0.0" ]
+
+		# test that isolated installs don't clean up target directory
+		cat <<EOF > "${GHCUP_BIN}/gmake"
+#!/bin/bash
+exit 1
+EOF
+		chmod +x "${GHCUP_BIN}/gmake"
+		mkdir isolated_tainted/
+		touch isolated_tainted/lol
+
+		! eghcup install ghc -i "$(pwd)/isolated_tainted" 8.10.5 --force
+		[ -e "$(pwd)/isolated_tainted/lol" ]
+		rm "${GHCUP_BIN}/gmake"
 	fi
 fi
 

CHANGELOG.md

@@ -1,10 +1,13 @@
 # Revision history for ghcup
 
-## 0.1.17.8 -- XXXX-XX-XX
+## 0.1.17.8 -- 2022-05-11
 
+* Fix a serious (but hard to trigger) bug when combining `--isolate <DIR>` with `--force`, please make sure to upgrade or avoid `--force`
 * Fix HLS build not cleaning up properly on failed installations, fixes [#361](https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/361)
-    - this also fixes a significant bug on installation failure when combining `--isolate DIR` with `--force`
 * Fix parsing of symlinks with multiple slashes, wrt [#353](https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/353)
+* Re-enable upgrade functionality for all configurations wrt [MR #250](https://gitlab.haskell.org/haskell/ghcup-hs/-/merge_requests/250) and [VSCode haskell issue #601](https://github.com/haskell/vscode-haskell/issues/601)
+* Fix `ghcup run --ghc 8.10` (for short versions) wrt [#360](https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/360)
+    - this also introduces a `--quick` switch for `ghcup run`
 
 ## 0.1.17.7 -- 2022-04-21
 

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 GHCupInternal 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 GHCupInternal 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

@@ -99,7 +99,7 @@ data HLSCompileOptions = HLSCompileOptions
     --[ Parsers ]--
     ---------------
 
-          
+
 compileP :: Parser CompileCommand
 compileP = subparser
   (  command
@@ -541,11 +541,11 @@ compile compileCommand settings Dirs{..} runAppState runLogger = do
                 pure ExitSuccess
               VLeft (V (AlreadyInstalled _ v)) -> do
                 runLogger $ logWarn $
-                  "GHC ver " <> prettyVer v <> " already installed; if you really want to reinstall it, you may want to run 'ghcup install ghc --force " <> prettyVer v <> "'"
+                  "GHC ver " <> prettyVer v <> " already installed, remove it first to reinstall"
                 pure ExitSuccess
               VLeft (V (DirNotEmpty fp)) -> do
-                runLogger $ logWarn $
+                runLogger $ logError $
-                  "Install directory " <> T.pack fp <> " is not empty. Use 'ghcup install ghc --isolate " <> T.pack fp <> " --force ..." <> "' to install regardless."
+                  "Install directory " <> T.pack fp <> " is not empty."
                 pure $ ExitFailure 3
               VLeft err@(V (BuildFailed tmpdir _)) -> do
                 case keepDirs settings of

app/ghcup/GHCup/OptParse/Install.hs

@@ -210,7 +210,7 @@ installOpts tool =
            )
           )
     <*> switch
-          (short 'f' <> long "force" <> help "Force install")
+          (short 'f' <> long "force" <> help "Force install (THIS IS UNSAFE, only use it in Dockerfiles or CI)")
  where
   setDefault = case tool of
     Nothing  -> False
@@ -421,20 +421,20 @@ install installCommand settings getAppState' runLogger = case installCommand of
 
               VLeft (V (AlreadyInstalled _ v, ())) -> do
                 runLogger $ logWarn $
-                  "GHC ver " <> prettyVer v <> " already installed; if you really want to reinstall it, you may want to run 'ghcup install ghc --force " <> prettyVer v <> "'"
+                  "GHC ver " <> prettyVer v <> " already installed, remove it first to reinstall"
                 pure ExitSuccess
               VLeft (V (AlreadyInstalled _ v)) -> do
                 runLogger $ logWarn $
-                  "GHC ver " <> prettyVer v <> " already installed; if you really want to reinstall it, you may want to run 'ghcup install ghc --force " <> prettyVer v <> "'"
+                  "GHC ver " <> prettyVer v <> " already installed, remove it first to reinstall"
                 pure ExitSuccess
 
               VLeft (V (DirNotEmpty fp)) -> do
-                runLogger $ logWarn $
+                runLogger $ logError $
-                  "Install directory " <> T.pack fp <> " is not empty. Use 'ghcup install ghc --isolate " <> T.pack fp <> " --force ..." <> "' to install regardless."
+                  "Install directory " <> T.pack fp <> " is not empty."
                 pure $ ExitFailure 3
               VLeft (V (DirNotEmpty fp, ())) -> do
-                runLogger $ logWarn $
+                runLogger $ logError $
-                  "Install directory " <> T.pack fp <> " is not empty. Use 'ghcup install ghc --isolate " <> T.pack fp <> " --force ..." <> "' to install regardless."
+                  "Install directory " <> T.pack fp <> " is not empty."
                 pure $ ExitFailure 3
 
               VLeft err@(V (BuildFailed tmpdir _)) -> do

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
+         tmp <- liftIO $ createTmpDir toolchain
-           Just bindir -> do
-             liftIO $ createDirRecursive' bindir
-             liftIO $ canonicalizePath bindir
-           Nothing -> do
-             d <- liftIO $ predictableTmpDir toolchain
-             liftIO $ createDirRecursive' d
-             liftIO $ canonicalizePath d
          liftE $ installToolChainFull toolchain tmp
          pure tmp
         else runLeanRUN leanAppstate $ do
          toolchain <- resolveToolchain
-         tmp <- case runBinDir of
+         tmp <- liftIO $ createTmpDir toolchain
-           Just bindir -> do
-             liftIO $ createDirRecursive' bindir
-             liftIO $ canonicalizePath bindir
-           Nothing -> do
-             d <- liftIO $ predictableTmpDir toolchain
-             liftIO $ createDirRecursive' d
-             liftIO $ canonicalizePath d
          liftE $ installToolChain toolchain tmp
          pure tmp
    case r of
@@ -269,9 +258,16 @@ run RunOptions{..} runAppState leanAppstate runLogger = do
 
   where
 
-   isToolTag :: ToolVersion -> Bool
+   createTmpDir :: Toolchain -> IO FilePath
-   isToolTag (ToolTag _) = True
+   createTmpDir toolchain =
-   isToolTag _           = False
+     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
+            Install installCommand     -> install installCommand settings appState runLogger
-            InstallCabalLegacy iopts -> install (Left (InstallCabal iopts)) settings appState runLogger
+            InstallCabalLegacy iopts   -> install (Left (InstallCabal iopts)) settings appState runLogger
-            Set setCommand           -> set setCommand runAppState runLeanAppState runLogger
+            Set setCommand             -> set setCommand runAppState runLeanAppState runLogger
-            UnSet unsetCommand       -> unset unsetCommand runLeanAppState runLogger
+            UnSet unsetCommand         -> unset unsetCommand runLeanAppState runLogger
-            List lo                  -> list lo no_color runAppState
+            List lo                    -> list lo no_color runAppState
-            Rm rmCommand             -> rm rmCommand runAppState runLogger
+            Rm rmCommand               -> rm rmCommand runAppState runLogger
-            DInfo                    -> dinfo runAppState runLogger
+            DInfo                      -> dinfo runAppState runLogger
-            Compile compileCommand   -> compile compileCommand settings dirs runAppState runLogger
+            Compile compileCommand     -> compile compileCommand settings dirs runAppState runLogger
-            Config configCommand     -> config configCommand settings keybindings runLogger
+            Config configCommand       -> config configCommand settings keybindings runLogger
             Whereis whereisOptions
-                    whereisCommand   -> whereis whereisCommand whereisOptions runAppState leanAppstate runLogger
+                    whereisCommand     -> whereis whereisCommand whereisOptions runAppState leanAppstate runLogger
-#ifndef DISABLE_UPGRADE
+            Upgrade uOpts force' fatal -> upgrade uOpts force' fatal dirs runAppState runLogger
-            Upgrade uOpts force'     -> upgrade uOpts force' dirs runAppState runLogger
+            ToolRequirements topts     -> toolRequirements topts runAppState runLogger
-#endif
+            ChangeLog changelogOpts    -> changelog changelogOpts runAppState runLogger
-            ToolRequirements topts   -> toolRequirements topts runAppState runLogger
+            Nuke                       -> nuke appState runLogger
-            ChangeLog changelogOpts  -> changelog changelogOpts runAppState runLogger
+            Prefetch pfCom             -> prefetch pfCom runAppState runLogger
-            Nuke                     -> nuke appState runLogger
+            GC gcOpts                  -> gc gcOpts runAppState runLogger
-            Prefetch pfCom           -> prefetch pfCom runAppState runLogger
+            Run runCommand             -> run runCommand appState leanAppstate 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
-  alreadyInstalling (Upgrade _ _) (GHCup, _) = pure True
-#endif
   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
@@ -221,6 +228,8 @@ See `ghcup compile ghc --help` for further information.
 
 ## Isolated installs
 
+**Before using isolated installs, make sure to have at least GHCup version 0.1.17.8!**
+
 Ghcup also enables you to install a tool (GHC, Cabal, HLS, Stack) at an isolated location of your choosing.
 These installs, as the name suggests, are separate from your main installs and DO NOT conflict with them.
 

ghcup.cabal

@@ -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

@@ -2605,6 +2605,7 @@ 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
@@ -2613,10 +2614,11 @@ 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
 
@@ -2643,15 +2645,18 @@ 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 "
+    Just pa
-      <> T.pack pa
+      | fatal -> throwE (GHCupShadowed pa destFile latestVer)
-      <> ". The upgrade will not be in effect, unless you remove "
+      | otherwise ->
-      <> T.pack pa
+        lift $ logWarn $ "ghcup is shadowed by "
-      <> " or make sure "
+          <> T.pack pa
-      <> T.pack destDir
+          <> ". The upgrade will not be in effect, unless you remove "
-      <> " comes before "
+          <> T.pack pa
-      <> T.pack (takeFileName pa)
+          <> " or make sure "
-      <> " in PATH."
+          <> 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 ]--

scripts/bootstrap/bootstrap-haskell

@@ -26,7 +26,7 @@
 
 plat="$(uname -s)"
 arch=$(uname -m)
-ghver="0.1.17.7"
+ghver="0.1.17.8"
 : "${GHCUP_BASE_URL:=https://downloads.haskell.org/~ghcup}"
 
 export GHCUP_SKIP_UPDATE_CHECK=yes