From e7e1ce259bcd834a233bc5a54e39109301a821bf Mon Sep 17 00:00:00 2001
From: David Kastrup <dak@gnu.org>
Date: Tue, 18 Aug 2015 11:03:03 +0200
Subject: [PATCH] Issue 4569: Keep \autochange from escaping an existing
 context hierarchy

---
 ly/music-functions-init.ly           | 24 +++++++++++-------------
 scm/define-music-display-methods.scm |  5 ++++-
 2 files changed, 15 insertions(+), 14 deletions(-)

diff --git a/ly/music-functions-init.ly b/ly/music-functions-init.ly
index 54590a4cdd..16b57a97d9 100644
--- a/ly/music-functions-init.ly
+++ b/ly/music-functions-init.ly
@@ -189,19 +189,17 @@ pitch where to switch staves may be specified.  The clefs for the staves are
 optional as well.  Setting clefs  works only for implicitly instantiated
 staves.")
   (let ;; keep the contexts alive for the full duration
-       ((skip (make-skip-music (make-duration-of-length
-                                     (ly:music-length music)))))
-    #{
-      <<
-        \context Staff = "up" $(or clef-1 #{ \with { \clef "treble" } #})
-          <<
-          #(make-autochange-music pitch music)
-          \new Voice { #skip }
-          >>
-        \context Staff = "down" $(or clef-2 #{ \with { \clef "bass" } #})
-          \new Voice { #skip }
-      >>
-    #}))
+       ((skip (make-duration-of-length (ly:music-length music)))
+        (clef-1 (or clef-1 #{ \with { \clef "treble" } #}))
+        (clef-2 (or clef-2 #{ \with { \clef "bass" } #})))
+    (make-simultaneous-music
+     (list
+      (descend-to-context (make-autochange-music pitch music) 'Staff
+                          "up" clef-1)
+      (context-spec-music (make-skip-music skip) 'Staff
+                          "up" clef-1)
+      (context-spec-music (make-skip-music skip) 'Staff
+                          "down" clef-2)))))
 
 balloonGrobText =
 #(define-music-function (grob-name offset text)
diff --git a/scm/define-music-display-methods.scm b/scm/define-music-display-methods.scm
index c1ee87bbf8..0b9cb54fbb 100644
--- a/scm/define-music-display-methods.scm
+++ b/scm/define-music-display-methods.scm
@@ -1119,7 +1119,10 @@ Otherwise, return #f."
                                  elements ((music 'ContextSpeccedMusic
                                                   context-id "up"
                                                   context-type 'Staff
-                                                  element (music 'SimultaneousMusic elements (?ac-music)))
+                                                  element ?ac-music)
+                                           (music 'ContextSpeccedMusic
+                                                  context-id "up"
+                                                  context-type 'Staff)
                                            (music 'ContextSpeccedMusic
                                                   context-id "down"
                                                   context-type 'Staff))))
-- 
2.39.2