Added remote.<name>.annex-push and remote.<name>.annex-pull

The former can be useful to make remotes that don't get fully synced with
local changes, which comes up in a lot of situations.

The latter was mostly added for symmetry, but could be useful (though less
likely to be).

Implementing `remote.<name>.annex-pull` was a bit tricky, as there's no one
place where git-annex pulls/fetches from remotes. I audited all
instances of "fetch" and "pull". A few cases were left not checking this
config:

* Git.Repair can try to pull missing refs from a remote, and if the local
  repo is corrupted, that seems a reasonable thing to do even though
  the config would normally prevent it.
* Assistant.WebApp.Gpg and Remote.Gcrypt and Remote.Git do fetches
  as part of the setup process of a remote. The config would probably not
  be set then, and having the setup fail seems worse than honoring it if it
  is already set.

I have not prevented all the code that does a "merge" from merging branches
from remotes with remote.<name>.annex-pull=false. That could perhaps
be done, but it would need a way to map from branch name to remote name,
and the way refspecs work makes that hard to get really correct. So if the
user fetches manually, the git-annex branch will get merged, for example.
Anther way of looking at/justifying this is that the setting is called
"annex-pull", not "annex-merge".

This commit was supported by the NSF-funded DataLad project.

3 files changed, 12 insertions, 5 deletions

diff --git a/RemoteDaemon/Common.hs b/RemoteDaemon/Common.hs
index 711771f97..366f6aaca 100644
--- a/RemoteDaemon/Common.hs
+++ b/RemoteDaemon/Common.hs
@@ -8,7 +8,7 @@
 module RemoteDaemon.Common
 	( liftAnnex
 	, inLocalRepo
-	, checkNewShas
+	, checkShouldFetch
 	, ConnectionStatus(..)
 	, robustConnection
 	) where
@@ -35,6 +35,13 @@ liftAnnex (TransportHandle _ annexstate) a = do
 inLocalRepo :: TransportHandle -> (Git.Repo -> IO a) -> IO a
 inLocalRepo (TransportHandle (LocalRepo g) _) a = a g
 
+-- Check if some shas should be fetched from the remote,
+-- and presumably later merged.
+checkShouldFetch :: RemoteGitConfig -> TransportHandle -> [Git.Sha] -> IO Bool
+checkShouldFetch gc transporthandle shas
+	| remoteAnnexPull gc = checkNewShas transporthandle shas
+	| otherwise = return False
+
 -- Check if any of the shas are actally new in the local git repo,
 -- to avoid unnecessary fetching.
 checkNewShas :: TransportHandle -> [Git.Sha] -> IO Bool
diff --git a/RemoteDaemon/Transport/Ssh.hs b/RemoteDaemon/Transport/Ssh.hs
index fdb75e871..772ae9771 100644
--- a/RemoteDaemon/Transport/Ssh.hs
+++ b/RemoteDaemon/Transport/Ssh.hs
@@ -36,7 +36,7 @@ transportUsingCmd cmd params rr@(RemoteRepo r gc) url h@(TransportHandle (LocalR
 	transportUsingCmd' cmd params rr url transporthandle ichan ochan
 
 transportUsingCmd' :: FilePath -> [CommandParam] -> Transport
-transportUsingCmd' cmd params (RemoteRepo r _) url transporthandle ichan ochan =
+transportUsingCmd' cmd params (RemoteRepo r gc) url transporthandle ichan ochan =
 	robustConnection 1 $ do
 		(Just toh, Just fromh, Just errh, pid) <-
 			createProcess (proc cmd (toCommand params))
@@ -74,7 +74,7 @@ transportUsingCmd' cmd params (RemoteRepo r _) url transporthandle ichan ochan =
 				send (CONNECTED url)
 				handlestdout fromh
 			Just (SshRemote.CHANGED (ChangedRefs shas)) -> do
-				whenM (checkNewShas transporthandle shas) $
+				whenM (checkShouldFetch gc transporthandle shas) $
 					fetch
 				handlestdout fromh
 			-- avoid reconnect on protocol error
diff --git a/RemoteDaemon/Transport/Tor.hs b/RemoteDaemon/Transport/Tor.hs
index afa249b33..b0fa3c189 100644
--- a/RemoteDaemon/Transport/Tor.hs
+++ b/RemoteDaemon/Transport/Tor.hs
@@ -129,7 +129,7 @@ serveClient th u r q = bracket setup cleanup start
 
 -- Connect to peer's tor hidden service.
 transport :: Transport
-transport (RemoteRepo r _) url@(RemoteURI uri) th ichan ochan =
+transport (RemoteRepo r gc) url@(RemoteURI uri) th ichan ochan =
 	case unformatP2PAddress (show uri) of
 		Nothing -> return ()
 		Just addr -> robustConnection 1 $ do
@@ -168,7 +168,7 @@ transport (RemoteRepo r _) url@(RemoteURI uri) th ichan ochan =
 		v <- runNetProto conn P2P.notifyChange
 		case v of
 			Right (Just (ChangedRefs shas)) -> do
-				whenM (checkNewShas th shas) $
+				whenM (checkShouldFetch gc th shas) $
 					fetch
 				handlepeer conn
 			_ -> return ConnectionClosed