diff --git a/ruby/ext/google/protobuf_c/protobuf.c b/ruby/ext/google/protobuf_c/protobuf.c
index bee8ac288f71..bc318366ad22 100644
--- a/ruby/ext/google/protobuf_c/protobuf.c
+++ b/ruby/ext/google/protobuf_c/protobuf.c
@@ -403,6 +403,9 @@ void ObjectCache_Add(const void *key, VALUE val) {
 #if USE_SECONDARY_MAP
   rb_mutex_unlock(secondary_map_mutex);
 #endif
+  if (ObjectCache_Get(key) != val) {
+      rb_bug("ObjectCache_Get(key) != val");
+  }
   PBRUBY_ASSERT(ObjectCache_Get(key) == val);
 }
 
diff --git a/ruby/ext/google/protobuf_c/protobuf.h b/ruby/ext/google/protobuf_c/protobuf.h
index c6af98fa4727..a4e31d157dd6 100644
--- a/ruby/ext/google/protobuf_c/protobuf.h
+++ b/ruby/ext/google/protobuf_c/protobuf.h
@@ -110,8 +110,12 @@ extern VALUE cTypeError;
   do {                      \
   } while (false && (expr))
 #else
+#ifdef RUBY_ASSERT
+#define PBRUBY_ASSERT RUBY_ASSERT
+#else
 #define PBRUBY_ASSERT(expr) assert(expr)
-#endif
+#endif // RUBY_ASSERT
+#endif // NDEBUG
 
 #define PBRUBY_MAX(x, y) (((x) > (y)) ? (x) : (y))
 
diff --git a/ruby/ext/google/protobuf_c/repeated_field.c b/ruby/ext/google/protobuf_c/repeated_field.c
index 700ca16f38a6..2be23f4242f3 100644
--- a/ruby/ext/google/protobuf_c/repeated_field.c
+++ b/ruby/ext/google/protobuf_c/repeated_field.c
@@ -432,7 +432,7 @@ static VALUE RepeatedField_dup(VALUE _self) {
  */
 VALUE RepeatedField_to_ary(VALUE _self) {
   RepeatedField* self = ruby_to_RepeatedField(_self);
-  int size = upb_Array_Size(self->array);
+  int size = self->array ? upb_Array_Size(self->array) : 0;
   VALUE ary = rb_ary_new2(size);
   int i;
 
diff --git a/ruby/tests/basic.rb b/ruby/tests/basic.rb
index 7351b9cd33e1..22ceab71f190 100755
--- a/ruby/tests/basic.rb
+++ b/ruby/tests/basic.rb
@@ -467,6 +467,19 @@ def test_map_wrappers_with_no_value
       run_asserts.call(m4)
     end
 
+    def test_gc_stress
+      GC.stress = true
+      o = Outer.new
+      o.items[0] = Inner.new
+      raw = Outer.encode(o)
+
+      10.times do
+        assert_equal o, Outer.decode(raw)
+      end
+    ensure
+      GC.stress = false
+    end
+
     def test_concurrent_decoding
       o = Outer.new
       o.items[0] = Inner.new