per-ractor Random::DEFAULT

Random generators are not Ractor-safe, so we need to prepare
per-ractor default random genearators. This patch set
`Random::DEFAULT = Randm` (not a Random instance, but the Random
class) and singleton methods like `Random.rand()` use a per-ractor
random generator.

[Feature #17322]

1 files changed, 15 insertions, 2 deletions

diff --git a/spec/ruby/core/random/default_spec.rb b/spec/ruby/core/random/default_spec.rb
index 1755154294..0333abed6b 100644
--- a/spec/ruby/core/random/default_spec.rb
+++ b/spec/ruby/core/random/default_spec.rb
@@ -1,8 +1,21 @@
 require_relative '../../spec_helper'
 
 describe "Random::DEFAULT" do
-  it "returns a Random instance" do
-    Random::DEFAULT.should be_an_instance_of(Random)
+
+  it "returns a random number generator" do
+    Random::DEFAULT.should respond_to(:rand)
+  end
+
+  ruby_version_is ''...'3.0' do
+    it "returns a Random instance" do
+      Random::DEFAULT.should be_an_instance_of(Random)
+    end
+  end
+
+  ruby_version_is '3.0' do
+    it "returns a Random instance" do
+      Random::DEFAULT.should be_an_instance_of(Class)
+    end
   end
 
   it "changes seed on reboot" do