fix: Update untraced to suppress logging "Calling finish on an ended Span" warnings (#1620)

* fix: Update `untraced` to suppress logging "Calling finish on an ended Span" warnings

* add tests for untraced

* disable Metrics/PerceivedComplexity in TracerProvider#internal_start_span

* remove setting ALWAYS_ON from test cases

* return a non-recording span without calling @sampler.should_sample

---------

Co-authored-by: Francis Bogsanyi <[email protected]>

Author: yoheyk

sdk/lib/opentelemetry/sdk/trace/tracer.rb

@@ -29,8 +29,6 @@ def start_root_span(name, attributes: nil, links: nil, start_timestamp: nil, kin
 
         def start_span(name, with_parent: nil, attributes: nil, links: nil, start_timestamp: nil, kind: nil)
           with_parent ||= Context.current
-          return super(name, with_parent: with_parent, attributes: attributes, links: links, start_timestamp: start_timestamp, kind: kind) if Common::Utilities.untraced?(with_parent)
-
           name ||= 'empty'
           kind ||= :internal
 

sdk/lib/opentelemetry/sdk/trace/tracer_provider.rb

@@ -126,16 +126,21 @@ def add_span_processor(span_processor)
         end
 
         # @api private
-        def internal_start_span(name, kind, attributes, links, start_timestamp, parent_context, instrumentation_scope) # rubocop:disable Metrics/MethodLength
+        def internal_start_span(name, kind, attributes, links, start_timestamp, parent_context, instrumentation_scope) # rubocop:disable Metrics/CyclomaticComplexity, Metrics/MethodLength, Metrics/PerceivedComplexity
           parent_span = OpenTelemetry::Trace.current_span(parent_context)
           parent_span_context = parent_span.context
 
           if parent_span_context.valid?
             parent_span_id = parent_span_context.span_id
             trace_id = parent_span_context.trace_id
           end
-
           trace_id ||= @id_generator.generate_trace_id
+
+          if OpenTelemetry::Common::Utilities.untraced?(parent_context)
+            span_id = parent_span_id || @id_generator.generate_span_id
+            return OpenTelemetry::Trace.non_recording_span(OpenTelemetry::Trace::SpanContext.new(trace_id: trace_id, span_id: span_id))
+          end
+
           result = @sampler.should_sample?(trace_id: trace_id, parent_context: parent_context, links: links, name: name, kind: kind, attributes: attributes)
           span_id = @id_generator.generate_span_id
           if result.recording? && !@stopped

sdk/test/opentelemetry/sdk/trace/tracer_test.rb

@@ -329,5 +329,28 @@
       _(span.status.code).must_equal(OpenTelemetry::Trace::Status::ERROR)
       _(span.status.description).must_equal('Unhandled exception of type: RuntimeError')
     end
+
+    it 'yields a no-op span within an untraced block' do
+      tracer.in_span('root') do
+        span_id = OpenTelemetry::Trace.current_span.context.span_id
+        OpenTelemetry::Common::Utilities.untraced do
+          tracer.in_span('op') do |span|
+            _(span).must_be_instance_of(OpenTelemetry::Trace::Span)
+            _(span.context.span_id).must_equal span_id
+            _(span.context.trace_flags).wont_be :sampled?
+            _(span).wont_be :recording?
+          end
+        end
+      end
+    end
+
+    it 'does not log "Calling finish on an ended Span" warnings when untraced? is called' do
+      OpenTelemetry::TestHelpers.with_test_logger do |log_stream|
+        tracer.in_span('root') do
+          OpenTelemetry::Common::Utilities.untraced { tracer.in_span('op') {} }
+        end
+        _(log_stream.string).wont_include 'Calling finish on an ended Span'
+      end
+    end
   end
 end