make remoteKeyToRemoteName safer

If it's passed a ConfigKey such as annex.version, avoid returning
an empty remote name and return Nothing instead. Also, foo.bar.baz is
not treated as a remote named "bar".

CmdLine/GitAnnex/Options.hs

@@ -449,8 +449,8 @@ completeRemotes = completer $ mkCompleter $ \input -> do
 	r <- maybe (pure Nothing) (Just <$$> Git.Config.read)
 		=<< Git.Construct.fromCwd
 	return $ filter (input `isPrefixOf`) $
-		map remoteKeyToRemoteName $
-			filter isRemoteKey $
+		mapMaybe remoteKeyToRemoteName $
+			filter isRemoteUrlKey $
 				maybe [] (M.keys . config) r
 		
 completeBackends :: HasCompleter f => Mod f a

Git/Construct.hs

@@ -133,11 +133,11 @@ localToUrl reference r
 
 {- Calculates a list of a repo's configured remotes, by parsing its config. -}
 fromRemotes :: Repo -> IO [Repo]
-fromRemotes repo = mapM construct remotepairs
+fromRemotes repo = catMaybes <$> mapM construct remotepairs
   where
 	filterconfig f = filter f $ M.toList $ config repo
 	filterkeys f = filterconfig (\(k,_) -> f k)
-	remotepairs = filterkeys isRemoteKey
+	remotepairs = filterkeys isRemoteUrlKey
 	construct (k,v) = remoteNamedFromKey k $
 		fromRemoteLocation (fromConfigValue v) repo
 
@@ -149,8 +149,10 @@ remoteNamed n constructor = do
 
 {- Sets the name of a remote based on the git config key, such as
  - "remote.foo.url". -}
-remoteNamedFromKey :: ConfigKey -> IO Repo -> IO Repo
-remoteNamedFromKey = remoteNamed . remoteKeyToRemoteName
+remoteNamedFromKey :: ConfigKey -> IO Repo -> IO (Maybe Repo)
+remoteNamedFromKey k r = case remoteKeyToRemoteName k of
+	Nothing -> pure Nothing
+	Just n -> Just <$> remoteNamed n r
 
 {- Constructs a new Repo for one of a Repo's remotes using a given
  - location (ie, an url). -}

Git/Remote.hs

@@ -23,14 +23,18 @@ import Network.URI
 import Git.FilePath
 #endif
 
-{- Is a git config key one that specifies the location of a remote? -}
-isRemoteKey :: ConfigKey -> Bool
-isRemoteKey (ConfigKey k) = "remote." `S.isPrefixOf` k && ".url" `S.isSuffixOf` k
+{- Is a git config key one that specifies the url of a remote? -}
+isRemoteUrlKey :: ConfigKey -> Bool
+isRemoteUrlKey (ConfigKey k) = "remote." `S.isPrefixOf` k && ".url" `S.isSuffixOf` k
 
-{- Get a remote's name from the config key that specifies its location. -}
-remoteKeyToRemoteName :: ConfigKey -> RemoteName
-remoteKeyToRemoteName (ConfigKey k) = decodeBS' $
-	S.intercalate "." $ dropFromEnd 1 $ drop 1 $ S8.split '.' k
+{- Get a remote's name from the a config key such as remote.name.url
+ - or any other per-remote config key. -}
+remoteKeyToRemoteName :: ConfigKey -> Maybe RemoteName
+remoteKeyToRemoteName (ConfigKey k)
+	| "remote." `S.isPrefixOf` k = 
+		let n = S.intercalate "." $ dropFromEnd 1 $ drop 1 $ S8.split '.' k
+		in if S.null n then Nothing else Just (decodeBS' n)
+	| otherwise = Nothing
 
 {- Construct a legal git remote name out of an arbitrary input string.
  -

Remote/Helper/Special.hs

@@ -61,7 +61,7 @@ import qualified Data.Map as M
 findSpecialRemotes :: String -> Annex [Git.Repo]
 findSpecialRemotes s = do
 	m <- fromRepo Git.config
-	liftIO $ mapM construct $ remotepairs m
+	liftIO $ catMaybes <$> mapM construct (remotepairs m)
   where
 	remotepairs = M.toList . M.filterWithKey match
 	construct (k,_) = Git.Construct.remoteNamedFromKey k