Windows: Fix bug that caused git-annex sync to fail due to missing environment variable.

I think that the problem was caused by windows not having a concept of an
env var that is set, but to the empty string. So, GIT_ANNEX_SSHOPTION
got set to "" and was not seen as set at all.

Easy fix, which also makes git-annex sync a little faster is to not set
GIT_SSH, when GIT_ANNEX_SSHOPTION has no options. Might as well let git use
ssh per usual in this case, no need to run git-annex as the proxy ssh
command..

Annex/Ssh.hs

@@ -266,7 +266,7 @@ inRepoWithSshOptionsTo remote gc a =
  - to set GIT_SSH=git-annex, and sets sshOptionsEnv. -}
 sshOptionsTo :: Git.Repo -> RemoteGitConfig -> Git.Repo -> Annex Git.Repo
 sshOptionsTo remote gc g 
-	| not (Git.repoIsUrl remote) || Git.repoIsHttp remote = uncached
+	| not (Git.repoIsUrl remote) || Git.repoIsHttp remote = unchanged
 	| otherwise = case Git.Url.hostuser remote of
 		Nothing -> uncached
 		Just host -> do
@@ -277,17 +277,21 @@ sshOptionsTo remote gc g
 					prepSocket sockfile
 					use (sshConnectionCachingParams sockfile)
   where
-	uncached = return g
+	unchanged = return g
 
 	use opts = do
-		let val = toSshOptionsEnv $ concat
+		let sshopts = 
 			[ opts
 			, map Param (remoteAnnexSshOptions gc)
 			]
-		command <- liftIO programPath
-		liftIO $ do
-			g' <- addGitEnv g sshOptionsEnv val
-			addGitEnv g' "GIT_SSH" command
+		if null sshopts
+			then unchanged
+			else do
+				let val = toSshOptionsEnv (concat sshopts)
+				command <- liftIO programPath
+				liftIO $ do
+					g' <- addGitEnv g sshOptionsEnv val
+					addGitEnv g' "GIT_SSH" command
 
 runSshOptions :: [String] -> String -> IO ()
 runSshOptions args s = do

debian/changelog

@@ -17,6 +17,8 @@ git-annex (5.20150732) UNRELEASED; urgency=medium
     make the proxied command fail the same way.
   * proxy: Fix removal of files deleted by the proxied command.
   * proxy: Fix behavior when run in subdirectory of git repo.
+  * Windows: Fix bug that caused git-annex sync to fail due to missing
+    environment variable.
 
  -- Joey Hess <id@joeyh.name>  Fri, 31 Jul 2015 12:31:39 -0400
 

doc/bugs/git-annex_sync_under_windows_fails_by_using_itself_as_the_ssh_command.mdwn

@@ -213,3 +213,5 @@ C:\data_organization\data>
 
 
 """]]
+
+> [[fixed|done]] I think. --[[Joey]]