Add spec for rb_protect setting errinfo.

(cherry picked from commit 398b0e9)

Author: aardvark179

spec/ruby/optional/capi/ext/kernel_spec.c

@@ -191,6 +191,14 @@ static VALUE kernel_spec_rb_protect_yield(VALUE self, VALUE obj, VALUE ary) {
   return res;
 }
 
+static VALUE kernel_spec_rb_protect_errinfo(VALUE self, VALUE obj, VALUE ary) {
+  int status = 0;
+  VALUE res = rb_protect(rb_yield, obj, &status);
+  rb_ary_store(ary, 0, INT2NUM(23));
+  rb_ary_store(ary, 1, res);
+  return rb_errinfo();
+}
+
 static VALUE kernel_spec_rb_protect_null_status(VALUE self, VALUE obj) {
   return rb_protect(rb_yield, obj, NULL);
 }
@@ -345,6 +353,7 @@ void Init_kernel_spec(void) {
   rb_define_method(cls, "rb_rescue", kernel_spec_rb_rescue, 4);
   rb_define_method(cls, "rb_rescue2", kernel_spec_rb_rescue2, -1);
   rb_define_method(cls, "rb_protect_yield", kernel_spec_rb_protect_yield, 2);
+  rb_define_method(cls, "rb_protect_errinfo", kernel_spec_rb_protect_errinfo, 2);
   rb_define_method(cls, "rb_protect_null_status", kernel_spec_rb_protect_null_status, 1);
   rb_define_method(cls, "rb_eval_string_protect", kernel_spec_rb_eval_string_protect, 2);
   rb_define_method(cls, "rb_catch", kernel_spec_rb_catch, 2);

spec/ruby/optional/capi/kernel_spec.rb

@@ -312,6 +312,12 @@
       @s.rb_protect_null_status(42) { |x| x + 1 }.should == 43
       @s.rb_protect_null_status(42) { |x| raise }.should == nil
     end
+
+    it "ppoulates errinfo with the captured exception" do
+      proof = []
+      @s.rb_protect_errinfo(77, proof) { |x| raise NameError }.class.should == NameError
+    end
+
   end
 
   describe "rb_eval_string_protect" do