[PROF-3514] Skip CPU time instrumentation if logging gem is detected

lib/ddtrace/profiling/ext/cpu.rb

@@ -43,9 +43,24 @@ def self.unsupported_reason
           elsif Gem::Specification.find_all_by_name('rollbar', ROLLBAR_INCOMPATIBLE_VERSIONS).any?
             'You have an incompatible rollbar gem version installed; ensure that you have rollbar >= 3.1.2 by ' \
             "adding `gem 'rollbar', '>= 3.1.2'` to your Gemfile or gems.rb file. " \
-            'See https://github.com/rollbar/rollbar-gem/pull/1018 for details.'
+            'See https://github.com/rollbar/rollbar-gem/pull/1018 for details'
+          elsif Gem::Specification.find_all_by_name('logging').any? && logging_inherit_context_enabled?
+            'The `logging` gem is installed and its thread inherit context feature is enabled. ' \
+            "Please add LOGGING_INHERIT_CONTEXT=false to your application's environment variables to disable the " \
+            'conflicting `logging` gem feature. ' \
+            'See https://github.com/TwP/logging/pull/230 for details'
           end
         end
+
+        private_class_method def self.logging_inherit_context_enabled?
+          # The logging gem provides a mechanism to disable the conflicting behavior, see
+          # https://github.com/TwP/logging/blob/ae9872d093833b2a5a34cbe1faa4e895a81f6845/lib/logging/diagnostic_context.rb#L418
+          # Here we check if the behavior is enabled
+          inherit_context_configuration = ENV['LOGGING_INHERIT_CONTEXT']
+
+          inherit_context_configuration.nil? ||
+          (inherit_context_configuration && !%w[false no 0].include?(inherit_context_configuration.downcase))
+        end
       end
     end
   end

spec/ddtrace/profiling/ext/cpu_spec.rb

@@ -77,7 +77,51 @@
               .and_return([])
           end
 
-          it { is_expected.to be nil }
+          context 'when logging gem is installed' do
+            before do
+              expect(Gem::Specification)
+                .to receive(:find_all_by_name)
+                .with('logging')
+                .and_return([instance_double(Gem::Specification)])
+            end
+
+            around do |example|
+              ClimateControl.modify('LOGGING_INHERIT_CONTEXT' => logging_inherit_context) do
+                example.run
+              end
+            end
+
+            context 'when no LOGGING_INHERIT_CONTEXT is defined' do
+              let(:logging_inherit_context) { nil }
+
+              it { is_expected.to include '`logging` gem' }
+            end
+
+            context 'when LOGGING_INHERIT_CONTEXT is set to any value other than false/no/0 (case-insensitive)' do
+              let(:logging_inherit_context) { 'YesPlease' }
+
+              it { is_expected.to include '`logging` gem' }
+            end
+
+            context 'when LOGGING_INHERIT_CONTEXT is set to false/no/0 (case-insensitive)' do
+              %w[false no FaLsE nO 0].each do |disabled_setting|
+                let(:logging_inherit_context) { disabled_setting }
+
+                it { is_expected.to be nil }
+              end
+            end
+          end
+
+          context 'when logging gem is not installed' do
+            before do
+              expect(Gem::Specification)
+                .to receive(:find_all_by_name)
+                .with('logging')
+                .and_return([])
+            end
+
+            it { is_expected.to be nil }
+          end
         end
       end
     end