sync in view branch updates the view branch

* sync: When run in a view branch, refresh the view branch to reflect any
    changes that have been made to the parent branch or metadata.

This is basically working, but probably needs some more work to deal with
all the edge cases of things sync does.

Sponsored-by: Lawrence Brogan on Patreon

Annex/View.hs

@@ -19,6 +19,7 @@ import qualified Git
 import qualified Git.DiffTree as DiffTree
 import qualified Git.Branch
 import qualified Git.LsFiles
+import qualified Git.LsTree
 import qualified Git.Ref
 import Git.UpdateIndex
 import Git.Sha
@@ -428,21 +429,30 @@ narrowView = applyView' viewedFileReuse getViewedFileMetaData
  - or a file in a dotdir in the top. 
  - Look up the metadata of annexed files, and generate any ViewedFiles,
  - and stage them.
- -
- - Must be run from top of repository.
  -}
 applyView' :: MkViewedFile -> (FilePath -> MetaData) -> View -> Annex Git.Branch
 applyView' mkviewedfile getfilemetadata view = do
 	top <- fromRepo Git.repoPath
 	(l, clean) <- inRepo $ Git.LsFiles.inRepoDetails [] [top]
-	liftIO . removeWhenExistsWith R.removeLink =<< fromRepo gitAnnexViewIndex
-	viewg <- withViewIndex gitRepo
-	withUpdateIndex viewg $ \uh -> do
-		forM_ l $ \(f, sha, mode) -> do
+	applyView'' mkviewedfile getfilemetadata view l clean $ 
+		\go (f, sha, mode) -> do
 			topf <- inRepo (toTopFilePath f)
-			go uh topf sha (toTreeItemType mode) =<< lookupKey f
-		liftIO $ void clean
+			go topf sha (toTreeItemType mode) =<< lookupKey f
 	genViewBranch view
+
+applyView''
+	:: MkViewedFile
+	-> (FilePath -> MetaData)
+	-> View
+	-> [t]
+	-> IO Bool
+	-> ((TopFilePath -> Sha -> Maybe TreeItemType -> Maybe Key -> Annex ()) -> t -> Annex ())
+	-> Annex ()
+applyView'' mkviewedfile getfilemetadata view l clean a = do
+	viewg <- withNewViewIndex gitRepo
+	withUpdateIndex viewg $ \uh -> do
+		forM_ l $ a (go uh)
+		liftIO $ void clean
   where
 	genviewedfiles = viewedFiles view mkviewedfile -- enables memoization
 
@@ -464,6 +474,44 @@ applyView' mkviewedfile getfilemetadata view = do
 		liftIO . Git.UpdateIndex.streamUpdateIndex' uh
 			=<< inRepo (Git.UpdateIndex.stageSymlink f sha)
 
+{- Updates the current view with any changes that have been made to its
+ - parent branch or the metadata since the view was created or last updated.
+ -
+ - When there were changes, returns a ref to a commit for the updated view.
+ - Does not update the view branch with it.
+ -
+ - This is not very optimised. An incremental update would be possible to
+ - implement and would be faster, but more complicated.
+ -}
+updateView :: View -> Annex (Maybe Git.Ref)
+updateView view = do
+	(l, clean) <- inRepo $ Git.LsTree.lsTree
+		Git.LsTree.LsTreeRecursive
+		(Git.LsTree.LsTreeLong True)
+		(viewParentBranch view)
+	applyView'' viewedFileFromReference getWorkTreeMetaData view l clean $
+		\go ti -> do
+			let ref = Git.Ref.branchFileRef (viewParentBranch view)
+				(getTopFilePath (Git.LsTree.file ti))
+			k <- case Git.LsTree.size ti of
+				Nothing -> catKey ref
+				Just sz -> catKey' ref sz
+			go
+				(Git.LsTree.file ti)
+				(Git.LsTree.sha ti)
+				(toTreeItemType (Git.LsTree.mode ti))
+				k
+	oldcommit <- inRepo $ Git.Ref.sha (branchView view)
+	oldtree <- maybe (pure Nothing) (inRepo . Git.Ref.tree) oldcommit
+	newtree <- withViewIndex $ inRepo Git.Branch.writeTree
+	if oldtree /= Just newtree
+		then Just <$> do
+			cmode <- annexCommitMode <$> Annex.getGitConfig
+			let msg = "updated " ++ fromRef (branchView view)
+			let parent = catMaybes [oldcommit]
+			inRepo (Git.Branch.commitTree cmode msg parent newtree)
+		else return Nothing
+
 {- Diff between currently checked out branch and staged changes, and
  - update metadata to reflect the changes that are being committed to the
  - view.
@@ -501,6 +549,11 @@ withViewChanges addmeta removemeta = do
 withViewIndex :: Annex a -> Annex a
 withViewIndex = withIndexFile ViewIndexFile . const
 
+withNewViewIndex :: Annex a -> Annex a
+withNewViewIndex a = do
+	liftIO . removeWhenExistsWith R.removeLink =<< fromRepo gitAnnexViewIndex
+	withViewIndex a
+
 {- Generates a branch for a view, using the view index file
  - to make a commit to the view branch. The view branch is not
  - checked out, but entering it will display the view. -}

CHANGELOG

@@ -9,6 +9,8 @@ git-annex (10.20230127) UNRELEASED; urgency=medium
   * Changed the name of view branches to include the parent branch.
     Existing view branches checked out using an old name will still work.
   * sync: Avoid pushing view branches to remotes.
+  * sync: When run in a view branch, refresh the view branch to reflect any
+    changes that have been made to the parent branch or metadata.
 
  -- Joey Hess <id@joeyh.name>  Mon, 06 Feb 2023 13:39:18 -0400
 

Command/Sync.hs

@@ -1,7 +1,7 @@
 {- git-annex command
  -
  - Copyright 2011 Joachim Breitner <mail@joachim-breitner.de>
- - Copyright 2011-2021 Joey Hess <id@joeyh.name>
+ - Copyright 2011-2023 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -59,10 +59,11 @@ import Annex.UUID
 import Logs.UUID
 import Logs.Export
 import Logs.PreferredContent
-import Logs.View (fromViewBranch)
+import Logs.View
 import Annex.AutoMerge
 import Annex.AdjustedBranch
 import Annex.AdjustedBranch.Merge
+import Annex.View
 import Annex.Ssh
 import Annex.BloomFilter
 import Annex.UpdateInstead
@@ -440,7 +441,6 @@ updateBranches (Just branch, madj) = do
 	-- to be updated, if the adjustment is not stable, and the usual
 	-- configuration does not update it.
 	case madj of
-		Nothing -> noop
 		Just adj -> do
 			let origbranch = branch
 			propigateAdjustedCommits origbranch adj
@@ -448,13 +448,27 @@ updateBranches (Just branch, madj) = do
 				annexAdjustedBranchRefresh <$> Annex.getGitConfig >>= \case
 					0 -> adjustedBranchRefreshFull adj origbranch
 					_ -> return ()
+		-- When in a view branch, update it to reflect any changes
+		-- of its parent branch or the metadata.
+		Nothing -> currentView >>= \case
+			Nothing -> noop
+			Just view -> updateView view >>= \case
+				Nothing -> noop
+				Just newcommit -> do
+					ok <- inRepo $ Git.Command.runBool
+						[ Param "merge"
+						, Param (Git.fromRef newcommit)
+						]
+					unless ok $
+						giveup $ "failed to update view"
 					
 	-- Update the sync branch to match the new state of the branch
 	inRepo $ updateBranch (syncBranch branch) branch
 
 updateBranch :: Git.Branch -> Git.Branch -> Git.Repo -> IO ()
 updateBranch syncbranch updateto g = 
-	unlessM go $ giveup $ "failed to update " ++ Git.fromRef syncbranch
+	unlessM go $
+		giveup $ "failed to update " ++ Git.fromRef syncbranch
   where
 	go = Git.Command.runBool
 		[ Param "branch"

Command/View.hs

@@ -35,7 +35,7 @@ start [] = giveup "Specify metadata to include in view"
 start ps = ifM safeToEnterView
 	( do
 		view <- mkView ps
-		go view  =<< currentView
+		go view =<< currentView
 	, giveup "Not safe to enter view."
 	)
   where

doc/git-annex-sync.mdwn

@@ -47,7 +47,10 @@ have the same value as the currently checked out branch.
 
 When [[git-annex-adjust]](1) has been used to check out an adjusted branch,
 running sync will propagate changes that have been made back to the 
-parent branch, without propagating the adjustments.
+parent branch, without propagating the adjustments. When
+[[git-annex-view]](1) has been used to check out a view branch,
+running sync will update the view branch to reflect any changes 
+to the parent branch or metadata.
 
 # OPTIONS
 

doc/todo/Metadata_changes_are_not_reflected_in_a_view/comment_4_6ab0e38d8be8a70d501108f207d41d82._comment

@@ -0,0 +1,29 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 4"""
+ date="2023-02-08T19:32:34Z"
+ content="""
+`git-annex sync` when in a view branch will now update it.
+
+Leaving this open for optimising it.
+
+Also because of this problem:
+
+	joey@darkstar:~/tmp/m#master(author=_)>git-annex sync
+	commit
+	On branch views/master(author=_)
+	nothing to commit, working tree clean
+	ok
+	merge synced/master
+	fatal: refusing to merge unrelated histories
+	failed
+
+Looks like it should not be trying to merge the synced/master
+branch into the view branch. But, this makes me wonder, does the master branch
+get updated with new files pulled from remotes? If not, the view branch
+won't be updated to have them either.
+
+Also, I think that it may try to import trees from importree special remotes,
+into the view branch. Perhaps those should also get imported but merged into
+the master branch...
+"""]]