Ensure non-breakpoints are also non-turnpoints.

[lilypond.git] / lily / page-turn-page-breaking.cc

diff --git a/lily/page-turn-page-breaking.cc b/lily/page-turn-page-breaking.cc
index 163cdd1fc015f8105ad4b66fd369519c55201dab..c9029cf7b53e649fde6ff4455b468976b9c9117c 100644 (file)
--- a/lily/page-turn-page-breaking.cc
+++ b/lily/page-turn-page-breaking.cc
@@ -32,7 +32,17 @@
 static bool
 is_break (Grob *g)
 {
-  return scm_is_symbol (g->get_property ("page-turn-permission"));
+  bool turnable = scm_is_symbol (g->get_property ("page-turn-permission"));
+
+  if (turnable &&
+      (!scm_is_symbol (g->get_property ("page-break-permission"))
+       || !scm_is_symbol (g->get_property ("line-break-permission"))))
+    {
+      programming_error ("found a page-turnable place which was not breakable");
+      turnable = false;
+    }
+
+  return turnable;
 }
 
 Page_turn_page_breaking::Page_turn_page_breaking (Paper_book *pb)