fix a case where file tracked by git unexpectedly becomes annex pointer file

smudge: When annex.largefiles=anything, files that were already stored in
git, and have not been modified could sometimes be converted to being
stored in the annex. Changes in 7.20191024 made this more of a problem.
This case is now detected and prevented.

Git/CatFile.hs

@@ -1,6 +1,6 @@
 {- git cat-file interface
  -
- - Copyright 2011-2018 Joey Hess <id@joeyh.name>
+ - Copyright 2011-2019 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -33,6 +33,7 @@ import Text.Read
 import Common
 import Git
 import Git.Sha
+import qualified Git.Ref
 import Git.Command
 import Git.Types
 import Git.FilePath
@@ -109,22 +110,23 @@ catObjectDetails h object = query (catFileProcess h) object newlinefallback $ \f
 				return (Just (content, sha, objtype))
 
 {- Gets the size and type of an object, without reading its content. -}
-catObjectMetaData :: CatFileHandle -> Ref -> IO (Maybe (Integer, ObjectType))
+catObjectMetaData :: CatFileHandle -> Ref -> IO (Maybe (Sha, FileSize, ObjectType))
 catObjectMetaData h object = query (checkFileProcess h) object newlinefallback $ \from -> do
 	resp <- hGetLine from
 	case parseResp object resp of
-		Just (ParsedResp _ size objtype) ->
-			return $ Just (size, objtype)
+		Just (ParsedResp sha size objtype) ->
+			return $ Just (sha, size, objtype)
 		Just DNE -> return Nothing
 		Nothing -> error $ "unknown response from git cat-file " ++ show (resp, object)
   where
 	-- Slow fallback path for filenames containing newlines.
 	newlinefallback = do
+		sha <- Git.Ref.sha object (gitRepo h)
 		sz <- querySize object (gitRepo h)
 		objtype <- queryObjectType object (gitRepo h)
-		return $ (,) <$> sz <*> objtype
+		return $ (,,) <$> sha <*> sz <*> objtype
 
-data ParsedResp = ParsedResp Sha Integer ObjectType | DNE
+data ParsedResp = ParsedResp Sha FileSize ObjectType | DNE
 
 query :: CoProcess.CoProcessHandle -> Ref -> IO a -> (Handle -> IO a) -> IO a
 query hdl object newlinefallback receive
@@ -180,7 +182,7 @@ querySingle o r repo reader = assertLocal repo $
 			, return Nothing
 			)
 
-querySize :: Ref -> Repo -> IO (Maybe Integer)
+querySize :: Ref -> Repo -> IO (Maybe FileSize)
 querySize r repo = maybe Nothing (readMaybe . takeWhile (/= '\n'))
 	<$> querySingle (Param "-s") r repo hGetContentsStrict
 

Git/HashObject.hs

@@ -23,12 +23,12 @@ import Data.ByteString.Builder
 
 type HashObjectHandle = CoProcess.CoProcessHandle
 
-hashObjectStart :: Repo -> IO HashObjectHandle
-hashObjectStart = gitCoProcessStart True
-	[ Param "hash-object"
-	, Param "-w"
-	, Param "--stdin-paths"
-	, Param "--no-filters"
+hashObjectStart :: Bool -> Repo -> IO HashObjectHandle
+hashObjectStart writeobject = gitCoProcessStart True $ catMaybes
+	[ Just (Param "hash-object")
+	, if writeobject then Just (Param "-w") else Nothing
+	, Just (Param "--stdin-paths")
+	, Just (Param "--no-filters")
 	]
 
 hashObjectStop :: HashObjectHandle -> IO ()

Git/UnionMerge.hs

@@ -31,7 +31,7 @@ import Git.FilePath
  -}
 merge :: Ref -> Ref -> Repo -> IO ()
 merge x y repo = do
-	hashhandle <- hashObjectStart repo
+	hashhandle <- hashObjectStart True repo
 	ch <- catFileStart repo
 	streamUpdateIndex repo
 		[ lsTree x repo