pre-commit: Avoid committing the git-annex branch

Except when a commit is made in a view, which changes metadata.

Make the assistant commit the git-annex branch after git commit of working
tree changes.

This allows using the annex.commitmessage-command in the assistant to
generate a commit message for the git-annex branch that relies on state
gathered during the commit of the working tree. Eg, it might reuse the
commit message.

Note that, when not using the assistant, a git-annex add still commits
the git-annex branch, so such a annex.commitmessage-command set up would
not work then. But if someone is using the assistant and wants
programmatic control over commit messages, this is useful. Someone not
using the assistant can get the same result by using annex.alwayscommit=false
during the git-annex add, and git-annex merge after they git commit.

pre-commit was never really intended to commit the git-annex branch
(except after recording changed metadata), but the assistant did sort of
rely on it. It does later commit the git-annex branch before pushing to
remotes, but I didn't want to risk building up lots of uncommitted changes
to it if that didn't happen frequently.

Sponsored-by: the NIH-funded NICEMAN (ReproNim TR&D3) project

Assistant/Threads/Committer.hs

@@ -1,6 +1,6 @@
 {- git-annex assistant commit thread
  -
- - Copyright 2012-2023 Joey Hess <id@joeyh.name>
+ - Copyright 2012-2024 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -19,7 +19,6 @@ import Assistant.TransferQueue
 import Assistant.Drop
 import Types.Transfer
 import Logs.Location
-import qualified Annex.Queue
 import Utility.ThreadScheduler
 import qualified Utility.Lsof as Lsof
 import qualified Utility.DirWatcher as DirWatcher
@@ -35,6 +34,8 @@ import Annex.InodeSentinal
 import Annex.CurrentBranch
 import Annex.FileMatcher
 import qualified Annex
+import qualified Annex.Queue
+import qualified Annex.Branch
 import Utility.InodeCache
 import qualified Database.Keys
 import qualified Command.Sync
@@ -248,6 +249,11 @@ commitStaged msg = do
 				]
 			when ok $
 				Command.Sync.updateBranches =<< getCurrentBranch
+			{- Commit the git-annex branch. This comes after
+			 - the commit of the staged changes, so that
+			 - annex.commitmessage-command can examine that
+			 - commit. -}
+			Annex.Branch.commit =<< Annex.Branch.commitMessage
 			return ok
 
 {- If there are PendingAddChanges, or InProcessAddChanges, the files