Make ContextSnapshotFactory nullable in VirtualThreadTaskExecutor to …

…support frameworks that wrap the whole task executor for context propagation (#1878)

graphql-dgs/src/main/java21/com.netflix.graphql.dgs.internal.VirtualThreadTaskExecutor/VirtualThreadTaskExecutor.java

@@ -16,9 +16,11 @@
 
 package com.netflix.graphql.dgs.internal;
 
+import io.micrometer.context.ContextSnapshot;
 import io.micrometer.context.ContextSnapshotFactory;
 import org.jetbrains.annotations.NotNull;
 import org.springframework.core.task.AsyncTaskExecutor;
+import org.springframework.lang.Nullable;
 
 import java.util.concurrent.Callable;
 import java.util.concurrent.Future;
@@ -32,18 +34,24 @@
 @SuppressWarnings("unused")
 public class VirtualThreadTaskExecutor implements AsyncTaskExecutor {
     private final ThreadFactory threadFactory;
+
+    @Nullable
     private final ContextSnapshotFactory contextSnapshotFactory;
 
-    public VirtualThreadTaskExecutor(ContextSnapshotFactory contextSnapshotFactory) {
+    public VirtualThreadTaskExecutor(@Nullable ContextSnapshotFactory contextSnapshotFactory) {
         this.contextSnapshotFactory = contextSnapshotFactory;
         this.threadFactory = Thread.ofVirtual().name("dgs-virtual-thread-", 0).factory();
     }
 
     @Override
     public void execute(@NotNull Runnable task) {
-        var contextSnapshot = contextSnapshotFactory.captureAll();
-        var wrapped = contextSnapshot.wrap(task);
-        threadFactory.newThread(wrapped).start();
+        if (contextSnapshotFactory != null) {
+            ContextSnapshot contextSnapshot = contextSnapshotFactory.captureAll();
+            var wrapped = contextSnapshot.wrap(task);
+            threadFactory.newThread(wrapped).start();
+        } else {
+            threadFactory.newThread(task).start();
+        }
     }
 
     @Override