assistant: Avoid startup hang on active *.lock file

Avoid hanging at startup when a process has a *.lock file open in the .git
directory.

The goal is to repair stale locks, not wait for all active locks to be
closed. This was causing problems for a non-git process that has its own
lock file in a subdir of .git/.

If .git/index_lock is a non-stale lock, this does let the assistant start
up regardless. Commits by the assistant will then fail, until the process
locking the index finishes. This is not a problem, because the same
behavior could already happen if the assistant is started and then another
process locks the index.

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

Assistant/Repair.hs

@@ -147,17 +147,10 @@ repairStaleLocks lockfiles = go =<< getsizes
 		<$> getFileSize lf
 	getsizes = liftIO $ catMaybes <$> mapM getsize lockfiles
 	go [] = return ()
-	go l = ifM (liftIO $ null <$> Lsof.query ("--" : map (fromOsPath . fst) l))
+	go l = whenM (liftIO $ null <$> Lsof.query ("--" : map (fromOsPath . fst) l)) $ do
-		( do
+		debug ["Waiting for 60 seconds to check stale git lock file"]
-			waitforit "to check stale git lock file"
-			l' <- getsizes
-			if l' == l
-				then liftIO $ mapM_ (removeWhenExistsWith removeFile . fst) l
-				else go l'
-		, do
-			waitforit "for git lock file writer"
-			go =<< getsizes
-		)
-	waitforit why = do
-		debug ["Waiting for 60 seconds", why]
 		liftIO $ threadDelaySeconds $ Seconds 60
+		l' <- getsizes
+		if l' == l
+			then liftIO $ mapM_ (removeWhenExistsWith removeFile . fst) l
+			else go l'

CHANGELOG

@@ -1,3 +1,10 @@
+git-annex (10.20250521) UNRELEASED; urgency=medium
+
+  * assistant: Avoid hanging at startup when a process has a *.lock file
+    open in the .git directory.
+
+ -- Joey Hess <id@joeyh.name>  Thu, 22 May 2025 12:43:38 -0400
+
 git-annex (10.20250520) upstream; urgency=medium
 
   * Preferred content now supports "balanced=groupname:lackingcopies"

doc/bugs/assistant_does_not_commit_anything__44___waiting__63__.mdwn

@@ -87,3 +87,5 @@ Please advise
 
 [[!meta author=yoh]]
 [[!tag projects/repronim]]
+
+> [[fixed|done]] --[[Joey]]

doc/bugs/assistant_does_not_commit_anything__44___waiting__63__/comment_4_73717884bf2129c55a894e7f1fff490c._comment

@@ -0,0 +1,17 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 4"""
+ date="2025-05-22T16:19:35Z"
+ content="""
+It's treating `*.lock` as git lock files. Any other filename won't have the
+problem.
+
+[[!commit 635c9a1549f28992b6ae370f6e8687170c971525]] has a rationalle for
+that, that git has other lock files than index.lock. It does seem to me to
+be doubtful that any other stale git lock than index.lock would cause
+significant trouble to the assistant.
+
+But this code is supposed to deal with stale locks. This lock is not
+stale; it has a process holding it open. So the assistant has no
+reason to wait on it. I've removed the wait loop.
+"""]]