Fix hlint warnings

1. short hashes now work
2. print the long hash in addition to the detected cabal version of HLS
3. add `--git-describe-version` switch as an alternative to
   `--overwrite-version`

Fix 1. and 2. for GHC as well.

.gitlab/script/ghcup_version.sh

@@ -97,17 +97,23 @@ rm -rf "${GHCUP_DIR}"
 eghcup --numeric-version
 
 eghcup install ghc ${GHC_VERSION}
+eghcup unset ghc ${GHC_VERSION}
 ls -lah "$(eghcup whereis -d ghc ${GHC_VERSION})"
 [ "`$(eghcup whereis ghc ${GHC_VERSION}) --numeric-version`" = "${GHC_VERSION}" ]
 [ "`eghcup run --ghc ${GHC_VERSION} -- ghc --numeric-version`" = "${GHC_VERSION}" ]
+[ "`ghcup run --ghc ${GHC_VERSION} -- ghc -e 'Control.Monad.join (Control.Monad.fmap System.IO.putStr System.Environment.getExecutablePath)'`" = "`$(ghcup whereis ghc ${GHC_VERSION}) -e 'Control.Monad.join (Control.Monad.fmap System.IO.putStr System.Environment.getExecutablePath)'`" ]
 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 1 || echo yes
-eghcup set cabal ${CABAL_VERSION}
-[ "`$(eghcup whereis cabal ${CABAL_VERSION}) --numeric-version`" = "${CABAL_VERSION}" ]
+
+# make sure no cabal is set when running 'ghcup run' to check that PATH propagages properly
+# https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/375
 [ "`eghcup run --cabal ${CABAL_VERSION} -- cabal --numeric-version`" = "${CABAL_VERSION}" ]
+eghcup set cabal ${CABAL_VERSION}
+
+[ "`$(eghcup whereis cabal ${CABAL_VERSION}) --numeric-version`" = "${CABAL_VERSION}" ]
 
 if [ "${OS}" != "FREEBSD" ] ; then
 	if [ "${ARCH}" = "64" ] ; then

app/ghcup/GHCup/OptParse/Compile.hs

@@ -82,7 +82,7 @@ data HLSCompileOptions = HLSCompileOptions
   { targetHLS    :: Either Version GitBranch
   , jobs         :: Maybe Int
   , setCompile   :: Bool
-  , ovewrwiteVer :: Maybe Version
+  , ovewrwiteVer :: Either Bool Version
   , isolateDir   :: Maybe FilePath
   , cabalProject :: Maybe (Either FilePath URI)
   , cabalProjectLocal :: Maybe URI
@@ -145,14 +145,16 @@ Examples:
 
   compileHLSFooter = [s|Discussion:
   Compiles and installs the specified HLS version.
-  The last argument is a list of GHC versions to compile for.
+  The --ghc arguments are necessary to specify which GHC version to build for/against.
   These need to be available in PATH prior to compilation.
 
 Examples:
-  # compile 1.4.0 for ghc 8.10.5 and 8.10.7
-  ghcup compile hls -v 1.4.0 -j 12 --ghc 8.10.5 --ghc 8.10.7
-  # compile from master for ghc 8.10.7, linking everything dynamically
-  ghcup compile hls -g master -j 12 --ghc 8.10.7 -- --ghc-options='-dynamic'|]
+  # compile 1.7.0.0 for ghc 8.10.5 and 8.10.7, passing '--allow-newer' to cabal
+  ghcup compile hls -v 1.7.0.0 -j 12 --ghc 8.10.5 --ghc 8.10.7 -- --allow-newer
+  # compile from master for ghc 9.2.3 and use 'git describe' to name the binary
+  ghcup compile hls -g master --git-describe-version --ghc 9.2.3
+  # compile a specific commit for ghc 9.2.3 and set a specifc version for the binary name
+  ghcup compile hls -g a32db0b -o 1.7.0.0-p1 --ghc 9.2.3|]
 
 
 ghcCompileOpts :: Parser GHCCompileOptions
@@ -280,7 +282,7 @@ hlsCompileOpts =
           (Right <$> (GitBranch <$> option
           str
           (short 'g' <> long "git-ref" <> metavar "GIT_REFERENCE" <> help
-            "The git commit/branch/ref to build from"
+            "The git commit/branch/ref to build from (accepts anything 'git checkout' accepts)"
           ) <*>
           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"])
@@ -295,8 +297,9 @@ hlsCompileOpts =
             )
           )
     <*> fmap (fromMaybe True) (invertableSwitch "set" Nothing True (help "Don't set as active version after install"))
-    <*> optional
-          (option
+    <*>
+         (
+          (Right <$> option
             (eitherReader
               (first (const "Not a valid version") . version . T.pack)
             )
@@ -305,6 +308,14 @@ hlsCompileOpts =
             <> (completer $ versionCompleter Nothing HLS)
             )
           )
+          <|>
+          (Left <$> (switch
+                      (long "git-describe-version"
+                         <> help "Use the output of 'git describe' (if building from git) as the VERSION component of the installed binary."
+                      )
+                    )
+          )
+          )
     <*> optional
           (option
             (eitherReader isolateParser)

app/ghcup/GHCup/OptParse/Run.hs

@@ -18,6 +18,7 @@ import           GHCup.Prelude
 import           GHCup.Prelude.File
 #ifdef IS_WINDOWS
 import           GHCup.Prelude.Process
+import           GHCup.Prelude.Process.Windows ( execNoMinGW )
 #endif
 import           GHCup.Prelude.Logger
 import           GHCup.Prelude.String.QQ
@@ -58,6 +59,7 @@ import qualified System.Posix.Process          as SPP
 data RunOptions = RunOptions
   { runAppendPATH :: Bool
   , runInstTool'  :: Bool
+  , runMinGWPath  :: Bool
   , runGHCVer     :: Maybe ToolVersion
   , runCabalVer   :: Maybe ToolVersion
   , runHLSVer     :: Maybe ToolVersion
@@ -82,6 +84,8 @@ runOpts =
           (short 'a' <> long "append" <> help "Append bin/ dir to PATH instead of prepending (this means that e.g. a system installation may take precedence)")
     <*> switch
           (short 'i' <> long "install" <> help "Install the tool, if missing")
+    <*> switch
+          (short 'm' <> long "mingw-path" <> help "On windows, add mingw64 PATHs to environment (does nothing on unix)")
     <*> optional
           (option
             (eitherReader toolVersionEither)
@@ -249,7 +253,9 @@ run RunOptions{..} runAppState leanAppstate runLogger = do
                void $ liftIO $ SPP.executeFile cmd True args (Just newEnv)
                pure ExitSuccess
 #else
-               r' <- runLeanRUN leanAppstate $ liftE $ lEM @_ @'[ProcessError] $ exec cmd args Nothing (Just newEnv)
+               r' <- if runMinGWPath
+                     then runLeanRUN leanAppstate $ liftE $ lEM @_ @'[ProcessError] $ exec cmd args Nothing (Just newEnv)
+                     else runLeanRUN leanAppstate $ liftE $ lEM @_ @'[ProcessError] $ execNoMinGW cmd args Nothing (Just newEnv)
                case r' of
                  VRight _ -> pure ExitSuccess
                  VLeft e -> do

app/ghcup/Main.hs

@@ -340,7 +340,7 @@ Report bugs at <https://gitlab.haskell.org/haskell/ghcup-hs/issues>|]
     (GHC, ver)   = cmp' GHC (Just $ ToolVersion (mkTVer over)) ver
   alreadyInstalling (Compile (CompileGHC GHCCompileOptions{ targetGhc = Left tver }))
     (GHC, ver)   = cmp' GHC (Just $ ToolVersion (mkTVer tver)) ver
-  alreadyInstalling (Compile (CompileHLS HLSCompileOptions{ ovewrwiteVer = Just over }))
+  alreadyInstalling (Compile (CompileHLS HLSCompileOptions{ ovewrwiteVer = Right over }))
     (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

docs/about.md

@@ -74,12 +74,15 @@ cabal-install/HLS/stack are installed in `~/.ghcup/bin/<tool>-<ver>` and have un
 
 ## Known users
 
-* Github actions:
-	- [actions/virtual-environments](https://github.com/actions/virtual-environments)
-	- [haskell/actions/setup](https://github.com/haskell/actions/tree/main/setup)
+* CI:
+	- [Github actions/virtual-environments](https://github.com/actions/virtual-environments)
+	- [Github haskell/actions/setup](https://github.com/haskell/actions/tree/main/setup)
+	- [haskell-ci](https://github.com/haskell-CI/haskell-ci)
 * mirrors:
 	- [sjtug](https://mirror.sjtu.edu.cn/docs/ghcup)
 * tools:
+	- [vscode-haskell](https://github.com/haskell/vscode-haskell)
+	- [nvim-lsp-installer](https://github.com/williamboman/nvim-lsp-installer)
 	- [vabal](https://github.com/Franciman/vabal)
 
 ## Known problems

docs/install.md

@@ -200,6 +200,14 @@ export PATH="$HOME/.cabal/bin:$HOME/.ghcup/bin:$PATH"
 
 See [ghcup.vim](https://github.com/hasufell/ghcup.vim).
 
+## VSCode integration
+The developers of the Haskell Language Server offer an [extension](https://github.com/haskell/vscode-haskell) tightly integrated with the [Haskell Language Server](https://github.com/haskell/haskell-language-server). To get started:
+
+1. Install GHCup. During installation, opt in to install the Haskell Language Server (HLS).
+2. Install the extension (from VSCode: Ctrl + P and then `ext install haskell.haskell`).
+3. Make sure your project uses the GHC version installed from GHCup (otherwise HLS is likely to fail on launch):
+    - instructions for [stack](https://docs.haskellstack.org/en/stable/yaml_configuration/#system-ghc)
+
 ## Get help
 
 * [Libera IRC chat on #haskell-ghcup or #haskell](https://kiwiirc.com/nextclient/irc.libera.chat/?nick=Guest%7C?#haskell,#haskell-ghcup)

ghcup.cabal

@@ -164,8 +164,10 @@ library
     cpp-options:   -DIS_WINDOWS
     other-modules:
       GHCup.Prelude.File.Windows
-      GHCup.Prelude.Process.Windows
       GHCup.Prelude.Windows
+    -- GHCup.OptParse.Run uses this
+    exposed-modules:
+      GHCup.Prelude.Process.Windows
 
     build-depends:
       , bzlib

lib/GHCup/GHC.hs

@@ -566,8 +566,11 @@ rmGHCVer ver = do
       lift $ recycleFile f
       when (not (null survivors)) $ throwE $ UninstallFailed dir survivors
     Nothing -> do
-      lift $ logInfo $ "Removing legacy directory recursively: " <> T.pack dir
-      lift $ recyclePathForcibly dir'
+      isDir <- liftIO $ doesDirectoryExist dir
+      isSyml <- liftIO $ handleIO (\_ -> pure False) $ pathIsSymbolicLink dir
+      when (isDir && not isSyml) $ do
+        lift $ logInfo $ "Removing legacy directory recursively: " <> T.pack dir
+        recyclePathForcibly dir'
 
   v' <-
     handle
@@ -681,28 +684,53 @@ compileGHC targetGhc ov bstrap jobs mbuildConfig patches aargs buildFlavour hadr
                     , "origin"
                     , fromString rep ]
 
-          let fetch_args =
-                    [ "fetch"
-                    , "--depth"
-                    , "1"
-                    , "--quiet"
-                    , "origin"
-                    , fromString ref ]
+          -- figure out if we can do a shallow clone
+          remoteBranches <- catchE @ProcessError @'[PatchFailed, ProcessError, NotFoundInPATH, DigestError, DownloadFailed, GPGError] @'[PatchFailed, NotFoundInPATH, DigestError, DownloadFailed, GPGError] (\(_ :: ProcessError) -> pure [])
+              $ fmap processBranches $ gitOut ["ls-remote", "--heads", "origin"] (fromGHCupPath tmpUnpack)
+          let shallow_clone
+                | isCommitHash ref                     = True
+                | fromString ref `elem` remoteBranches = True
+                | otherwise                            = False
+          lift $ logDebug $ "Shallow clone: " <> T.pack (show shallow_clone)
+
+          -- fetch
+          let fetch_args
+                | shallow_clone = ["fetch", "--depth", "1", "--quiet", "origin", fromString ref]
+                | otherwise     = ["fetch", "--tags",       "--quiet", "origin"                ]
           lEM $ git fetch_args
 
-          lEM $ git [ "checkout", "FETCH_HEAD" ]
+          -- initial checkout
+          lEM $ git [ "checkout", fromString ref ]
+
+          -- gather some info
+          git_describe <- if shallow_clone
+                          then pure Nothing
+                          else fmap Just $ liftE $ gitOut ["describe", "--tags"] (fromGHCupPath tmpUnpack)
+          chash <- liftE $ gitOut ["rev-parse", "HEAD" ] (fromGHCupPath tmpUnpack)
+
+          -- clone submodules
           lEM $ git [ "submodule", "update", "--init", "--depth", "1" ]
+
+          -- apply patches
           liftE $ applyAnyPatch patches (fromGHCupPath tmpUnpack)
+
+          -- bootstrap
           lEM $ execWithGhcEnv "python3" ["./boot"] (Just $ fromGHCupPath tmpUnpack) "ghc-bootstrap"
           lEM $ execWithGhcEnv "sh" ["./configure"] (Just $ fromGHCupPath tmpUnpack) "ghc-bootstrap"
           CapturedProcess {..} <- lift $ makeOut
             ["show!", "--quiet", "VALUE=ProjectVersion" ] (Just $ fromGHCupPath tmpUnpack)
-          case _exitCode of
-            ExitSuccess -> throwEither . MP.parse ghcProjectVersion "" . decUTF8Safe' $ _stdOut
+          tver <- case _exitCode of
+            ExitSuccess -> throwEither . MP.parse ghcProjectVersion "" . T.pack . stripNewlineEnd . T.unpack . decUTF8Safe' $ _stdOut
             ExitFailure c -> fail ("Could not figure out GHC project version. Exit code was: " <> show c <> ". Error was: " <> T.unpack (decUTF8Safe' _stdErr))
 
-        liftE $ catchWarn $ lEM @_ @'[ProcessError] $ darwinNotarization _rPlatform (fromGHCupPath tmpUnpack)
-        lift $ logInfo $ "Git version " <> T.pack ref <> " corresponds to GHC version " <> prettyVer tver
+          liftE $ catchWarn $ lEM @_ @'[ProcessError] $ darwinNotarization _rPlatform (fromGHCupPath tmpUnpack)
+          lift $ logInfo $ "Examining git ref " <> T.pack ref <> "\n  " <>
+                           "GHC version (from Makefile): " <> prettyVer tver <>
+                           (if not shallow_clone then "\n  " <> "'git describe' output: " <> fromJust git_describe else mempty) <>
+                           (if isCommitHash ref then mempty else "\n  " <> "commit hash: " <> chash)
+          liftIO $ threadDelay 5000000 -- give the user a sec to intervene
+
+          pure tver
 
         pure (tmpUnpack, tmpUnpack, GHCTargetVersion Nothing tver)
     -- the version that's installed may differ from the

lib/GHCup/HLS.hs

@@ -327,7 +327,7 @@ compileHLS :: ( MonadMask m
            => Either Version GitBranch
            -> [Version]
            -> Maybe Int
-           -> Maybe Version
+           -> Either Bool Version
            -> InstallDir
            -> Maybe (Either FilePath URI)
            -> Maybe URI
@@ -349,7 +349,7 @@ compileHLS targetHLS ghcs jobs ov installDir cabalProject cabalProjectLocal patc
   Dirs { .. } <- lift getDirs
 
 
-  (workdir, tver) <- case targetHLS of
+  (workdir, tver, git_describe) <- case targetHLS of
     -- unpack from version tarball
     Left tver -> do
       lift $ logDebug $ "Requested to compile: " <> prettyVer tver
@@ -369,13 +369,13 @@ compileHLS targetHLS ghcs jobs ov installDir cabalProject cabalProjectLocal patc
                        (liftE . intoSubdir tmpUnpack)
                        (view dlSubdir dlInfo)
 
-      pure (workdir, tver)
+      pure (workdir, tver, Nothing)
 
     -- clone from git
     Right GitBranch{..} -> do
       tmpUnpack <- lift mkGhcupTmpDir
       let git args = execLogged "git" ("--no-pager":args) (Just $ fromGHCupPath tmpUnpack) "git" Nothing
-      tver <- reThrowAll @_ @'[ProcessError] DownloadFailed $ do
+      reThrowAll @_ @'[ProcessError] DownloadFailed $ do
         let rep = fromMaybe "https://github.com/haskell/haskell-language-server.git" repo
         lift $ logInfo $ "Fetching git repo " <> T.pack rep <> " at ref " <> T.pack ref <> " (this may take a while)"
         lEM $ git [ "init" ]
@@ -384,33 +384,61 @@ compileHLS targetHLS ghcs jobs ov installDir cabalProject cabalProjectLocal patc
                   , "origin"
                   , fromString rep ]
 
-        let fetch_args =
-                  [ "fetch"
-                  , "--depth"
-                  , "1"
-                  , "--quiet"
-                  , "origin"
-                  , fromString ref ]
+        -- figure out if we can do a shallow clone
+        remoteBranches <- catchE @ProcessError @'[ProcessError] @'[] (\_ -> pure [])
+            $ fmap processBranches $ gitOut ["ls-remote", "--heads", "origin"] (fromGHCupPath tmpUnpack)
+        let shallow_clone
+              | gitDescribeRequested                 = False
+              | isCommitHash ref                     = True
+              | fromString ref `elem` remoteBranches = True
+              | otherwise                            = False
+
+        lift $ logDebug $ "Shallow clone: " <> T.pack (show shallow_clone)
+
+        -- fetch
+        let fetch_args
+              | shallow_clone = ["fetch", "--depth", "1", "--quiet", "origin", fromString ref]
+              | otherwise     = ["fetch", "--tags",       "--quiet", "origin"                ]
         lEM $ git fetch_args
 
-        lEM $ git [ "checkout", "FETCH_HEAD" ]
-        (Just gpd) <- parseGenericPackageDescriptionMaybe <$> liftIO (B.readFile (fromGHCupPath tmpUnpack </> "haskell-language-server.cabal"))
-        pure . (\c -> Version Nothing c [] Nothing)
-          . NE.fromList . fmap (NE.fromList . (:[]) . digits . fromIntegral)
-          . versionNumbers
-          . pkgVersion
-          . package
-          . packageDescription
-          $ gpd
+        -- checkout
+        lEM $ git [ "checkout", fromString ref ]
 
-      liftE $ catchWarn $ lEM @_ @'[ProcessError] $ darwinNotarization _rPlatform (fromGHCupPath tmpUnpack)
-      lift $ logInfo $ "Git version " <> T.pack ref <> " corresponds to HLS version " <> prettyVer tver
+        -- gather some info
+        git_describe <- if shallow_clone
+                        then pure Nothing
+                        else fmap Just $ gitOut ["describe", "--tags"] (fromGHCupPath tmpUnpack)
+        chash <- gitOut ["rev-parse", "HEAD" ] (fromGHCupPath tmpUnpack)
+        (Just gpd) <- parseGenericPackageDescriptionMaybe
+          <$> liftIO (B.readFile (fromGHCupPath tmpUnpack </> "haskell-language-server.cabal"))
+        let tver = (\c -> Version Nothing c [] Nothing)
+                 . NE.fromList . fmap (NE.fromList . (:[]) . digits . fromIntegral)
+                 . versionNumbers
+                 . pkgVersion
+                 . package
+                 . packageDescription
+                 $ gpd
 
-      pure (tmpUnpack, tver)
+        liftE $ catchWarn $ lEM @_ @'[ProcessError] $ darwinNotarization _rPlatform (fromGHCupPath tmpUnpack)
+        lift $ logInfo $ "Examining git ref " <> T.pack ref <> "\n  " <>
+                                    "HLS version (from cabal file): " <> prettyVer tver <>
+                                    (if not shallow_clone then "\n  " <> "'git describe' output: " <> fromJust git_describe else mempty) <>
+                                    (if isCommitHash ref then mempty else "\n  " <> "commit hash: " <> chash)
+
+        pure (tmpUnpack, tver, git_describe)
 
   -- the version that's installed may differ from the
   -- compiled version, so the user can overwrite it
-  let installVer = fromMaybe tver ov
+  installVer <- case ov of
+                  Left True -> case git_describe of
+                                 -- git describe
+                                 Just h -> either (fail . displayException) pure . version $ h
+                                 -- git describe, but not building from git, lol
+                                 Nothing -> pure tver
+                  -- default: use detected version
+                  Left False -> pure tver
+                  -- overwrite version with users value
+                  Right v -> pure v
 
   liftE $ runBuildAction
     workdir
@@ -464,7 +492,7 @@ compileHLS targetHLS ghcs jobs ov installDir cabalProject cabalProjectLocal patc
         pure ghcInstallDir
 
       forM_ artifacts $ \artifact -> do
-        logInfo $ T.pack (show artifact)
+        logDebug $ T.pack (show artifact)
         liftIO $ renameFile (artifact </> "haskell-language-server" <.> exeExt)
           (tmpInstallDir </> "haskell-language-server-" <> takeFileName artifact <.> exeExt)
         liftIO $ renameFile (artifact </> "haskell-language-server-wrapper" <.> exeExt)
@@ -479,6 +507,10 @@ compileHLS targetHLS ghcs jobs ov installDir cabalProject cabalProjectLocal patc
     )
 
   pure installVer
+ where
+  gitDescribeRequested = case ov of
+                           Left b -> b
+                           _      -> False
 
 
     -----------------
@@ -614,8 +646,11 @@ rmHLSVer ver = do
       lift $ recycleFile f
       when (not (null survivors)) $ throwE $ UninstallFailed hlsDir survivors
     Nothing -> do
-      lift $ logInfo $ "Removing legacy directory recursively: " <> T.pack hlsDir
-      recyclePathForcibly hlsDir'
+      isDir <- liftIO $ doesDirectoryExist hlsDir
+      isSyml <- liftIO $ handleIO (\_ -> pure False) $ pathIsSymbolicLink hlsDir
+      when (isDir && not isSyml) $ do
+        lift $ logInfo $ "Removing legacy directory recursively: " <> T.pack hlsDir
+        recyclePathForcibly hlsDir'
 
   when (Just ver == isHlsSet) $ do
     -- set latest hls

lib/GHCup/Prelude/Process/Windows.hs

@@ -206,10 +206,36 @@ exec :: MonadIO m
      -> Maybe [(String, String)] -- ^ optional environment
      -> m (Either ProcessError ())
 exec exe args chdir env = do
+  -- https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/375
+  forM_ (Map.fromList <$> env) $ \cEnv -> do
+    let paths = ["PATH", "Path"]
+        curPaths = (\x -> maybe [] splitSearchPath (Map.lookup x cEnv)) =<< paths
+        newPath = intercalate [searchPathSeparator] curPaths
+    liftIO $ setEnv "PATH" ""
+    liftIO $ setEnv "Path" newPath
   cp <- createProcessWithMingwPath ((proc exe args) { cwd = chdir, env = env })
   exit_code <- liftIO $ withCreateProcess cp $ \_ _ _ p -> waitForProcess p
   pure $ toProcessError exe args exit_code
 
+-- | Like 'exec', except doesn't add msys2 stuff to PATH.
+execNoMinGW :: MonadIO m
+     => FilePath       -- ^ thing to execute
+     -> [FilePath]     -- ^ args for the thing
+     -> Maybe FilePath   -- ^ optionally chdir into this
+     -> Maybe [(String, String)] -- ^ optional environment
+     -> m (Either ProcessError ())
+execNoMinGW exe args chdir env = do
+  -- https://gitlab.haskell.org/haskell/ghcup-hs/-/issues/375
+  forM_ (Map.fromList <$> env) $ \cEnv -> do
+    let paths = ["PATH", "Path"]
+        curPaths = (\x -> maybe [] splitSearchPath (Map.lookup x cEnv)) =<< paths
+        newPath = intercalate [searchPathSeparator] curPaths
+    liftIO $ setEnv "PATH" ""
+    liftIO $ setEnv "Path" newPath
+  let cp = (proc exe args) { cwd = chdir, env = env }
+  exit_code <- liftIO $ withCreateProcess cp $ \_ _ _ p -> waitForProcess p
+  pure $ toProcessError exe args exit_code
+
 
 -- | Thin wrapper around `executeFile`.
 execShell :: MonadIO m

lib/GHCup/Utils.hs

@@ -61,6 +61,7 @@ import           Control.Monad.Reader
 import           Control.Monad.Trans.Resource
                                          hiding ( throwM )
 import           Control.Monad.IO.Unlift        ( MonadUnliftIO( withRunInIO ) )
+import           Data.Char                      ( isHexDigit )
 import           Data.Bifunctor                 ( first )
 import           Data.ByteString                ( ByteString )
 import           Data.Either
@@ -1275,3 +1276,35 @@ warnAboutHlsCompatibility = do
         T.pack (prettyShow supportedGHC)
 
     _ -> return ()
+
+
+
+    -----------
+    --[ Git ]--
+    -----------
+
+
+
+isCommitHash :: String -> Bool
+isCommitHash str' = let hex = all isHexDigit str'
+                        len = length str'
+                    in hex && len == 40
+
+
+gitOut :: (MonadReader env m, HasLog env, MonadIO m) => [String] -> FilePath -> Excepts '[ProcessError] m T.Text
+gitOut args dir = do
+  CapturedProcess {..} <- lift $ executeOut "git" args (Just dir)
+  case _exitCode of
+    ExitSuccess   -> pure $ T.pack $ stripNewlineEnd $ T.unpack $ decUTF8Safe' _stdOut
+    ExitFailure c -> do
+      let pe = NonZeroExit c "git" args
+      lift $ logDebug $ T.pack (prettyShow pe)
+      throwE pe
+
+processBranches :: T.Text -> [String]
+processBranches str' = let lines'   = lines (T.unpack str')
+                           words'   = fmap words lines'
+                           refs     = catMaybes $ fmap (`atMay` 1) words'
+                           branches = catMaybes $ fmap (stripPrefix "refs/heads/") $ filter (isPrefixOf "refs/heads/") refs
+                       in branches
+

scripts/bootstrap/bootstrap-haskell

@@ -133,6 +133,15 @@ _eghcup() {
     fi
 }
 
+ecabal() {
+	edo _ecabal "$@"
+}
+
+_ecabal() {
+    # shellcheck disable=SC2086
+    "${GHCUP_BIN}/cabal" "$@"
+}
+
 _done() {
 	echo
 	echo "==============================================================================="
@@ -537,7 +546,7 @@ adjust_cabal_config() {
     else
         cabal_bin="$HOME/AppData/Roaming/cabal/bin"
     fi
-    edo cabal user-config -a "extra-prog-path: $(cygpath -w "$GHCUP_BIN"), $(cygpath -w "$cabal_bin"), $(cygpath -w "$GHCUP_MSYS2"/mingw64/bin), $(cygpath -w "$GHCUP_MSYS2"/usr/bin)" -a "extra-include-dirs: $(cygpath -w "$GHCUP_MSYS2"/mingw64/include)" -a "extra-lib-dirs: $(cygpath -w "$GHCUP_MSYS2"/mingw64/lib)" -f init
+    ecabal user-config -a "extra-prog-path: $(cygpath -w "$GHCUP_BIN"), $(cygpath -w "$cabal_bin"), $(cygpath -w "$GHCUP_MSYS2"/mingw64/bin), $(cygpath -w "$GHCUP_MSYS2"/usr/bin)" -a "extra-include-dirs: $(cygpath -w "$GHCUP_MSYS2"/mingw64/include)" -a "extra-lib-dirs: $(cygpath -w "$GHCUP_MSYS2"/mingw64/lib)" -f init
 }
 
 ask_cabal_config_init() {
@@ -688,7 +697,7 @@ find_shell
 echo
 echo "Welcome to Haskell!"
 echo
-echo "This script will download and install the following binaries:"
+echo "This script can download and install the following binaries:"
 echo "  * ghcup - The Haskell toolchain installer"
 echo "  * ghc   - The Glasgow Haskell Compiler"
 echo "  * cabal - The Cabal build tool for managing Haskell software"

scripts/bootstrap/bootstrap-haskell.ps1

@@ -242,7 +242,7 @@ if ($Silent -and !($InstallDir)) {
 	Print-Msg -color Magenta -msg (@'
 Welcome to Haskell!
 
-This script will download and install the following programs:
+This script can 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