eval_error.c: fix loop on exception in message

* error.c (rb_get_message): accessor to the message.

* eval_error.c (rb_ec_error_print): handle exceptions on fetching
  the message.  [Bug #14566]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@63133 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

3 files changed, 35 insertions, 13 deletions

diff --git a/error.c b/error.c
index ba6f1ea689..c8b9404c63 100644
--- a/error.c
+++ b/error.c
@@ -980,7 +980,16 @@ exc_to_s(VALUE exc)
 }
 
 /* FIXME: Include eval_error.c */
-void rb_error_write(VALUE errinfo, VALUE errat, VALUE str, VALUE highlight, VALUE reverse);
+void rb_error_write(VALUE errinfo, VALUE emesg, VALUE errat, VALUE str, VALUE highlight, VALUE reverse);
+
+VALUE
+rb_get_message(VALUE exc)
+{
+    VALUE e = rb_check_funcall(exc, id_message, 0, 0);
+    if (e == Qundef) return Qnil;
+    if (!RB_TYPE_P(e, T_STRING)) e = rb_check_string_type(e);
+    return e;
+}
 
 /*
  * call-seq:
@@ -1015,7 +1024,7 @@ exc_s_to_tty_p(VALUE self)
 static VALUE
 exc_full_message(int argc, VALUE *argv, VALUE exc)
 {
-    VALUE opt, str, errat;
+    VALUE opt, str, emesg, errat;
     enum {kw_highlight, kw_order, kw_max_};
     static ID kw[kw_max_];
     VALUE args[kw_max_] = {Qnil, Qnil};
@@ -1051,8 +1060,9 @@ exc_full_message(int argc, VALUE *argv, VALUE exc)
     }
     str = rb_str_new2("");
     errat = rb_get_backtrace(exc);
+    emesg = rb_get_message(exc);
 
-    rb_error_write(exc, errat, str, args[kw_highlight], args[kw_order]);
+    rb_error_write(exc, emesg, errat, str, args[kw_highlight], args[kw_order]);
     return str;
 }
 
diff --git a/eval_error.c b/eval_error.c
index 5495a36c19..99941163d5 100644
--- a/eval_error.c
+++ b/eval_error.c
@@ -221,9 +221,9 @@ print_backtrace(const VALUE eclass, const VALUE errat, const VALUE str, int reve
 }
 
 void
-rb_error_write(VALUE errinfo, VALUE errat, VALUE str, VALUE highlight, VALUE reverse)
+rb_error_write(VALUE errinfo, VALUE emesg, VALUE errat, VALUE str, VALUE highlight, VALUE reverse)
 {
-    volatile VALUE eclass = Qundef, emesg = Qundef;
+    volatile VALUE eclass;
 
     if (NIL_P(errinfo))
 	return;
@@ -231,13 +231,7 @@ rb_error_write(VALUE errinfo, VALUE errat, VALUE str, VALUE highlight, VALUE rev
     if (errat == Qundef) {
 	errat = Qnil;
     }
-    if ((eclass = CLASS_OF(errinfo)) != Qundef) {
-	VALUE e = rb_check_funcall(errinfo, rb_intern("message"), 0, 0);
-	if (e != Qundef) {
-	    if (!RB_TYPE_P(e, T_STRING)) e = rb_check_string_type(e);
-	    emesg = e;
-	}
-    }
+    eclass = CLASS_OF(errinfo);
     if (NIL_P(reverse) || NIL_P(highlight)) {
 	VALUE tty = (VALUE)rb_stderr_tty_p();
 	if (NIL_P(reverse)) reverse = tty;
@@ -269,11 +263,14 @@ rb_error_write(VALUE errinfo, VALUE errat, VALUE str, VALUE highlight, VALUE rev
     }
 }
 
+VALUE rb_get_message(VALUE exc);
+
 void
 rb_ec_error_print(rb_execution_context_t * volatile ec, volatile VALUE errinfo)
 {
     volatile int raised_flag = ec->raised_flag;
     volatile VALUE errat = Qundef;
+    volatile VALUE emesg = Qundef;
 
     if (NIL_P(errinfo))
 	return;
@@ -283,8 +280,12 @@ rb_ec_error_print(rb_execution_context_t * volatile ec, volatile VALUE errinfo)
     if (EC_EXEC_TAG() == TAG_NONE) {
 	errat = rb_get_backtrace(errinfo);
     }
+    if (emesg == Qundef) {
+	emesg = Qnil;
+	emesg = rb_get_message(errinfo);
+    }
 
-    rb_error_write(errinfo, errat, Qnil, Qnil, Qnil);
+    rb_error_write(errinfo, emesg, errat, Qnil, Qnil, Qnil);
 
     EC_POP_TAG();
     ec->errinfo = errinfo;
diff --git a/test/ruby/test_exception.rb b/test/ruby/test_exception.rb
index 61521cbfff..43115de3bd 100644
--- a/test/ruby/test_exception.rb
+++ b/test/ruby/test_exception.rb
@@ -1309,4 +1309,15 @@ $stderr = $stdout; raise "\x82\xa0"') do |outs, errs, status|
       assert_operator(message, :end_with?, top)
     end
   end
+
+  def test_exception_in_message
+    code = "#{<<~"begin;"}\n#{<<~'end;'}"
+    begin;
+      class Bug14566 < StandardError
+        def message; raise self.class; end
+      end
+      raise Bug14566
+    end;
+    assert_in_out_err([], code, [], /Bug14566/, success: false, timeout: 1)
+  end
 end