From c111b332c789d30cdb22cfd8858ca8cc6117c61c Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Tue, 29 Aug 2017 17:08:22 -0700
Subject: [PATCH 01/19] create stub `System.Terminal` module

---
 src/System/Terminal.hsc | 9 +++++++++
 stack.cabal             | 1 +
 2 files changed, 10 insertions(+)
 create mode 100644 src/System/Terminal.hsc

diff --git a/src/System/Terminal.hsc b/src/System/Terminal.hsc
new file mode 100644
index 0000000000..ffde47b034
--- /dev/null
+++ b/src/System/Terminal.hsc
@@ -0,0 +1,9 @@
+{-# LANGUAGE ForeignFunctionInterface #-}
+
+module System.Terminal
+( getTerminalWidth
+) where
+
+-- | Get the width, in columns, of the terminal if we can.
+getTerminalWidth :: IO (Maybe Int)
+getTerminalWidth = pure Nothing
diff --git a/stack.cabal b/stack.cabal
index 0fab39b501..5738eea124 100644
--- a/stack.cabal
+++ b/stack.cabal
@@ -187,6 +187,7 @@ library
                      System.Process.PagerEditor
                      System.Process.Read
                      System.Process.Run
+                     System.Terminal
   other-modules:     Hackage.Security.Client.Repository.HttpLib.HttpClient
   build-depends:     Cabal >= 2.0 && < 2.1
                    , aeson (>= 1.0 && < 1.2)

From da253f29b365d464049f4f05b84986f5508c03ae Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Tue, 29 Aug 2017 17:15:11 -0700
Subject: [PATCH 02/19] prepare for protecting windows from POSIX-only term
 detection

---
 src/System/Terminal.hsc | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/src/System/Terminal.hsc b/src/System/Terminal.hsc
index ffde47b034..3e5efd97ce 100644
--- a/src/System/Terminal.hsc
+++ b/src/System/Terminal.hsc
@@ -1,4 +1,7 @@
+{-# LANGUAGE CPP #-}
+#ifndef WINDOWS
 {-# LANGUAGE ForeignFunctionInterface #-}
+#endif
 
 module System.Terminal
 ( getTerminalWidth
@@ -6,4 +9,8 @@ module System.Terminal
 
 -- | Get the width, in columns, of the terminal if we can.
 getTerminalWidth :: IO (Maybe Int)
+#ifndef WINDOWS
 getTerminalWidth = pure Nothing
+#else
+getTerminalWidth = pure Nothing
+#endif

From 0cf7ba9f5f17f7250a243ceb99d5f8869e28f852 Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Tue, 29 Aug 2017 17:26:23 -0700
Subject: [PATCH 03/19] create type to store C's winsize struct

Just does the part we actually care about, the width in columns
---
 src/System/Terminal.hsc | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/src/System/Terminal.hsc b/src/System/Terminal.hsc
index 3e5efd97ce..f9025cd129 100644
--- a/src/System/Terminal.hsc
+++ b/src/System/Terminal.hsc
@@ -7,6 +7,22 @@ module System.Terminal
 ( getTerminalWidth
 ) where
 
+import           Foreign
+import           Foreign.C.Types
+
+#include <sys/ioctl.h>
+#include <unistd.h>
+
+newtype WindowWidth = WindowWidth CUShort
+    deriving (Eq, Ord, Show)
+
+instance Storable WindowWidth where
+  sizeOf _ = (#size struct winsize)
+  alignment _ = (#alignment struct winsize)
+  peek p = WindowWidth <$> (#peek struct winsize, ws_col) p
+  poke p (WindowWidth w) = do
+    (#poke struct winsize, ws_col) p w
+
 -- | Get the width, in columns, of the terminal if we can.
 getTerminalWidth :: IO (Maybe Int)
 #ifndef WINDOWS

From 2910f35d383e29cbc1de3f5f9cde3d32252db90f Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Tue, 29 Aug 2017 17:35:47 -0700
Subject: [PATCH 04/19] implement `getTerminalWidth`

---
 src/System/Terminal.hsc | 12 +++++++++++-
 1 file changed, 11 insertions(+), 1 deletion(-)

diff --git a/src/System/Terminal.hsc b/src/System/Terminal.hsc
index f9025cd129..0bcfd2884d 100644
--- a/src/System/Terminal.hsc
+++ b/src/System/Terminal.hsc
@@ -23,10 +23,20 @@ instance Storable WindowWidth where
   poke p (WindowWidth w) = do
     (#poke struct winsize, ws_col) p w
 
+foreign import ccall "sys/ioctl.h ioctl"
+  ioctl :: CInt -> CInt -> Ptr WindowWidth -> IO CInt
+
 -- | Get the width, in columns, of the terminal if we can.
 getTerminalWidth :: IO (Maybe Int)
 #ifndef WINDOWS
-getTerminalWidth = pure Nothing
+getTerminalWidth =
+  alloca $ \p -> do
+    errno <- ioctl (#const STDOUT_FILENO) (#const TIOCGWINSZ) p
+    if errno < 0
+      then return Nothing
+      else do
+        WindowWidth w <- peek p
+        return . Just . fromIntegral $ w
 #else
 getTerminalWidth = pure Nothing
 #endif

From 72de4929d01cdf73489652d027fa6970fcbb5de4 Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Tue, 29 Aug 2017 17:36:41 -0700
Subject: [PATCH 05/19] wrap more stuff in windows check

---
 src/System/Terminal.hsc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/src/System/Terminal.hsc b/src/System/Terminal.hsc
index 0bcfd2884d..b6ed5f4d76 100644
--- a/src/System/Terminal.hsc
+++ b/src/System/Terminal.hsc
@@ -7,6 +7,7 @@ module System.Terminal
 ( getTerminalWidth
 ) where
 
+#ifndef WINDOWS
 import           Foreign
 import           Foreign.C.Types
 
@@ -25,6 +26,7 @@ instance Storable WindowWidth where
 
 foreign import ccall "sys/ioctl.h ioctl"
   ioctl :: CInt -> CInt -> Ptr WindowWidth -> IO CInt
+#endif
 
 -- | Get the width, in columns, of the terminal if we can.
 getTerminalWidth :: IO (Maybe Int)

From b2cb9467849fec156f07af58326bee7deff2f5c5 Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Tue, 29 Aug 2017 20:38:31 -0700
Subject: [PATCH 06/19] require hsc2hs build tool

---
 stack.cabal | 1 +
 1 file changed, 1 insertion(+)

diff --git a/stack.cabal b/stack.cabal
index 5738eea124..22fddf593e 100644
--- a/stack.cabal
+++ b/stack.cabal
@@ -268,6 +268,7 @@ library
                    , store-core >= 0.4 && < 0.5
                    , annotated-wl-pprint
                    , file-embed >= 0.0.10
+  build-tools:       hsc2hs >= 0.68
   if os(windows)
     cpp-options:     -DWINDOWS
     build-depends:   Win32

From 2855cbc2a01c87673a98dd5769f4835f759ee001 Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Wed, 30 Aug 2017 00:01:11 -0700
Subject: [PATCH 07/19] make low-level print funcs take terminal width as a
 param

---
 src/Stack/PrettyPrint.hs                |  2 +-
 src/Text/PrettyPrint/Leijen/Extended.hs | 18 +++++++++---------
 2 files changed, 10 insertions(+), 10 deletions(-)

diff --git a/src/Stack/PrettyPrint.hs b/src/Stack/PrettyPrint.hs
index e2a51db7a9..207e17e0a4 100644
--- a/src/Stack/PrettyPrint.hs
+++ b/src/Stack/PrettyPrint.hs
@@ -51,7 +51,7 @@ displayWithColor
     => a -> m T.Text
 displayWithColor x = do
     useAnsi <- liftM logUseColor $ view logOptionsL
-    return $ if useAnsi then displayAnsi x else displayPlain x
+    return $ (if useAnsi then displayAnsi else displayPlain) 120 x
 
 -- TODO: switch to using implicit callstacks once 7.8 support is dropped
 
diff --git a/src/Text/PrettyPrint/Leijen/Extended.hs b/src/Text/PrettyPrint/Leijen/Extended.hs
index d811e85ac2..e958b141a0 100644
--- a/src/Text/PrettyPrint/Leijen/Extended.hs
+++ b/src/Text/PrettyPrint/Leijen/Extended.hs
@@ -176,24 +176,24 @@ instance HasAnsiAnn AnsiAnn where
 instance HasAnsiAnn () where
     getAnsiAnn _ = mempty
 
-displayPlain :: Display a => a -> T.Text
-displayPlain = LT.toStrict . displayAnsiSimple . renderDefault . fmap (const mempty) . display
+displayPlain :: Display a => Int -> a -> T.Text
+displayPlain w = LT.toStrict . displayAnsiSimple . renderDefault w . fmap (const mempty) . display
 
 -- TODO: tweak these settings more?
 -- TODO: options for settings if this is released as a lib
 
-renderDefault :: Doc a -> SimpleDoc a
-renderDefault = renderPretty 1 120
+renderDefault :: Int -> Doc a -> SimpleDoc a
+renderDefault = renderPretty 1
 
-displayAnsi :: (Display a, HasAnsiAnn (Ann a)) => a -> T.Text
-displayAnsi = LT.toStrict . displayAnsiSimple . renderDefault . toAnsiDoc . display
+displayAnsi :: (Display a, HasAnsiAnn (Ann a)) => Int -> a -> T.Text
+displayAnsi w = LT.toStrict . displayAnsiSimple . renderDefault w . toAnsiDoc . display
 
 hDisplayAnsi
     :: (Display a, HasAnsiAnn (Ann a), MonadIO m)
-    => Handle -> a -> m ()
-hDisplayAnsi h x = liftIO $ do
+    => Handle -> Int -> a -> m ()
+hDisplayAnsi h w x = liftIO $ do
     useAnsi <- hSupportsANSI h
-    T.hPutStr h $ if useAnsi then displayAnsi x else displayPlain x
+    T.hPutStr h $ if useAnsi then displayAnsi w x else displayPlain w x
 
 displayAnsiSimple :: SimpleDoc AnsiAnn -> LT.Text
 displayAnsiSimple doc =

From 54ad0f37cca4f01155ae72febade7f74f6cef186 Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Wed, 30 Aug 2017 18:04:59 -0700
Subject: [PATCH 08/19] add a command-line option to set/override the terminal
 width

---
 src/Stack/Options/GlobalParser.hs | 5 +++++
 src/Stack/Types/Config.hs         | 2 ++
 2 files changed, 7 insertions(+)

diff --git a/src/Stack/Options/GlobalParser.hs b/src/Stack/Options/GlobalParser.hs
index e329b56d88..0f96239412 100644
--- a/src/Stack/Options/GlobalParser.hs
+++ b/src/Stack/Options/GlobalParser.hs
@@ -40,6 +40,10 @@ globalOptsParser currentDir kind defLogLevel =
          completeWith ["always", "never", "auto"] <>
          help "Specify when to use color in output; WHEN is 'always', 'never', or 'auto'" <>
          hide)) <*>
+    optionalFirst (option auto
+        (long "terminal-width" <>
+         metavar "INT" <>
+         help "Specify the width of the terminal, used for pretty-print messages")) <*>
     optionalFirst
         (strOption
             (long "stack-yaml" <>
@@ -64,6 +68,7 @@ globalOptsFromMonoid defaultTerminal GlobalOptsMonoid{..} = GlobalOpts
     , globalCompiler = getFirst globalMonoidCompiler
     , globalTerminal = fromFirst defaultTerminal globalMonoidTerminal
     , globalColorWhen = fromFirst ColorAuto globalMonoidColorWhen
+    , globalTermWidth = getFirst globalMonoidTermWidth
     , globalStackYaml = maybe SYLDefault SYLOverride $ getFirst globalMonoidStackYaml }
 
 initOptsParser :: Parser InitOpts
diff --git a/src/Stack/Types/Config.hs b/src/Stack/Types/Config.hs
index 51bd8576e4..1f233b984f 100644
--- a/src/Stack/Types/Config.hs
+++ b/src/Stack/Types/Config.hs
@@ -442,6 +442,7 @@ data GlobalOpts = GlobalOpts
     , globalCompiler     :: !(Maybe (CompilerVersion 'CVWanted)) -- ^ Compiler override
     , globalTerminal     :: !Bool -- ^ We're in a terminal?
     , globalColorWhen    :: !ColorWhen -- ^ When to use ansi terminal colors
+    , globalTermWidth    :: !(Maybe Int) -- ^ Terminal width override
     , globalStackYaml    :: !(StackYamlLoc FilePath) -- ^ Override project stack.yaml
     } deriving (Show)
 
@@ -465,6 +466,7 @@ data GlobalOptsMonoid = GlobalOptsMonoid
     , globalMonoidCompiler     :: !(First (CompilerVersion 'CVWanted)) -- ^ Compiler override
     , globalMonoidTerminal     :: !(First Bool) -- ^ We're in a terminal?
     , globalMonoidColorWhen    :: !(First ColorWhen) -- ^ When to use ansi colors
+    , globalMonoidTermWidth    :: !(First Int) -- ^ Terminal width override
     , globalMonoidStackYaml    :: !(First FilePath) -- ^ Override project stack.yaml
     } deriving (Show, Generic)
 

From 83a018e010e1420d65d1b3ffb746e0213aeee229 Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Wed, 30 Aug 2017 23:15:55 -0700
Subject: [PATCH 09/19] add the term width stuff to LogOptions

Includes actually querying the terminal width automatically when
it's not overriden.
---
 src/Stack/Runners.hs      |  1 +
 src/Stack/Types/Runner.hs | 12 +++++++++++-
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/src/Stack/Runners.hs b/src/Stack/Runners.hs
index 6628bf4215..b7711d91bc 100644
--- a/src/Stack/Runners.hs
+++ b/src/Stack/Runners.hs
@@ -214,6 +214,7 @@ withRunnerGlobal GlobalOpts{..} = withRunner
   globalTimeInLog
   globalTerminal
   globalColorWhen
+  globalTermWidth
   (isJust globalReExecVersion)
 
 withMiniConfigAndLock
diff --git a/src/Stack/Types/Runner.hs b/src/Stack/Types/Runner.hs
index bd5ec43725..8edac7cb47 100644
--- a/src/Stack/Types/Runner.hs
+++ b/src/Stack/Types/Runner.hs
@@ -45,6 +45,7 @@ import           System.Console.ANSI
 import           System.FilePath
 import           System.IO
 import           System.Log.FastLogger
+import           System.Terminal
 
 -- | Monadic environment.
 data Runner = Runner
@@ -77,6 +78,7 @@ newtype Sticky = Sticky
 
 data LogOptions = LogOptions
   { logUseColor      :: Bool
+  , logTermWidth     :: Int
   , logUseUnicode    :: Bool
   , logUseTime       :: Bool
   , logMinLevel      :: LogLevel
@@ -243,19 +245,24 @@ withRunner :: MonadIO m
            -> Bool -- ^ use time?
            -> Bool -- ^ terminal?
            -> ColorWhen
+           -> Maybe Int -- ^ terminal width override
            -> Bool -- ^ reexec?
            -> (Runner -> m a)
            -> m a
-withRunner logLevel useTime terminal colorWhen reExec inner = do
+withRunner logLevel useTime terminal colorWhen widthOverride reExec inner = do
   useColor <- case colorWhen of
     ColorNever -> return False
     ColorAlways -> return True
     ColorAuto -> liftIO $ hSupportsANSI stderr
+  termWidth <- case widthOverride >>= checkWidth of
+      Nothing -> fromMaybe 100 <$> liftIO getTerminalWidth
+      Just w -> return w
   canUseUnicode <- liftIO getCanUseUnicode
   withSticky terminal $ \sticky -> inner Runner
     { runnerReExec = reExec
     , runnerLogOptions = LogOptions
         { logUseColor = useColor
+        , logTermWidth = termWidth
         , logUseUnicode = canUseUnicode
         , logUseTime = useTime
         , logMinLevel = logLevel
@@ -264,6 +271,9 @@ withRunner logLevel useTime terminal colorWhen reExec inner = do
     , runnerTerminal = terminal
     , runnerSticky = sticky
     }
+  where checkWidth w
+          | w < 20 = Nothing
+          | otherwise = Just w
 
 -- | Taken from GHC: determine if we should use Unicode syntax
 getCanUseUnicode :: IO Bool

From d95758c5b8961912f1ee20680c4ce3adede959f3 Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Wed, 30 Aug 2017 23:17:16 -0700
Subject: [PATCH 10/19] replace terminal width numbers with named constants

---
 src/Stack/Constants.hs    | 8 ++++++++
 src/Stack/Types/Runner.hs | 5 +++--
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/Stack/Constants.hs b/src/Stack/Constants.hs
index 8f66db4e0f..b0a6a6bd31 100644
--- a/src/Stack/Constants.hs
+++ b/src/Stack/Constants.hs
@@ -28,6 +28,8 @@ module Stack.Constants
     ,platformVariantEnvVar
     ,compilerOptionsCabalFlag
     ,ghcColorForceFlag
+    ,minTerminalWidth
+    ,defaultTerminalWidth
     )
     where
 
@@ -216,3 +218,9 @@ compilerOptionsCabalFlag Ghcjs = "--ghcjs-options"
 
 ghcColorForceFlag :: String
 ghcColorForceFlag = "-fdiagnostics-color=always"
+
+minTerminalWidth :: Int
+minTerminalWidth = 20
+
+defaultTerminalWidth :: Int
+defaultTerminalWidth = 100
diff --git a/src/Stack/Types/Runner.hs b/src/Stack/Types/Runner.hs
index 8edac7cb47..9f39452500 100644
--- a/src/Stack/Types/Runner.hs
+++ b/src/Stack/Types/Runner.hs
@@ -41,6 +41,7 @@ import           Language.Haskell.TH
 import           Language.Haskell.TH.Syntax (lift)
 import           Lens.Micro
 import           Stack.Prelude              hiding (lift)
+import           Stack.Constants
 import           System.Console.ANSI
 import           System.FilePath
 import           System.IO
@@ -255,7 +256,7 @@ withRunner logLevel useTime terminal colorWhen widthOverride reExec inner = do
     ColorAlways -> return True
     ColorAuto -> liftIO $ hSupportsANSI stderr
   termWidth <- case widthOverride >>= checkWidth of
-      Nothing -> fromMaybe 100 <$> liftIO getTerminalWidth
+      Nothing -> fromMaybe defaultTerminalWidth <$> liftIO getTerminalWidth
       Just w -> return w
   canUseUnicode <- liftIO getCanUseUnicode
   withSticky terminal $ \sticky -> inner Runner
@@ -272,7 +273,7 @@ withRunner logLevel useTime terminal colorWhen widthOverride reExec inner = do
     , runnerSticky = sticky
     }
   where checkWidth w
-          | w < 20 = Nothing
+          | w < minTerminalWidth = Nothing
           | otherwise = Just w
 
 -- | Taken from GHC: determine if we should use Unicode syntax

From a20048981acf2d2f5e8ae01bb35b8f25886ccf74 Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Wed, 30 Aug 2017 23:33:22 -0700
Subject: [PATCH 11/19] use the terminal width when pretty-printing

---
 src/Stack/PrettyPrint.hs | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/Stack/PrettyPrint.hs b/src/Stack/PrettyPrint.hs
index 207e17e0a4..3b308f72a2 100644
--- a/src/Stack/PrettyPrint.hs
+++ b/src/Stack/PrettyPrint.hs
@@ -51,7 +51,8 @@ displayWithColor
     => a -> m T.Text
 displayWithColor x = do
     useAnsi <- liftM logUseColor $ view logOptionsL
-    return $ (if useAnsi then displayAnsi else displayPlain) 120 x
+    termWidth <- liftM logTermWidth $ view logOptionsL
+    return $ (if useAnsi then displayAnsi else displayPlain) termWidth x
 
 -- TODO: switch to using implicit callstacks once 7.8 support is dropped
 

From 9d10d34e2d2e4ea03a15b6c2121f1e74ecd4b443 Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Thu, 31 Aug 2017 00:34:01 -0700
Subject: [PATCH 12/19] improve terminal-width min/max behavior

- implement a maximum
- clip to the range instead of just ignoring invalid values
- actually check the detected width too, not just a user-supplied one
---
 src/Stack/Constants.hs    |  4 ++++
 src/Stack/Types/Runner.hs | 13 +++++++------
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/src/Stack/Constants.hs b/src/Stack/Constants.hs
index b0a6a6bd31..2f9c3b4367 100644
--- a/src/Stack/Constants.hs
+++ b/src/Stack/Constants.hs
@@ -29,6 +29,7 @@ module Stack.Constants
     ,compilerOptionsCabalFlag
     ,ghcColorForceFlag
     ,minTerminalWidth
+    ,maxTerminalWidth
     ,defaultTerminalWidth
     )
     where
@@ -222,5 +223,8 @@ ghcColorForceFlag = "-fdiagnostics-color=always"
 minTerminalWidth :: Int
 minTerminalWidth = 20
 
+maxTerminalWidth :: Int
+maxTerminalWidth = 200
+
 defaultTerminalWidth :: Int
 defaultTerminalWidth = 100
diff --git a/src/Stack/Types/Runner.hs b/src/Stack/Types/Runner.hs
index 9f39452500..7fefff1f1c 100644
--- a/src/Stack/Types/Runner.hs
+++ b/src/Stack/Types/Runner.hs
@@ -255,9 +255,9 @@ withRunner logLevel useTime terminal colorWhen widthOverride reExec inner = do
     ColorNever -> return False
     ColorAlways -> return True
     ColorAuto -> liftIO $ hSupportsANSI stderr
-  termWidth <- case widthOverride >>= checkWidth of
-      Nothing -> fromMaybe defaultTerminalWidth <$> liftIO getTerminalWidth
-      Just w -> return w
+  termWidth <- clipWidth <$> maybe (fromMaybe defaultTerminalWidth
+                                    <$> liftIO getTerminalWidth)
+                                   pure widthOverride
   canUseUnicode <- liftIO getCanUseUnicode
   withSticky terminal $ \sticky -> inner Runner
     { runnerReExec = reExec
@@ -272,9 +272,10 @@ withRunner logLevel useTime terminal colorWhen widthOverride reExec inner = do
     , runnerTerminal = terminal
     , runnerSticky = sticky
     }
-  where checkWidth w
-          | w < minTerminalWidth = Nothing
-          | otherwise = Just w
+  where clipWidth w
+          | w < minTerminalWidth = minTerminalWidth
+          | w > maxTerminalWidth = maxTerminalWidth
+          | otherwise = w
 
 -- | Taken from GHC: determine if we should use Unicode syntax
 getCanUseUnicode :: IO Bool

From cc94e9eca10fef5889ae008af39a38bdf707a953 Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Thu, 31 Aug 2017 00:35:01 -0700
Subject: [PATCH 13/19] use a more reasonable minimum terminal width

---
 src/Stack/Constants.hs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Stack/Constants.hs b/src/Stack/Constants.hs
index 2f9c3b4367..3cfc7cd0bc 100644
--- a/src/Stack/Constants.hs
+++ b/src/Stack/Constants.hs
@@ -221,7 +221,7 @@ ghcColorForceFlag :: String
 ghcColorForceFlag = "-fdiagnostics-color=always"
 
 minTerminalWidth :: Int
-minTerminalWidth = 20
+minTerminalWidth = 40
 
 maxTerminalWidth :: Int
 maxTerminalWidth = 200

From 0f607b3d0c2e7211281e6564bd4613f86c6b332b Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Thu, 31 Aug 2017 02:04:47 -0700
Subject: [PATCH 14/19] fix test compilations due to terminal width

---
 src/test/Stack/ConfigSpec.hs | 2 +-
 src/test/Stack/NixSpec.hs    | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/test/Stack/ConfigSpec.hs b/src/test/Stack/ConfigSpec.hs
index 576c862a03..4d6cd62502 100644
--- a/src/test/Stack/ConfigSpec.hs
+++ b/src/test/Stack/ConfigSpec.hs
@@ -76,7 +76,7 @@ spec = beforeAll setup $ do
 
   describe "loadConfig" $ do
     let loadConfig' inner =
-          withRunner logLevel True False ColorAuto False $ \runner -> do
+          withRunner logLevel True False ColorAuto Nothing False $ \runner -> do
             lc <- runRIO runner $ loadConfig mempty Nothing SYLDefault
             inner lc
     -- TODO(danburton): make sure parent dirs also don't have config file
diff --git a/src/test/Stack/NixSpec.hs b/src/test/Stack/NixSpec.hs
index 410cfb4b79..870ca9e3be 100644
--- a/src/test/Stack/NixSpec.hs
+++ b/src/test/Stack/NixSpec.hs
@@ -46,7 +46,7 @@ setup = unsetEnv "STACK_YAML"
 spec :: Spec
 spec = beforeAll setup $ do
   let loadConfig' cmdLineArgs =
-        withRunner LevelDebug True False ColorAuto False $ \runner ->
+        withRunner LevelDebug True False ColorAuto Nothing False $ \runner ->
         runRIO runner $ loadConfig cmdLineArgs Nothing SYLDefault
       inTempDir test = do
         currentDirectory <- getCurrentDirectory

From baf9a6ba09cdb3351a77ccc80f43bc7c94ebd9c2 Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Thu, 31 Aug 2017 11:02:27 -0700
Subject: [PATCH 15/19] pin hsc2hs as an extra-dep

Hopefully this will get it built automatically on appveyor when
we need it.
---
 stack.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/stack.yaml b/stack.yaml
index 42e341e260..edbb2335dd 100644
--- a/stack.yaml
+++ b/stack.yaml
@@ -24,3 +24,4 @@ extra-deps:
 - path-io-1.3.3
 - extra-1.6
 - monad-logger-0.3.25
+- hsc2hs-0.68.2

From 1d5a7bc2daec55ef3151ff34392b56d4c460c47d Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Thu, 31 Aug 2017 11:30:30 -0700
Subject: [PATCH 16/19] manually force appveyor to install hsc2hs first

---
 appveyor.yml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/appveyor.yml b/appveyor.yml
index ed2d3fd4b3..2a4c76852e 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -20,4 +20,5 @@ test_script:
 - stack setup > nul
 # The ugly echo "" hack is to avoid complaints about 0 being an invalid file
 # descriptor
+- stack install hsc2hs
 - echo "" | stack --no-terminal test --jobs 1

From 43cd310a8b87bcd9e7a6b29b8ed470865046b387 Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Thu, 31 Aug 2017 13:39:34 -0700
Subject: [PATCH 17/19] stop trying to use hsc2hs on windows

We're not actually using it on windows anyway, and it's causing
problems on appveyor.
---
 appveyor.yml              | 1 -
 src/Stack/Types/Runner.hs | 5 +++++
 src/System/Terminal.hsc   | 9 ---------
 stack.cabal               | 4 ++--
 4 files changed, 7 insertions(+), 12 deletions(-)

diff --git a/appveyor.yml b/appveyor.yml
index 2a4c76852e..ed2d3fd4b3 100644
--- a/appveyor.yml
+++ b/appveyor.yml
@@ -20,5 +20,4 @@ test_script:
 - stack setup > nul
 # The ugly echo "" hack is to avoid complaints about 0 being an invalid file
 # descriptor
-- stack install hsc2hs
 - echo "" | stack --no-terminal test --jobs 1
diff --git a/src/Stack/Types/Runner.hs b/src/Stack/Types/Runner.hs
index 7fefff1f1c..2bb74639f0 100644
--- a/src/Stack/Types/Runner.hs
+++ b/src/Stack/Types/Runner.hs
@@ -46,7 +46,9 @@ import           System.Console.ANSI
 import           System.FilePath
 import           System.IO
 import           System.Log.FastLogger
+#ifndef WINDOWS
 import           System.Terminal
+#endif
 
 -- | Monadic environment.
 data Runner = Runner
@@ -276,6 +278,9 @@ withRunner logLevel useTime terminal colorWhen widthOverride reExec inner = do
           | w < minTerminalWidth = minTerminalWidth
           | w > maxTerminalWidth = maxTerminalWidth
           | otherwise = w
+#ifdef WINDOWS
+        getTerminalWidth = pure Nothing
+#endif
 
 -- | Taken from GHC: determine if we should use Unicode syntax
 getCanUseUnicode :: IO Bool
diff --git a/src/System/Terminal.hsc b/src/System/Terminal.hsc
index b6ed5f4d76..3ca408d91c 100644
--- a/src/System/Terminal.hsc
+++ b/src/System/Terminal.hsc
@@ -1,13 +1,9 @@
-{-# LANGUAGE CPP #-}
-#ifndef WINDOWS
 {-# LANGUAGE ForeignFunctionInterface #-}
-#endif
 
 module System.Terminal
 ( getTerminalWidth
 ) where
 
-#ifndef WINDOWS
 import           Foreign
 import           Foreign.C.Types
 
@@ -26,11 +22,9 @@ instance Storable WindowWidth where
 
 foreign import ccall "sys/ioctl.h ioctl"
   ioctl :: CInt -> CInt -> Ptr WindowWidth -> IO CInt
-#endif
 
 -- | Get the width, in columns, of the terminal if we can.
 getTerminalWidth :: IO (Maybe Int)
-#ifndef WINDOWS
 getTerminalWidth =
   alloca $ \p -> do
     errno <- ioctl (#const STDOUT_FILENO) (#const TIOCGWINSZ) p
@@ -39,6 +33,3 @@ getTerminalWidth =
       else do
         WindowWidth w <- peek p
         return . Just . fromIntegral $ w
-#else
-getTerminalWidth = pure Nothing
-#endif
diff --git a/stack.cabal b/stack.cabal
index 22fddf593e..418be1b9fb 100644
--- a/stack.cabal
+++ b/stack.cabal
@@ -187,7 +187,6 @@ library
                      System.Process.PagerEditor
                      System.Process.Read
                      System.Process.Run
-                     System.Terminal
   other-modules:     Hackage.Security.Client.Repository.HttpLib.HttpClient
   build-depends:     Cabal >= 2.0 && < 2.1
                    , aeson (>= 1.0 && < 1.2)
@@ -268,7 +267,6 @@ library
                    , store-core >= 0.4 && < 0.5
                    , annotated-wl-pprint
                    , file-embed >= 0.0.10
-  build-tools:       hsc2hs >= 0.68
   if os(windows)
     cpp-options:     -DWINDOWS
     build-depends:   Win32
@@ -276,6 +274,8 @@ library
     build-depends:   unix >= 2.7.0.1
                    , pid1 >= 0.1 && < 0.2
                    , bindings-uname >= 0.1
+    build-tools:     hsc2hs >= 0.68
+    exposed-modules: System.Terminal
   default-language:  Haskell2010
 
 executable stack

From c8c4f9499dab470041c55d6837f94a8e92b4f0fd Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Thu, 31 Aug 2017 14:17:53 -0700
Subject: [PATCH 18/19] document some constants

---
 src/Stack/Constants.hs | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/src/Stack/Constants.hs b/src/Stack/Constants.hs
index 3cfc7cd0bc..eb14e1477a 100644
--- a/src/Stack/Constants.hs
+++ b/src/Stack/Constants.hs
@@ -217,14 +217,20 @@ compilerOptionsCabalFlag :: WhichCompiler -> String
 compilerOptionsCabalFlag Ghc = "--ghc-options"
 compilerOptionsCabalFlag Ghcjs = "--ghcjs-options"
 
+-- | The flag to pass to GHC when we want to force its output to be
+-- colorized.
 ghcColorForceFlag :: String
 ghcColorForceFlag = "-fdiagnostics-color=always"
 
+-- | The minimum allowed terminal width. Used for pretty-printing.
 minTerminalWidth :: Int
 minTerminalWidth = 40
 
+-- | The maximum allowed terminal width. Used for pretty-printing.
 maxTerminalWidth :: Int
 maxTerminalWidth = 200
 
+-- | The default terminal width. Used for pretty-printing when we can't
+-- automatically detect it and when the user doesn't supply one.
 defaultTerminalWidth :: Int
 defaultTerminalWidth = 100

From e4ba9d986ee415186deeeed2c0073bfc183b7ebb Mon Sep 17 00:00:00 2001
From: Joshua Simmons <joshua.simmons@emptypath.com>
Date: Thu, 31 Aug 2017 14:42:52 -0700
Subject: [PATCH 19/19] add term-width changes to the changelog

---
 ChangeLog.md | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/ChangeLog.md b/ChangeLog.md
index 0ba781cda0..d0541843fa 100644
--- a/ChangeLog.md
+++ b/ChangeLog.md
@@ -39,6 +39,12 @@ Behavior changes:
 * Addition of `stack build --copy-compiler-tool`, to allow tools like
   intero to be installed globally for a particular compiler.
   [#2643](https://github.com/commercialhaskell/stack/issues/2643)
+* Stack will now try to detect the width of the running terminal
+  (only on POSIX for the moment) and use that to better display
+  output messages. Work is ongoing, so some messages will not
+  be optimal yet. The terminal width can be overriden with the
+  new `--terminal-width` command-line option (this works even on
+  non-POSIX).
 
 Other enhancements: