merge improved fsck types from git-repair and some associated changes

3 files changed, 44 insertions, 39 deletions

diff --git a/Git/Fsck.hs b/Git/Fsck.hs
index 8bfddb4ba..8555aa0c1 100644
--- a/Git/Fsck.hs
+++ b/Git/Fsck.hs
@@ -6,11 +6,12 @@
  -}
 
 module Git.Fsck (
-	FsckResults,
+	FsckResults(..),
 	MissingObjects,
 	findBroken,
 	foundBroken,
 	findMissing,
+	knownMissing,
 ) where
 
 import Common
@@ -23,9 +24,7 @@ import qualified Data.Set as S
 
 type MissingObjects = S.Set Sha
 
-{- If fsck succeeded, Just a set of missing objects it found.
- - If it failed, Nothing. -}
-type FsckResults = Maybe MissingObjects
+data FsckResults = FsckFoundMissing MissingObjects | FsckFailed
 
 {- Runs fsck to find some of the broken objects in the repository.
  - May not find all broken objects, if fsck fails on bad data in some of
@@ -42,8 +41,8 @@ findBroken batchmode r = do
 	let objs = findShas output
 	badobjs <- findMissing objs r
 	if S.null badobjs && not fsckok
-		then return Nothing
-		else return $ Just badobjs
+		then return FsckFailed
+		else return $ FsckFoundMissing badobjs
   where
 	(command, params) = ("git", fsckParams r)
 	(command', params')
@@ -51,8 +50,12 @@ findBroken batchmode r = do
 		| otherwise = (command, params)
 
 foundBroken :: FsckResults -> Bool
-foundBroken Nothing = True
-foundBroken (Just s) = not (S.null s)
+foundBroken FsckFailed = True
+foundBroken (FsckFoundMissing s) = not (S.null s)
+
+knownMissing :: FsckResults -> MissingObjects
+knownMissing FsckFailed = S.empty
+knownMissing (FsckFoundMissing s) = s
 
 {- Finds objects that are missing from the git repsitory, or are corrupt.
  -
diff --git a/Git/Index.hs b/Git/Index.hs
index 5b660bb30..d9d5b03bf 100644
--- a/Git/Index.hs
+++ b/Git/Index.hs
@@ -7,6 +7,8 @@
 
 module Git.Index where
 
+import Common
+import Git
 import Utility.Env
 
 {- Forces git to use the specified index file.
@@ -19,9 +21,12 @@ import Utility.Env
 override :: FilePath -> IO (IO ())
 override index = do
 	res <- getEnv var
-	setEnv var index True
-	return $ reset res
+	void $ setEnv var index True
+	return $ void $ reset res
   where
 	var = "GIT_INDEX_FILE"
 	reset (Just v) = setEnv var v True
 	reset _ = unsetEnv var
+
+indexFile :: Repo -> FilePath
+indexFile r = localGitDir r </> "index"
diff --git a/Git/Repair.hs b/Git/Repair.hs
index 2fe9f3896..5afa5f93e 100644
--- a/Git/Repair.hs
+++ b/Git/Repair.hs
@@ -15,7 +15,6 @@ module Git.Repair (
 	removeTrackingBranches,
 	checkIndex,
 	missingIndex,
-	nukeIndex,
 	emptyGoodCommits,
 ) where
 
@@ -26,6 +25,7 @@ import Git.Objects
 import Git.Sha
 import Git.Types
 import Git.Fsck
+import Git.Index
 import qualified Git.Config as Config
 import qualified Git.Construct as Construct
 import qualified Git.LsTree as LsTree
@@ -43,16 +43,16 @@ import qualified Data.ByteString.Lazy as L
 import Data.Tuple.Utils
 
 {- Given a set of bad objects found by git fsck, which may not
- - be complete, finds and removes all corrupt objects, and
- - returns a list of missing objects, which need to be
- - found elsewhere to finish recovery.
+ - be complete, finds and removes all corrupt objects,
+ - and returns missing objects.
  -}
-cleanCorruptObjects :: FsckResults -> Repo -> IO (Maybe MissingObjects)
+cleanCorruptObjects :: FsckResults -> Repo -> IO FsckResults
 cleanCorruptObjects fsckresults r = do
 	void $ explodePacks r
 	objs <- listLooseObjectShas r
+	mapM_ (tryIO . allowRead . looseObjectFile r) objs
 	bad <- findMissing objs r
-	void $ removeLoose r $ S.union bad (fromMaybe S.empty fsckresults)
+	void $ removeLoose r $ S.union bad (knownMissing fsckresults)
 	-- Rather than returning the loose objects that were removed, re-run
 	-- fsck. Other missing objects may have been in the packs,
 	-- and this way fsck will find them.
@@ -98,20 +98,17 @@ explodePacks r = do
  - If another clone of the repository exists locally, which might not be a
  - remote of the repo being repaired, its path can be passed as a reference
  - repository.
- 
- - Can also be run with Nothing, if it's not known which objects are
- - missing, just that some are. (Ie, fsck failed badly.)
  -}
-retrieveMissingObjects :: Maybe MissingObjects -> Maybe FilePath -> Repo -> IO (Maybe MissingObjects)
+retrieveMissingObjects :: FsckResults -> Maybe FilePath -> Repo -> IO FsckResults
 retrieveMissingObjects missing referencerepo r
-	| missing == Just S.empty = return $ Just S.empty
+	| not (foundBroken missing) = return missing
 	| otherwise = withTmpDir "tmprepo" $ \tmpdir -> do
 		unlessM (boolSystem "git" [Params "init", File tmpdir]) $
 			error $ "failed to create temp repository in " ++ tmpdir
 		tmpr <- Config.read =<< Construct.fromAbsPath tmpdir
 		stillmissing <- pullremotes tmpr (remotes r) fetchrefstags missing
-		if stillmissing == Just S.empty
-			then return $ Just S.empty
+		if S.null (knownMissing stillmissing)
+			then return stillmissing
 			else pullremotes tmpr (remotes r) fetchallrefs stillmissing
   where
 	pullremotes tmpr [] fetchrefs stillmissing = case referencerepo of
@@ -121,12 +118,12 @@ retrieveMissingObjects missing referencerepo r
 				void $ explodePacks tmpr
 				void $ copyObjects tmpr r
 				case stillmissing of
-					Nothing -> return $ Just S.empty
-					Just s -> Just <$> findMissing (S.toList s) r
+					FsckFailed -> return $ FsckFailed
+					FsckFoundMissing s -> FsckFoundMissing <$> findMissing (S.toList s) r
 			, return stillmissing
 			)
 	pullremotes tmpr (rmt:rmts) fetchrefs ms
-		| ms == Just S.empty = return $ Just S.empty
+		| not (foundBroken ms) = return ms
 		| otherwise = do
 			putStrLn $ "Trying to recover missing objects from remote " ++ repoDescribe rmt ++ "."
 			ifM (fetchfrom (repoLocation rmt) fetchrefs tmpr)
@@ -134,10 +131,10 @@ retrieveMissingObjects missing referencerepo r
 					void $ explodePacks tmpr
 					void $ copyObjects tmpr r
 					case ms of
-						Nothing -> pullremotes tmpr rmts fetchrefs ms
-						Just s -> do
+						FsckFailed -> pullremotes tmpr rmts fetchrefs ms
+						FsckFoundMissing s -> do
 							stillmissing <- findMissing (S.toList s) r
-							pullremotes tmpr rmts fetchrefs (Just stillmissing)
+							pullremotes tmpr rmts fetchrefs (FsckFoundMissing stillmissing)
 				, pullremotes tmpr rmts fetchrefs ms
 				)
 	fetchfrom fetchurl ps = runBool $
@@ -368,7 +365,7 @@ rewriteIndex missing r
 	| otherwise = do
 		(bad, good, cleanup) <- partitionIndex missing r
 		unless (null bad) $ do
-			nukeIndex r
+			nukeFile (indexFile r)
 			UpdateIndex.streamUpdateIndex r
 				=<< (catMaybes <$> mapM reinject good)
 		void cleanup
@@ -380,9 +377,6 @@ rewriteIndex missing r
 			UpdateIndex.stageFile sha blobtype file r
 	reinject _ = return Nothing
 
-nukeIndex :: Repo -> IO ()
-nukeIndex r = nukeFile (localGitDir r </> "index")
-
 newtype GoodCommits = GoodCommits (S.Set Sha)
 
 emptyGoodCommits :: GoodCommits
@@ -423,6 +417,9 @@ preRepair g = do
 		nukeFile headfile
 		writeFile headfile "ref: refs/heads/master"
 	explodePackedRefsFile g
+	unless (repoIsLocalBare g) $ do
+		let f = indexFile g
+		void $ tryIO $ allowWrite f
   where
 	headfile = localGitDir g </> "HEAD"
 	validhead s = "ref: refs/" `isPrefixOf` s || isJust (extractSha s)
@@ -449,7 +446,7 @@ runRepair' fsckresult forced referencerepo g = do
 	missing <- cleanCorruptObjects fsckresult g
 	stillmissing <- retrieveMissingObjects missing referencerepo g
 	case stillmissing of
-		Just s
+		FsckFoundMissing s
 			| S.null s -> if repoIsLocalBare g
 				then successfulfinish S.empty []
 				else ifM (checkIndex S.empty g)
@@ -471,13 +468,13 @@ runRepair' fsckresult forced referencerepo g = do
 						, "missing objects could not be recovered!"
 						]
 					unsuccessfulfinish s
-		Nothing
+		FsckFailed
 			| forced -> ifM (pure (repoIsLocalBare g) <||> checkIndex S.empty g)
 				( do
-					missing' <- cleanCorruptObjects Nothing g
+					missing' <- cleanCorruptObjects FsckFailed g
 					case missing' of
-						Nothing -> return (False, S.empty, [])
-						Just stillmissing' -> continuerepairs stillmissing'
+						FsckFailed -> return (False, S.empty, [])
+						FsckFoundMissing stillmissing' -> continuerepairs stillmissing'
 				, corruptedindex
 				)
 			| otherwise -> unsuccessfulfinish S.empty
@@ -517,7 +514,7 @@ runRepair' fsckresult forced referencerepo g = do
 				return (True, stillmissing, modifiedbranches)
 	
 	corruptedindex = do
-		nukeIndex g
+		nukeFile (indexFile g)
 		-- The corrupted index can prevent fsck from finding other
 		-- problems, so re-run repair.
 		fsckresult' <- findBroken False g