add the javascript backtrace on top of the (ruby) backtrace

lib/rhino/error.rb

@@ -46,6 +46,14 @@ module Rhino
       end
     end
     
+    def backtrace
+      if js_backtrace = javascript_backtrace
+        js_backtrace.push(*super)
+      else
+        super
+      end
+    end
+    
     def javascript_backtrace(keep_elements = false)
       if cause.is_a?(JS::RhinoException)
         cause.getScriptStack.map do |element| # ScriptStackElement[]

spec/rhino/error_spec.rb

@@ -78,7 +78,6 @@ describe Rhino::JSError do
     begin
       Rhino::Context.eval "throw 42"
     rescue => e
-      e.javascript_backtrace.should_not be nil
       e.javascript_backtrace.should be_a Enumerable
       e.javascript_backtrace.size.should == 1
       e.javascript_backtrace[0].should == "at <eval>:1"
@@ -93,5 +92,17 @@ describe Rhino::JSError do
       fail "expected to rescue"
     end
   end
+
+  it "backtrace starts with the javascript part" do
+    begin
+      Rhino::Context.eval "throw 42"
+    rescue => e
+      e.backtrace.should be_a Array
+      e.backtrace[0].should == "at <eval>:1"
+      e.backtrace[1].should_not be nil
+    else
+      fail "expected to rescue"
+    end
+  end
   
 end