From: Neil Puttock <n.puttock@gmail.com>
Date: Fri, 19 Jun 2009 22:26:29 +0000 (+0100)
Subject: Fix #781.
X-Git-Tag: release/2.12.3-1~81
X-Git-Url: https://git.donarmstrong.com/lilypond.git?a=commitdiff_plain;h=90192e0047f4b2c1ebf23ff77f670c7d9e6c2869;p=lilypond.git

Fix #781.

- don't dereference non-existent event-cause, which may occur if the
Ambitus_engraver is erroneously added to both the Staff and Voice contexts:
in such a situation, Ambitus_engraver::acknowledge_note_head () will acknowledge
an AmbitusNoteHead, which has no event-cause.
(cherry picked from commit d511b69c1cb8836bc0b7b49b9f396cf06fef19ac)
---

diff --git a/lily/ambitus-engraver.cc b/lily/ambitus-engraver.cc
index 202e691d21..2585bd8bc1 100644
--- a/lily/ambitus-engraver.cc
+++ b/lily/ambitus-engraver.cc
@@ -121,15 +121,15 @@ void
 Ambitus_engraver::acknowledge_note_head (Grob_info info)
 {
   Stream_event *nr = info.event_cause ();
-  SCM p = nr->get_property ("pitch");
-  /*
-    If the engraver is added to a percussion context,
-    filter out unpitched note heads.
-  */
-  if (!unsmob_pitch (p))
-    return;
   if (nr && nr->in_event_class ("note-event"))
     {
+      SCM p = nr->get_property ("pitch");
+      /*
+	If the engraver is added to a percussion context,
+	filter out unpitched note heads.
+      */
+      if (!unsmob_pitch (p))
+	return;
       Pitch pitch = *unsmob_pitch (p);
       Drul_array<bool> expands = pitch_interval_.add_point (pitch);
       if (expands[UP])