merge revision(s) 7b9476fbfab738d1eb01b4b4c4af9a1680513019: [Backport #17642]

	Ractor.allocate should not be allowed

	Ractor.allocate and Ractor#dup should not be allowed like Thread.
	[Bug #17642]
	---
	 bootstraptest/test_ractor.rb | 18 ++++++++++++++++++
	 ractor.c                     |  2 ++
	 2 files changed, 20 insertions(+)

3 files changed, 22 insertions, 2 deletions

diff --git a/bootstraptest/test_ractor.rb b/bootstraptest/test_ractor.rb
index 1c29a2b799..878b846487 100644
--- a/bootstraptest/test_ractor.rb
+++ b/bootstraptest/test_ractor.rb
@@ -8,6 +8,24 @@ assert_equal 'Ractor', %q{
   Ractor.new{}.class
 }
 
+# Ractor.allocate is not supported
+assert_equal "[:ok, :ok]", %q{
+  rs = []
+  begin
+    Ractor.allocate
+  rescue => e
+    rs << :ok if e.message == 'allocator undefined for Ractor'
+  end
+
+  begin
+    Ractor.new{}.dup
+  rescue
+    rs << :ok if e.message == 'allocator undefined for Ractor'
+  end
+
+  rs
+}
+
 # A Ractor can have a name
 assert_equal 'test-name', %q{
   r = Ractor.new name: 'test-name' do
diff --git a/ractor.c b/ractor.c
index 420b2051b2..8de13954ce 100644
--- a/ractor.c
+++ b/ractor.c
@@ -2047,6 +2047,8 @@ void
 Init_Ractor(void)
 {
     rb_cRactor = rb_define_class("Ractor", rb_cObject);
+    rb_undef_alloc_func(rb_cRactor);
+
     rb_eRactorError          = rb_define_class_under(rb_cRactor, "Error", rb_eRuntimeError);
     rb_eRactorIsolationError = rb_define_class_under(rb_cRactor, "IsolationError", rb_eRactorError);
     rb_eRactorRemoteError    = rb_define_class_under(rb_cRactor, "RemoteError", rb_eRactorError);
diff --git a/version.h b/version.h
index df2dd51989..24206183b7 100644
--- a/version.h
+++ b/version.h
@@ -12,11 +12,11 @@
 # define RUBY_VERSION_MINOR RUBY_API_VERSION_MINOR
 #define RUBY_VERSION_TEENY 0
 #define RUBY_RELEASE_DATE RUBY_RELEASE_YEAR_STR"-"RUBY_RELEASE_MONTH_STR"-"RUBY_RELEASE_DAY_STR
-#define RUBY_PATCHLEVEL 52
+#define RUBY_PATCHLEVEL 53
 
 #define RUBY_RELEASE_YEAR 2021
 #define RUBY_RELEASE_MONTH 3
-#define RUBY_RELEASE_DAY 11
+#define RUBY_RELEASE_DAY 12
 
 #include "ruby/version.h"