[PROF-8667] Split profiling tests into ractor and non-ractor suites. (#…

…3320)

Co-authored-by: Ivo Anjo <ivo.anjo@datadoghq.com>

Rakefile

@@ -17,6 +17,12 @@ TEST_METADATA = {
   'appsec:main' => {
     '' => '✅ 2.1 / ✅ 2.2 / ✅ 2.3 / ✅ 2.4 / ✅ 2.5 / ✅ 2.6 / ✅ 2.7 / ✅ 3.0 / ✅ 3.1 / ✅ 3.2 / ✅ 3.3 / ✅ jruby'
   },
+  'profiling:main' => {
+    '' => '✅ 2.1 / ✅ 2.2 / ✅ 2.3 / ✅ 2.4 / ✅ 2.5 / ✅ 2.6 / ✅ 2.7 / ✅ 3.0 / ✅ 3.1 / ✅ 3.2 / ✅ 3.3 / ✅ jruby'
+  },
+  'profiling:ractors' => {
+    '' => '❌ 2.1 / ❌ 2.2 / ❌ 2.3 / ❌ 2.4 / ❌ 2.5 / ❌ 2.6 / ❌ 2.7 / ✅ 3.0 / ✅ 3.1 / ✅ 3.2 / ✅ 3.3 / ✅ jruby'
+  },
   'contrib' => {
     '' => '✅ 2.1 / ✅ 2.2 / ✅ 2.3 / ✅ 2.4 / ✅ 2.5 / ✅ 2.6 / ✅ 2.7 / ✅ 3.0 / ✅ 3.1 / ✅ 3.2 / ✅ 3.3 / ✅ jruby'
   },
@@ -323,20 +329,16 @@ desc 'Run RSpec'
 namespace :spec do
   task all: [:main, :benchmark,
              :rails, :railsredis, :railsredis_activesupport, :railsactivejob,
-             :elasticsearch, :http, :redis, :sidekiq, :sinatra, :hanami, :hanami_autoinstrument]
+             :elasticsearch, :http, :redis, :sidekiq, :sinatra, :hanami, :hanami_autoinstrument,
+             :profiling]
 
   desc '' # "Explicitly hiding from `rake -T`"
   RSpec::Core::RakeTask.new(:main) do |t, args|
     t.pattern = 'spec/**/*_spec.rb'
-    t.exclude_pattern = 'spec/**/{contrib,benchmark,redis,opentracer,auto_instrument,opentelemetry}/**/*_spec.rb,'\
+    t.exclude_pattern = 'spec/**/{contrib,benchmark,redis,opentracer,auto_instrument,opentelemetry,profiling}/**/*_spec.rb,'\
                         ' spec/**/{auto_instrument,opentelemetry}_spec.rb'
     t.rspec_opts = args.to_a.join(' ')
   end
-  if RUBY_ENGINE == 'ruby' && OS.linux? && Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('2.3.0')
-    # "bundle exec rake compile" currently only works on MRI Ruby on Linux
-    Rake::Task[:main].enhance([:clean])
-    Rake::Task[:main].enhance([:compile])
-  end
 
   RSpec::Core::RakeTask.new(:benchmark) do |t, args|
     t.pattern = 'spec/ddtrace/benchmark/**/*_spec.rb'
@@ -535,6 +537,40 @@ namespace :spec do
   end
 
   task appsec: [:'appsec:all']
+
+  namespace :profiling do
+    task all: [:main, :ractors]
+
+    task :compile_native_extensions do
+      # "bundle exec rake compile" currently only works on MRI Ruby on Linux
+      if RUBY_ENGINE == 'ruby' && OS.linux? && Gem::Version.new(RUBY_VERSION) >= Gem::Version.new('2.3.0')
+        Rake::Task[:clean].invoke
+        Rake::Task[:compile].invoke
+      end
+    end
+
+    # Datadog Profiling main specs without Ractor creation
+    # NOTE: Ractor creation will transition the entire Ruby VM into multi-ractor mode. This cannot be undone
+    #       and, as such, may introduce side-effects between tests and make them flaky depending on order of
+    #       execution. By splitting in two separate suites, the side-effect impact should be mitigated as
+    #       the non-ractor VM will never trigger the transition into multi-ractor mode.
+    desc '' # "Explicitly hiding from `rake -T`"
+    RSpec::Core::RakeTask.new(:main) do |t, args|
+      t.pattern = 'spec/datadog/profiling/**/*_spec.rb,spec/datadog/profiling_spec.rb'
+      t.rspec_opts = [*args.to_a, '-t ~ractors'].join(' ')
+    end
+
+    desc '' # "Explicitly hiding from `rake -T`"
+    RSpec::Core::RakeTask.new(:ractors) do |t, args|
+      t.pattern = 'spec/datadog/profiling/**/*_spec.rb'
+      t.rspec_opts = [*args.to_a, '-t ractors'].join(' ')
+    end
+
+    # Make sure each profiling test suite has a dependency on compiled native extensions
+    Rake::Task[:all].prerequisite_tasks.each { |t| t.enhance([:compile_native_extensions]) }
+  end
+
+  task profiling: [:'profiling:all']
 end
 
 if defined?(RuboCop::RakeTask)

spec/datadog/core/configuration/components_spec.rb

@@ -1070,18 +1070,23 @@
       end
 
       context 'is enabled' do
-        before do
-          skip 'Profiling not supported.' unless Datadog::Profiling.supported?
+        # Using a generic double rather than instance_double since if profiling is not supported by the
+        # current CI runner we won't even load the Datadog::Profiling::Profiler class.
+        let(:profiler) { instance_double('Datadog::Profiling::Profiler') }
 
+        before do
           allow(settings.profiling)
             .to receive(:enabled)
             .and_return(true)
-          allow(profiler_setup_task).to receive(:run)
+          expect(Datadog::Profiling::Component).to receive(:build_profiler_component).with(
+            settings: settings,
+            agent_settings: agent_settings,
+            optional_tracer: anything,
+          ).and_return(profiler)
         end
 
         it do
-          expect(components.profiler)
-            .to receive(:start)
+          expect(profiler).to receive(:start)
 
           startup!
         end

spec/datadog/core/configuration_spec.rb

@@ -316,30 +316,6 @@
         end
       end
 
-      context 'when the profiler' do
-        context 'is not changed' do
-          before { skip_if_profiling_not_supported(self) }
-
-          context 'and profiling is enabled' do
-            before do
-              allow(test_class.configuration.profiling)
-                .to receive(:enabled)
-                .and_return(true)
-
-              allow_any_instance_of(Datadog::Profiling::Profiler)
-                .to receive(:start)
-              allow_any_instance_of(Datadog::Profiling::Tasks::Setup)
-                .to receive(:run)
-            end
-
-            it 'starts the profiler' do
-              configure
-              expect(test_class.send(:components).profiler).to have_received(:start)
-            end
-          end
-        end
-      end
-
       context 'when reconfigured multiple times' do
         context 'with runtime metrics active' do
           before do

spec/datadog/profiling/collectors/cpu_and_wall_time_worker_spec.rb

@@ -676,7 +676,7 @@
       end
     end
 
-    context 'when called from a background ractor' do
+    context 'when called from a background ractor', :ractors => true do
       # Even though we're not testing it explicitly, the GC profiling hooks can sometimes be called when running these
       # specs. Unfortunately, there's a VM crash in that case as well -- https://bugs.ruby-lang.org/issues/18464 --
       # so this must be disabled when interacting with Ractors.

spec/datadog/profiling/native_extension_spec.rb

@@ -82,7 +82,7 @@
         it { is_expected.to be true }
       end
 
-      context 'on a background Ractor' do
+      context 'on a background Ractor', :ractors => true do
         # @ivoanjo: When we initially added this test, our test suite kept deadlocking in CI in a later test (not on
         # this one).
         #