Reactor: avoid attaching context if it's already attached (#11393)

Reactor: avoid attaching context if it's already attached

Co-authored-by: andrea.marziali <andrea.marziali@datadoghq.com>

Author: amarziali

dd-java-agent/instrumentation/reactive-streams-1.0/src/main/java/datadog/trace/instrumentation/reactivestreams/PublisherInstrumentation.java

@@ -63,7 +63,7 @@ public static ContextScope onSubscribe(
       final Context current =
           InstrumentationContext.get(Subscriber.class, Context.class)
               .putIfAbsent(s, context != null ? context : activeContext);
-      if (current != null) {
+      if (current != null && activeContext != current) {
         return current.attach();
       }
 

dd-java-agent/instrumentation/reactive-streams-1.0/src/main/java/datadog/trace/instrumentation/reactivestreams/SubscriberInstrumentation.java

@@ -56,7 +56,7 @@ public static ContextScope before(@Advice.This final Subscriber self) {
         return null;
       }
       final Context context = InstrumentationContext.get(Subscriber.class, Context.class).get(self);
-      return context == null ? null : context.attach();
+      return context == null || context == currentContext ? null : context.attach();
     }
 
     @Advice.OnMethodExit(onThrowable = Throwable.class, suppress = Throwable.class)