Make git clean filter preserve the backend that was used for a file.

Annex/Ingest.hs

@@ -11,6 +11,7 @@ module Annex.Ingest (
 	lockDown,
 	ingestAdd,
 	ingest,
+	ingest',
 	finishIngestDirect,
 	finishIngestUnlocked,
 	cleanOldKeys,
@@ -140,9 +141,12 @@ ingestAdd ld@(Just (LockedDown cfg source)) = do
  - tree or the index.
  -}
 ingest :: Maybe LockedDown -> Annex (Maybe Key, Maybe InodeCache)
-ingest Nothing = return (Nothing, Nothing)
-ingest (Just (LockedDown cfg source)) = withTSDelta $ \delta -> do
-	backend <- chooseBackend $ keyFilename source
+ingest = ingest' Nothing
+
+ingest' :: Maybe Backend -> Maybe LockedDown -> Annex (Maybe Key, Maybe InodeCache)
+ingest' _ Nothing = return (Nothing, Nothing)
+ingest' preferredbackend (Just (LockedDown cfg source)) = withTSDelta $ \delta -> do
+	backend <- maybe (chooseBackend $ keyFilename source) (return . Just) preferredbackend
 	k <- genKey source backend
 	let src = contentLocation source
 	ms <- liftIO $ catchMaybeIO $ getFileStatus src

CHANGELOG

@@ -31,6 +31,7 @@ git-annex (6.20160528) UNRELEASED; urgency=medium
   * Make lock and unlock work in v6 repos on files whose content is not
     present.
   * Fix update of associated files db when unlocking a file in a v6 repo.
+  * Make git clean filter preserve the backend that was used for a file.
 
  -- Joey Hess <id@joeyh.name>  Fri, 27 May 2016 13:12:48 -0400
 

Command/Smudge.hs

@@ -13,9 +13,11 @@ import Annex.Content
 import Annex.Link
 import Annex.FileMatcher
 import Annex.Ingest
+import Annex.CatFile
 import Logs.Location
 import qualified Database.Keys
 import Git.FilePath
+import Backend
 
 import qualified Data.ByteString.Lazy as B
 
@@ -78,8 +80,16 @@ clean file = do
 				-- and not stdin, we need to consume all
 				-- stdin, or git will get annoyed.
 				B.length b `seq` return ()
+				-- Look up the backend that was used
+				-- for this file before, so that when
+				-- git re-cleans a file its backend does
+				-- not change.
+				currbackend <- maybe Nothing (maybeLookupBackendName . keyBackendName)
+					<$> catKeyFile file
 				liftIO . emitPointer
-					=<< go =<< ingest =<< lockDown cfg file
+					=<< go
+					=<< ingest' currbackend
+					=<< lockDown cfg file
 			, liftIO $ B.hPut stdout b
 			)
 	stop

doc/bugs/git_annex_adjust_--unlock_seems_to_cause_migration_of_a_file_to_another_backend.mdwn

@@ -56,3 +56,5 @@ git-annex version: 6.20160523+gitg33c00ab-1~ndall+1
 
 
 [[!meta author=yoh]]
+
+> [[fixed|done]] --[[Joey]]