Re: bus error in eval.c

On Mar 9, 2004, at 8:44 PM, Ryan Davis wrote:

> I found a bus error while debugging a pathological case between 1.6 
> and 1.8 that makes my code run 100x slower in 1.8. I think I have the 
> proper patch for it. WOOT. I just found the minimally reproducible 
> test case:
>
> 	class Hash
> 	  alias :old_inspect :inspect
> 	  def inspect
> 	    raise "no"
> 	  end
> 	end
>
> 	eval "{}.blah"
>
> I've gotten this to work on ruby 1.8.1 (from cvs) on both 
> macosx/darwin and freebsd.

I messed up my fix. Correct version is most likely:

diff -d -u -r1.616.2.14 eval.c
--- eval.c      25 Feb 2004 00:38:35 -0000      1.616.2.14
+++ eval.c      10 Mar 2004 04:57:47 -0000
@@ -6047,11 +6047,13 @@

                 errat = get_backtrace(ruby_errinfo);
                 mesg  = rb_attr_get(ruby_errinfo, rb_intern("mesg"));
-               if (!NIL_P(mesg) && TYPE(mesg) == T_STRING) {
+               if (!NIL_P(errat) && TYPE(errat) == T_ARRAY) {
+                 if (!NIL_P(mesg) && TYPE(mesg) == T_STRING) {
                     rb_str_update(mesg, 0, 0, rb_str_new2(": "));
                     rb_str_update(mesg, 0, 0, RARRAY(errat)->ptr[0]);
+                 }
+                 RARRAY(errat)->ptr[0] = RARRAY(backtrace(-2))->ptr[0];
                 }
-               RARRAY(errat)->ptr[0] = RARRAY(backtrace(-2))->ptr[0];
             }
             rb_exc_raise(ruby_errinfo);
         }