WIP

jetty-core/jetty-server/src/main/java/org/eclipse/jetty/server/internal/HttpConnection.java

@@ -608,10 +608,7 @@ public boolean onIdleExpired(TimeoutException timeout)
     {
         if (_httpChannel.getRequest() == null)
             return true;
-        Runnable task = _httpChannel.onIdleTimeout(timeout);
-
-        if (task != null)
-            ExceptionUtil.mustExecute(getExecutor(), task);
+        ExceptionUtil.mustExecute(getExecutor(), _httpChannel.onIdleTimeout(timeout));
         return false; // We've handle the exception
     }
 

jetty-core/jetty-server/src/test/java/org/eclipse/jetty/server/HttpChannelTest.java

@@ -1229,10 +1229,11 @@ public boolean handle(Request request, Response response, Callback callback)
         assertThat(demand.getCount(), is(1L));
 
         Callback.Completable callback = new Callback.Completable();
-        // Writes are possible, unless a pending write is failed.
+
+        // Writes are not possible
         handling.get().write(false, null, callback);
         assertTrue(callback.isDone());
-        assertFalse(callback.isCompletedExceptionally());
+        assertTrue(callback.isCompletedExceptionally());
 
         // Run the onFailure task.
         try (StacklessLogging ignore = new StacklessLogging(Response.class))

jetty-core/jetty-util/src/main/java/org/eclipse/jetty/util/ExceptionUtil.java

@@ -214,6 +214,9 @@ else if (s == MAX_SUPPRESSED)
     // TODO javadoc
     public static void mustExecute(Executor executor, Runnable task)
     {
+        if (task == null)
+            return;
+
         if (executor instanceof TryExecutor tryExecutor && tryExecutor.tryExecute(task))
             return;