Add Ruby 3.0.2 patches to fix method override bug

These patches are necessary to fix https://bugs.ruby-lang.org/issues/17725
which is unreleased.

This is currently breaking our Ruby 3 build, so until 3.0.3 is out
let's apply these independently.

patches/ruby/3.0.2/dont_alias_array_size.patch

@@ -0,0 +1,22 @@
+commit fa0279d947c3962c3f8c32852278d3ebb964cb19
+Author: Koichi Sasada <ko1@atdot.net>
+Date:   Wed Jul 28 13:40:30 2021 +0900
+
+    should not share same `def` for specialized method
+    
+    Because the key of redefine table is `def`, `def` should be
+    unique for each optimized method (`alias` is not allowed).
+
+diff --git a/array.c b/array.c
+index 3cb57a0872..36f712bcac 100644
+--- a/array.c
++++ b/array.c
+@@ -8384,7 +8384,7 @@ Init_Array(void)
+     rb_define_method(rb_cArray, "each_index", rb_ary_each_index, 0);
+     rb_define_method(rb_cArray, "reverse_each", rb_ary_reverse_each, 0);
+     rb_define_method(rb_cArray, "length", rb_ary_length, 0);
+-    rb_define_alias(rb_cArray,  "size", "length");
++    rb_define_method(rb_cArray, "size", rb_ary_length, 0);
+     rb_define_method(rb_cArray, "empty?", rb_ary_empty_p, 0);
+     rb_define_method(rb_cArray, "find_index", rb_ary_index, -1);
+     rb_define_method(rb_cArray, "index", rb_ary_index, -1);

patches/ruby/3.0.2/override_optimized_methods.patch

@@ -0,0 +1,85 @@
+commit fb4cf204a662a8cd9dafef6f31f2bd0db9129abe
+Author: Koichi Sasada <ko1@atdot.net>
+Date:   Thu May 13 03:10:18 2021 +0900
+
+    use me->def instead of me for opt_table
+    
+    `vm_opt_method_table` is me=>bop table to manage the optimized
+    methods (by specialized instruction). However, `me` can be invalidated
+    to invalidate the method cache entry.
+    [Bug #17725]
+    
+    To solve the issue, use `me-def` instead of `me` which simply copied
+    at invalidation timing.
+    
+    A test by @jeremyevans https://github.com/ruby/ruby/pull/4376
+
+diff --git a/test/ruby/test_method.rb b/test/ruby/test_method.rb
+index 240821c9e2..0bd5dc63dd 100644
+--- a/test/ruby/test_method.rb
++++ b/test/ruby/test_method.rb
+@@ -1303,6 +1303,21 @@ class TestMethod < Test::Unit::TestCase
+     end;
+   end
+ 
++  def test_override_optimized_method_on_class_using_prepend
++    assert_separately(%w(--disable-gems), <<-'end;', timeout: 30)
++      # Bug #17725 [ruby-core:102884]
++      $VERBOSE = nil
++      String.prepend(Module.new)
++      class String
++        def + other
++          'blah blah'
++        end
++      end
++
++      assert_equal('blah blah', 'a' + 'b')
++    end;
++  end
++
+   def test_eqq
+     assert_operator(0.method(:<), :===, 5)
+     assert_not_operator(0.method(:<), :===, -5)
+diff --git a/vm.c b/vm.c
+index accd12644e..8a044efa1f 100644
+--- a/vm.c
++++ b/vm.c
+@@ -1798,7 +1798,7 @@ rb_iter_break_value(VALUE val)
+ 
+ /* optimization: redefine management */
+ 
+-static st_table *vm_opt_method_table = 0;
++static st_table *vm_opt_method_def_table = 0;
+ static st_table *vm_opt_mid_table = 0;
+ 
+ static int
+@@ -1852,9 +1852,8 @@ rb_vm_check_redefinition_opt_method(const rb_method_entry_t *me, VALUE klass)
+        klass = RBASIC_CLASS(klass);
+     }
+     if (vm_redefinition_check_method_type(me->def)) {
+-	if (st_lookup(vm_opt_method_table, (st_data_t)me, &bop)) {
+-	    int flag = vm_redefinition_check_flag(klass);
+-
++        if (st_lookup(vm_opt_method_def_table, (st_data_t)me->def, &bop)) {
++            int flag = vm_redefinition_check_flag(klass);
+ 	    ruby_vm_redefined_flag[bop] |= flag;
+ 	}
+     }
+@@ -1885,7 +1884,7 @@ add_opt_method(VALUE klass, ID mid, VALUE bop)
+     const rb_method_entry_t *me = rb_method_entry_at(klass, mid);
+ 
+     if (me && vm_redefinition_check_method_type(me->def)) {
+-	st_insert(vm_opt_method_table, (st_data_t)me, (st_data_t)bop);
++	st_insert(vm_opt_method_def_table, (st_data_t)me->def, (st_data_t)bop);
+ 	st_insert(vm_opt_mid_table, (st_data_t)mid, (st_data_t)Qtrue);
+     }
+     else {
+@@ -1899,7 +1898,7 @@ vm_init_redefined_flag(void)
+     ID mid;
+     VALUE bop;
+ 
+-    vm_opt_method_table = st_init_numtable();
++    vm_opt_method_def_table = st_init_numtable();
+     vm_opt_mid_table = st_init_numtable();
+ 
+ #define OP(mid_, bop_) (mid = id##mid_, bop = BOP_##bop_, ruby_vm_redefined_flag[bop] = 0)