sync with special remotes with an annex:: url

Check explicitly for an annex:: url, not just any url. While no built-in
special remotes set an url, except ones that can be synced with, it
seems possible that some external special remote sets an url for its own
use, but did not expect it to be used by git-annex sync et al.

The assistant also syncs with them.

Assistant/DaemonStatus.hs

@@ -64,7 +64,7 @@ calcSyncRemotes = do
 
 	return $ \dstatus -> dstatus
 		{ syncRemotes = syncable
-		, syncGitRemotes = filter (Remote.gitSyncableRemoteType . Remote.remotetype) syncable
+		, syncGitRemotes = filter Remote.gitSyncableRemote syncable
 		, syncDataRemotes = dataremotes
 		, exportRemotes = exportremotes
 		, downloadRemotes = contentremotes

Command/Sync.hs

@@ -267,8 +267,8 @@ seek' o = startConcurrency transferStages $ do
 
 	remotes <- syncRemotes (syncWith o)
 	warnSyncContentTransition o remotes
-	-- Remotes that are git repositories, not (necessarily) special remotes.
-	let gitremotes = filter (Remote.gitSyncableRemoteType . Remote.remotetype) remotes
+	-- Remotes that git can push to and pull from.
+	let gitremotes = filter Remote.gitSyncableRemote remotes
 	-- Remotes that contain annex object content.
 	contentremotes <- filter (\r -> Remote.uuid r /= NoUUID)
 		<$> filterM (not <$$> liftIO . getDynamicConfig . remoteAnnexIgnore . Remote.gitconfig) remotes

Remote.hs

@@ -26,7 +26,6 @@ module Remote (
 	remoteTypes,
 	remoteList,
 	remoteList',
-	gitSyncableRemoteType,
 	remoteMap,
 	remoteMap',
 	uuidDescriptions,
@@ -61,6 +60,8 @@ module Remote (
 	claimingUrl,
 	claimingUrl',
 	isExportSupported,
+	gitSyncableRemote,
+	gitSyncableRemoteType,
 ) where
 
 import Data.Ord
@@ -445,3 +446,12 @@ claimingUrl' remotefilter url = do
 	fromMaybe web <$> firstM checkclaim (filter remotefilter rs)
   where
 	checkclaim = maybe (pure False) (`id` url) . claimUrl
+
+{- Is this a remote of a type we can sync with, or a special remote
+ - with an annex:: url configured? -}
+gitSyncableRemote :: Remote -> Bool
+gitSyncableRemote r
+	| gitSyncableRemoteType (remotetype r) = True
+	| otherwise = case remoteUrl (gitconfig r) of
+		Just u | "annex::" `isPrefixOf` u -> True
+		_ -> False

Remote/List.hs

@@ -109,7 +109,11 @@ updateRemote remote = do
 			Remote.Git.configRead False r
 		| otherwise = return r
 
-{- Checks if a remote is syncable using git. -}
+{- Types of remotes that are always syncable using git.
+ -
+ - This does not include special remotes that may or may not have an
+ - annex:: url that allows using git-remote-annex with them.
+ -}
 gitSyncableRemoteType :: RemoteType -> Bool
 gitSyncableRemoteType t = t `elem`
 	[ Remote.Git.remote

Types/GitConfig.hs

@@ -374,6 +374,7 @@ data RemoteGitConfig = RemoteGitConfig
 	, remoteAnnexAllowUnverifiedDownloads :: Bool
 	, remoteAnnexConfigUUID :: Maybe UUID
 	, remoteAnnexAllowEncryptedGitRepo :: Bool
+	, remoteUrl :: Maybe String
 
 	{- These settings are specific to particular types of remotes
 	 - including special remotes. -}
@@ -480,6 +481,12 @@ extractRemoteGitConfig r remotename = do
 		, remoteAnnexExternalType = notempty $ getmaybe "externaltype"
 		, remoteAnnexAllowEncryptedGitRepo = 
 			getbool "allow-encrypted-gitrepo" False
+		, remoteUrl = 
+			case Git.Config.getMaybe (remoteConfig remotename "url") r of
+				Just (ConfigValue b)
+					| B.null b -> Nothing
+					| otherwise -> Just (decodeBS b)
+				_ -> Nothing
 		}
   where
 	getbool k d = fromMaybe d $ getmaybebool k

doc/todo/git-remote-annex.mdwn

@@ -10,8 +10,6 @@ will be available to users who don't use datalad.
 
 This is implememented and working. Remaining todo list for it:
 
-* git-annex sync doesn't pull/push to these remotes, and should.
-
 * Cloning from an annex:: url with importtree=yes doesn't work
   (with or without exporttree=yes). This is because the ContentIdentifier
   db is not populated. It should be possible to work around this.