sync --content now supports --hide-missing adjusted branches

This relies on git ls-files --with-tree, which I'm using in a way that
its man page does not document. Hm. I emailed the git list to try to get
the docs improved, but at least the git test suite does test the same
kind of use case I'm using here.

Performance impact when not in an adjusted branch is limited to some
additional MVar accesses, and a single git call to determine the name of
the current branch. So very minimal.

When in an adjusted branch, the performance impact is
in Annex.WorkTree.lookupFile, which starts doing an equal amount of work
for files that didn't exist as it already did for files that were
unlocked.

This commit was sponsored by Jochen Bartl on Patreon.

Annex/CatFile.hs

@@ -1,6 +1,6 @@
 {- git cat-file interface, with handle automatically stored in the Annex monad
  -
- - Copyright 2011-2015 Joey Hess <id@joeyh.name>
+ - Copyright 2011-2018 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
@@ -16,9 +16,11 @@ module Annex.CatFile (
 	catObjectMetaData,
 	catFileStop,
 	catKey,
+	catSymLinkTarget,
 	catKeyFile,
 	catKeyFileHEAD,
-	catSymLinkTarget,
+	catKeyFileHidden,
+	catObjectMetaDataHidden,
 ) where
 
 import qualified Data.ByteString.Lazy as L
@@ -34,6 +36,8 @@ import Git.FilePath
 import Git.Index
 import qualified Git.Ref
 import Annex.Link
+import Annex.CurrentBranch
+import Types.AdjustedBranch
 import Utility.FileSystemEncoding
 
 catFile :: Git.Branch -> FilePath -> Annex L.ByteString
@@ -142,3 +146,16 @@ catKeyFile f = ifM (Annex.getState Annex.daemon)
 
 catKeyFileHEAD :: FilePath -> Annex (Maybe Key)
 catKeyFileHEAD f = catKey $ Git.Ref.fileFromRef Git.Ref.headRef f
+
+{- Look in the original branch from whence an adjusted branch is based
+ - to find the file. But only when the adjustment hides some files. -}
+catKeyFileHidden :: FilePath -> CurrBranch -> Annex (Maybe Key) 
+catKeyFileHidden = hiddenCat catKey
+
+catObjectMetaDataHidden :: FilePath -> CurrBranch -> Annex (Maybe (Integer, ObjectType))
+catObjectMetaDataHidden = hiddenCat catObjectMetaData
+
+hiddenCat :: (Ref -> Annex (Maybe a)) -> FilePath -> CurrBranch -> Annex (Maybe a)
+hiddenCat a f (Just origbranch, Just adj)
+	| adjustmentHidesFiles adj = a (Git.Ref.fileFromRef origbranch f)
+hiddenCat _ _ _ = return Nothing

Annex/WorkTree.hs

@@ -1,6 +1,6 @@
 {- git-annex worktree files
  -
- - Copyright 2013-2016 Joey Hess <id@joeyh.name>
+ - Copyright 2013-2018 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU GPL version 3 or higher.
  -}
@@ -13,6 +13,7 @@ import Annex.CatFile
 import Annex.Version
 import Annex.Content
 import Annex.ReplaceFile
+import Annex.CurrentBranch
 import Config
 import Git.FilePath
 import qualified Git.Ref
@@ -28,19 +29,20 @@ import qualified Database.Keys.SQL
  -
  - An unlocked file will not have a link on disk, so fall back to
  - looking for a pointer to a key in git.
+ -
+ - When in an adjusted branch that may have hidden the file, looks for a
+ - pointer to a key in the original branch.
  -}
 lookupFile :: FilePath -> Annex (Maybe Key)
 lookupFile file = isAnnexLink file >>= \case
-	Just key -> makeret key
+	Just key -> return (Just key)
 	Nothing -> ifM (versionSupportsUnlockedPointers <||> isDirect)
 		( ifM (liftIO $ doesFileExist file)
-			( maybe (return Nothing) makeret =<< catKeyFile file
-			, return Nothing
+			( catKeyFile file
+			, catKeyFileHidden file =<< getCurrentBranch
 			)
 		, return Nothing 
 		)
-  where
-	makeret = return . Just
 
 {- Modifies an action to only act on files that are already annexed,
  - and passes the key on to it. -}

CHANGELOG

@@ -6,6 +6,8 @@ git-annex (6.20181012) UNRELEASED; urgency=medium
     again will update the branch as needed. This is mostly
     useful with --hide-missing to hide/unhide files after their content
     has been dropped or received.
+  * git-annex sync --content supports --hide-missing; it can
+    be used to get the content of hidden files.
   * Removed the old Android app.
   * Removed support for building with very old ghc < 8.0.1,
     and with yesod < 1.4.3, and without concurrent-output,

CmdLine/Seek.hs

@@ -29,6 +29,7 @@ import Logs.Transfer
 import Remote.List
 import qualified Remote
 import Annex.CatFile
+import Annex.CurrentBranch
 import Annex.Content
 import Annex.InodeSentinal
 import qualified Database.Keys
@@ -270,17 +271,33 @@ seekHelper a l = inRepo $ \g ->
 -- An item in the work tree, which may be a file or a directory.
 newtype WorkTreeItem = WorkTreeItem FilePath
 
+-- When in an adjusted branch that hides some files, it may not exist
+-- in the current work tree, but in the original branch. This allows
+-- seeking for such files.
+newtype AllowHidden = AllowHidden Bool
+
 -- Many git commands seek work tree items matching some criteria,
 -- and silently skip over anything that does not exist. But users expect
 -- an error message when one of the files they provided as a command-line
 -- parameter doesn't exist, so this checks that each exists.
 workTreeItems :: CmdParams -> Annex [WorkTreeItem]
-workTreeItems ps = do
+workTreeItems = workTreeItems' (AllowHidden False)
+
+workTreeItems' :: AllowHidden -> CmdParams -> Annex [WorkTreeItem]
+workTreeItems' (AllowHidden allowhidden) ps = do
+	currbranch <- getCurrentBranch
 	forM_ ps $ \p ->
-		unlessM (isJust <$> liftIO (catchMaybeIO $ getSymbolicLinkStatus p)) $ do
+		unlessM (exists p <||> hidden currbranch p) $ do
 			toplevelWarning False (p ++ " not found")
 			Annex.incError
 	return (map WorkTreeItem ps)
+  where
+	exists p = isJust <$> liftIO (catchMaybeIO $ getSymbolicLinkStatus p)
+	hidden currbranch p
+		| allowhidden = do
+			f <- liftIO $ relPathCwdToFile p
+			isJust <$> catObjectMetaDataHidden f currbranch
+		| otherwise = return False
 
 notSymlink :: FilePath -> IO Bool
 notSymlink f = liftIO $ not . isSymbolicLink <$> getSymbolicLinkStatus f

Command/Sync.hs

@@ -556,26 +556,35 @@ seekSyncContent o rs currbranch = do
 	bloom <- case keyOptions o of
 		Just WantAllKeys -> Just <$> genBloomFilter (seekworktree mvar [])
 		_ -> case currbranch of
-			(origbranch, Just adj) | adjustmentHidesFiles adj -> do
-				seekbranch origbranch (contentOfOption o)
-				pure Nohing
-			_ = do
+                	(Just origbranch, Just adj) | adjustmentHidesFiles adj -> do
+				l <- workTreeItems' (AllowHidden True) (contentOfOption o)
+				seekincludinghidden origbranch mvar l (const noop)
+				pure Nothing
+			_ -> do
 				l <- workTreeItems (contentOfOption o)
 				seekworktree mvar l (const noop)
 				pure Nothing
 	withKeyOptions' (keyOptions o) False
-		(return (seekkeys mvar bloom))
+		(return (gokey mvar bloom))
 		(const noop)
 		[]
 	finishCommandActions
 	liftIO $ not <$> isEmptyMVar mvar
   where
-	seekworktree mvar l bloomfeeder = seekHelper LsFiles.inRepo l >>=
-		mapM_ (\f -> ifAnnexed f (go (Right bloomfeeder) mvar (AssociatedFile (Just f))) noop)
+	seekworktree mvar l bloomfeeder = 
+		seekHelper LsFiles.inRepo l
+			>>= gofiles bloomfeeder mvar
 
-	seekbranch origbranch l = 
+	seekincludinghidden origbranch mvar l bloomfeeder = 
+		seekHelper (LsFiles.inRepoOrBranch origbranch) l 
+			>>= gofiles bloomfeeder mvar
 
-	seekkeys mvar bloom (k, _) = go (Left bloom) mvar (AssociatedFile Nothing) k
+	gofiles bloomfeeder mvar = mapM_ $ \f ->
+		ifAnnexed f
+			(go (Right bloomfeeder) mvar (AssociatedFile (Just f)))
+			noop
+	
+	gokey mvar bloom (k, _) = go (Left bloom) mvar (AssociatedFile Nothing) k
 
 	go ebloom mvar af k = commandAction $ do
 		whenM (syncFile ebloom rs af k) $

Git/LsFiles.hs

@@ -7,6 +7,7 @@
 
 module Git.LsFiles (
 	inRepo,
+	inRepoOrBranch,
 	notInRepo,
 	notInRepoIncludingEmptyDirectories,
 	allFiles,
@@ -34,14 +35,22 @@ import Git.Sha
 import Numeric
 import System.Posix.Types
 
-{- Scans for files that are checked into git at the specified locations. -}
+{- Scans for files that are checked into git's index at the specified locations. -}
 inRepo :: [FilePath] -> Repo -> IO ([FilePath], IO Bool)
-inRepo l = pipeNullSplit $ 
+inRepo = inRepo' [] 
+
+inRepo' :: [CommandParam] -> [FilePath] -> Repo -> IO ([FilePath], IO Bool)
+inRepo' ps l = pipeNullSplit $ 
 	Param "ls-files" :
 	Param "--cached" :
 	Param "-z" :
-	Param "--" :
-	map File l
+	ps ++
+	(Param "--" : map File l)
+
+{- Files that are checked into the index or have been committed to a
+ - branch. -}
+inRepoOrBranch :: Branch -> [FilePath] -> Repo -> IO ([FilePath], IO Bool)
+inRepoOrBranch (Ref b) = inRepo' [Param $ "--with-tree=" ++ b]
 
 {- Scans for files at the specified locations that are not checked into git. -}
 notInRepo :: Bool -> [FilePath] -> Repo -> IO ([FilePath], IO Bool)

doc/git-annex-adjust.mdwn

@@ -54,11 +54,15 @@ This command can only be used in a v6 git-annex repository.
   changes, so if you `git annex drop` files, they will become broken
   links in the usual way. And when files that were missing are copied into the
   repository from elsewhere, they won't immediatly become visible in the
-  branch. 
+  branch.
   
   To update the adjusted branch to reflect changes to content availability, 
   run `git annex adjust --hide-missing` again.
 
+  Despite missing files being hidden, `git annex sync --content` will
+  still operate on them, and can be used to download missing
+  files from remotes.
+
   This option can be combined with --unlock or --fix.
 
 # SEE ALSO

doc/git-annex-sync.mdwn

@@ -70,15 +70,15 @@ by running "git annex sync" on the remote.
 * `--content`, `--no-content`
 
   Normally, syncing does not transfer the contents of annexed files.
-  The --content option causes the content of files in the work tree
+  The --content option causes the content of annexed files
   to also be uploaded and downloaded as necessary.
 
   The `annex.synccontent` configuration can be set to true to make content
   be synced by default.
 
-  Normally this tries to get each annexed file in the work tree
-  that the local repository  does not yet have, and then copies each
-  file in the work tree to every remote that it is syncing with.
+  Normally this tries to get each annexed file that the local repository
+  does not yet have, and then copies each file to every remote that it
+  is syncing with.
   This behavior can be overridden by configuring the preferred content
   of a repository. See [[git-annex-preferred-content]](1).
 
@@ -88,7 +88,7 @@ by running "git annex sync" on the remote.
 
 * `--content-of=path` `-C path`
 
-  While --content operates on all annexed files in the work tree,
+  While --content operates on all annexed files,
   --content-of allows limiting the transferred files to ones in a given
   location.
 

doc/todo/hide_missing_files/comment_4_e3bf8aaecc0f612873609c92814dcd12._comment

@@ -14,8 +14,6 @@ reports about it being too slow. ;)
 
 What still needs to be done:
 
-* `git annex sync --content` needs to scan the original branch, not the
-  adjusted branch, to find files to transfer.
 * `git annex sync` needs to update the adjusted branch.
 * The assistant also needs to scan the original branch when looking for
   files to download.