--no-push and remote.name.annex-push prevent exporting trees to special remotes

Users may want sync to only export, or only import and this is broadly
analagous to push and pull, so it makes sense to use the same
configuration for it.

Assistant/Threads/Exporter.hs

@@ -64,7 +64,7 @@ exportToRemotes rs = do
 		forM rs $ \r -> do
 			Annex.changeState $ \st -> st { Annex.errcounter = 0 }
 			start <- liftIO getCurrentTime
-			void $ Command.Sync.seekExportContent rs
+			void $ Command.Sync.seekExportContent Nothing rs
 				=<< getCurrentBranch
 			-- Look at command error counter to see if the export
 			-- didn't work.

CHANGELOG

@@ -11,6 +11,8 @@ git-annex (7.20190220) UNRELEASED; urgency=medium
     themselves.
   * Remote tracking branches are updated when importing and exporting to
     special remotes, in ways analagous to how git fetch and git push do.
+  * sync, assistant: --no-push and remote.name.annex-push prevent exporting
+    trees to special remotes.
   * Fix storage of metadata values containing newlines.
     (Reversion introduced in version 7.20190122.)
   * Sped up git-annex export in repositories with lots of keys.

Command/Sync.hs

@@ -49,6 +49,7 @@ import Annex.Content
 import Command.Get (getKey')
 import qualified Command.Move
 import qualified Command.Export
+import qualified Command.Import
 import Annex.Drop
 import Annex.UUID
 import Logs.UUID
@@ -191,8 +192,10 @@ seek o = allowConcurrentOutput $ do
 				-- Send content to any exports first, in 
 				-- case that lets content be dropped from
 				-- other repositories.
-				exportedcontent <- withbranch $ seekExportContent exportremotes
-				syncedcontent <- withbranch $ seekSyncContent o dataremotes
+				exportedcontent <- withbranch $
+					seekExportContent (Just o) exportremotes
+				syncedcontent <- withbranch $
+					seekSyncContent o dataremotes
 				-- Transferring content can take a while,
 				-- and other changes can be pushed to the
 				-- git-annex branch on the remotes in the
@@ -687,10 +690,13 @@ syncFile ebloom rs af k = onlyActionOn' k $ do
  - 
  - Returns True if any file transfers were made.
  -}
-seekExportContent :: [Remote] -> CurrBranch -> Annex Bool
-seekExportContent rs (currbranch, _) = or <$> forM rs go
+seekExportContent :: Maybe SyncOptions -> [Remote] -> CurrBranch -> Annex Bool
+seekExportContent o rs (currbranch, _) = or <$> forM rs go
   where
-	go r = bracket
+	go r
+		| not (maybe True pullOption o) = return False
+		| not (remoteAnnexPush (Remote.gitconfig r)) = return False
+		| otherwise = bracket
 			(Export.openDb (Remote.uuid r))
 			Export.closeDb
 			(\db -> Export.writeLockDbWhile db (go' r db))

doc/git-annex-sync.mdwn

@@ -51,7 +51,8 @@ by running "git annex sync" on the remote.
 
 * `--pull`, `--no-pull`
 
-  By default, git pulls from remotes. Use --no-pull to disable all pulling.
+  By default, git pulls from remotes and imports from some special remotes.
+  Use --no-pull to disable all pulling.
 
   When `remote.<name>.annex-pull` or `remote.<name>.annex-sync`
   are set to false, pulling is disabled for those remotes, and using
@@ -59,8 +60,8 @@ by running "git annex sync" on the remote.
 
 * `--push`, `--no-push` 
 
-  By default, git pushes changes to remotes.
-  Use --no-push to disable all pushing.
+  By default, git pushes changes to remotes and exports to some 
+  special remotes. Use --no-push to disable all pushing.
   
   When `remote.<name>.annex-push` or `remote.<name>.annex-sync` are
   set to false, or `remote.<name>.annex-readonly` is set to true,