1 files changed, 22 insertions, 1 deletions

diff --git a/spec/ruby/optional/capi/ext/mutex_spec.c b/spec/ruby/optional/capi/ext/mutex_spec.c
index c2fdf917ac..d2c8f98e89 100644
--- a/spec/ruby/optional/capi/ext/mutex_spec.c
+++ b/spec/ruby/optional/capi/ext/mutex_spec.c
@@ -29,15 +29,34 @@ VALUE mutex_spec_rb_mutex_sleep(VALUE self, VALUE mutex, VALUE timeout) {
   return rb_mutex_sleep(mutex, timeout);
 }
 
-
 VALUE mutex_spec_rb_mutex_callback(VALUE arg) {
   return rb_funcall(arg, rb_intern("call"), 0);
 }
 
+VALUE mutex_spec_rb_mutex_naughty_callback(VALUE arg) {
+  int *result = (int *) arg;
+  return (VALUE) result;
+}
+
+VALUE mutex_spec_rb_mutex_callback_basic(VALUE arg) {
+  return arg;
+}
+
 VALUE mutex_spec_rb_mutex_synchronize(VALUE self, VALUE mutex, VALUE value) {
   return rb_mutex_synchronize(mutex, mutex_spec_rb_mutex_callback, value);
 }
 
+VALUE mutex_spec_rb_mutex_synchronize_with_naughty_callback(VALUE self, VALUE mutex) {
+  // a naughty callback accepts or returns not a Ruby object but arbitrary value
+  int arg = 42;
+  VALUE result = rb_mutex_synchronize(mutex, mutex_spec_rb_mutex_naughty_callback, (VALUE) &arg);
+  return INT2NUM(*((int *) result));
+}
+
+VALUE mutex_spec_rb_mutex_synchronize_with_native_callback(VALUE self, VALUE mutex, VALUE value) {
+  return rb_mutex_synchronize(mutex, mutex_spec_rb_mutex_callback_basic, value);
+}
+
 void Init_mutex_spec(void) {
   VALUE cls = rb_define_class("CApiMutexSpecs", rb_cObject);
   rb_define_method(cls, "rb_mutex_new", mutex_spec_rb_mutex_new, 0);
@@ -47,6 +66,8 @@ void Init_mutex_spec(void) {
   rb_define_method(cls, "rb_mutex_unlock", mutex_spec_rb_mutex_unlock, 1);
   rb_define_method(cls, "rb_mutex_sleep", mutex_spec_rb_mutex_sleep, 2);
   rb_define_method(cls, "rb_mutex_synchronize", mutex_spec_rb_mutex_synchronize, 2);
+  rb_define_method(cls, "rb_mutex_synchronize_with_naughty_callback", mutex_spec_rb_mutex_synchronize_with_naughty_callback, 1);
+  rb_define_method(cls, "rb_mutex_synchronize_with_native_callback", mutex_spec_rb_mutex_synchronize_with_native_callback, 2);
 }
 
 #ifdef __cplusplus