Update Environment::VMCache helpers for Ruby 3.2 metrics

Issue #2534

lib/datadog/core/environment/vm_cache.rb

@@ -20,6 +20,9 @@ module VMCache
         # Whenever a constant creation busts the global constant cache
         # this value is incremented. This has a measurable performance impact
         # and thus show be avoided after application warm up.
+        #
+        # This was removed in Ruby 3.2.
+        # @see https://github.com/ruby/ruby/blob/master/doc/NEWS/NEWS-3.2.0.md#implementation-improvements
         def global_constant_state
           ::RubyVM.stat[:global_constant_state]
         end
@@ -38,6 +41,20 @@ def global_method_state
           ::RubyVM.stat[:global_method_state]
         end
 
+        # Introduced in Ruby 3.2 to match an improved cache implementation.
+        #
+        # @see https://bugs.ruby-lang.org/issues/18589
+        def constant_cache_invalidations
+          ::RubyVM.stat[:constant_cache_invalidations]
+        end
+
+        # Introduced in Ruby 3.2 to match an improved cache implementation.
+        #
+        # @see https://bugs.ruby-lang.org/issues/18589
+        def constant_cache_misses
+          ::RubyVM.stat[:constant_cache_misses]
+        end
+
         def available?
           defined?(::RubyVM) && ::RubyVM.respond_to?(:stat)
         end

spec/datadog/core/environment/vm_cache_spec.rb

@@ -22,21 +22,67 @@
     describe '.global_constant_state' do
       subject(:global_constant_state) { described_class.global_constant_state }
 
-      it { is_expected.to be_a_kind_of(Integer) }
+      context 'on Ruby <= 3.1' do
+        before { skip('Test only runs on Ruby <= 3.1') if RUBY_VERSION >= '3.2.0' }
+
+        it { is_expected.to be_a_kind_of(Integer) }
+      end
+
+      context 'on Ruby >= 3.2' do
+        before { skip('Test only runs on Ruby >= 3.2') if RUBY_VERSION < '3.2.0' }
+
+        it { is_expected.to be nil }
+      end
     end
 
     describe '.global_method_state' do
       subject(:global_method_state) { described_class.global_method_state }
 
-      context 'with Ruby < 3', if: RUBY_VERSION < '3.0.0' do
+      context 'on Ruby 2.x' do
+        before { skip('Test only runs on Ruby 2.x') unless RUBY_VERSION.start_with?('2.') }
+
         it { is_expected.to be_a_kind_of(Integer) }
       end
 
-      context 'with Ruby >= 3', if: RUBY_VERSION >= '3.0.0' do
+      context 'on Ruby >= 3.x' do
+        before { skip('Test only runs on Ruby >= 3.x') if RUBY_VERSION.start_with?('2.') }
+
         it 'has moved to a per-class method cache' do
           is_expected.to be_nil
         end
       end
     end
+
+    describe '.constant_cache_invalidations' do
+      subject(:constant_cache_invalidations) { described_class.constant_cache_invalidations }
+
+      context 'on Ruby <= 3.1' do
+        before { skip('Test only runs on Ruby <= 3.1') if RUBY_VERSION >= '3.2.0' }
+
+        it { is_expected.to be nil }
+      end
+
+      context 'on Ruby >= 3.2' do
+        before { skip('Test only runs on Ruby >= 3.2') if RUBY_VERSION < '3.2.0' }
+
+        it { is_expected.to be_a_kind_of(Integer) }
+      end
+    end
+
+    describe '.constant_cache_misses' do
+      subject(:constant_cache_misses) { described_class.constant_cache_misses }
+
+      context 'on Ruby <= 3.1' do
+        before { skip('Test only runs on Ruby <= 3.1') if RUBY_VERSION >= '3.2.0' }
+
+        it { is_expected.to be nil }
+      end
+
+      context 'on Ruby >= 3.2' do
+        before { skip('Test only runs on Ruby >= 3.2') if RUBY_VERSION < '3.2.0' }
+
+        it { is_expected.to be_a_kind_of(Integer) }
+      end
+    end
   end
 end