Don't print to stdout during logging

Without this, each time the env script gets executed it will add a copy
of the paths to PATH. This can happen when shells are nested.

The "case" trick was inspired by:
184a899f45/src/cli/self_update/env.sh

app/ghcup/GHCup/OptParse/Compile.hs

@@ -212,7 +212,7 @@ ghcCompileOpts =
             (fmap Left $ option
               str
               (short 'p' <> long "patchdir" <> metavar "PATCH_DIR" <> help
-                "Absolute path to patch directory (applies all .patch and .diff files in order using -p1)"
+                "Absolute path to patch directory (applies all .patch and .diff files in order using -p1. This order is determined by a quilt series file if it exists, or the patches are lexicographically ordered)"
               )
             )
           )

docs/dev.md

@@ -12,8 +12,7 @@ organised tree-ish in `GHCup.Utils` and `GHCup.Utils.*`.
 Anything dealing with ghcup specific directories is in
 `GHCup.Utils.Dirs`.
 
-Download information on where to fetch bindists from is in the appropriate
-yaml files: `data/metadata/ghcup-<yaml-ver>.yaml`.
+Download information on where to fetch bindists from is in the [ghcup-metadata](https://github.com/haskell/ghcup-metadata) repository.
 
 ## Design decisions
 

docs/guide.md

@@ -32,6 +32,17 @@ ghcup install cabal
 ghcup upgrade
 ```
 
+### Tags and shortcuts
+
+GHCup has a number of tags and version shortcuts, that can be used as arguments to **install**/**set** etc.
+All of the following are valid arguments to `ghcup install ghc`:
+
+* `latest`, `recommended`
+* `base-4.15.1.0`
+* `9.0.2`, `9.0`, `9`
+
+If the argument is omitted, the default is `recommended`.
+
 ## Configuration
 
 A configuration file can be put in `~/.ghcup/config.yaml`. The default config file
@@ -138,6 +149,31 @@ and produce the binaries `ghc-8.10.2-eff` and `ghc-head` respectively.
 GHCup always needs to know which version the bindist corresponds to (this is not automatically
 detected).
 
+## Mirrors
+
+GHCup allows to use custom mirrors/download-info hosted by yourself or 3rd parties.
+
+To use a mirror, set the following option in `~/.ghcup/config.yaml`:
+
+```yml
+url-source:
+  # Accepts file/http/https scheme
+  OwnSource: "https://some-url/ghcup-0.0.6.yaml"
+```
+
+See [config.yaml](https://gitlab.haskell.org/haskell/ghcup-hs/-/blob/master/data/config.yaml)
+for more options.
+
+Alternatively you can do it via a cli switch:
+
+```sh
+ghcup --url-source=https://some-url/ghcup-0.0.6.yaml list
+```
+
+### Known mirrors
+
+1. [https://mirror.sjtu.edu.cn/docs/ghcup](https://mirror.sjtu.edu.cn/docs/ghcup)
+
 ## Isolated installs
 
 Ghcup also enables you to install a tool (GHC, Cabal, HLS, Stack) at an isolated location of your choosing.

docs/install.md

@@ -24,6 +24,14 @@ Set-ExecutionPolicy Bypass -Scope Process -Force;[System.Net.ServicePointManager
 
 If you want to know what these scripts do, check out the [source code at the repository](https://gitlab.haskell.org/haskell/ghcup-hs/-/tree/master/scripts/bootstrap). Advanced users may want to perform a [manual installation](#manual-install) and GPG verify the binaries.
 
+### Which versions get installed?
+
+GHCup has two main channels for every tool: **recommended** and **latest**. By default, it installs *recommended*.
+
+*latest* follows the latest release of every tool, while *recommended* is at the discretion of the GHCup maintainers and based on community adoption (hackage libraries, tools like HLS, stackage support, etc.) and known bugs.
+
+Also see [tags and shortcuts](../guide/#tags-and-shortcuts) for more information.
+
 ## First steps
 
 1. To get started with creating a Haskell project, follow the [Getting Started with Haskell and Cabal](https://cabal.readthedocs.io/en/latest/getting-started.html) guide

lib/GHCup/Platform.hs

@@ -4,7 +4,7 @@
 {-# LANGUAGE FlexibleInstances     #-}
 {-# LANGUAGE OverloadedStrings     #-}
 {-# LANGUAGE QuasiQuotes           #-}
-{-# LANGUAGE TemplateHaskell       #-}
+{-# LANGUAGE TemplateHaskellQuotes #-}
 
 
 {-|

lib/GHCup/Utils.hs

@@ -3,7 +3,7 @@
 {-# LANGUAGE FlexibleContexts      #-}
 {-# LANGUAGE OverloadedStrings     #-}
 {-# LANGUAGE QuasiQuotes           #-}
-{-# LANGUAGE TemplateHaskell       #-}
+{-# LANGUAGE TemplateHaskellQuotes #-}
 {-# LANGUAGE TypeApplications      #-}
 {-# LANGUAGE ViewPatterns          #-}
 
@@ -879,20 +879,28 @@ makeOut args workdir = do
   executeOut mymake args workdir
 
 
--- | Try to apply patches in order. Fails with 'PatchFailed'
--- on first failure.
+-- | Try to apply patches in order. The order is determined by
+-- a quilt series file (in the patch directory) if one exists,
+-- else the patches are applied in lexicographical order.
+-- Fails with 'PatchFailed' on first failure.
 applyPatches :: (MonadReader env m, HasDirs env, HasLog env, MonadIO m)
              => FilePath   -- ^ dir containing patches
              -> FilePath   -- ^ dir to apply patches in
              -> Excepts '[PatchFailed] m ()
 applyPatches pdir ddir = do
-  patches <- (fmap . fmap) (pdir </>) $ liftIO $ findFiles
-      pdir
-      (makeRegexOpts compExtended
-                     execBlank
-                     ([s|.+\.(patch|diff)$|] :: ByteString)
-      )
-  forM_ (sort patches) $ \patch' -> applyPatch patch' ddir
+  let lexicographical = (fmap . fmap) (pdir </>) $ sort <$> findFiles
+        pdir
+        (makeRegexOpts compExtended
+                       execBlank
+                       ([s|.+\.(patch|diff)$|] :: ByteString)
+        )
+  let quilt = map (pdir </>) . lines <$> readFile (pdir </> "series")
+
+  patches <- liftIO $ quilt `catchIO` (\e ->
+    if isDoesNotExistError e || isPermissionError e then
+      lexicographical 
+    else throwIO e)
+  forM_ patches $ \patch' -> applyPatch patch' ddir
 
 
 applyPatch :: (MonadReader env m, HasDirs env, HasLog env, MonadIO m)

lib/GHCup/Utils/File/Posix.hs

@@ -35,6 +35,7 @@ import           Data.Sequence                  ( Seq, (|>) )
 import           Data.List
 import           Data.Word8
 import           GHC.IO.Exception
+import           System.IO                      ( stderr )
 import           System.IO.Error
 import           System.FilePath
 import           System.Directory
@@ -142,14 +143,14 @@ execLogged exe args chdir lfile env = do
   printToRegion :: Fd -> Fd -> Int -> MVar Bool -> Bool -> IO ()
   printToRegion fileFd fdIn size pState no_color = do
     -- init region
-    forM_ [1..size] $ \_ -> BS.putStr "\n"
+    forM_ [1..size] $ \_ -> BS.hPut stderr "\n"
 
     void $ flip runStateT mempty
       $ do
         handle
           (\(ex :: SomeException) -> do
             ps <- liftIO $ takeMVar pState
-            when ps (liftIO $ BS.putStr (pos1 <> moveLineUp size <> clearScreen))
+            when ps (liftIO $ BS.hPut stderr (pos1 <> moveLineUp size <> clearScreen))
             throw ex
           ) $ readTilEOF lineAction fdIn
 
@@ -184,7 +185,7 @@ execLogged exe args chdir lfile env = do
         Just (TP.Window _ w) -> do
           regs <- get
           liftIO $ forM_ (Sq.zip regs (Sq.fromList [0..(Sq.length regs - 1)])) $ \(bs, i) -> do
-              BS.putStr
+              BS.hPut stderr
               . overwriteNthLine (size - i)
               . trim w
               . blue

lib/GHCup/Utils/File/Windows.hs

@@ -196,7 +196,8 @@ execLogged exe args chdir lfile env = do
           then pure ()
           else do
             void $ BS.appendFile logFile some
-            void $ BS.hPut stdout some
+            -- subprocess stdout also goes to stderr for logging
+            void $ BS.hPut stderr some
             go
         
 

lib/GHCup/Utils/String/QQ.hs

@@ -1,4 +1,4 @@
-{-# LANGUAGE TemplateHaskell #-}
+{-# LANGUAGE TemplateHaskellQuotes #-}
 
 {-|
 Module      : GHCup.Utils.String.QQ

lib/GHCup/Utils/Version/QQ.hs

@@ -4,7 +4,7 @@
 {-# LANGUAGE DeriveLift         #-}
 {-# LANGUAGE FlexibleInstances  #-}
 {-# LANGUAGE StandaloneDeriving #-}
-{-# LANGUAGE TemplateHaskell    #-}
+{-# LANGUAGE TemplateHaskellQuotes #-}
 
 
 {-|

scripts/bootstrap/bootstrap-haskell

@@ -280,7 +280,20 @@ download_ghcup() {
 
 	# we may overwrite this in adjust_bashrc
 	cat <<-EOF > "${GHCUP_DIR}"/env || die "Failed to create env file"
-		export PATH="\$HOME/.cabal/bin:${GHCUP_BIN}:\$PATH"
+		case ":\$PATH:" in
+			*:"${GHCUP_BIN}":*)
+				;;
+			*)
+				export PATH="${GHCUP_BIN}:\$PATH"
+				;;
+		esac
+		case ":\$PATH:" in
+			*:"\$HOME/.cabal/bin":*)
+				;;
+			*)
+				export PATH="\$HOME/.cabal/bin:\$PATH"
+				;;
+		esac
 		EOF
 
 	# shellcheck disable=SC1090
@@ -368,12 +381,38 @@ adjust_bashrc() {
 	case $1 in
 		1)
 			cat <<-EOF > "${GHCUP_DIR}"/env || die "Failed to create env file"
-				export PATH="\$HOME/.cabal/bin:${GHCUP_BIN}:\$PATH"
+				case ":\$PATH:" in
+					*:"${GHCUP_BIN}":*)
+						;;
+					*)
+						export PATH="${GHCUP_BIN}:\$PATH"
+						;;
+				esac
+				case ":\$PATH:" in
+					*:"\$HOME/.cabal/bin":*)
+						;;
+					*)
+						export PATH="\$HOME/.cabal/bin:\$PATH"
+						;;
+				esac
 				EOF
 			;;
 		2)
 			cat <<-EOF > "${GHCUP_DIR}"/env || die "Failed to create env file"
-				export PATH="\$PATH:\$HOME/.cabal/bin:${GHCUP_BIN}"
+				case ":\$PATH:" in
+					*:"\$HOME/.cabal/bin":*)
+						;;
+					*)
+						export PATH="\$PATH:\$HOME/.cabal/bin"
+						;;
+				esac
+				case ":\$PATH:" in
+					*:"${GHCUP_BIN}":*)
+						;;
+					*)
+						export PATH="\$PATH:${GHCUP_BIN}"
+						;;
+				esac
 				EOF
 			;;
 		*) ;;

scripts/bootstrap/bootstrap-haskell.ps1

@@ -29,11 +29,11 @@ param (
     [switch]$InstallStack,
     # Whether to install hls as well
     [switch]$InstallHLS,
-    # Specify the bootstrap url (default: 'https://www.haskell.org/ghcup/sh/bootstrap-haskell')
-    [string]$InstallDir,
-    # Instead of installing a new MSys2, use an existing installation
-    [string]$BootstrapUrl,
     # Specify the install root (default: 'C:\')
+    [string]$InstallDir,
+    # Specify the bootstrap url (default: 'https://www.haskell.org/ghcup/sh/bootstrap-haskell')
+    [string]$BootstrapUrl,
+    # Instead of installing a new MSys2, use an existing installation
     [string]$ExistingMsys2Dir,
     # Specify the cabal root directory (default: '$InstallDir\cabal')
     [string]$CabalDir