updateproxy, updatecluster check annexobjects=yes

updateproxy, updatecluster: Prevent using an exporttree=yes special remote
that does not have annexobjects=yes, since it will not work.

CHANGELOG

@@ -9,6 +9,8 @@ git-annex (10.20240732) UNRELEASED; urgency=medium
   * post-retrieve: When proxying is enabled for an exporttree=yes
     special remote and the configured remote.name.annex-tracking-branch
     is received, the tree is exported to the special remote.
+  * updateproxy, updatecluster: Prevent using an exporttree=yes special
+    remote that does not have annexobjects=yes, since it will not work.
   * git-remote-annex: Store objects in exportree=yes special remotes
     in the same paths used by annexobjects=yes.
   * When proxying an upload to a special remote, verify the hash.

Command/UpdateCluster.hs

@@ -34,10 +34,17 @@ seek = withNothing $ do
 start :: CommandStart
 start = startingCustomOutput (ActionItemOther Nothing) $ do
 	rs <- R.remoteList
-	let getnode r = do
-		clusternames <- remoteAnnexClusterNode (R.gitconfig r)
-		return $ M.fromList $ zip clusternames (repeat (S.singleton r))
-	let myclusternodes = M.unionsWith S.union (mapMaybe getnode rs)
+	let getnode r = case remoteAnnexClusterNode (R.gitconfig r) of
+		Nothing -> return Nothing
+		Just [] -> return Nothing
+		Just clusternames -> 
+			ifM (Command.UpdateProxy.checkCanProxy r "Cannot use this special remote as a cluster node.")
+				( return $ Just $ M.fromList $
+					zip clusternames (repeat (S.singleton r))
+				, return Nothing
+				)
+	myclusternodes <- M.unionsWith S.union . catMaybes
+		<$> mapM getnode rs
 	myclusters <- annexClusters <$> Annex.getGitConfig
 	recordedclusters <- getClusters
 	descs <- R.uuidDescriptions

Command/UpdateProxy.hs

@@ -14,6 +14,7 @@ import Logs.Cluster
 import Annex.UUID
 import qualified Remote as R
 import qualified Types.Remote as R
+import Annex.SpecialRemote.Config
 import Utility.SafeOutput
 
 import qualified Data.Map as M
@@ -30,8 +31,8 @@ seek = withNothing (commandAction start)
 start :: CommandStart
 start = startingCustomOutput (ActionItemOther Nothing) $ do
 	rs <- R.remoteList
-	let remoteproxies = S.fromList $ map mkproxy $
-		filter (isproxy . R.gitconfig) rs
+	remoteproxies <- S.fromList . map mkproxy
+		<$> filterM isproxy rs
 	clusterproxies <- getClusterProxies remoteproxies
 	let proxies = S.union remoteproxies clusterproxies
 	u <- getUUID
@@ -54,9 +55,33 @@ start = startingCustomOutput (ActionItemOther Nothing) $ do
 						"Stopped proxying for " ++ proxyRemoteName p
 				_ -> noop
 	
-	isproxy c = remoteAnnexProxy c || not (null (remoteAnnexClusterNode c))
-	
 	mkproxy r = Proxy (R.uuid r) (R.name r)
+	
+	isproxy r
+		| remoteAnnexProxy (R.gitconfig r) || not (null (remoteAnnexClusterNode (R.gitconfig r))) = 
+			checkCanProxy r "Cannot proxy to this special remote."
+		| otherwise = pure False
+
+checkCanProxy :: Remote -> String -> Annex Bool
+checkCanProxy r cannotmessage = 
+	ifM (R.isExportSupported r)
+		( if annexObjects (R.config r)
+			then pure True
+			else do
+				warnannexobjects
+				pure False
+		, pure True
+		)
+  where
+	warnannexobjects = warning $ UnquotedString $ unwords
+		[ R.name r
+		, "is configured with exporttree=yes, but without"
+		, "annexobjects=yes."
+		, cannotmessage
+		, "Suggest you run: git-annex enableremote"
+		, R.name r
+		, "annexobjects=yes"
+		]
 
 -- Automatically proxy nodes of any cluster this repository is configured
 -- to serve as a gateway for. Also proxy other cluster nodes that are

doc/git-annex-updateproxy.mdwn

@@ -28,6 +28,14 @@ a proxy.
 
 Proxies can only be accessed via ssh or by an annex+http url.
 
+To set up proxying to a special remote that is configured with
+exporttree=yes, its necessary for it to also be configured with
+annexobjects=yes. And, "remote.<name>.annex-tracking-branch" needs to
+be configured to the branch that will be exported to the special remote.
+When that branch is pushed to the proxy, it will update the tree exported
+to the special remote. When files are copied to the remote via the proxy,
+it will also update the exported tree.
+
 # OPTIONS
 
 * The [[git-annex-common-options]](1) can be used.
@@ -36,6 +44,7 @@ Proxies can only be accessed via ssh or by an annex+http url.
 
 * [[git-annex]](1)
 * [[git-annex-updatecluster]](1)
+* [[git-annex-export]](1)
 
 # AUTHOR
 

doc/todo/git-annex_proxies.mdwn

@@ -41,9 +41,6 @@ Planned schedule of work:
 	  export not supported
 	failed
 
-* Prevent `updateproxy` from enabling an exporttree=yes special remote
-  that does not have annexobjects=yes, to avoid foot shooting.
-
 * Handle cases where a single key is used by multiple files in the exported
   tree. Need to download from the special remote in order to export
   multiple copies to it. (In particular, this is needed when using
@@ -69,6 +66,10 @@ Planned schedule of work:
 * When getting from a P2P HTTP remote, prompt for credentials when
   required, instead of failing.
 
+* Prevent `updateproxy` and `updatecluster` from adding
+  an exporttree=yes special remote that does not have
+  annexobjects=yes, to avoid foot shooting.
+
 ## items deferred until later for p2p protocol over http
 
 * `git-annex p2phttp` should support serving several repositories at the same