cabal2nix 2.1.1 → 2.2

raw patch · 10 files changed

+58/−60 lines, 10 filesPVP ok

version bump matches the API change (PVP)

API changes (from Hackage documentation)

Files

• README.md +2/−30
• cabal2nix.cabal +13/−4
• cabal2nix/Main.hs +4/−1
• src/Distribution/Nixpkgs/Fetch.hs +3/−2
• src/Distribution/Nixpkgs/Haskell/Derivation.hs +6/−1
• src/Distribution/Nixpkgs/Haskell/FromCabal.hs +1/−0
• src/Distribution/Nixpkgs/Haskell/FromCabal/License.hs +5/−2
• src/Distribution/Nixpkgs/Haskell/FromCabal/Name.hs +1/−0
• src/Distribution/Nixpkgs/Haskell/FromCabal/PostProcess.hs +16/−13
• src/Distribution/Nixpkgs/Haskell/PackageSourceSpec.hs +7/−7

@@ -10,13 +10,12 @@       pname = "mtl";       version = "2.2.1";       sha256 = "1icdbj2rshzn0m1zz5wa7v3xvkf6qw811p4s7jgqwvx1ydwrvrfa";-      buildDepends = [ base transformers ];+      libraryHaskellDepends = [ base transformers ];       homepage = "http://github.com/ekmett/mtl";       description = "Monad classes, using functional dependencies";       license = stdenv.lib.licenses.bsd3;     } - Cabal files can be referred to using the magic URL `cabal://NAME-VERSION`, which will automatically download the file from Hackage. Alternatively, a direct `http://host/path/pkg.cabal` URL can be provided, as well as a@@ -41,7 +40,7 @@       pname = "mtl";       version = "2.2.1";       src = ./.;-      buildDepends = [ base transformers ];+      libraryHaskellDepends = [ base transformers ];       homepage = "http://github.com/ekmett/mtl";       description = "Monad classes, using functional dependencies";       license = stdenv.lib.licenses.bsd3;@@ -55,30 +54,3 @@ * directory * source archive (zip, tar.gz, ...) from http or https URL or local file. * git, mercurial, svn or bazaar repository--How to compile this package------------------------------The `cabal2nix.cabal` file for this package is automatically generated by the-`generate-cabal-file.hs` program. The easiest way to accomplish that is to run--    nix-shell release.nix -A cabal2nix.ghc7102.x86_64-linux.env --run "runhaskell generate-cabal-file.hs >cabal2nix.cabal"--where `x86_64-linux` should be replaced with whatever system ID is appropriate-for your local machine. Basically, `generate-cabal-file.hs` requires the-[cartel](http://hackage.haskell.org/package/cartel) library and `git` to run.--With the Cabal file in place, this is a normal Haskell project that can be-compiled with `cabal-install`.--Users of Nix can build this package by running--    nix-build release.nix -A cabal2nix.ghc7102.x86_64-linux--where, again, `x86_64-linux` should be replaced with the appropriate value.-This gives you an executable at `result/bin/cabal2nix`. If you'd like to-install the latest release version, then--    nix-env -f "<nixpkgs>" -iA cabal2nix--is the way to go.

@@ -3,7 +3,7 @@ -- see: https://github.com/sol/hpack  name:           cabal2nix-version:        2.1.1+version:        2.2 synopsis:       Convert Cabal files into Nix build instructions. description:    Convert Cabal files into Nix build instructions. Users of Nix can install the latest version by running:                 .@@ -16,39 +16,48 @@                 Andres Loeh,                 Benno Fünfstück,                 Mateusz Kowalczyk,-                Mathijs Kwik,                 Michael Alan Dorman,+                Mathijs Kwik,                 Shea Levy,                 Dmitry Malikov,                 Eric Seidel,+                Hamish Mackenzie,                 Nikolay Amiantov,                 Aycan iRiCAN,+                Bryan Gardiner,+                Joe Hermaszewski,                 John Wiegley,                 Philipp Hausmann,                 Spencer Janssen,+                Tom Hunger,                 William Casarin,+                koral,                 Adam Vogt,-                Bryan Gardiner,+                Alexey Shmalko,                 Corey O'Connor,                 Cray Elliott,                 Felix Kunzmann,                 Gabriel Ebner,                 Gergely Risko,+                Jacob Mitchell,+                Joachim Fasting,                 John Albietz,                 John Chee,                 Jussi Maki,                 Mark Laws,                 Mark Wotton,+                Matthew Stewart,                 Matvey Aksenov,                 Nicolas Rolland,                 Oliver Charles,                 Pascal Wittmann,                 Patrick John Wheeler,+                Profpatsch,                 Raymond Gauthier,                 Renzo Carbonara,+                Rodney Lorrimar,                 Sibi,                 Tanner Doshier,-                Tom Hunger,                 Viktar Basharymau,                 danbst,                 karsten gebbert,

@@ -45,6 +45,7 @@   , optFlags :: [String]   , optCompiler :: CompilerId   , optSystem :: Platform+  , optSubpath :: Maybe FilePath   , optUrl :: String   }   deriving (Show)@@ -68,6 +69,7 @@           <*> many (strOption $ short 'f' <> long "flag" <> help "Cabal flag (may be specified multiple times)")           <*> option (readP parse) (long "compiler" <> help "compiler to use when evaluating the Cabal file" <> value buildCompilerId <> showDefaultWith display)           <*> option (readP parsePlatform) (long "system" <> help "target system to use when evaluating the Cabal file" <> value buildPlatform <> showDefaultWith display)+          <*> optional (strOption $ long "subpath" <> metavar "PATH" <> help "Path to Cabal file's directory relative to the URI (default is root directory)")           <*> strArgument (metavar "URI")  readP :: P.ReadP a a -> ReadM a@@ -112,7 +114,7 @@ main = bracket (return ()) (\() -> hFlush stdout >> hFlush stderr) $ \() -> do   Options {..} <- execParser pinfo -  pkg <- getPackage optHackageDb $ Source optUrl (fromMaybe "" optRevision) (maybe UnknownHash Guess optSha256)+  pkg <- getPackage optHackageDb $ Source optUrl (fromMaybe "" optRevision) (maybe UnknownHash Guess optSha256) (fromMaybe "." optSubpath)    let       deriv :: Derivation@@ -124,6 +126,7 @@                                             []                                             (pkgCabal pkg)               & src .~ pkgSource pkg+              & subpath .~ (fromMaybe "." optSubpath)               & runHaddock .~ optHaddock               & jailbreak .~ optJailbreak               & hyperlinkSource .~ optHyperlinkSource

@@ -31,6 +31,7 @@   , sourceRevision  :: String       -- ^ Revision to use. For protocols where this doesn't make sense (such as HTTP), this                                     --   should be the empty string.   , sourceHash      :: Hash         -- ^ The expected hash of the source, if available.+  , sourceCabalDir  :: String       -- ^ Directory where Cabal file is found.   } deriving (Show, Eq, Ord, Generic)  instance NFData Source@@ -68,7 +69,7 @@   parseJSON _ = error "invalid DerivationSource"  fromDerivationSource :: DerivationSource -> Source-fromDerivationSource DerivationSource{..} = Source derivUrl derivRevision $ Certain derivHash+fromDerivationSource DerivationSource{..} = Source derivUrl derivRevision (Certain derivHash) "."  -- | Fetch a source, trying any of the various nix-prefetch-* scripts. fetch :: forall a. (String -> MaybeT IO a)      -- ^ This function is passed the output path name as an argument.@@ -104,7 +105,7 @@   localArchive :: FilePath -> MaybeT IO (DerivationSource, a)   localArchive path = do     absolutePath <- liftIO $ canonicalizePath path-    unpacked <- snd <$> fetchWith (False, "zip", []) (Source ("file://" ++ absolutePath) "" UnknownHash)+    unpacked <- snd <$> fetchWith (False, "zip", []) (Source ("file://" ++ absolutePath) "" UnknownHash ".")     process (DerivationSource "" absolutePath "" "", unpacked)    process :: (DerivationSource, FilePath) -> MaybeT IO (DerivationSource, a)

@@ -4,7 +4,7 @@ {-# LANGUAGE FlexibleInstances, MultiParamTypeClasses #-}  module Distribution.Nixpkgs.Haskell.Derivation-  ( Derivation, nullDerivation, pkgid, revision, src, isLibrary, isExecutable+  ( Derivation, nullDerivation, pkgid, revision, src, subpath, isLibrary, isExecutable   , extraFunctionArgs, libraryDepends, executableDepends, testDepends, configureFlags   , cabalFlags, runHaddock, jailbreak, doCheck, testTarget, hyperlinkSource, enableSplitObjs   , enableLibraryProfiling, enableExecutableProfiling, phaseOverrides, editedCabalFile, metaSection@@ -36,6 +36,7 @@   { _pkgid                      :: PackageIdentifier   , _revision                   :: Int   , _src                        :: DerivationSource+  , _subpath                    :: FilePath   , _isLibrary                  :: Bool   , _isExecutable               :: Bool   , _extraFunctionArgs          :: Set Binding@@ -65,6 +66,7 @@   { _pkgid = error "undefined Derivation.pkgid"   , _revision = error "undefined Derivation.revision"   , _src = error "undefined Derivation.src"+  , _subpath = error "undefined Derivation.subpath"   , _isLibrary = error "undefined Derivation.isLibrary"   , _isExecutable = error "undefined Derivation.isExecutable"   , _extraFunctionArgs = error "undefined Derivation.extraFunctionArgs"@@ -104,6 +106,7 @@       [ attr "pname"   $ doubleQuotes $ disp (packageName _pkgid)       , attr "version" $ doubleQuotes $ disp (packageVersion _pkgid)       , sourceAttr _src+      , onlyIf (_subpath /= ".") $ attr "postUnpack" postUnpack       , onlyIf (_revision > 0) $ attr "revision" $ doubleQuotes $ int _revision       , onlyIf (not (null _editedCabalFile) && _revision > 0) $ attr "editedCabalFile" $ string _editedCabalFile       , listattr "configureFlags" empty (map (show . show) renderedFlags)@@ -149,3 +152,5 @@            , rbrace <> semi            ]         | otherwise = attr "src" $ text derivUrl++      postUnpack = string $ "sourceRoot+=/" ++ _subpath ++ "; echo source root reset to $sourceRoot"

@@ -103,6 +103,7 @@       | i `elem` ["clang","lldb","llvm"] = binding # (i, path # ["self","llvmPackages",i])     -- TODO: evil!       | i == "gtk2"                      = binding # (i, path # ["pkgs","gnome2","gtk"])       | i == "gtk3"                      = binding # (i, path # ["pkgs","gnome3","gtk"])+      | i == "gtksourceview3"            = binding # (i, path # ["pkgs","gnome3","gtksourceview"])       | Just p <- nixpkgsResolver i, init (view (reference . path) p) `Set.member` goodScopes = p       | otherwise                        = bindNull i 

@@ -1,7 +1,9 @@ module Distribution.Nixpkgs.Haskell.FromCabal.License ( fromCabalLicense ) where  import Distribution.Nixpkgs.License-import Distribution.License ( License(..) )+import Distribution.License ( License(..), knownLicenses )+import Distribution.Text (display)+import Data.List (intercalate) import Data.Version  -- TODO: Programatically strip trailing zeros from license version numbers.@@ -31,4 +33,5 @@ fromCabalLicense (Apache (Just (Version [2,0] [])))     = Known "stdenv.lib.licenses.asl20" fromCabalLicense ISC                                    = Known "stdenv.lib.licenses.isc" fromCabalLicense OtherLicense                           = Unknown Nothing-fromCabalLicense l                                      = error $ "Distribution.Nixpkgs.Haskell.FromCabal.License.fromCabalLicense: unknown license " ++ show l+fromCabalLicense l                                      = error $ "Distribution.Nixpkgs.Haskell.FromCabal.License.fromCabalLicense: unknown license"+                                                            ++ show l ++"\nChoose one of: " ++ intercalate ", " (map display knownLicenses)

@@ -70,6 +70,7 @@ libNixName "gtk+-2.0"                           = return "gtk2" libNixName "gtk+-3.0"                           = return "gtk3" libNixName "gtk-x11-2.0"                        = return "gtk_x11"+libNixName "gtksourceview-3.0"                  = return "gtksourceview3" libNixName "hidapi-libusb"                      = return "hidapi" libNixName "icudata"                            = return "icu" libNixName "icui18n"                            = return "icu"

@@ -38,11 +38,13 @@   , ("Agda >= 2.5", set (executableDepends . tool . contains (pkg "emacs")) True . set phaseOverrides agda25PostInstall)   , ("alex < 3.1.5",  set (testDepends . tool . contains (pkg "perl")) True)   , ("alex",  set (executableDepends . tool . contains (bind "self.happy")) True)+  , ("alsa-core", over (metaSection . platforms) (Set.filter (\(Platform _ os) -> os == Linux)))                                                                                                      , ("bustle", set (libraryDepends . pkgconfig . contains "system-glib = pkgs.glib") True)   , ("bindings-GLFW", over (libraryDepends . system) (Set.union (Set.fromList [bind "pkgs.xorg.libXext", bind "pkgs.xorg.libXfixes"])))+  , ("bindings-lxc", over (metaSection . platforms) (Set.filter (\(Platform _ os) -> os == Linux)))                                                                                                      , ("bustle", set (libraryDepends . pkgconfig . contains "system-glib = pkgs.glib") True)   , ("bustle", set (libraryDepends . pkgconfig . contains "system-glib = pkgs.glib") True)-  , ("Cabal", set doCheck False) -- test suite doesn't work in Nix   , ("cabal-helper", set doCheck False) -- https://github.com/DanielG/cabal-helper/issues/17   , ("cabal-install", set doCheck False . set phaseOverrides cabalInstallPostInstall)+  , ("Cabal", set doCheck False) -- test suite doesn't work in Nix   , ("darcs", set phaseOverrides darcsInstallPostInstall . set doCheck False)   , ("dbus", set doCheck False) -- don't execute tests that try to access the network   , ("dns", set testTarget "spec")      -- don't execute tests that try to access the network@@ -50,40 +52,40 @@   , ("freenect < 1.2.1", over configureFlags (Set.union (Set.fromList ["--extra-include-dirs=${pkgs.freenect}/include/libfreenect", "--extra-lib-dirs=${pkgs.freenect}/lib"])))   , ("gf", set phaseOverrides gfPhaseOverrides . set doCheck False)   , ("gi-cairo", giCairoPhaseOverrides)                     -- https://github.com/haskell-gi/haskell-gi/issues/36-  , ("gi-gst", giGstLibOverrides "gstreamer")               -- https://github.com/haskell-gi/haskell-gi/issues/36   , ("gi-gstaudio", giGstLibOverrides "gst-plugins-base")   -- https://github.com/haskell-gi/haskell-gi/issues/36   , ("gi-gstbase", giGstLibOverrides "gst-plugins-base")    -- https://github.com/haskell-gi/haskell-gi/issues/36+  , ("gi-gst", giGstLibOverrides "gstreamer")               -- https://github.com/haskell-gi/haskell-gi/issues/36   , ("gi-gstvideo", giGstLibOverrides "gst-plugins-base")   -- https://github.com/haskell-gi/haskell-gi/issues/36   , ("gi-javascriptcore < 4.0.0.0", webkitgtk24xHook)       -- https://github.com/haskell-gi/haskell-gi/issues/36-  , ("gi-pango", giCairoPhaseOverrides)                     -- https://github.com/haskell-gi/haskell-gi/issues/36-  , ("gi-pangocairo", giCairoPhaseOverrides)                     -- https://github.com/haskell-gi/haskell-gi/issues/36-  , ("gi-webkit", webkitgtk24xHook)   -- https://github.com/haskell-gi/haskell-gi/issues/36   , ("gio", set (libraryDepends . pkgconfig . contains "system-glib = pkgs.glib") True)-  , ("git", set doCheck False)          -- https://github.com/vincenthz/hit/issues/33+  , ("gi-pangocairo", giCairoPhaseOverrides)                     -- https://github.com/haskell-gi/haskell-gi/issues/36+  , ("gi-pango", giCairoPhaseOverrides)                     -- https://github.com/haskell-gi/haskell-gi/issues/36   , ("git-annex", gitAnnexHook)   , ("github-backup", set (executableDepends . tool . contains (pkg "git")) True)+  , ("git", set doCheck False)          -- https://github.com/vincenthz/hit/issues/33+  , ("gi-webkit", webkitgtk24xHook)   -- https://github.com/haskell-gi/haskell-gi/issues/36   , ("GlomeVec", set (libraryDepends . pkgconfig . contains (bind "self.llvmPackages.llvm")) True)   , ("goatee-gtk", over (metaSection . platforms) (Set.filter (\(Platform _ os) -> os /= OSX)))   , ("gtk3", gtk3Hook)   , ("haddock", haddockHook) -- https://github.com/haskell/haddock/issues/511   , ("hakyll", set (testDepends . tool . contains (pkg "utillinux")) True) -- test suite depends on "rev"   , ("haskell-src-exts", set doCheck False)-  , ("HFuse", set phaseOverrides hfusePreConfigure)   , ("hfsevents", hfseventsOverrides)+  , ("HFuse", set phaseOverrides hfusePreConfigure)   , ("hlibgit2 >= 0.18.0.14", set (testDepends . tool . contains (pkg "git")) True)   , ("hmatrix", set phaseOverrides "preConfigure = \"sed -i hmatrix.cabal -e 's@/usr/@/dont/hardcode/paths/@'\";")   , ("holy-project", set doCheck False)         -- attempts to access the network   , ("hoogle", set testTarget "--test-option=--no-net")   , ("hsignal < 0.2.7.4", set phaseOverrides "prePatch = \"rm -v Setup.lhs\";") -- https://github.com/amcphail/hsignal/issues/1   , ("hslua", over (libraryDepends . each) (replace (pkg "lua") (pkg "lua5_1")))-  , ("http-client", set doCheck False)          -- attempts to access the network   , ("http-client-openssl >= 0.2.0.1", set doCheck False) -- attempts to access the network+  , ("http-client", set doCheck False)          -- attempts to access the network   , ("http-client-tls >= 0.2.2", set doCheck False) -- attempts to access the network   , ("http-conduit", set doCheck False)         -- attempts to access the network   , ("imagemagick", set (libraryDepends . pkgconfig . contains (pkg "imagemagick")) True) -- https://github.com/NixOS/cabal2nix/issues/136   , ("include-file <= 0.1.0.2", set (libraryDepends . haskell . contains (bind "self.random")) True) -- https://github.com/Daniel-Diaz/include-file/issues/1-  , ("js-jquery", set doCheck False)            -- attempts to access the network   , ("jsaddle", set (dependencies . haskell . contains (bind "self.ghcjs-base")) False)+  , ("js-jquery", set doCheck False)            -- attempts to access the network   , ("libconfig", over (libraryDepends . system) (replace "config = null" (pkg "libconfig")))   , ("liquid-fixpoint", set (executableDepends . system . contains (pkg "ocaml")) True . set (testDepends . system . contains (pkg "z3")) True)   , ("liquidhaskell", set (testDepends . system . contains (pkg "z3")) True)@@ -92,11 +94,11 @@   , ("mysql", set (libraryDepends . system . contains (pkg "mysql")) True)   , ("network-attoparsec", set doCheck False) -- test suite requires network access   , ("numeric-qq", set doCheck False) -- test suite doesn't finish even after 1+ days-  , ("pandoc", set jailbreak False) -- jailbreak-cabal break the build+  , ("opencv", set phaseOverrides "hardeningDisable = [ \"bindnow\" ];")   , ("pandoc >= 1.16.0.2", set doCheck False) -- https://github.com/jgm/pandoc/issues/2709 and https://github.com/fpco/stackage/issues/1332   , ("pandoc-citeproc", set doCheck False) -- https://github.com/jgm/pandoc-citeproc/issues/172+  , ("pandoc", set jailbreak False) -- jailbreak-cabal break the build   , ("purescript", set doCheck False) -- test suite doesn't cope with Nix build env-  , ("opencv", set phaseOverrides "hardeningDisable = [ \"bindnow\" ];")   , ("qtah-cpp-qt5", set (libraryDepends . system . contains (bind "pkgs.qt5.qtbase")) True)   , ("qtah-qt5", set (libraryDepends . tool . contains (bind "pkgs.qt5.qtbase")) True)   , ("readline", over (libraryDepends . system) (Set.union (pkgs ["readline", "ncurses"])))@@ -112,13 +114,14 @@   , ("thyme", set (libraryDepends . tool . contains (bind "self.cpphs")) True) -- required on Darwin   , ("twilio", set doCheck False)         -- attempts to access the network   , ("tz", set phaseOverrides "preConfigure = \"export TZDIR=${pkgs.tzdata}/share/zoneinfo\";")-  , ("webkitgtk3", webkitgtk24xHook)   -- https://github.com/haskell-gi/haskell-gi/issues/36+  , ("udev", over (metaSection . platforms) (Set.filter (\(Platform _ os) -> os == Linux)))                                                                                                      , ("bustle", set (libraryDepends . pkgconfig . contains "system-glib = pkgs.glib") True)   , ("webkitgtk3-javascriptcore", webkitgtk24xHook)   -- https://github.com/haskell-gi/haskell-gi/issues/36+  , ("webkitgtk3", webkitgtk24xHook)   -- https://github.com/haskell-gi/haskell-gi/issues/36   , ("websockets", set doCheck False)   -- https://github.com/jaspervdj/websockets/issues/104   , ("Win32", over (metaSection . platforms) (Set.filter (\(Platform _ os) -> os == Windows)))   , ("Win32-shortcut", over (metaSection . platforms) (Set.filter (\(Platform _ os) -> os == Windows)))-  , ("wxc", wxcHook)   , ("wxcore", set (libraryDepends . pkgconfig . contains (pkg "wxGTK")) True)+  , ("wxc", wxcHook)   , ("X11", over (libraryDepends . system) (Set.union (Set.fromList $ map bind ["pkgs.xorg.libXinerama","pkgs.xorg.libXext","pkgs.xorg.libXrender"])))   , ("xmonad", set phaseOverrides xmonadPostInstall)   , ("zip-archive", over (testDepends . tool) (replace (bind "self.zip") (pkg "zip")))

@@ -32,18 +32,18 @@ getPackage :: Maybe String -> Source -> IO Package getPackage optHackageDB source = do   (derivSource, pkgDesc) <- fetchOrFromDB optHackageDB source-  flip Package pkgDesc <$> maybe (sourceFromHackage (sourceHash source) $ showPackageIdentifier pkgDesc) return derivSource+  flip Package pkgDesc <$> maybe (sourceFromHackage (sourceHash source) (showPackageIdentifier pkgDesc) $ sourceCabalDir source) return derivSource   fetchOrFromDB :: Maybe String -> Source -> IO (Maybe DerivationSource, Cabal.GenericPackageDescription) fetchOrFromDB optHackageDB src   | "cabal://" `isPrefixOf` sourceUrl src = fmap ((,) Nothing) . fromDB optHackageDB . drop (length "cabal://") $ sourceUrl src   | otherwise                             = do-    r <- fetch cabalFromPath src+    r <- fetch (\dir -> cabalFromPath (dir </> sourceCabalDir src)) src     case r of       Nothing ->         hPutStrLn stderr "*** failed to fetch source. Does the URL exist?" >> exitFailure-      Just (derivSource, (externalSource, pkgDesc)) ->+      Just (derivSource, (externalSource, pkgDesc)) -> do         return (derivSource <$ guard externalSource, pkgDesc)  fromDB :: Maybe String -> String -> IO Cabal.GenericPackageDescription@@ -77,8 +77,8 @@   createDirectoryIfMissing True cacheDir   return $ cacheDir </> pid <.> "sha256" -sourceFromHackage :: Hash -> String -> IO DerivationSource-sourceFromHackage optHash pkgId = do+sourceFromHackage :: Hash -> String -> String -> IO DerivationSource+sourceFromHackage optHash pkgId cabalDir = do   cacheFile <- hashCachePath pkgId   cachedHash <-     case optHash of@@ -99,7 +99,7 @@       seq (length hash) $       DerivationSource "url" url "" hash <$ writeFile cacheFile hash     UnknownHash -> do-      maybeHash <- runMaybeT (derivHash . fst <$> fetchWith (False, "url", []) (Source url "" UnknownHash))+      maybeHash <- runMaybeT (derivHash . fst <$> fetchWith (False, "url", []) (Source url "" UnknownHash cabalDir))       case maybeHash of         Just hash ->           seq (length hash) $@@ -133,7 +133,7 @@   cabals <- liftIO $ getDirectoryContents dir >>= filterM doesFileExist . map (dir </>) . filter (".cabal" `isSuffixOf`)   case cabals of     [cabalFile] -> cabalFromFile True cabalFile-    _       -> liftIO $ hPutStrLn stderr "*** found zero or more than one cabal file. Exiting." >> exitFailure+    _       -> liftIO $ hPutStrLn stderr ("*** found zero or more than one cabal file (" ++ show cabals ++ "). Exiting.") >> exitFailure  handleIO :: (Exception.IOException -> IO a) -> IO a -> IO a handleIO = Exception.handle