fixed the race breaking moving files from archive in direct mode

assistant: Fix bug in direct mode that could occur when a symlink is moved
out of an archive directory, and resulted in the file not being set to
direct mode when it was transferred.

The bug was that the direct mode mapping was not up-to-date when the
transferrer finished. So, finding no direct mode place to store the object,
it was put into .git/annex in indirect mode.

To fix this, just make the watcher update the direct mode mapping to
include the new file before it starts the transfer. (Seems we don't need to
update it to remove the old file if the link was moved, because the direct
mode code will notice it's not present and the mapping gets updated for its
removal later.)

The reason this was a race, and was probably not seen often is because
the committer came along and updated the direct mode mapping as part of
adding the moved symlink. But when the file was sufficiently small or
the remote sufficiently fast, this could happen after the transfer
finished.

Assistant/Threads/SanityChecker.hs

@@ -19,6 +19,7 @@ import qualified Git.Config
 import Utility.ThreadScheduler
 import qualified Assistant.Threads.Watcher as Watcher
 import Utility.LogFile
+import Config
 
 import Data.Time.Clock.POSIX
 
@@ -105,7 +106,8 @@ dailyCheck = do
 		liftAnnex $ warning msg
 		void $ addAlert $ sanityCheckFixAlert msg
 	addsymlink file s = do
-		Watcher.runHandler Watcher.onAddSymlink file s
+		isdirect <- liftAnnex isDirect
+		Watcher.runHandler (Watcher.onAddSymlink isdirect) file s
 		insanity $ "found unstaged symlink: " ++ file
 
 hourlyCheck :: Assistant ()

Assistant/Threads/Watcher.hs

@@ -82,7 +82,7 @@ runWatcher = do
 	direct <- liftAnnex isDirect
 	addhook <- hook $ if direct then onAddDirect else onAdd
 	delhook <- hook onDel
-	addsymlinkhook <- hook onAddSymlink
+	addsymlinkhook <- hook $ onAddSymlink direct
 	deldirhook <- hook onDelDir
 	errhook <- hook onErr
 	let hooks = mkWatchHooks
@@ -193,10 +193,12 @@ onAddDirect file fs = do
  - Or, if it is a git-annex symlink, ensure it points to the content
  - before adding it.
  -}
-onAddSymlink :: Handler
+onAddSymlink :: Bool -> Handler
-onAddSymlink file filestatus = go =<< liftAnnex (Backend.lookupFile file)
+onAddSymlink isdirect file filestatus = go =<< liftAnnex (Backend.lookupFile file)
   where
 	go (Just (key, _)) = do
+		when isdirect $
+			liftAnnex $ void $ addAssociatedFile key file
 		link <- liftAnnex $ calcGitLink file key
 		ifM ((==) (Just link) <$> liftIO (catchMaybeIO $ readSymbolicLink file))
 			( do

debian/changelog

@@ -15,6 +15,9 @@ git-annex (4.20130228) UNRELEASED; urgency=low
     very non-aggressively.
   * webapp: New preferences page allows enabling/disabling debug logging
     at runtime, as well as configuring numcopies and diskreserve.
+  * assistant: Fix bug in direct mode that could occur when a symlink is
+    moved out of an archive directory, and resulted in the file not being
+    set to direct mode when it was transferred.
 
  -- Joey Hess <joeyh@debian.org>  Wed, 27 Feb 2013 23:20:40 -0400