Fix Issue 770: Lyrics attached to a voice-derived context are off by 1

The Lyric_combine_music_iterator had an explicit check if the CreateContext
event was really for a context of type "Voice". Unfortunately, that
check fails if the lyrics are supposed to be attached to a CueVoice
context (or some self-defined Voice-derived context!), because
"CueVoice"!="Voice".

Unfortunately, I don't know how to check whether a context "CVoice"
(identified only by a the context type string; we don't have any
Context* object!) is an alias for Voice. If we had the Context* object,
we could use is_alias, but we only have the string "CVoice" and need to
check if a context of that type is an alias for "Voice".

However, I don't think that check is necessary at all. It simply prevents
find_voice from being called in cases when no Voice is generated (and thus
no new context to possibly attach the lyrics to). If that check is removed,
find_voice will also be called for any other context created while
waiting for a voice to attach the lyrics to, but it will not find an
appropriate voice anyway.

diff --git a/input/regression/lyric-combine-derived-voice.ly b/input/regression/lyric-combine-derived-voice.ly
new file mode 100644 (file)
index 0000000..a5f4316
--- /dev/null
+++ b/input/regression/lyric-combine-derived-voice.ly
@@ -0,0 +1,18 @@
+\version "2.15.4"
+\header {
+  texidoc = "For Voice-derived contexts like CueVoice, the lyrics should
+still start with the first note."
+}
+
+\score {
+  \new Staff <<
+    \new Voice \relative c'' {
+      g2 
+      <<
+          { \voiceOne r2 }
+          \new CueVoice = "cue" { \voiceTwo g4 g }
+      >>
+  }
+  \context Lyrics \lyricsto "cue" { A B }
+  >>
+}

diff --git a/lily/lyric-combine-music-iterator.cc b/lily/lyric-combine-music-iterator.cc
index 7487e2f91b2b1ccb5a88591846119fdec6041aef..65784f130f141cfef14926a6b3fdbc142c54c9f6 100644 (file)
--- a/lily/lyric-combine-music-iterator.cc
+++ b/lily/lyric-combine-music-iterator.cc
@@ -225,13 +225,9 @@ Lyric_combine_music_iterator::check_new_context (SCM sev)
   if (!ok ())
     return ;
   
-  // TODO: Check first if type=Voice and if id matches
-  Stream_event * ev = unsmob_stream_event (sev);
-  if (ev->get_property ("type") != ly_symbol2scm ("Voice"))
-    return ;
-  
+  // Search for a possible candidate voice to attach the lyrics to. If none
+  // is found, we'll try next time again.
   Context *voice = find_voice ();
-
   if (voice)
     {
       set_music_context (voice);