Future fix NPE, fast path for completed, fewer lines

src/main/java/io/vertx/core/Future.java

@@ -612,6 +612,20 @@ static <T> Future<T> fromCompletionStage(CompletionStage<T> completionStage, Con
     return promise.future();
   }
 
+  /**
+   @see CompletableFuture#getNow
+   @see #isComplete
+   */
+  default T getNow (T valueIfAbsent) {
+    if (succeeded()) {
+      return result();
+    } else if (failed()) {
+      throw Utils.throwAsUnchecked(cause());
+    } else {
+      return valueIfAbsent; // !isComplete
+    }
+  }
+
   /**
    * Park the current thread until the {@code future} is completed, when the future
    * is completed the thread is un-parked and
@@ -627,21 +641,19 @@ static <T> Future<T> fromCompletionStage(CompletionStage<T> completionStage, Con
    * @throws IllegalStateException when called from an event-loop thread or a non Vert.x thread
    */
   default T await() {
+    if (isComplete()) {
+      return getNow(null);
+    }
+
     io.vertx.core.impl.WorkerExecutor executor = io.vertx.core.impl.WorkerExecutor.unwrapWorkerExecutor();
     io.vertx.core.impl.WorkerExecutor.TaskController cont = executor.current();
     onComplete(ar -> cont.resume());
     try {
       cont.suspendAndAwaitResume();
     } catch (InterruptedException e) {
-      Utils.throwAsUnchecked(e.getCause());
-      return null;
-    }
-    if (succeeded()) {
-      return result();
-    } else {
-      Utils.throwAsUnchecked(cause());
-      return null;
+      throw Utils.throwAsUnchecked(e.getCause() != null ? e.getCause() : e);// should it be simply throwAsUnchecked(e) ?
     }
+    return getNow(null);
   }
 
   /**

src/main/java/io/vertx/core/impl/Utils.java

@@ -46,7 +46,7 @@ public static boolean isWindows() {
   }
 
   @SuppressWarnings("unchecked")
-  public static <E extends Throwable> void throwAsUnchecked(Throwable t) throws E {
+  public static <E extends Throwable> RuntimeException throwAsUnchecked(Throwable t) throws E {
     throw (E) t;
   }
 }

src/test/java/io/vertx/core/FutureTest.java

@@ -15,6 +15,7 @@
 import io.vertx.core.impl.NoStackTraceThrowable;
 import io.vertx.core.impl.future.PromiseInternal;
 import io.vertx.test.core.Repeat;
+import org.junit.Ignore;
 import org.junit.Test;
 
 import java.lang.reflect.Field;
@@ -1810,4 +1811,29 @@ private void completedFutureTimeout(Context ctx, Future<String> future) throws E
     }));
     await();
   }
+
+  @Test @Ignore
+  public void npe (){
+    vertx.deployVerticle(new AbstractVerticle() {
+      @Override public void start (){
+        var p = Promise.promise();
+        var thread = Thread.currentThread();
+
+        System.out.println(thread);
+        thread.interrupt();
+
+        try {
+          p.future().await();// bug: java.lang.NullPointerException: Cannot throw exception because "t" is null
+          fail("must fail with InterruptedException");
+        } catch (Throwable e){
+          if (e instanceof InterruptedException){
+            testComplete();
+          } else {
+            fail(e);
+          }
+        }
+      }
+    }, new DeploymentOptions().setThreadingModel(ThreadingModel.VIRTUAL_THREAD));
+    await();
+  }
 }