fix handling of staged unlocked files

Command/Lock.hs

@@ -11,6 +11,7 @@ import Control.Monad.State (liftIO)
 import System.Directory
 import System.Posix.Files
 
+import Types
 import Command
 import Messages
 import qualified Annex
@@ -19,15 +20,8 @@ import qualified GitRepo as Git
 {- Undo unlock -}
 start :: SubCmdStartString
 start file = do
-	-- Want to avoid calling git checkout on files that are not
-	-- annexed -- but without the symlink to the annex, cannot tell
-	-- for sure if the file was annexed. So, check if git thinks the
-	-- file's type has changed (from a symlink to a regular file).
-	g <- Annex.gitRepo
-	test <- liftIO $
-		Git.pipeRead g ["diff", "--name-only", "--diff-filter=T", file]
-	s <- liftIO $ getSymbolicLinkStatus file
-	if (null test || isSymbolicLink s)
+	locked <- isLocked file
+	if locked
 		then return Nothing
 		else do
 			showStart "lock" file
@@ -37,5 +31,26 @@ perform :: FilePath -> SubCmdPerform
 perform file = do
 	liftIO $ removeFile file
 	g <- Annex.gitRepo
-	liftIO $ Git.run g ["checkout", file]
+	-- first reset the file to drop any changes checked into the index
+	liftIO $ Git.run g ["reset", "-q", "--", file]
+	-- checkout the symlink
+	liftIO $ Git.run g ["checkout", "--", file]
 	return $ Just $ return True -- no cleanup needed
+
+{- Checks if a file is unlocked for edit.
+ -
+ - But, without the symlink to the annex, cannot tell for sure if the
+ - file was annexed before. So, check if git thinks the file's type has
+ - changed (from a symlink to a regular file). -}
+isLocked :: FilePath -> Annex Bool
+isLocked file = do
+	g <- Annex.gitRepo
+	changed <- typechanged g Nothing
+	changedCached <- typechanged g $ Just "--cached"
+	s <- liftIO $ getSymbolicLinkStatus file
+	return $ null (changed++changedCached) || isSymbolicLink s
+	where
+		typechanged g Nothing = typechanged' g params
+		typechanged g (Just param) = typechanged' g $ params++[param]
+		typechanged' g p = liftIO $ Git.pipeRead g $ p++[file]
+		params = ["diff", "--name-only", "--diff-filter=T"]