Change manpage command to man

And make it pipe output to `man -l -`.

cabal-install/Distribution/Client/Compat/Process.hs

@@ -35,6 +35,9 @@ import qualified System.Process    as P
 --   exception.  This variant catches \"does not exist\" and
 --   \"permission denied\" exceptions and turns them into
 --   @ExitFailure@s.
+--
+-- TODO: this doesn't use 'Distrubution.Compat.Process'.
+--
 readProcessWithExitCode :: FilePath -> [String] -> String -> IO (ExitCode, String, String)
 readProcessWithExitCode cmd args input =
   P.readProcessWithExitCode cmd args input

cabal-install/Distribution/Client/Manpage.hs

@@ -14,23 +14,65 @@
 module Distribution.Client.Manpage
   ( -- * Manual page generation
     manpage
+  , manpageCmd
+  , ManpageFlags
+  , defaultManpageFlags
+  , manpageOptions
   ) where
 
+import Distribution.Client.Compat.Prelude
+import Prelude ()
+
+import Distribution.Client.ManpageFlags
+import Distribution.Client.Setup        (globalCommand)
+import Distribution.Compat.Process      (createProcess)
 import Distribution.Simple.Command
-import Distribution.Client.Setup (globalCommand)
+import Distribution.Simple.Flag         (fromFlagOrDefault)
+import System.Exit                      (exitWith)
+import System.IO                        (hClose, hPutStr)
 
-import Data.Char (toUpper)
-import Data.List (intercalate)
+import qualified System.Process as Process
 
 data FileInfo = FileInfo String String -- ^ path, description
 
+-------------------------------------------------------------------------------
+--
+-------------------------------------------------------------------------------
+
 -- | A list of files that should be documented in the manual page.
 files :: [FileInfo]
 files =
   [ (FileInfo "~/.cabal/config" "The defaults that can be overridden with command-line options.")
   , (FileInfo "~/.cabal/world"  "A list of all packages whose installation has been explicitly requested.")
   ]
 
+manpageCmd :: String -> [CommandSpec a] -> ManpageFlags -> IO ()
+manpageCmd pname commands flags
+    | fromFlagOrDefault False (manpageRaw flags)
+    = putStrLn contents
+    | otherwise
+    = do
+        let cmd  = "man"
+            args = ["-l", "-"]
+
+        (mb_in, _, _, ph) <- createProcess (Process.proc cmd args)
+            { Process.std_in  = Process.CreatePipe
+            , Process.std_out = Process.Inherit
+            , Process.std_err = Process.Inherit
+            }
+
+        -- put contents
+        for_ mb_in $ \hin -> do
+            hPutStr hin contents
+            hClose hin
+
+        -- wait for process to exit, propagate exit code
+        ec <- Process.waitForProcess ph
+        exitWith ec
+  where
+    contents :: String
+    contents = manpage pname commands
+
 -- | Produces a manual page with @troff@ markup.
 manpage :: String -> [CommandSpec a] -> String
 manpage pname commands = unlines $

cabal-install/Distribution/Client/ManpageFlags.hs

@@ -0,0 +1,40 @@
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE LambdaCase    #-}
+module Distribution.Client.ManpageFlags
+( ManpageFlags (..)
+, defaultManpageFlags
+, manpageOptions,
+) where
+
+import Distribution.Client.Compat.Prelude
+
+import Distribution.Simple.Command (OptionField (..), ShowOrParseArgs (..), option)
+import Distribution.Simple.Setup   (Flag (..), toFlag, trueArg, optionVerbosity)
+import Distribution.Verbosity      (Verbosity, normal)
+
+data ManpageFlags = ManpageFlags
+  { manpageVerbosity :: Flag Verbosity
+  , manpageRaw       :: Flag Bool
+  } deriving (Eq, Show, Generic)
+
+instance Monoid ManpageFlags  where
+  mempty = gmempty
+  mappend = (<>)
+
+instance Semigroup ManpageFlags where
+  (<>) = gmappend
+
+defaultManpageFlags :: ManpageFlags
+defaultManpageFlags = ManpageFlags
+    { manpageVerbosity = toFlag normal
+    , manpageRaw       = toFlag False
+    }
+
+manpageOptions :: ShowOrParseArgs -> [OptionField ManpageFlags]
+manpageOptions _ =
+    [ optionVerbosity manpageVerbosity (\v flags -> flags { manpageVerbosity = v })
+    , option "" ["raw"]
+      "Output raw troff content"
+      manpageRaw (\v flags -> flags { manpageRaw = v })
+      trueArg
+    ]

cabal-install/Distribution/Client/Setup.hs

@@ -144,6 +144,7 @@ import Distribution.Client.GlobalFlags
          ( GlobalFlags(..), defaultGlobalFlags
          , RepoContext(..), withRepoContext
          )
+import Distribution.Client.ManpageFlags (ManpageFlags, defaultManpageFlags, manpageOptions)
 
 import Data.List
          ( deleteFirstsBy )
@@ -1435,16 +1436,16 @@ uninstallCommand = CommandUI {
     commandOptions      = \_ -> []
   }
 
-manpageCommand :: CommandUI (Flag Verbosity)
+manpageCommand :: CommandUI ManpageFlags
 manpageCommand = CommandUI {
-    commandName         = "manpage",
+    commandName         = "man",
     commandSynopsis     = "Outputs manpage source.",
     commandDescription  = Just $ \_ ->
       "Output manpage source to STDOUT.\n",
     commandNotes        = Nothing,
-    commandUsage        = usageFlags "manpage",
-    commandDefaultFlags = toFlag normal,
-    commandOptions      = \_ -> [optionVerbosity id const]
+    commandUsage        = usageFlags "man",
+    commandDefaultFlags = defaultManpageFlags,
+    commandOptions      = manpageOptions
   }
 
 runCommand :: CommandUI (BuildFlags, BuildExFlags)

cabal-install/Setup.hs

@@ -54,7 +54,7 @@ buildManpage lbi verbosity = do
       manpage = buildDir lbi </> "cabal/cabal.1"
   manpageHandle <- openFile manpage WriteMode
   notice verbosity ("Generating manual page " ++ manpage ++ " ...")
-  _ <- runProcess cabal ["manpage"] Nothing Nothing Nothing (Just manpageHandle) Nothing
+  _ <- runProcess cabal ["man","--raw"] Nothing Nothing Nothing (Just manpageHandle) Nothing
   return ()
 
 installManpage :: PackageDescription -> LocalBuildInfo -> Verbosity -> CopyDest -> IO ()

cabal-install/cabal-install.cabal

@@ -218,6 +218,7 @@ executable cabal
         Distribution.Client.JobControl
         Distribution.Client.List
         Distribution.Client.Manpage
+        Distribution.Client.ManpageFlags
         Distribution.Client.Nix
         Distribution.Client.Outdated
         Distribution.Client.PackageHash

cabal-install/cabal-install.cabal.pp

@@ -150,6 +150,7 @@
         Distribution.Client.JobControl
         Distribution.Client.List
         Distribution.Client.Manpage
+        Distribution.Client.ManpageFlags
         Distribution.Client.Nix
         Distribution.Client.Outdated
         Distribution.Client.PackageHash

cabal-install/main/Main.hs

@@ -138,7 +138,8 @@ import Distribution.Client.Sandbox.Types      (UseSandbox(..), whenUsingSandbox)
 import Distribution.Client.Tar                (createTarGzFile)
 import Distribution.Client.Types              (Password (..))
 import Distribution.Client.Init               (initCabal)
-import Distribution.Client.Manpage            (manpage)
+import Distribution.Client.Manpage            (manpageCmd)
+import Distribution.Client.ManpageFlags       (ManpageFlags (..))
 import qualified Distribution.Client.Win32SelfUpgrade as Win32SelfUpgrade
 import Distribution.Client.Utils              (determineNumJobs
                                               ,relaxEncodingErrors
@@ -1244,13 +1245,13 @@ actAsSetupAction actAsSetupFlags args _globalFlags =
     Make      -> Make.defaultMainArgs args
     Custom    -> error "actAsSetupAction Custom"
 
-manpageAction :: [CommandSpec action] -> Flag Verbosity -> [String] -> Action
-manpageAction commands flagVerbosity extraArgs _ = do
-  let verbosity = fromFlag flagVerbosity
+manpageAction :: [CommandSpec action] -> ManpageFlags -> [String] -> Action
+manpageAction commands flags extraArgs _ = do
+  let verbosity = fromFlag (manpageVerbosity flags)
   unless (null extraArgs) $
     die' verbosity $ "'manpage' doesn't take any extra arguments: " ++ unwords extraArgs
   pname <- getProgName
   let cabalCmd = if takeExtension pname == ".exe"
                  then dropExtension pname
                  else pname
-  putStrLn $ manpage cabalCmd commands
+  manpageCmd cabalCmd commands flags

cabal-testsuite/PackageTests/Manpage/cabal.out

@@ -1 +1 @@
-# cabal manpage
+# cabal man

cabal-testsuite/PackageTests/Manpage/cabal.test.hs

@@ -1,5 +1,5 @@
 import Test.Cabal.Prelude
 main = cabalTest $ do
-    r <- cabal' "manpage" []
+    r <- cabal' "man" ["--raw"]
     assertOutputContains ".B cabal install" r
     assertOutputDoesNotContain ".B cabal manpage" r

cabal-testsuite/Test/Cabal/Prelude.hs

@@ -294,7 +294,7 @@ cabalG' global_args cmd args = do
           -- Sandboxes manage dist dir
           | testHaveSandbox env
           = install_args
-          | cmd `elem` ["v1-update", "outdated", "user-config", "manpage", "v1-freeze", "check"]
+          | cmd `elem` ["v1-update", "outdated", "user-config", "man", "v1-freeze", "check"]
           = [ ]
           -- new-build commands are affected by testCabalProjectFile
           | cmd == "v2-sdist" = [ "--project-file", testCabalProjectFile env ]