avoid unncessary IO

Git/Config.hs

@@ -66,10 +66,9 @@ global = do
 	home <- myHomeDir
 	ifM (doesFileExist $ home </> ".gitconfig")
 		( do
-			repo <- Git.Construct.fromUnknown
-			repo' <- withHandle StdoutHandle createProcessSuccess p $
-				hRead repo
-			return $ Just repo'
+			repo <- withHandle StdoutHandle createProcessSuccess p $
+				hRead (Git.Construct.fromUnknown)
+			return $ Just repo
 		, return Nothing
 		)
   where

Git/Construct.hs

@@ -19,8 +19,8 @@ module Git.Construct (
 	fromRemotes,
 	fromRemoteLocation,
 	repoAbsPath,
-	newFrom,
 	checkForRepo,
+	newFrom,
 ) where
 
 #ifndef mingw32_HOST_OS
@@ -48,7 +48,7 @@ fromCwd = getCurrentDirectory >>= seekUp
 			Nothing -> case upFrom dir of
 				Nothing -> return Nothing
 				Just d -> seekUp d
-			Just loc -> Just <$> newFrom loc
+			Just loc -> pure $ Just $ newFrom loc
 
 {- Local Repo constructor, accepts a relative or absolute path. -}
 fromPath :: FilePath -> IO Repo
@@ -62,7 +62,7 @@ fromAbsPath dir
 	| otherwise =
 		error $ "internal error, " ++ dir ++ " is not absolute"
   where
-	ret = newFrom . LocalUnknown
+	ret = pure . newFrom . LocalUnknown
 	{- Git always looks for "dir.git" in preference to
 	 - to "dir", even if dir ends in a "/". -}
 	canondir = dropTrailingPathSeparator dir
@@ -90,13 +90,13 @@ fromUrl url
 fromUrlStrict :: String -> IO Repo
 fromUrlStrict url
 	| startswith "file://" url = fromAbsPath $ unEscapeString $ uriPath u
-	| otherwise = newFrom $ Url u
+	| otherwise = pure $ newFrom $ Url u
   where
 	u = fromMaybe bad $ parseURI url
 	bad = error $ "bad url " ++ url
 
 {- Creates a repo that has an unknown location. -}
-fromUnknown :: IO Repo
+fromUnknown :: Repo
 fromUnknown = newFrom Unknown
 
 {- Converts a local Repo into a remote repo, using the reference repo
@@ -223,8 +223,8 @@ checkForRepo dir =
 		gitdirprefix = "gitdir: "
 	gitSignature file = doesFileExist $ dir </> file
 
-newFrom :: RepoLocation -> IO Repo
-newFrom l = return Repo
+newFrom :: RepoLocation -> Repo
+newFrom l = Repo
 	{ location = l
 	, config = M.empty
 	, fullconfig = M.empty
@@ -234,4 +234,3 @@ newFrom l = return Repo
 	, gitGlobalOpts = []
 	}
 
-

Git/CurrentRepo.hs

@@ -50,8 +50,8 @@ get = do
 	configure (Just d) _ = do
 		absd <- absPath d
 		curr <- getCurrentDirectory
-		r <- newFrom $ Local { gitdir = absd, worktree = Just curr }
-		Git.Config.read r
+		Git.Config.read $ newFrom $
+			Local { gitdir = absd, worktree = Just curr }
 	configure Nothing Nothing = error "Not in a git repository."
 
 	addworktree w r = changelocation r $

Remote/BitTorrent.hs

@@ -44,7 +44,7 @@ remote = RemoteType {
 -- There is only one bittorrent remote, and it always exists.
 list :: Annex [Git.Repo]
 list = do
-	r <- liftIO $ Git.Construct.remoteNamed "bittorrent" Git.Construct.fromUnknown
+	r <- liftIO $ Git.Construct.remoteNamed "bittorrent" (pure Git.Construct.fromUnknown)
 	return [r]
 
 gen :: Git.Repo -> UUID -> RemoteConfig -> RemoteGitConfig -> Annex (Maybe Remote)

Remote/Helper/Special.hs

@@ -59,7 +59,7 @@ findSpecialRemotes s = do
 	liftIO $ mapM construct $ remotepairs m
   where
 	remotepairs = M.toList . M.filterWithKey match
-	construct (k,_) = Git.Construct.remoteNamedFromKey k Git.Construct.fromUnknown
+	construct (k,_) = Git.Construct.remoteNamedFromKey k (pure Git.Construct.fromUnknown)
 	match k _ = startswith "remote." k && endswith (".annex-"++s) k
 
 {- Sets up configuration for a special remote in .git/config. -}

Remote/Web.hs

@@ -38,7 +38,7 @@ remote = RemoteType {
 -- a new release to the survivors by carrier pigeon.)
 list :: Annex [Git.Repo]
 list = do
-	r <- liftIO $ Git.Construct.remoteNamed "web" Git.Construct.fromUnknown
+	r <- liftIO $ Git.Construct.remoteNamed "web" (pure Git.Construct.fromUnknown)
 	return [r]
 
 gen :: Git.Repo -> UUID -> RemoteConfig -> RemoteGitConfig -> Annex (Maybe Remote)