sync, assistant: Include repository name in head branch commit message.

Note that while the assistant detects changes made to remote names, I left
the commit message fixed rather than calculating it after every commit. It
doesn't seem worth the CPU to do the latter.

Assistant/Threads/Committer.hs

@@ -50,6 +50,7 @@ commitThread = namedThread "Committer" $ do
 	delayadd <- liftAnnex $
 		maybe delayaddDefault (return . Just . Seconds)
 			=<< annexDelayAdd <$> Annex.getGitConfig
+	msg <- liftAnnex Command.Sync.commitMsg
 	waitChangeTime $ \(changes, time) -> do
 		readychanges <- handleAdds havelsof delayadd changes
 		if shouldCommit False time (length readychanges) readychanges
@@ -60,7 +61,7 @@ commitThread = namedThread "Committer" $ do
 					, "changes"
 					]
 				void $ alertWhile commitAlert $
-					liftAnnex commitStaged
+					liftAnnex $ commitStaged msg
 				recordCommit
 				let numchanges = length readychanges
 				mapM_ checkChangeContent readychanges
@@ -212,15 +213,15 @@ shouldCommit scanning now len changes
 	recentchanges = filter thissecond changes
 	timeDelta c = now `diffUTCTime` changeTime c
 
-commitStaged :: Annex Bool
-commitStaged = do
+commitStaged :: String -> Annex Bool
+commitStaged msg = do
 	{- This could fail if there's another commit being made by
 	 - something else. -}
 	v <- tryNonAsync Annex.Queue.flush
 	case v of
 		Left _ -> return False
 		Right _ -> do
-			ok <- Command.Sync.commitStaged Git.Branch.AutomaticCommit ""
+			ok <- Command.Sync.commitStaged Git.Branch.AutomaticCommit msg
 			when ok $
 				Command.Sync.updateSyncBranch =<< inRepo Git.Branch.current
 			return ok

Command/Sync.hs

@@ -12,6 +12,7 @@ module Command.Sync (
 	mergeLocal,
 	mergeRemote,
 	commitStaged,
+	commitMsg,
 	pushBranch,
 	updateBranch,
 	syncBranch,
@@ -41,10 +42,12 @@ import qualified Command.Move
 import Logs.Location
 import Annex.Drop
 import Annex.UUID
+import Logs.UUID
 import Annex.AutoMerge
 import Annex.Ssh
 
 import Control.Concurrent.MVar
+import qualified Data.Map as M
 
 cmd :: [Command]
 cmd = [withOptions syncOptions $
@@ -145,8 +148,8 @@ syncRemotes rs = ifM (Annex.getState Annex.fast) ( nub <$> pickfast , wanted )
 
 commit :: CommandStart
 commit = next $ next $ do
-	commitmessage <- fromMaybe "git-annex automatic sync"
-		<$> Annex.getField (optionName messageOption)
+	commitmessage <- maybe commitMsg return
+		=<< Annex.getField (optionName messageOption)
 	showStart "commit" ""
 	Annex.Branch.commit "update"
 	ifM isDirect
@@ -163,6 +166,12 @@ commit = next $ next $ do
 			return True
 		)
 
+commitMsg :: Annex String
+commitMsg = do
+	u <- getUUID
+	m <- uuidMap
+	return $ "git-annex in " ++ fromMaybe "unknown" (M.lookup u m)
+
 commitStaged :: Git.Branch.CommitMode -> String -> Annex Bool
 commitStaged commitmode commitmessage = go =<< inRepo Git.Branch.currentUnsafe
   where

debian/changelog

@@ -25,6 +25,7 @@ git-annex (5.20150206) UNRELEASED; urgency=medium
   * metadata: When setting metadata, do not recurse into directories by
     default, since that can be surprising behavior and difficult to recover
     from. The old behavior is available by using --force.
+  * sync, assistant: Include repository name in head branch commit message.
 
  -- Joey Hess <id@joeyh.name>  Fri, 06 Feb 2015 13:57:08 -0400
 

doc/todo/do_not_commit_with_empty_messages.mdwn

@@ -8,3 +8,8 @@ Could not commit staged changes.
 </pre>
 
 This was trying to fix [[a broken merge|forum/canceling_wrong_repository_merge/]]... --[[anarcat]]
+
+> While I think it's silly to use empty dummy commit messages when there
+> is nothing of value to say about the commit, I guess I can add value
+> by putting in the name of the repository where the commit was made. So,
+> [[done]] --[[Joey]] 

doc/todo/do_not_commit_with_empty_messages/comment_1_3cff336e58c26eafade4a37b0c9e0634._comment

@@ -0,0 +1,11 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 1"""
+ date="2015-02-11T17:15:04Z"
+ content="""
+It's completely legal for git commits to have empty commit messages. Why
+would rebase care? Seems like a bug in rebase.
+
+Note that only the git-annex assistant currently uses empty commit
+messages.
+"""]]