git style filename quoting controlled by core.quotePath

This is by no means complete, but escaping filenames in actionItemDesc does
cover most commands.

Note that for ActionItemBranchFilePath, the value is branch:file, and I
choose to only quote the file part (if necessary). I considered quoting the
whole thing. But, branch names cannot contain control characters, and while
they can contain unicode, git coes not quote unicode when displaying branch
names. So, it would be surprising for git-annex to quote unicode in a
branch name.

The find command is the most obvious command that still needs to be
dealt with. There are probably other places that filenames also get
displayed, eg embedded in error messages.

Some other commands use ActionItemOther with a filename, I think that
ActionItemOther should either be pre-sanitized, or should explicitly not
be used for filenames, so that needs more work.

When --json is used, unicode does not get escaped, but control
characters were already escaped in json.

(Key escaping may turn out to be needed, but I'm ignoring that for now.)

Sponsored-by: unqueued on Patreon

Messages.hs

@@ -1,6 +1,6 @@
 {- git-annex output messages
  -
- - Copyright 2010-2021 Joey Hess <id@joeyh.name>
+ - Copyright 2010-2023 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -62,7 +62,6 @@ import Types.Messages
 import Types.ActionItem
 import Types.Concurrency
 import Types.Command (StartMessage(..), SeekInput)
-import Types.Transfer (transferKey)
 import Messages.Internal
 import Messages.Concurrent
 import Annex.Debug
@@ -76,11 +75,13 @@ showStart command file si = outputMessage json $
   where
 	json = JSON.start command (Just file) Nothing si
 
-showStartKey :: String -> Key -> ActionItem -> SeekInput -> Annex ()
-showStartKey command key ai si = outputMessage json $
-	encodeBS command <> " " <> actionItemDesc ai <> " "
+showStartActionItem :: String -> ActionItem -> SeekInput -> Annex ()
+showStartActionItem command ai si = do
+	qp <- coreQuotePath <$> Annex.getGitConfig
+	outputMessage json $
+		encodeBS command <> " " <> actionItemDesc qp ai <> " "
   where
-	json = JSON.start command (actionItemFile ai) (Just key) si
+	json = JSON.start command (actionItemFile ai) (actionItemKey ai) si
 
 showStartOther :: String -> Maybe String -> SeekInput -> Annex ()
 showStartOther command mdesc si = outputMessage json $ encodeBS $
@@ -90,11 +91,11 @@ showStartOther command mdesc si = outputMessage json $ encodeBS $
 
 showStartMessage :: StartMessage -> Annex ()
 showStartMessage (StartMessage command ai si) = case ai of
-	ActionItemAssociatedFile _ k -> showStartKey command k ai si
-	ActionItemKey k -> showStartKey command k ai si
-	ActionItemBranchFilePath _ k -> showStartKey command k ai si
-	ActionItemFailedTransfer t _ -> showStartKey command (transferKey t) ai si
-	ActionItemTreeFile file -> showStart command file si
+	ActionItemAssociatedFile _ _ -> showStartActionItem command ai si
+	ActionItemKey _ -> showStartActionItem command ai si
+	ActionItemBranchFilePath _ _ -> showStartActionItem command ai si
+	ActionItemFailedTransfer _ _ -> showStartActionItem command ai si
+	ActionItemTreeFile _ -> showStartActionItem command ai si
 	ActionItemOther msg -> showStartOther command msg si
 	OnlyActionOn _ ai' -> showStartMessage (StartMessage command ai' si)
 showStartMessage (StartUsualMessages command ai si) = do
@@ -235,7 +236,7 @@ showFullJSON v = withMessageState $ bufferJSON (JSON.complete v)
 {- Performs an action that outputs nonstandard/customized output, and
  - in JSON mode wraps its output in JSON.start and JSON.end, so it's
  - a complete JSON document.
- - This is only needed when showStart and showEndOk is not used.
+ - This is only needed when showStart* and showEndOk is not used.
  -}
 showCustom :: String -> SeekInput -> Annex Bool -> Annex ()
 showCustom command si a = do