git post-checkout and post-merge hooks

* init, upgrade: Install git post-checkout and post-merge hooks that run
  git annex smudge --update.
* precommit: Run git annex smudge --update, because the post-merge
  hook is not run when there is a merge conflict. So the work tree will
  be updated when a commit is made to resolve the merge conflict.
* precommit: Run git annex smudge --update, because the post-merge
  hook is not run when there is a merge conflict. So the work tree will
  be updated when a commit is made to resolve the merge conflict.
* Note that git has no hooks run after git stash or git cherry-pick,
  so the user will have to manually run git annex smudge --update
  after such commands.

Nothing currently installs the hooks into v6 repos that already exist.
Something will need to be done about that, either move this behavior to v7,
or document that the user will need to manually fix up their v6 repos.

This commit was sponsored by Eric Drechsel on Patreon.

Annex/Hook.hs

@@ -32,6 +32,17 @@ postReceiveHook = Git.Hook "post-receive"
 	[ mkHookScript "git annex post-receive"
 	]
 
+postCheckoutHook :: Git.Hook
+postCheckoutHook = Git.Hook "post-checkout" smudgeHook []
+
+postMergeHook :: Git.Hook
+postMergeHook = Git.Hook "post-merge" smudgeHook []
+
+-- Only run git-annex smudge --update when git-annex supports it.
+-- Older versions of git-annex didn't need this hook.
+smudgeHook :: String
+smudgeHook = mkHookScript "if git annex smudge --update >/dev/null 2>&1; then git-annex smudge --update; fi"
+
 preCommitAnnexHook :: Git.Hook
 preCommitAnnexHook = Git.Hook "pre-commit-annex" "" []
 

Annex/Init.hs

@@ -112,6 +112,9 @@ initialize' ai mversion = checkCanInitialize ai $ do
 	whenM versionSupportsUnlockedPointers $ do
 		configureSmudgeFilter
 		scanUnlockedFiles
+		unlessM isBareRepo $ do
+			hookWrite postCheckoutHook
+			hookWrite postMergeHook
 	checkAdjustedClone >>= \case
 		NeedUpgradeForAdjustedClone -> 
 			void $ upgrade True  versionForAdjustedClone

CHANGELOG

@@ -26,6 +26,14 @@ git-annex (6.20181012) UNRELEASED; urgency=medium
     honor annex.thin. Now git annex smudge --update has to be run
     after a checkout to update unlocked files in the working tree 
     with annexed file contents.
+  * init, upgrade: Install git post-checkout and post-merge hooks that run 
+    git annex smudge --update.
+  * precommit: Run git annex smudge --update, because the post-merge
+    hook is not run when there is a merge conflict. So the work tree will
+    be updated when a commit is made to resolve the merge conflict.
+  * Note that git has no hooks run after git stash or git cherry-pick,
+    so the user will have to manually run git annex smudge --update
+    after such commands.
 
  -- Joey Hess <id@joeyh.name>  Sat, 13 Oct 2018 00:52:02 -0400
 

Command/PreCommit.hs

@@ -13,6 +13,7 @@ import Command
 import Config
 import qualified Command.Add
 import qualified Command.Fix
+import qualified Command.Smudge
 import Annex.Direct
 import Annex.Hook
 import Annex.Link
@@ -54,11 +55,21 @@ seek ps = lockPreCommitHook $ ifM isDirect
 				flip withFilesToBeCommitted l $ \f -> commandAction $
 					maybe stop (Command.Fix.start Command.Fix.FixSymlinks f)
 						=<< isAnnexLink f
+				ifM versionSupportsUnlockedPointers
+					-- after a merge conflict or git
+					-- cherry-pick or stash, pointer
+					-- files in the worktree won't
+					-- be populated, so populate them
+					-- here
+					( Command.Smudge.updateSmudged 
+						-- When there's a false index,
+						-- restaging the files won't work.
+						. Restage =<< liftIO Git.haveFalseIndex
 					-- inject unlocked files into the annex
 					-- (not needed when repo version uses
 					-- unlocked pointer files)
-				unlessM versionSupportsUnlockedPointers $
-					withFilesOldUnlockedToBeCommitted (commandAction . startInjectUnlocked) l
+					, withFilesOldUnlockedToBeCommitted (commandAction . startInjectUnlocked) l
+					)
 			)
 		runAnnexHook preCommitAnnexHook
 		-- committing changes to a view updates metadata

Command/Smudge.hs

@@ -67,7 +67,7 @@ smudge file = do
 		Just k -> do
 			topfile <- inRepo (toTopFilePath file)
 			Database.Keys.addAssociatedFile k topfile
-			smudgeLog k topfile
+			void $ smudgeLog k topfile
 	liftIO $ B.putStr b
 	stop
 

Upgrade/V5.hs

@@ -17,6 +17,7 @@ import Annex.Direct
 import Annex.Content
 import Annex.CatFile
 import Annex.WorkTree
+import Annex.Hook
 import qualified Database.Keys
 import qualified Annex.Content.Direct as Direct
 import qualified Git
@@ -63,6 +64,9 @@ upgrade automatic = do
 		 - adjust branch. Instead, update HEAD manually. -}
 		inRepo $ setHeadRef b
 	configureSmudgeFilter
+	unlessM isBareRepo $ do
+		hookWrite postCheckoutHook
+		hookWrite postMergeHook
 	-- Inode sentinal file was only used in direct mode and when
 	-- locking down files as they were added. In v6, it's used more
 	-- extensively, so make sure it exists, since old repos that didn't