Fixed Netty scheduled executor context propagation on newer versions of netty starting at 4.1.44 (2019-12-18).

Author: AlexeyKuznetsov-DD

dd-java-agent/instrumentation/java/java-concurrent/java-concurrent-1.8/build.gradle

@@ -15,7 +15,7 @@ addTestSuiteForDir('latestDepTest', 'test')
 dependencies {
   testImplementation project(':dd-java-agent:instrumentation:datadog:tracing:trace-annotation')
   testImplementation libs.guava
-  testImplementation group: 'io.netty', name: 'netty-all', version: '4.1.9.Final'
+  testImplementation group: 'io.netty', name: 'netty-all', version: '4.1.50.Final'
   testImplementation group: 'org.apache.tomcat.embed', name: 'tomcat-embed-core', version: '7.0.0'
   // Tomcat 10.1.+ seems to require Java 11. Limit to fix build.
   // TODO: Tomcat 10.0.10 has a copy of the JSR166 ThreadPoolExecutor so it needs special instrumentation

dd-java-agent/instrumentation/java/java-concurrent/java-concurrent-1.8/src/main/java/datadog/trace/instrumentation/java/concurrent/runnable/RunnableFutureInstrumentation.java

@@ -31,6 +31,8 @@
 import java.util.Map;
 import java.util.concurrent.Callable;
 import java.util.concurrent.RunnableFuture;
+import java.util.concurrent.ScheduledFuture;
+import java.util.concurrent.TimeUnit;
 import net.bytebuddy.asm.Advice;
 import net.bytebuddy.description.type.TypeDescription;
 import net.bytebuddy.matcher.ElementMatcher;
@@ -147,6 +149,13 @@ public static <T> void captureScope(@Advice.This RunnableFuture<T> task) {
   public static final class Run {
     @Advice.OnMethodEnter
     public static <T> AgentScope activate(@Advice.This RunnableFuture<T> task) {
+      // Newer Netty versions may run scheduled tasks once before they expire to enqueue them.
+      if (task instanceof ScheduledFuture
+          && task.getClass().getName().endsWith(".netty.util.concurrent.ScheduledFutureTask")
+          && ((ScheduledFuture<?>) task).getDelay(TimeUnit.NANOSECONDS) > 0) {
+        return null;
+      }
+
       return startTaskScope(InstrumentationContext.get(RunnableFuture.class, State.class), task);
     }