Restore the original order of const_added and inherited callbacks

Originally, if a class was defined with the class keyword, the cref had a
const_added callback, and the superclass an inherited callback, const_added was
called first, and inherited second.

This was discussed in

    https://bugs.ruby-lang.org/issues/21143

and an attempt at changing this order was made.

While both constant assignment and inheritance have happened before these
callbacks are invoked, it was deemed nice to have the same order as in

    C = Class.new

This was mostly for alignment: In that last use case things happen at different
times and therefore the order of execution is kind of obvious, whereas when the
class keyword is involved, the order is opaque to the user and it is up to the
interpreter.

However, soon in

    https://bugs.ruby-lang.org/issues/21193

Matz decided to play safe and keep the existing order.

This reverts commits:

    de097fbe5f3df105bd2a26e72db06b0f5139bc1a
    de48e47ddf78aba02fd9623bc7ce685540a10743

9 files changed, 26 insertions, 98 deletions

diff --git a/class.c b/class.c
index 9716aab78c..b39e693837 100644
--- a/class.c
+++ b/class.c
@@ -1004,9 +1004,8 @@ rb_define_class(const char *name, VALUE super)
     }
     klass = rb_define_class_id(id, super);
     rb_vm_register_global_object(klass);
-    rb_const_set_raw(rb_cObject, id, klass);
+    rb_const_set(rb_cObject, id, klass);
     rb_class_inherited(super, klass);
-    rb_const_added(klass, id);
 
     return klass;
 }
@@ -1044,10 +1043,8 @@ rb_define_class_id_under_no_pin(VALUE outer, ID id, VALUE super)
     }
     klass = rb_define_class_id(id, super);
     rb_set_class_path_string(klass, outer, rb_id2str(id));
-
-    rb_const_set_raw(outer, id, klass);
+    rb_const_set(outer, id, klass);
     rb_class_inherited(super, klass);
-    rb_const_added(outer, id);
 
     return klass;
 }
diff --git a/internal/variable.h b/internal/variable.h
index 007ea23aa8..1a2e2fd81d 100644
--- a/internal/variable.h
+++ b/internal/variable.h
@@ -16,8 +16,6 @@
 #include "shape.h"              /* for rb_shape_t */
 
 /* variable.c */
-void rb_const_added(VALUE klass, ID const_name);
-void rb_const_set_raw(VALUE klass, ID id, VALUE val);
 void rb_gc_mark_global_tbl(void);
 void rb_gc_update_global_tbl(void);
 size_t rb_generic_ivar_memsize(VALUE);
diff --git a/spec/ruby/core/class/fixtures/callback_order.rb b/spec/ruby/core/class/fixtures/callback_order.rb
deleted file mode 100644
index b7b52ab778..0000000000
--- a/spec/ruby/core/class/fixtures/callback_order.rb
+++ /dev/null
@@ -1,31 +0,0 @@
-module CoreClassSpecs
-  module Callbacks
-    class Base
-      def self.inherited(subclass)
-        subclass.const_set(:INHERITED_NAME, subclass.name)
-        ORDER << [
-          :inherited,
-          subclass,
-          eval("defined?(#{subclass.name})"),
-          Object.const_source_location(subclass.name) ? :location : :unknown_location,
-        ]
-        super
-      end
-    end
-
-    ORDER = []
-
-    def self.const_added(const_name)
-      ORDER << [
-        :const_added,
-        const_name,
-        eval("defined?(#{const_name})"),
-        const_source_location(const_name) ? :location : :unknown_location,
-      ]
-      super
-    end
-
-    class Child < Base
-    end
-  end
-end
diff --git a/spec/ruby/core/class/inherited_spec.rb b/spec/ruby/core/class/inherited_spec.rb
index 15d0c3ddb9..8ef8bb8c35 100644
--- a/spec/ruby/core/class/inherited_spec.rb
+++ b/spec/ruby/core/class/inherited_spec.rb
@@ -1,6 +1,5 @@
 require_relative '../../spec_helper'
 require_relative 'fixtures/classes'
-require_relative 'fixtures/callback_order'
 
 describe "Class.inherited" do
 
@@ -99,16 +98,4 @@ describe "Class.inherited" do
     -> { Class.new(top) }.should_not raise_error
   end
 
-  it "is invoked after the class is named when using class definition syntax" do
-    CoreClassSpecs::Callbacks::Child::INHERITED_NAME.should == "CoreClassSpecs::Callbacks::Child"
-  end
-
-  ruby_version_is "3.5" do # https://bugs.ruby-lang.org/issues/21143
-    it "is invoked before `const_added`" do
-      CoreClassSpecs::Callbacks::ORDER.should == [
-        [:inherited, CoreClassSpecs::Callbacks::Child, "constant", :location],
-        [:const_added, :Child, "constant", :location],
-      ]
-    end
-  end
 end
diff --git a/spec/ruby/optional/capi/class_spec.rb b/spec/ruby/optional/capi/class_spec.rb
index 21a887f047..7abb5d4ed9 100644
--- a/spec/ruby/optional/capi/class_spec.rb
+++ b/spec/ruby/optional/capi/class_spec.rb
@@ -385,17 +385,6 @@ describe "C-API Class function" do
         CApiClassSpecs.const_get(cls.name)
       }.should raise_error(NameError, /wrong constant name/)
     end
-
-    ruby_version_is "3.5" do
-      it "calls .inherited before .const_added" do
-        ScratchPad.record([])
-        @s.rb_define_class_id_under(CApiClassSpecs::Callbacks, :Subclass, CApiClassSpecs::Callbacks)
-        ScratchPad.recorded.should == [
-          [:inherited, "CApiClassSpecs::Callbacks::Subclass", :location],
-          [:const_added, :Subclass, :location],
-        ]
-      end
-    end
   end
 
   describe "rb_define_class_id_under" do
diff --git a/spec/ruby/optional/capi/fixtures/class.rb b/spec/ruby/optional/capi/fixtures/class.rb
index 2560fef17d..b463e3b4c3 100644
--- a/spec/ruby/optional/capi/fixtures/class.rb
+++ b/spec/ruby/optional/capi/fixtures/class.rb
@@ -101,14 +101,4 @@ class CApiClassSpecs
     module M
     end
   end
-
-  class Callbacks
-    def self.inherited(child)
-      ScratchPad << [:inherited, child.name, Object.const_source_location(child.name) ? :location : :unknown_location]
-    end
-
-    def self.const_added(const_name)
-      ScratchPad << [:const_added, const_name, const_source_location(const_name) ? :location : :unknown_location]
-    end
-  end
 end
diff --git a/test/ruby/test_settracefunc.rb b/test/ruby/test_settracefunc.rb
index 5542ad248a..55c07abbea 100644
--- a/test/ruby/test_settracefunc.rb
+++ b/test/ruby/test_settracefunc.rb
@@ -168,14 +168,14 @@ class TestSetTraceFunc < Test::Unit::TestCase
                  events.shift)
     assert_equal(["line", 4, __method__, self.class],
                  events.shift)
-    assert_equal(["c-call", 4, :inherited, Class],
-                 events.shift)
-    assert_equal(["c-return", 4, :inherited, Class],
-                 events.shift)
     assert_equal(["c-call", 4, :const_added, Module],
                  events.shift)
     assert_equal(["c-return", 4, :const_added, Module],
                  events.shift)
+    assert_equal(["c-call", 4, :inherited, Class],
+                 events.shift)
+    assert_equal(["c-return", 4, :inherited, Class],
+                 events.shift)
     assert_equal(["class", 4, nil, nil],
                  events.shift)
     assert_equal(["line", 5, nil, nil],
@@ -411,10 +411,10 @@ class TestSetTraceFunc < Test::Unit::TestCase
 
     [["c-return", 2, :add_trace_func, Thread],
      ["line", 3, __method__, self.class],
-     ["c-call", 3, :inherited, Class],
-     ["c-return", 3, :inherited, Class],
      ["c-call", 3, :const_added, Module],
      ["c-return", 3, :const_added, Module],
+     ["c-call", 3, :inherited, Class],
+     ["c-return", 3, :inherited, Class],
      ["class", 3, nil, nil],
      ["line", 4, nil, nil],
      ["c-call", 4, :method_added, Module],
@@ -558,10 +558,10 @@ class TestSetTraceFunc < Test::Unit::TestCase
      [:line,     5, 'xyzzy', self.class,  method,           self,        :inner, :nothing],
      [:c_return, 4, "xyzzy", Array,       :reverse_each,    [1],         nil, [1]],
      [:line,     7, 'xyzzy', self.class,  method,           self,        :outer, :nothing],
-     [:c_call,   7, "xyzzy", Class,       :inherited,       Object,      nil, :nothing],
-     [:c_return, 7, "xyzzy", Class,       :inherited,       Object,      nil, nil],
      [:c_call,   7, "xyzzy", Module,      :const_added,     TestSetTraceFunc, nil, :nothing],
      [:c_return, 7, "xyzzy", Module,      :const_added,     TestSetTraceFunc, nil, nil],
+     [:c_call,   7, "xyzzy", Class,       :inherited,       Object,      nil, :nothing],
+     [:c_return, 7, "xyzzy", Class,       :inherited,       Object,      nil, nil],
      [:class,    7, "xyzzy", nil,         nil,              xyzzy.class, nil,    :nothing],
      [:line,     8, "xyzzy", nil,         nil,              xyzzy.class, nil,    :nothing],
      [:line,     9, "xyzzy", nil,         nil,              xyzzy.class, :XYZZY_outer, :nothing],
diff --git a/variable.c b/variable.c
index 68e54a21ab..b043689327 100644
--- a/variable.c
+++ b/variable.c
@@ -2624,6 +2624,7 @@ rb_autoload(VALUE module, ID name, const char *feature)
 }
 
 static void const_set(VALUE klass, ID id, VALUE val);
+static void const_added(VALUE klass, ID const_name);
 
 struct autoload_arguments {
     VALUE module;
@@ -2732,7 +2733,7 @@ rb_autoload_str(VALUE module, ID name, VALUE feature)
     VALUE result = rb_mutex_synchronize(autoload_mutex, autoload_synchronized, (VALUE)&arguments);
 
     if (result == Qtrue) {
-        rb_const_added(module, name);
+        const_added(module, name);
     }
 }
 
@@ -3603,8 +3604,8 @@ set_namespace_path(VALUE named_namespace, VALUE namespace_path)
     RB_VM_LOCK_LEAVE();
 }
 
-void
-rb_const_added(VALUE klass, ID const_name)
+static void
+const_added(VALUE klass, ID const_name)
 {
     if (GET_VM()->running) {
         VALUE name = ID2SYM(const_name);
@@ -3680,16 +3681,10 @@ const_set(VALUE klass, ID id, VALUE val)
 }
 
 void
-rb_const_set_raw(VALUE klass, ID id, VALUE val)
-{
-    const_set(klass, id, val);
-}
-
-void
 rb_const_set(VALUE klass, ID id, VALUE val)
 {
     const_set(klass, id, val);
-    rb_const_added(klass, id);
+    const_added(klass, id);
 }
 
 static struct autoload_data *
diff --git a/vm_insnhelper.c b/vm_insnhelper.c
index cae307d743..9aa2034b41 100644
--- a/vm_insnhelper.c
+++ b/vm_insnhelper.c
@@ -5751,26 +5751,29 @@ vm_check_if_module(ID id, VALUE mod)
 }
 
 static VALUE
+declare_under(ID id, VALUE cbase, VALUE c)
+{
+    rb_set_class_path_string(c, cbase, rb_id2str(id));
+    rb_const_set(cbase, id, c);
+    return c;
+}
+
+static VALUE
 vm_declare_class(ID id, rb_num_t flags, VALUE cbase, VALUE super)
 {
     /* new class declaration */
     VALUE s = VM_DEFINECLASS_HAS_SUPERCLASS_P(flags) ? super : rb_cObject;
-    VALUE c = rb_define_class_id(id, s);
+    VALUE c = declare_under(id, cbase, rb_define_class_id(id, s));
     rb_define_alloc_func(c, rb_get_alloc_func(c));
-    rb_set_class_path_string(c, cbase, rb_id2str(id));
-    rb_const_set_raw(cbase, id, c);
     rb_class_inherited(s, c);
-    rb_const_added(cbase, id);
     return c;
 }
 
 static VALUE
 vm_declare_module(ID id, VALUE cbase)
 {
-    VALUE m = rb_module_new();
-    rb_set_class_path_string(m, cbase, rb_id2str(id));
-    rb_const_set(cbase, id, m);
-    return m;
+    /* new module declaration */
+    return declare_under(id, cbase, rb_module_new());
 }
 
 NORETURN(static void unmatched_redefinition(const char *type, VALUE cbase, ID id, VALUE old));