refactor: Remove duplication logic in start_span (#1281)

* refactor: Remove duplication logic in start_span

There are 2 places where checked mostly the same: parent span id and
trace id base on parent_span. Because there is no other places in gems,
that use method `internal_start_span`, leave that logic there
and removed unused attributes.

* Remove extract to constant default name

* Applied proposal from github comments

* Changed variable name to fit param name

* Remove extra blank line

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

Author: miry

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

@@ -29,16 +29,10 @@ 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)
           name ||= 'empty'
-
+          kind ||= :internal
           with_parent ||= Context.current
-          parent_span = OpenTelemetry::Trace.current_span(with_parent)
-          parent_span_context = OpenTelemetry::Trace.current_span(with_parent).context
-          if parent_span_context.valid?
-            parent_span_id = parent_span_context.span_id
-            trace_id = parent_span_context.trace_id
-          end
 
-          @tracer_provider.internal_create_span(name, kind, trace_id, parent_span_id, attributes, links, start_timestamp, with_parent, parent_span, @instrumentation_library)
+          @tracer_provider.internal_create_span(name, kind, attributes, links, start_timestamp, with_parent, @instrumentation_library)
         end
       end
     end

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

@@ -126,15 +126,16 @@ def add_span_processor(span_processor)
         end
 
         # @api private
-        def internal_create_span(name, kind, trace_id, parent_span_id, attributes, links, start_timestamp, parent_context, parent_span, instrumentation_library) # rubocop:disable Metrics/MethodLength, Metrics/AbcSize
+        def internal_create_span(name, kind, attributes, links, start_timestamp, parent_context, instrumentation_library) # rubocop:disable Metrics/MethodLength, Metrics/AbcSize
+          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
-          name ||= 'empty'
+
           trace_id ||= @id_generator.generate_trace_id
-          kind ||= :internal
           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