git-annex adjust --lock-missing

Like --hide-missing the branch does not get updated when content
availability changes.

Seems to basically work, but sync does not update it yet.

Also, when a file is present and so unlocked, git mv followed by
git-annex sync results in the basis branch being updated to contain the
file with the new name, unlocked. This seems different than what
happens in an adjusted unlocked branch, where the commit propigates back
locked. Probably the reverse adjustment code needs to be improved to
handle this case.

Annex/AdjustedBranch.hs

@@ -11,6 +11,7 @@ module Annex.AdjustedBranch (
 	Adjustment(..),
 	LinkAdjustment(..),
 	PresenceAdjustment(..),
+	LinkMissingAdjustment(..),
 	adjustmentHidesFiles,
 	OrigBranch,
 	AdjBranch(..),
@@ -76,31 +77,55 @@ instance AdjustTreeItem Adjustment where
 		adjustTreeItem p t >>= \case
 			Nothing -> return Nothing
 			Just t' -> adjustTreeItem l t'
+	adjustTreeItem (LinkMissingAdjustment l) t = adjustTreeItem l t
 
 instance AdjustTreeItem LinkAdjustment where
-	adjustTreeItem UnlockAdjustment = ifSymlink adjustToPointer noAdjust
-	adjustTreeItem LockAdjustment = ifSymlink noAdjust adjustToSymlink
-	adjustTreeItem FixAdjustment = ifSymlink adjustToSymlink noAdjust
-	adjustTreeItem UnFixAdjustment = ifSymlink (adjustToSymlink' gitAnnexLinkCanonical) noAdjust
+	adjustTreeItem UnlockAdjustment =
+		ifSymlink adjustToPointer noAdjust
+	adjustTreeItem LockAdjustment =
+		ifSymlink noAdjust adjustToSymlink
+	adjustTreeItem FixAdjustment =
+		ifSymlink adjustToSymlink noAdjust
+	adjustTreeItem UnFixAdjustment =
+		ifSymlink (adjustToSymlink' gitAnnexLinkCanonical) noAdjust
 
 instance AdjustTreeItem PresenceAdjustment where
-	adjustTreeItem HideMissingAdjustment = \ti@(TreeItem _ _ s) ->
-		catKey s >>= \case
-			Just k -> ifM (inAnnex k)
-				( return (Just ti)
-				, return Nothing
-				)
-			Nothing -> return (Just ti)
-	adjustTreeItem ShowMissingAdjustment = noAdjust
+	adjustTreeItem HideMissingAdjustment = 
+		ifPresent noAdjust hideAdjust
+	adjustTreeItem ShowMissingAdjustment =
+		noAdjust
 
-ifSymlink :: (TreeItem -> Annex a) -> (TreeItem -> Annex a) -> TreeItem -> Annex a
+instance AdjustTreeItem LinkMissingAdjustment where
+	adjustTreeItem LockMissingAdjustment = 
+		ifPresent adjustToPointer adjustToSymlink
+	adjustTreeItem UnlockMissingAdjustment =
+		noAdjust
+
+ifSymlink
+	:: (TreeItem -> Annex a)
+	-> (TreeItem -> Annex a)
+	-> TreeItem
+	-> Annex a
 ifSymlink issymlink notsymlink ti@(TreeItem _f m _s)
 	| toTreeItemType m == Just TreeSymlink = issymlink ti
 	| otherwise = notsymlink ti
 
+ifPresent
+	:: (TreeItem -> Annex (Maybe TreeItem))
+	-> (TreeItem -> Annex (Maybe TreeItem))
+	-> TreeItem
+	-> Annex (Maybe TreeItem)
+ifPresent ispresent notpresent ti@(TreeItem _ _ s) =
+	catKey s >>= \case
+		Just k -> ifM (inAnnex k) (ispresent ti, notpresent ti)
+		Nothing -> return (Just ti)
+
 noAdjust :: TreeItem -> Annex (Maybe TreeItem)
 noAdjust = return . Just
 
+hideAdjust :: TreeItem -> Annex (Maybe TreeItem)
+hideAdjust _ = return Nothing
+
 adjustToPointer :: TreeItem -> Annex (Maybe TreeItem)
 adjustToPointer ti@(TreeItem f _m s) = catKey s >>= \case
 	Just k -> do
@@ -197,7 +222,20 @@ checkoutAdjustedBranch (AdjBranch b) checkoutparams = do
  - But, it can be implemented more efficiently than that.
  -}
 updateAdjustedBranch :: Adjustment -> AdjBranch -> OrigBranch -> Annex Bool
-updateAdjustedBranch adj@(PresenceAdjustment _ _) (AdjBranch currbranch) origbranch = do
+updateAdjustedBranch adj@(PresenceAdjustment _ _) currbranch origbranch =
+	updateAdjustedBranch' adj currbranch origbranch
+updateAdjustedBranch adj@(LinkMissingAdjustment _) currbranch origbranch =
+	updateAdjustedBranch' adj currbranch origbranch
+updateAdjustedBranch adj@(LinkAdjustment _) _ origbranch =
+	preventCommits $ \commitlck -> do
+		-- Not really needed here, but done for consistency.
+		_ <- propigateAdjustedCommits' origbranch adj commitlck
+		-- No need to do anything else, because link adjustments
+		-- are stable.
+		return True
+
+updateAdjustedBranch' :: Adjustment -> AdjBranch -> OrigBranch -> Annex Bool
+updateAdjustedBranch' adj (AdjBranch currbranch) origbranch = do
 	b <- preventCommits $ \commitlck -> do
 		-- Avoid losing any commits that the adjusted branch has that
 		-- have not yet been propigated back to the origbranch.
@@ -216,11 +254,6 @@ updateAdjustedBranch adj@(PresenceAdjustment _ _) (AdjBranch currbranch) origbra
 	-- Make git checkout quiet to avoid warnings about disconnected
 	-- branch tips being lost.
 	checkoutAdjustedBranch b [Param "--quiet"]
-updateAdjustedBranch adj@(LinkAdjustment _) _ origbranch = preventCommits $ \commitlck -> do
-	-- Not really needed here, but done for consistency.
-	_ <- propigateAdjustedCommits' origbranch adj commitlck
-	-- No need to do anything else, because link adjustments are stable.
-	return True
 
 adjustToCrippledFileSystem :: Annex ()
 adjustToCrippledFileSystem = do