change sync content transition plan and fine tune warning

Only display warning when git-annex sync (without --content or
--no-content) is used with repositories that have preferred content
configured.

Sponsored-by: Leon Schuermann on Patreon

Command/Sync.hs

@@ -256,8 +256,6 @@ instance DeferredParseClass SyncOptions where
 
 seek :: SyncOptions -> CommandSeek
 seek o = do
-	warnSyncContentTransition o
-	
 	prepMerge
 	
 	seek' o
@@ -267,6 +265,7 @@ seek' o = startConcurrency transferStages $ do
 	let withbranch a = a =<< getCurrentBranch
 
 	remotes <- syncRemotes (syncWith o)
+	warnSyncContentTransition o remotes
 	-- Remotes that are git repositories, not (necesarily) special remotes.
 	let gitremotes = filter (Remote.gitSyncableRemoteType . Remote.remotetype) remotes
 	-- Remotes that contain annex object content.
@@ -1102,23 +1101,28 @@ shouldSyncContent o
 			HasGitConfig (Just c) -> return c
 			_ -> return d
 
--- Transition started May 2023, should wait until that has been in a Debian
--- stable release before completing the transition.
-warnSyncContentTransition :: SyncOptions -> Annex ()
-warnSyncContentTransition o
+-- See doc/todo/finish_sync_content_transition.mdwn
+warnSyncContentTransition :: SyncOptions -> [Remote] -> Annex ()
+warnSyncContentTransition o remotes
 	| operationMode o /= SyncMode = noop
 	| isJust (noContentOption o) || isJust (contentOption o) = noop
 	| not (null (contentOfOption o)) = noop
 	| otherwise = getGitConfigVal' annexSyncContent >>= \case
 		HasGlobalConfig (Just _) -> noop
 		HasGitConfig (Just _) -> noop
-		_ -> showwarning
+		_ -> do
+			m <- preferredContentMap
+			hereu <- getUUID
+			when (any (`M.member` m) (hereu:map Remote.uuid remotes)) $
+				showwarning
   where
 	showwarning = earlyWarning $
-		"git-annex sync will change default behavior to operate on"
-		<> " --content in a future version of git-annex. Recommend"
-		<> " you explicitly use --no-content (or -g) to prepare for"
-		<> " that change. (Or you can configure annex.synccontent)"
+		"git-annex sync will change default behavior in the future to"
+		<> " send content to repositories that have"
+		<> " preferred content configured. If you do not want this to"
+		<> " send any content, use --no-content (or -g)"
+		<> " to prepare for that change."
+		<> " (Or you can configure annex.synccontent)"
 
 notOnlyAnnex :: SyncOptions -> Annex Bool
 notOnlyAnnex o = not <$> onlyAnnex o

doc/bugs/Changing_sync_to_include_content_breaks_UX.mdwn

@@ -64,3 +64,5 @@ Absolutely.  I've been using git-annex since nearly the beginning; and use it ex
 Thanks for writing git-annex.  It's the reason I've been sponsoring you on Patreon for years.
 
 Please don't break backwards compatibility.  Even in the user experience :-)
+
+> [[closing|done]] per new plan --[[Joey]]

doc/bugs/Changing_sync_to_include_content_breaks_UX/comment_19_bdc211b026d3b05de127f6ed5a3d19b0._comment

@@ -0,0 +1,21 @@
+[[!comment format=mdwn
+ username="joey"
+ subject="""comment 19"""
+ date="2023-08-14T16:56:48Z"
+ content="""
+Changing the default preferred content expression to `present` rather than
+`anything` would affect other things like `get --auto` and the assistant. I
+don't think that is a good idea.
+
+My idea in comment #15 is a special case for sync and not a wider change.
+
+It will have a special case either way. The current special case means
+that users who have set preferred content need to remember to use `sync
+--content`. The new special case will only manifest as a difference in
+behavior between `sync` and `sync --content` (and `get --auto` etc)
+for users with no preferred content configured.
+
+I do think that's a valuable narrowing of the special case.
+
+Gone ahead and changed the warning.
+"""]]

doc/git-annex-sync.mdwn

@@ -16,6 +16,7 @@ previously been added to the repository. Then it does the equivilant of
 
 However, unlike those commands, this command does not transfer annexed
 content by default. That will change in a future version of git-annex,
+when syncing with repositories that have preferred content configured.
 
 # OPTIONS
 

doc/todo/finish_sync_content_transition.mdwn

@@ -0,0 +1,14 @@
+This transition is from `git-annex sync` needing `--content` to send
+content to repositories that have preferred content configured, to sending
+content by default to such repositories.
+
+There should be no change in behavior with repositories that don't have
+preferred content configured. `sync` without `--content` won't populate them
+since that would be a surprising thing and a warning based transition was
+judged by the community to be not sufficient to avoid that possible large
+surprise. (See [[bugs/Changing_sync_to_include_content_breaks_UX]])
+
+A warning was added in August 2023 when it's run in a way that will change
+behavior. It would be good to wait until all git-annex users have gotten
+the version with the warning, and used it for a while, before finishing the
+transition.

doc/todo/v11_changes.mdwn

@@ -10,10 +10,3 @@ version.
   after upgrading to the repo version that enables this. Depending on the
   timing of v11, this may need to be put in a v12 upgrade that is delayed
   some amount of time (eg 1 year) after v11.
-
-* Finish the transition of git-annex sync defaulting to --content.
-  A warning was added in May 2023 when it's run in a way that will change
-  behavior. It would be good to wait until all git-annex users have
-  gotten the version with the warning, and used it for a while,
-  before finishing the transition. This does not need to be tied to a
-  repository version change really, but it would be reasonable to do so.