Fix a potential failure to parse git config

Git has an obnoxious special case in git config, a line "foo" is the same
as "foo = true". That means there is no way to examine the output of
git config and tell if it was run with --null or not, since a "foo"
in the first line could be such a boolean, or could be followed by its
value on the next line if --null were used.

So, rather than trying to do such a detection, track the style of config
at all the points where it's generated.

Annex/UUID.hs

@@ -111,7 +111,7 @@ storeUUIDIn configfield = setConfig configfield . fromUUID
 setUUID :: Git.Repo -> UUID -> IO Git.Repo
 setUUID r u = do
 	let s = encodeBS' $ show configkeyUUID ++ "=" ++ fromUUID u
-	Git.Config.store s r
+	Git.Config.store s Git.Config.ConfigList r
 
 -- Dummy uuid for the whole web. Do not alter.
 webUUID :: UUID

CHANGELOG

@@ -6,6 +6,7 @@ git-annex (8.20200331) UNRELEASED; urgency=medium
   * Sped up query commands that read the git-annex branch by around 9%.
   * Various speed improvements gained by using ByteStrings for git refs and
     shas.
+  * Fix a potential failure to parse git config.
 
  -- Joey Hess <id@joeyh.name>  Mon, 30 Mar 2020 15:58:34 -0400
 

CmdLine/GitAnnex/Options.hs

@@ -96,7 +96,7 @@ gitAnnexGlobalOptions = commonGlobalOptions ++
 	setgitconfig v = Annex.adjustGitRepo $ \r -> 
 		if Param v `elem` gitGlobalOpts r
 			then return r
-			else Git.Config.store (encodeBS' v) $ 
+			else Git.Config.store (encodeBS' v) Git.Config.ConfigList $ 
 				r { gitGlobalOpts = gitGlobalOpts r ++ [Param "-c", Param v] }
 	setdesktopnotify v = Annex.changeState $ \s -> s { Annex.desktopnotify = Annex.desktopnotify s <> v }
 

Command/Map.hs

@@ -222,18 +222,18 @@ tryScan r
 		Nothing -> return $ Just r
 	| otherwise = liftIO $ safely $ Git.Config.read r
   where
-	pipedconfig pcmd params = liftIO $ safely $
+	pipedconfig st pcmd params = liftIO $ safely $
 		withHandle StdoutHandle createProcessSuccess p $
-			Git.Config.hRead r
+			Git.Config.hRead r st
 	  where
 		p = proc pcmd $ toCommand params
 
 	configlist = Ssh.onRemote NoConsumeStdin r
-		(pipedconfig, return Nothing) "configlist" [] []
+		(pipedconfig Git.Config.ConfigList, return Nothing) "configlist" [] []
 	manualconfiglist = do
 		gc <- Annex.getRemoteGitConfig r
 		(sshcmd, sshparams) <- Ssh.toRepo NoConsumeStdin r gc remotecmd
-		liftIO $ pipedconfig sshcmd sshparams
+		liftIO $ pipedconfig Git.Config.ConfigNullList sshcmd sshparams
 	  where
 		remotecmd = "sh -c " ++ shellEscape
 			(cddir ++ " && " ++ "git config --null --list")

Git/Config.hs

@@ -59,7 +59,7 @@ read' repo = go repo
 	go Repo { location = LocalUnknown d } = git_config d
 	go _ = assertLocal repo $ error "internal"
 	git_config d = withHandle StdoutHandle createProcessSuccess p $
-		hRead repo
+		hRead repo ConfigNullList
 	  where
 		params = ["config", "--null", "--list"]
 		p = (proc "git" params)
@@ -74,7 +74,7 @@ global = do
 	ifM (doesFileExist $ home </> ".gitconfig")
 		( do
 			repo <- withHandle StdoutHandle createProcessSuccess p $
-				hRead (Git.Construct.fromUnknown)
+				hRead (Git.Construct.fromUnknown) ConfigNullList
 			return $ Just repo
 		, return Nothing
 		)
@@ -83,18 +83,18 @@ global = do
 	p = (proc "git" params)
 
 {- Reads git config from a handle and populates a repo with it. -}
-hRead :: Repo -> Handle -> IO Repo
-hRead repo h = do
+hRead :: Repo -> ConfigStyle -> Handle -> IO Repo
+hRead repo st h = do
 	val <- S.hGetContents h
-	store val repo
+	store val st repo
 
 {- Stores a git config into a Repo, returning the new version of the Repo.
  - The git config may be multiple lines, or a single line.
  - Config settings can be updated incrementally.
  -}
-store :: S.ByteString -> Repo -> IO Repo
-store s repo = do
-	let c = parse s
+store :: S.ByteString -> ConfigStyle -> Repo -> IO Repo
+store s st repo = do
+	let c = parse s st
 	updateLocation $ repo
 		{ config = (M.map Prelude.head c) `M.union` config repo
 		, fullconfig = M.unionWith (++) c (fullconfig repo)
@@ -137,21 +137,19 @@ updateLocation' r l = do
 			return $ l { worktree = Just (toRawFilePath p) }
 	return $ r { location = l' }
 
+data ConfigStyle = ConfigList | ConfigNullList
+
 {- Parses git config --list or git config --null --list output into a
  - config map. -}
-parse :: S.ByteString -> M.Map ConfigKey [ConfigValue]
-parse s
+parse :: S.ByteString -> ConfigStyle -> M.Map ConfigKey [ConfigValue]
+parse s st
 	| S.null s = M.empty
-	-- --list output will have a '=' in the first line
-	-- (The first line of --null --list output is the name of a key,
-	-- which is assumed to never contain '='.)
-	| S.elem eq firstline = sep eq $ S.split nl s
-	-- --null --list output separates keys from values with newlines
-	| otherwise = sep nl $ S.split 0 s
+	| otherwise = case st of
+		ConfigList -> sep eq $ S.split nl s
+		ConfigNullList -> sep nl $ S.split 0 s
   where
 	nl = fromIntegral (ord '\n')
 	eq = fromIntegral (ord '=')
-	firstline = S.takeWhile (/= nl) s
 
 	sep c = M.fromListWith (++)
 		. map (\(k,v) -> (ConfigKey k, [ConfigValue (S.drop 1 v)])) 
@@ -186,14 +184,14 @@ coreBare = "core.bare"
 {- Runs a command to get the configuration of a repo,
  - and returns a repo populated with the configuration, as well as the raw
  - output and any standard output of the command. -}
-fromPipe :: Repo -> String -> [CommandParam] -> IO (Either SomeException (Repo, S.ByteString, S.ByteString))
-fromPipe r cmd params = try $
+fromPipe :: Repo -> String -> [CommandParam] -> ConfigStyle -> IO (Either SomeException (Repo, S.ByteString, S.ByteString))
+fromPipe r cmd params st = try $
 	withOEHandles createProcessSuccess p $ \(hout, herr) -> do
 		geterr <- async $ S.hGetContents herr
 		getval <- async $ S.hGetContents hout
 		val <- wait getval
 		err <- wait geterr
-		r' <- store val r
+		r' <- store val st r
 		return (r', val, err)
   where
 	p = proc cmd $ toCommand params
@@ -206,7 +204,7 @@ fromFile r f = fromPipe r "git"
 	, Param "--file"
 	, File f
 	, Param "--list"
-	]
+	] ConfigList
 
 {- Changes a git config setting in the specified config file.
  - (Creates the file if it does not already exist.) -}

Remote/GCrypt.hs

@@ -474,7 +474,7 @@ getGCryptId fast r gc
 	| Git.repoIsLocal r || Git.repoIsLocalUnknown r = extract <$>
 		liftIO (catchMaybeIO $ Git.Config.read r)
 	| not fast = extract . liftM fst3 <$> getM (eitherToMaybe <$>)
-		[ Ssh.onRemote NoConsumeStdin r (\f p -> liftIO (Git.Config.fromPipe r f p), return (Left $ error "configlist failed")) "configlist" [] []
+		[ Ssh.onRemote NoConsumeStdin r (\f p -> liftIO (Git.Config.fromPipe r f p Git.Config.ConfigList), return (Left $ error "configlist failed")) "configlist" [] []
 		, getConfigViaRsync r gc
 		]
 	| otherwise = return (Nothing, r)

Remote/Git.hs

@@ -249,7 +249,7 @@ tryGitConfigRead autoinit r
 	| haveconfig r = return r -- already read
 	| Git.repoIsSsh r = storeUpdatedRemote $ do
 		v <- Ssh.onRemote NoConsumeStdin r
-			(pipedconfig autoinit (Git.repoDescribe r), return (Left $ giveup "configlist failed"))
+			(pipedconfig Git.Config.ConfigList autoinit (Git.repoDescribe r), return (Left $ giveup "configlist failed"))
 			"configlist" [] configlistfields
 		case v of
 			Right r'
@@ -264,8 +264,8 @@ tryGitConfigRead autoinit r
   where
 	haveconfig = not . M.null . Git.config
 
-	pipedconfig mustincludeuuuid configloc cmd params = do
-		v <- liftIO $ Git.Config.fromPipe r cmd params
+	pipedconfig st mustincludeuuuid configloc cmd params = do
+		v <- liftIO $ Git.Config.fromPipe r cmd params st
 		case v of
 			Right (r', val, _err) -> do
 				unless (isUUIDConfigured r' || S.null val || not mustincludeuuuid) $ do
@@ -282,7 +282,7 @@ tryGitConfigRead autoinit r
 			liftIO $ hClose h
 			let url = Git.repoLocation r ++ "/config"
 			ifM (liftIO $ Url.downloadQuiet nullMeterUpdate url tmpfile uo)
-				( Just <$> pipedconfig False url "git" [Param "config", Param "--null", Param "--list", Param "--file", File tmpfile]
+				( Just <$> pipedconfig Git.Config.ConfigNullList False url "git" [Param "config", Param "--null", Param "--list", Param "--file", File tmpfile]
 				, return Nothing
 				)
 		case v of