Don't segfault on invalid engraver names.

Generate the definition for procedure scheme engravers properly.

2 files changed, 25 insertions, 10 deletions

diff --git a/input/regression/invalid-engraver.ly b/input/regression/invalid-engraver.ly
new file mode 100644
index 0000000000..e3a1fa5731
--- /dev/null
+++ b/input/regression/invalid-engraver.ly
@@ -0,0 +1,16 @@
+\version "2.13.23"
+
+#(ly:set-option 'warning-as-error #f)
+
+\header {
+  texidoc = "Engravers which do not exist produce a warning."
+}
+
+\layout {
+  \context {
+    \Voice
+    \consists "Rhythmic_column_engraver_foo"
+  }
+}
+
+{ a4 }
diff --git a/lily/translator-group.cc b/lily/translator-group.cc
index dc2b772428..84a97bf52e 100644
--- a/lily/translator-group.cc
+++ b/lily/translator-group.cc
@@ -153,35 +153,34 @@ Translator_group::create_child_translator (SCM sev)
   for (SCM s = trans_names; scm_is_pair (s); s = scm_cdr (s))
     {
       SCM definition = scm_car (s);
+      bool is_scheme = false;
 
       Translator *type = 0;
-      Translator *instance = type;
       if (ly_is_symbol (definition))
-	{
-	  type = get_translator (definition);
-	  instance = type->clone ();
-	}
+	type = get_translator (definition);
       else if (ly_is_pair (definition))
 	{
 	  type = get_translator (ly_symbol2scm ("Scheme_engraver"));
-	  instance = type->clone ();
-	  dynamic_cast<Scheme_engraver*> (instance)->init_from_scheme (definition);
+	  is_scheme = true;
 	}
       else if (ly_is_procedure (definition))
 	{
 	  // `definition' is a procedure, which takes the context as
 	  // an argument and evaluates to an a-list scheme engraver
 	  // definition.
-	  SCM def = scm_call_1 (definition, cs);
+	  definition = scm_call_1 (definition, cs);
 	  type = get_translator (ly_symbol2scm ("Scheme_engraver"));
-	  instance = type->clone ();
-	  dynamic_cast<Scheme_engraver*> (instance)->init_from_scheme (def);
+	  is_scheme = true;
 	}
 	 
       if (!type)
 	warning (_f ("cannot find: `%s'", ly_symbol2string (scm_car (s)).c_str ()));
       else
 	{
+	  Translator *instance = type->clone ();
+	  if (is_scheme)
+	    dynamic_cast<Scheme_engraver *> (instance)->init_from_scheme (definition);
+
 	  SCM str = instance->self_scm ();
 
 	  if (instance->must_be_last ())