Use `open-browser` for proper `haddock --open` on Windows

cabal-install/cabal-install.cabal

@@ -238,6 +238,7 @@ library
         hackage-security >= 0.6.2.0 && < 0.7,
         text       >= 1.2.3    && < 1.3 || >= 2.0 && < 2.2,
         parsec     >= 3.1.13.0 && < 3.2,
+        open-browser >= 0.2.1.0 && < 0.3,
         regex-base  >= 0.94.0.0 && <0.95,
         regex-posix >= 0.96.0.0 && <0.97,
         safe-exceptions >= 0.1.7.0 && < 0.2,

cabal-install/src/Distribution/Client/ProjectBuilding/UnpackedPackage.hs

@@ -2,6 +2,7 @@
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE RecordWildCards #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 
 -- | This module exposes functions to build and register unpacked packages.
 --
@@ -58,7 +59,6 @@ import Distribution.Client.Types hiding
   )
 import Distribution.Client.Utils
   ( ProgressPhase (..)
-  , findOpenProgramLocation
   , progressMessage
   )
 
@@ -85,6 +85,7 @@ import Distribution.Types.BuildType
 import Distribution.Types.PackageDescription.Lens (componentModules)
 
 import Distribution.Simple.Utils
+import Distribution.System (Platform (..))
 import Distribution.Version
 
 import qualified Data.ByteString as BS
@@ -92,12 +93,14 @@ import qualified Data.ByteString.Lazy as LBS
 import qualified Data.ByteString.Lazy.Char8 as LBS.Char8
 import qualified Data.List.NonEmpty as NE
 
-import Control.Exception (Handler (..), SomeAsyncException, assert, catches)
+import Control.Exception (ErrorCall, Handler (..), SomeAsyncException, assert, catches)
 import System.Directory (canonicalizePath, createDirectoryIfMissing, doesDirectoryExist, doesFileExist, removeFile)
 import System.FilePath (dropDrive, normalise, takeDirectory, (<.>), (</>))
 import System.IO (Handle, IOMode (AppendMode), withFile)
 import System.Semaphore (SemaphoreName (..))
 
+import Web.Browser (openBrowser)
+
 import Distribution.Client.Errors
 import Distribution.Compat.Directory (listDirectory)
 
@@ -420,7 +423,7 @@ buildInplaceUnpackedPackage
   buildSettings@BuildTimeSettings{buildSettingHaddockOpen}
   registerLock
   cacheLock
-  pkgshared@ElaboratedSharedConfig{pkgConfigPlatform = platform}
+  pkgshared@ElaboratedSharedConfig{pkgConfigPlatform = Platform _ os}
   plan
   rpkg@(ReadyPackage pkg)
   buildStatus
@@ -527,10 +530,13 @@ buildInplaceUnpackedPackage
                 docDir = case distHaddockOutputDir of
                   Nothing -> distBuildDirectory distDirLayout dparams </> "doc" </> "html" </> name
                   Just dir -> dir
-            exe <- findOpenProgramLocation platform
-            case exe of
-              Right open -> runProgramInvocation verbosity (simpleProgramInvocation open [dest])
-              Left err -> dieWithException verbosity $ FindOpenProgramLocationErr err
+            catch
+              (void $ openBrowser dest)
+              ( \(_ :: ErrorCall) ->
+                  dieWithException verbosity $
+                    FindOpenProgramLocationErr $
+                      "Unsupported OS: " <> show os
+              )
         PBInstallPhase{runCopy = _runCopy, runRegister} -> do
           -- PURPOSELY omitted: no copy!
 

cabal-install/src/Distribution/Client/Utils.hs

@@ -28,7 +28,6 @@ module Distribution.Client.Utils
   , existsAndIsMoreRecentThan
   , tryFindAddSourcePackageDesc
   , tryFindPackageDesc
-  , findOpenProgramLocation
   , relaxEncodingErrors
   , ProgressPhase (..)
   , progressMessage
@@ -69,13 +68,11 @@ import Distribution.Compat.Environment
 import Distribution.Compat.Time (getModTime)
 import Distribution.Simple.Setup (Flag (..))
 import Distribution.Simple.Utils (dieWithException, findPackageDesc, noticeNoWrap)
-import Distribution.System (OS (..), Platform (..))
 import Distribution.Version
 import System.Directory
   ( canonicalizePath
   , doesDirectoryExist
   , doesFileExist
-  , findExecutable
   , getCurrentDirectory
   , getDirectoryContents
   , removeFile
@@ -397,26 +394,6 @@ tryFindPackageDesc verbosity depPath err = do
     Right file -> return file
     Left _ -> dieWithException verbosity $ TryFindPackageDescErr err
 
-findOpenProgramLocation :: Platform -> IO (Either String FilePath)
-findOpenProgramLocation (Platform _ os) =
-  let
-    locate name = do
-      exe <- findExecutable name
-      case exe of
-        Just s -> pure (Right s)
-        Nothing -> pure (Left ("Couldn't find file-opener program `" <> name <> "`"))
-    xdg = locate "xdg-open"
-   in
-    case os of
-      Windows -> pure (Right "start")
-      OSX -> locate "open"
-      Linux -> xdg
-      FreeBSD -> xdg
-      OpenBSD -> xdg
-      NetBSD -> xdg
-      DragonFly -> xdg
-      _ -> pure (Left ("Couldn't determine file-opener program for " <> show os))
-
 -- | Phase of building a dependency. Represents current status of package
 -- dependency processing. See #4040 for details.
 data ProgressPhase