error.c: redefined backtrace

* error.c (rb_get_backtrace): honor redefined Exception#backtrace
  method.  [ruby-core:78097] [Bug #12925]

* eval.c (setup_exception): rescue exceptions during backtrace
  setup.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@56767 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

1 files changed, 13 insertions, 10 deletions

diff --git a/error.c b/error.c
index 4503742896..e03a4eea39 100644
--- a/error.c
+++ b/error.c
@@ -885,17 +885,20 @@ exc_backtrace(VALUE exc)
 VALUE
 rb_get_backtrace(VALUE exc)
 {
-    VALUE info, klass = rb_eException;
     ID mid = id_backtrace;
-    rb_thread_t *th = GET_THREAD();
-    if (NIL_P(exc))
-	return Qnil;
-    EXEC_EVENT_HOOK(th, RUBY_EVENT_C_CALL, exc, mid, mid, klass, Qundef);
-    info = exc_backtrace(exc);
-    EXEC_EVENT_HOOK(th, RUBY_EVENT_C_RETURN, exc, mid, mid, klass, info);
-    if (NIL_P(info))
-	return Qnil;
-    return rb_check_backtrace(info);
+    if (rb_method_basic_definition_p(CLASS_OF(exc), id_backtrace)) {
+	VALUE info, klass = rb_eException;
+	rb_thread_t *th = GET_THREAD();
+	if (NIL_P(exc))
+	    return Qnil;
+	EXEC_EVENT_HOOK(th, RUBY_EVENT_C_CALL, exc, mid, mid, klass, Qundef);
+	info = exc_backtrace(exc);
+	EXEC_EVENT_HOOK(th, RUBY_EVENT_C_RETURN, exc, mid, mid, klass, info);
+	if (NIL_P(info))
+	    return Qnil;
+	return rb_check_backtrace(info);
+    }
+    return rb_funcall(exc, mid, 0, 0);
 }
 
 /*