From eeef16e190cdabc2ba474622720f8e3df7bac43b Mon Sep 17 00:00:00 2001
From: Jeremy Evans <code@jeremyevans.net>
Date: Fri, 10 Jul 2020 14:38:00 -0700
Subject: [PATCH] Prevent SystemStackError when calling super in module with
 activated refinement

Without this, if a refinement defines a method that calls super and
includes a module with a module that calls super and has a activated
refinement at the point super is called, the module method super call
will end up calling back into the refinement method, creating a loop.

Fixes [Bug #17007]
---
 test/ruby/test_refinement.rb | 31 +++++++++++++++++++++++++++++++
 vm_insnhelper.c              |  3 +++
 2 files changed, 34 insertions(+)

diff --git a/test/ruby/test_refinement.rb b/test/ruby/test_refinement.rb
index 785113de77..e4a5cd25d2 100644
--- a/test/ruby/test_refinement.rb
+++ b/test/ruby/test_refinement.rb
@@ -484,6 +484,37 @@ class TestRefinement < Test::Unit::TestCase
     assert_equal("M#baz C#baz", RefineModule.call_baz)
   end
 
+  module RefineIncludeActivatedSuper
+    class C
+      def foo
+        ["C"]
+      end
+    end
+
+    module M; end
+
+    refinement = Module.new do
+      R = refine C do
+        def foo
+          ["R"] + super
+        end
+
+        include M
+      end
+    end
+
+    using refinement
+    M.define_method(:foo){["M"] + super()}
+
+    def self.foo
+      C.new.foo
+    end
+  end
+
+  def test_refine_include_activated_super
+    assert_equal(["R", "M", "C"], RefineIncludeActivatedSuper.foo)
+  end
+
   def test_refine_neither_class_nor_module
     assert_raise(TypeError) do
       Module.new {
diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index b69fd55259..e6228fb466 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -3034,6 +3034,9 @@ search_refined_method(rb_execution_context_t *ec, rb_control_frame_t *cfp, struc
         if (ref_me) {
             if (vm_cc_call(cc) == vm_call_super_method) {
                 const rb_control_frame_t *top_cfp = current_method_entry(ec, cfp);
+                if (refinement == find_refinement(CREF_REFINEMENTS(vm_get_cref(top_cfp->ep)), vm_cc_cme(cc)->owner)) {
+                    continue;
+                }
                 const rb_callable_method_entry_t *top_me = rb_vm_frame_method_entry(top_cfp);
                 if (top_me && rb_method_definition_eq(ref_me->def, top_me->def)) {
                     continue;