merge revision(s) 39a2ba5cc559900c30c3143da32446c2f20a7484: [Backport #17806]

	Method cache: fix refinement entry handling

	To invalidate some callable method entries, we replace the entry in the
	class. Most types of method entries are on the method table of the
	origin class, but refinement entries without an orig_me are housed in
	the method table of the class itself. They are there because refinements
	take priority over prepended methods.

	By unconditionally inserting a copy of the refinement entry into the
	origin class, clearing the method cache created situations where there
	are refinement entry duplicates in the lookup chain, leading to infinite
	loops and other problems.

	Update the replacement logic to use the right class that houses the
	method entry. Also, be more selective about cache invalidation when
	moving refinement entries for prepend. This avoids calling
	clear_method_cache_by_id_in_class() before refinement entries are in the
	place it expects.

	[Bug #17806]
	---
	 class.c                      |  4 +++-
	 test/ruby/test_refinement.rb | 49 ++++++++++++++++++++++++++++++++++++++++++++
	 vm_method.c                  | 13 ++++++++++--
	 3 files changed, 63 insertions(+), 3 deletions(-)

4 files changed, 64 insertions, 4 deletions

diff --git a/class.c b/class.c
index 47f35b1f90..b607135e2f 100644
--- a/class.c
+++ b/class.c
@@ -1134,10 +1134,12 @@ cache_clear_refined_method(ID key, VALUE value, void *data)
 {
     rb_method_entry_t *me = (rb_method_entry_t *) value;
 
-    if (me->def->type == VM_METHOD_TYPE_REFINED) {
+    if (me->def->type == VM_METHOD_TYPE_REFINED && me->def->body.refined.orig_me) {
         VALUE klass = (VALUE)data;
         rb_clear_method_cache(klass, me->called_id);
     }
+    // Refined method entries without an orig_me is going to stay in the method
+    // table of klass, like before the move, so no need to clear the cache.
 
     return ID_TABLE_CONTINUE;
 }
diff --git a/test/ruby/test_refinement.rb b/test/ruby/test_refinement.rb
index c364de46e4..b386c3a8d7 100644
--- a/test/ruby/test_refinement.rb
+++ b/test/ruby/test_refinement.rb
@@ -2488,6 +2488,55 @@ class TestRefinement < Test::Unit::TestCase
     }
   end
 
+  def test_defining_after_cached
+    klass = Class.new
+    refinement = Module.new { refine(klass) { def foo; end } }
+    klass.new.foo rescue nil # cache the refinement method entry
+    klass.define_method(:foo) { 42 }
+    assert_equal(42, klass.new.foo)
+  end
+
+  # [Bug #17806]
+  def test_two_refinements_for_prepended_class
+    assert_normal_exit %q{
+      module R1
+        refine Hash do
+          def foo; :r1; end
+        end
+      end
+
+      class Hash
+        prepend(Module.new)
+      end
+
+      class Hash
+        def foo; end
+      end
+
+      {}.method(:foo) # put it on pCMC
+
+      module R2
+        refine Hash do
+          def foo; :r2; end
+        end
+      end
+
+      {}.foo
+    }
+  end
+
+  # [Bug #17806]
+  def test_redefining_refined_for_prepended_class
+    klass = Class.new { def foo; end }
+    _refinement = Module.new do
+      refine(klass) { def foo; :refined; end }
+    end
+    klass.prepend(Module.new)
+    klass.new.foo # cache foo
+    klass.define_method(:foo) { :second }
+    assert_equal(:second, klass.new.foo)
+  end
+
   private
 
   def eval_using(mod, s)
diff --git a/version.h b/version.h
index 70e00e7b80..a9ea2b3e39 100644
--- a/version.h
+++ b/version.h
@@ -12,7 +12,7 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 2
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 91
+#define RUBY_PATCHLEVEL 92
 
 #define RUBY_RELEASE_YEAR 2021
 #define RUBY_RELEASE_MONTH 5
diff --git a/vm_method.c b/vm_method.c
index 453cbed499..a467ac173c 100644
--- a/vm_method.c
+++ b/vm_method.c
@@ -8,6 +8,7 @@
 
 static int vm_redefinition_check_flag(VALUE klass);
 static void rb_vm_check_redefinition_opt_method(const rb_method_entry_t *me, VALUE klass);
+static inline rb_method_entry_t *lookup_method_table(VALUE klass, ID id);
 
 #define object_id           idObject_id
 #define added               idMethod_added
@@ -173,9 +174,17 @@ clear_method_cache_by_id_in_class(VALUE klass, ID mid)
                     // invalidate cc by invalidating cc->cme
                     VALUE owner = cme->owner;
                     VM_ASSERT(BUILTIN_TYPE(owner) == T_CLASS);
+                    VALUE klass_housing_cme;
+                    if (cme->def->type == VM_METHOD_TYPE_REFINED && !cme->def->body.refined.orig_me) {
+                        klass_housing_cme = owner;
+                    }
+                    else {
+                        klass_housing_cme = RCLASS_ORIGIN(owner);
+                    }
+                    // replace the cme that will be invalid
+                    VM_ASSERT(lookup_method_table(klass_housing_cme, mid) == (const rb_method_entry_t *)cme);
                     const rb_method_entry_t *new_cme = rb_method_entry_clone((const rb_method_entry_t *)cme);
-                    VALUE origin = RCLASS_ORIGIN(owner);
-                    rb_method_table_insert(origin, RCLASS_M_TBL(origin), mid, new_cme);
+                    rb_method_table_insert(klass_housing_cme, RCLASS_M_TBL(klass_housing_cme), mid, new_cme);
                 }
 
                 vm_me_invalidate_cache((rb_callable_method_entry_t *)cme);