Fix issue 542: Harden Grob::relative_coordinate()

diff --git a/lily/grob.cc b/lily/grob.cc
index fbb4683f4a7f2173c1d9e70b2afe7d86db73cd20..7f78b5ff60112937bc5745106da7e2b96535fcab 100644 (file)
--- a/lily/grob.cc
+++ b/lily/grob.cc
@@ -265,7 +265,8 @@ Grob::translate_axis (Real y, Axis a)
 Real
 Grob::relative_coordinate (Grob const *refp, Axis a) const
 {
-  if (refp == this)
+  /* eaa - hmmm, should we do a programming_error() here? */
+  if ((this == NULL) || (refp == this))
     return 0.0;
 
   /* We catch PARENT_L_ == nil case with this, but we crash if we did