Remove Void*Promise (#11348)

Motivation:

Sometime in the past we introduced the concept of Void*Promise. As it turned out this was not a good idea at all as basically each handler in the pipeline need to be very careful to correctly handle this. We should better just remove this "optimization".

Modifications:

- Remove Void*Promise and all the related APIs
- Remove tests which were related to Void*Promise

Result:

Less error-prone API

codec-http/src/main/java/io/netty/handler/codec/http/DelegatingChannelHandlerContext.java

@@ -260,9 +260,4 @@ abstract class DelegatingChannelHandlerContext implements ChannelHandlerContext
     public ChannelFuture newFailedFuture(Throwable cause) {
         return ctx.newFailedFuture(cause);
     }
-
-    @Override
-    public ChannelPromise voidPromise() {
-        return ctx.voidPromise();
-    }
 }

codec-http/src/main/java/io/netty/handler/codec/http/HttpServerKeepAliveHandler.java

@@ -82,7 +82,7 @@ public class HttpServerKeepAliveHandler implements ChannelHandler {
             }
         }
         if (msg instanceof LastHttpContent && !shouldKeepAlive()) {
-            promise = promise.unvoid().addListener(ChannelFutureListener.CLOSE);
+            promise.addListener(ChannelFutureListener.CLOSE);
         }
         ctx.write(msg, promise);
     }

codec-http/src/main/java/io/netty/handler/codec/http/websocketx/WebSocketProtocolHandler.java

@@ -101,7 +101,7 @@ abstract class WebSocketProtocolHandler extends MessageToMessageDecoder<WebSocke
             ReferenceCountUtil.release(msg);
             promise.setFailure(new ClosedChannelException());
         } else if (msg instanceof CloseWebSocketFrame) {
-            closeSent(promise.unvoid());
+            closeSent(promise);
             ctx.write(msg).addListener(new ChannelPromiseNotifier(false, closeSent));
         } else {
             ctx.write(msg, promise);

codec-http/src/test/java/io/netty/handler/codec/http/HttpServerKeepAliveHandlerTest.java

@@ -131,20 +131,6 @@ public class HttpServerKeepAliveHandlerTest {
         assertFalse(channel.finishAndReleaseAll());
     }
 
-    @Test
-    public void testConnectionCloseHeaderHandledCorrectlyForVoidPromise() throws Exception {
-        HttpResponse response = new DefaultFullHttpResponse(httpVersion, responseStatus);
-        response.headers().set(HttpHeaderNames.CONNECTION, HttpHeaderValues.CLOSE);
-        setupMessageLength(response);
-
-        channel.writeAndFlush(response, channel.voidPromise());
-        HttpResponse writtenResponse = channel.readOutbound();
-
-        assertFalse(channel.isOpen());
-        ReferenceCountUtil.release(writtenResponse);
-        assertFalse(channel.finishAndReleaseAll());
-    }
-
     @Test
     public void test_PipelineKeepAlive() {
         FullHttpRequest firstRequest = new DefaultFullHttpRequest(httpVersion, HttpMethod.GET, "/v1/foo/bar");

codec-http2/src/main/java/io/netty/handler/codec/http2/AbstractHttp2StreamChannel.java

@@ -33,7 +33,6 @@ import io.netty.channel.DefaultChannelPipeline;
 import io.netty.channel.EventLoop;
 import io.netty.channel.MessageSizeEstimator;
 import io.netty.channel.RecvByteBufAllocator;
-import io.netty.channel.VoidChannelPromise;
 import io.netty.channel.WriteBufferWaterMark;
 import io.netty.handler.codec.http2.Http2FrameCodec.DefaultHttp2FrameStream;
 import io.netty.util.DefaultAttributeMap;
@@ -110,7 +109,7 @@ abstract class AbstractHttp2StreamChannel extends DefaultAttributeMap implements
 
             // Notify the child-channel and close it.
             streamChannel.pipeline().fireExceptionCaught(cause);
-            streamChannel.unsafe().close(streamChannel.unsafe().voidPromise());
+            streamChannel.unsafe().close(streamChannel.newPromise());
         }
     }
 
@@ -505,11 +504,6 @@ abstract class AbstractHttp2StreamChannel extends DefaultAttributeMap implements
         return pipeline().newFailedFuture(cause);
     }
 
-    @Override
-    public ChannelPromise voidPromise() {
-        return pipeline().voidPromise();
-    }
-
     @Override
     public int hashCode() {
         return id().hashCode();
@@ -572,8 +566,6 @@ abstract class AbstractHttp2StreamChannel extends DefaultAttributeMap implements
     }
 
     private final class Http2ChannelUnsafe implements Unsafe {
-        private final VoidChannelPromise unsafeVoidPromise =
-                new VoidChannelPromise(AbstractHttp2StreamChannel.this, false);
         @SuppressWarnings("deprecation")
         private RecvByteBufAllocator.Handle recvHandle;
         private boolean writeDoneAndNoFlush;
@@ -653,7 +645,7 @@ abstract class AbstractHttp2StreamChannel extends DefaultAttributeMap implements
                 if (closePromise.isDone()) {
                     // Closed already.
                     promise.setSuccess();
-                } else if (!(promise instanceof VoidChannelPromise)) { // Only needed if no VoidChannelPromise.
+                } else  {
                     // This means close() was called before so we just register a listener and return
                     closePromise.addListener((ChannelFutureListener) future -> promise.setSuccess());
                 }
@@ -672,7 +664,7 @@ abstract class AbstractHttp2StreamChannel extends DefaultAttributeMap implements
             // as otherwise we may send a RST on a stream in an invalid state and cause a connection error.
             if (parent().isActive() && !readEOS && Http2CodecUtil.isStreamIdValid(stream.id())) {
                 Http2StreamFrame resetFrame = new DefaultHttp2ResetFrame(Http2Error.CANCEL).stream(stream());
-                write(resetFrame, unsafe().voidPromise());
+                write(resetFrame, newPromise());
                 flush();
             }
 
@@ -692,12 +684,12 @@ abstract class AbstractHttp2StreamChannel extends DefaultAttributeMap implements
             closePromise.setSuccess();
             promise.setSuccess();
 
-            fireChannelInactiveAndDeregister(voidPromise(), wasActive);
+            fireChannelInactiveAndDeregister(newPromise(), wasActive);
         }
 
         @Override
         public void closeForcibly() {
-            close(unsafe().voidPromise());
+            close(newPromise());
         }
 
         @Override
@@ -738,7 +730,7 @@ abstract class AbstractHttp2StreamChannel extends DefaultAttributeMap implements
         }
 
         private void safeSetSuccess(ChannelPromise promise) {
-            if (!(promise instanceof VoidChannelPromise) && !promise.trySuccess()) {
+            if (!promise.trySuccess()) {
                 logger.warn("Failed to mark a promise as success because it is done already: {}", promise);
             }
         }
@@ -1031,11 +1023,6 @@ abstract class AbstractHttp2StreamChannel extends DefaultAttributeMap implements
             flush0(parentContext());
         }
 
-        @Override
-        public ChannelPromise voidPromise() {
-            return unsafeVoidPromise;
-        }
-
         @Override
         public ChannelOutboundBuffer outboundBuffer() {
             // Always return null as we not use the ChannelOutboundBuffer and not even support it.

codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2Connection.java

@@ -124,8 +124,6 @@ public class DefaultHttp2Connection implements Http2Connection {
         if (closePromise != null) {
             if (closePromise == promise) {
                 // Do nothing
-            } else if ((promise instanceof ChannelPromise) && ((ChannelPromise) closePromise).isVoid()) {
-                closePromise = promise;
             } else {
                 closePromise.addListener(new UnaryPromiseNotifier<>(promise));
             }

codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2ConnectionEncoder.java

@@ -120,7 +120,6 @@ public class DefaultHttp2ConnectionEncoder implements Http2ConnectionEncoder, Ht
     @Override
     public ChannelFuture writeData(final ChannelHandlerContext ctx, final int streamId, ByteBuf data, int padding,
             final boolean endOfStream, ChannelPromise promise) {
-        promise = promise.unvoid();
         final Http2Stream stream;
         try {
             stream = requireStream(streamId);
@@ -227,7 +226,6 @@ public class DefaultHttp2ConnectionEncoder implements Http2ConnectionEncoder, Ht
             if (!endOfStream || !flowController.hasFlowControlled(stream)) {
                 // The behavior here should mirror that in FlowControlledHeaders
 
-                promise = promise.unvoid();
                 boolean isInformational = validateHeadersSentState(stream, headers, connection.isServer(), endOfStream);
 
                 ChannelFuture future = sendHeaders(frameWriter, ctx, streamId, headers, hasPriority, streamDependency,
@@ -349,7 +347,6 @@ public class DefaultHttp2ConnectionEncoder implements Http2ConnectionEncoder, Ht
             // Reserve the promised stream.
             connection.local().reservePushStream(promisedStreamId, stream);
 
-            promise = promise.unvoid();
             ChannelFuture future = frameWriter.writePushPromise(ctx, streamId, promisedStreamId, headers, padding,
                                                                 promise);
             // Writing headers may fail during the encode state if they violate HPACK limits.
@@ -550,7 +547,7 @@ public class DefaultHttp2ConnectionEncoder implements Http2ConnectionEncoder, Ht
         FlowControlledHeaders(Http2Stream stream, Http2Headers headers, boolean hasPriority,
                               int streamDependency, short weight, boolean exclusive,
                               int padding, boolean endOfStream, ChannelPromise promise) {
-            super(stream, padding, endOfStream, promise.unvoid());
+            super(stream, padding, endOfStream, promise);
             this.headers = headers;
             this.hasPriorty = hasPriority;
             this.streamDependency = streamDependency;

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2ConnectionHandler.java

@@ -203,7 +203,7 @@ public class Http2ConnectionHandler extends ByteToMessageDecoder implements Http
 
             // We need to remove all streams (not just the active ones).
             // See https://github.com/netty/netty/issues/4838.
-            connection().close(ctx.voidPromise());
+            connection().close(ctx.newPromise());
         }
 
         /**
@@ -457,7 +457,6 @@ public class Http2ConnectionHandler extends ByteToMessageDecoder implements Http
             ctx.close(promise);
             return;
         }
-        promise = promise.unvoid();
         // Avoid NotYetConnectedException and avoid sending before connection preface
         if (!ctx.channel().isActive() || !prefaceSent()) {
             ctx.close(promise);
@@ -760,7 +759,7 @@ public class Http2ConnectionHandler extends ByteToMessageDecoder implements Http
                                      ChannelPromise promise) {
         final Http2Stream stream = connection().stream(streamId);
         if (stream == null) {
-            return resetUnknownStream(ctx, streamId, errorCode, promise.unvoid());
+            return resetUnknownStream(ctx, streamId, errorCode, promise);
         }
 
        return resetStream(ctx, stream, errorCode, promise);
@@ -768,7 +767,6 @@ public class Http2ConnectionHandler extends ByteToMessageDecoder implements Http
 
     private ChannelFuture resetStream(final ChannelHandlerContext ctx, final Http2Stream stream,
                                       long errorCode, ChannelPromise promise) {
-        promise = promise.unvoid();
         if (stream.isResetSent()) {
             // Don't write a RST_STREAM frame if we have already written one.
             return promise.setSuccess();
@@ -801,7 +799,6 @@ public class Http2ConnectionHandler extends ByteToMessageDecoder implements Http
     @Override
     public ChannelFuture goAway(final ChannelHandlerContext ctx, final int lastStreamId, final long errorCode,
                                 final ByteBuf debugData, ChannelPromise promise) {
-        promise = promise.unvoid();
         final Http2Connection connection = connection();
         try {
             if (!connection.goAwaySent(lastStreamId, errorCode, debugData)) {

codec-http2/src/main/java/io/netty/handler/codec/http2/Http2ControlFrameLimitEncoder.java

@@ -106,7 +106,7 @@ final class Http2ControlFrameLimitEncoder extends DecoratingHttp2ConnectionEncod
 
             // We did not reach the limit yet, add the listener to decrement the number of outstanding control frames
             // once the promise was completed
-            return promise.unvoid().addListener(outstandingControlFramesListener);
+            return promise.addListener(outstandingControlFramesListener);
         }
         return promise;
     }

codec-http2/src/test/java/io/netty/handler/codec/http2/DefaultHttp2ConnectionEncoderTest.java

@@ -48,7 +48,6 @@ import static io.netty.handler.codec.http2.Http2CodecUtil.DEFAULT_PRIORITY_WEIGH
 import static io.netty.handler.codec.http2.Http2Error.PROTOCOL_ERROR;
 import static io.netty.handler.codec.http2.Http2Stream.State.HALF_CLOSED_REMOTE;
 import static io.netty.handler.codec.http2.Http2Stream.State.RESERVED_LOCAL;
-import static io.netty.handler.codec.http2.Http2TestUtil.newVoidPromise;
 import static io.netty.util.CharsetUtil.UTF_8;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.hamcrest.CoreMatchers.instanceOf;
@@ -268,35 +267,6 @@ public class DefaultHttp2ConnectionEncoderTest {
         assertTrue(promise2.isSuccess());
     }
 
-    @Test
-    public void dataFramesShouldMergeUseVoidPromise() throws Exception {
-        createStream(STREAM_ID, false);
-        final ByteBuf data = dummyData().retain();
-
-        ChannelPromise promise1 = newVoidPromise(channel);
-        encoder.writeData(ctx, STREAM_ID, data, 0, true, promise1);
-        ChannelPromise promise2 = newVoidPromise(channel);
-        encoder.writeData(ctx, STREAM_ID, data, 0, true, promise2);
-
-        // Now merge the two payloads.
-        List<FlowControlled> capturedWrites = payloadCaptor.getAllValues();
-        FlowControlled mergedPayload = capturedWrites.get(0);
-        mergedPayload.merge(ctx, capturedWrites.get(1));
-        assertEquals(16, mergedPayload.size());
-        assertFalse(promise1.isSuccess());
-        assertFalse(promise2.isSuccess());
-
-        // Write the merged payloads and verify it was written correctly.
-        mergedPayload.write(ctx, 16);
-        assertEquals(0, mergedPayload.size());
-        assertEquals("abcdefghabcdefgh", writtenData.get(0));
-        assertEquals(0, data.refCnt());
-
-        // The promises won't be set since there are no listeners.
-        assertFalse(promise1.isSuccess());
-        assertFalse(promise2.isSuccess());
-    }
-
     @Test
     public void dataFramesDontMergeWithHeaders() throws Exception {
         createStream(STREAM_ID, false);
@@ -315,26 +285,6 @@ public class DefaultHttp2ConnectionEncoderTest {
         assertEquals(0, data.refCnt());
     }
 
-    @Test
-    public void writeHeadersUsingVoidPromise() throws Exception {
-        final Throwable cause = new RuntimeException("fake exception");
-        when(writer.writeHeaders(eq(ctx), eq(STREAM_ID), any(Http2Headers.class),
-                                 anyInt(), anyBoolean(), any(ChannelPromise.class)))
-                .then((Answer<ChannelFuture>) invocationOnMock -> {
-                    ChannelPromise promise = invocationOnMock.getArgument(5);
-                    assertFalse(promise.isVoid());
-                    return promise.setFailure(cause);
-                });
-        createStream(STREAM_ID, false);
-        // END_STREAM flag, so that a listener is added to the future.
-        encoder.writeHeaders(ctx, STREAM_ID, EmptyHttp2Headers.INSTANCE, 0, true, newVoidPromise(channel));
-
-        verify(writer).writeHeaders(eq(ctx), eq(STREAM_ID), any(Http2Headers.class),
-                                    anyInt(), anyBoolean(), any(ChannelPromise.class));
-        // When using a void promise, the error should be propagated via the channel pipeline.
-        verify(pipeline).fireExceptionCaught(cause);
-    }
-
     private void assertSplitPaddingOnEmptyBuffer(ByteBuf data) throws Exception {
         createStream(STREAM_ID, false);
         when(frameSizePolicy.maxFrameSize()).thenReturn(5);

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2ConnectionHandlerTest.java

@@ -28,7 +28,6 @@ import io.netty.channel.ChannelPromise;
 import io.netty.channel.DefaultChannelConfig;
 import io.netty.channel.DefaultChannelPromise;
 import io.netty.handler.codec.http.HttpResponseStatus;
-import io.netty.handler.codec.http2.Http2CodecUtil.SimpleChannelPromiseAggregator;
 import io.netty.handler.codec.http2.Http2Exception.ShutdownHint;
 import io.netty.util.ReferenceCountUtil;
 import io.netty.util.concurrent.EventExecutor;
@@ -54,7 +53,6 @@ import static io.netty.handler.codec.http2.Http2Error.PROTOCOL_ERROR;
 import static io.netty.handler.codec.http2.Http2Error.STREAM_CLOSED;
 import static io.netty.handler.codec.http2.Http2Stream.State.CLOSED;
 import static io.netty.handler.codec.http2.Http2Stream.State.IDLE;
-import static io.netty.handler.codec.http2.Http2TestUtil.newVoidPromise;
 import static io.netty.util.CharsetUtil.US_ASCII;
 import static io.netty.util.CharsetUtil.UTF_8;
 import static java.util.concurrent.TimeUnit.SECONDS;
@@ -85,7 +83,6 @@ public class Http2ConnectionHandlerTest {
 
     private Http2ConnectionHandler handler;
     private ChannelPromise promise;
-    private ChannelPromise voidPromise;
 
     @Mock
     private Http2Connection connection;
@@ -143,7 +140,6 @@ public class Http2ConnectionHandlerTest {
         MockitoAnnotations.initMocks(this);
 
         promise = new DefaultChannelPromise(channel, ImmediateEventExecutor.INSTANCE);
-        voidPromise = new DefaultChannelPromise(channel, ImmediateEventExecutor.INSTANCE);
 
         when(channel.metadata()).thenReturn(new ChannelMetadata(false));
         DefaultChannelConfig config = new DefaultChannelConfig(channel);
@@ -195,7 +191,6 @@ public class Http2ConnectionHandlerTest {
         when(ctx.channel()).thenReturn(channel);
         when(ctx.newSucceededFuture()).thenReturn(future);
         when(ctx.newPromise()).thenReturn(promise);
-        when(ctx.voidPromise()).thenReturn(voidPromise);
         when(ctx.write(any())).thenReturn(future);
         when(ctx.executor()).thenReturn(executor);
         doAnswer(in -> {
@@ -635,36 +630,6 @@ public class Http2ConnectionHandlerTest {
         verifyNoMoreInteractions(frameWriter);
     }
 
-    @Test
-    public void canSendGoAwayUsingVoidPromise() throws Exception {
-        handler = newHandler();
-        ByteBuf data = dummyData();
-        long errorCode = Http2Error.INTERNAL_ERROR.code();
-        handler = newHandler();
-        final Throwable cause = new RuntimeException("fake exception");
-        doAnswer((Answer<ChannelFuture>) invocation -> {
-            ChannelPromise promise = invocation.getArgument(4);
-            assertFalse(promise.isVoid());
-            // This is what DefaultHttp2FrameWriter does... I hate mocking :-(.
-            SimpleChannelPromiseAggregator aggregatedPromise =
-                    new SimpleChannelPromiseAggregator(promise, channel, ImmediateEventExecutor.INSTANCE);
-            aggregatedPromise.newPromise();
-            aggregatedPromise.doneAllocatingPromises();
-            return aggregatedPromise.setFailure(cause);
-        }).when(frameWriter).writeGoAway(
-                any(ChannelHandlerContext.class), anyInt(), anyLong(), any(ByteBuf.class), any(ChannelPromise.class));
-        handler.goAway(ctx, STREAM_ID, errorCode, data, newVoidPromise(channel));
-        verify(pipeline).fireExceptionCaught(cause);
-    }
-
-    @Test
-    public void canCloseStreamWithVoidPromise() throws Exception {
-        handler = newHandler();
-        handler.closeStream(stream, ctx.voidPromise());
-        verify(stream, times(1)).close();
-        verifyNoMoreInteractions(stream);
-    }
-
     @Test
     public void channelReadCompleteTriggersFlush() throws Exception {
         handler = newHandler();
@@ -702,16 +667,6 @@ public class Http2ConnectionHandlerTest {
         verifyZeroInteractions(frameWriter);
     }
 
-    @Test
-    public void writeRstStreamForUnknownStreamUsingVoidPromise() throws Exception {
-        writeRstStreamUsingVoidPromise(NON_EXISTANT_STREAM_ID);
-    }
-
-    @Test
-    public void writeRstStreamForKnownStreamUsingVoidPromise() throws Exception {
-        writeRstStreamUsingVoidPromise(STREAM_ID);
-    }
-
     @Test
     public void gracefulShutdownTimeoutWhenConnectionErrorHardShutdownTest() throws Exception {
         gracefulShutdownTimeoutWhenConnectionErrorTest0(ShutdownHint.HARD_SHUTDOWN);
@@ -788,21 +743,6 @@ public class Http2ConnectionHandlerTest {
         assertTrue(promise2.isSuccess());
     }
 
-    private void writeRstStreamUsingVoidPromise(int streamId) throws Exception {
-        handler = newHandler();
-        final Throwable cause = new RuntimeException("fake exception");
-        when(stream.id()).thenReturn(STREAM_ID);
-        when(frameWriter.writeRstStream(eq(ctx), eq(streamId), anyLong(), any(ChannelPromise.class)))
-                .then((Answer<ChannelFuture>) invocationOnMock -> {
-                    ChannelPromise promise = invocationOnMock.getArgument(3);
-                    assertFalse(promise.isVoid());
-                    return promise.setFailure(cause);
-                });
-        handler.resetStream(ctx, streamId, STREAM_CLOSED.code(), newVoidPromise(channel));
-        verify(frameWriter).writeRstStream(eq(ctx), eq(streamId), anyLong(), any(ChannelPromise.class));
-        verify(pipeline).fireExceptionCaught(cause);
-    }
-
     private static ByteBuf dummyData() {
         return Unpooled.buffer().writeBytes("abcdefgh".getBytes(UTF_8));
     }

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2FrameInboundWriter.java

@@ -340,10 +340,5 @@ final class Http2FrameInboundWriter {
         public ChannelFuture newFailedFuture(Throwable cause) {
             return channel.newFailedFuture(cause);
         }
-
-        @Override
-        public ChannelPromise voidPromise() {
-            return channel.voidPromise();
-        }
     }
 }

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2MultiplexTest.java

@@ -856,7 +856,7 @@ public abstract class Http2MultiplexTest<C extends Http2FrameCodec> {
         // and verify that this only affect the writability of the parent channel while the child stays writable
         // until it used all of its credits.
         parentChannel.unsafe().outboundBuffer().addMessage(
-                Unpooled.buffer().writeZero(800), 800, parentChannel.voidPromise());
+                Unpooled.buffer().writeZero(800), 800, parentChannel.newPromise());
         assertFalse(parentChannel.isWritable());
 
         assertTrue(childChannel.isWritable());
@@ -959,7 +959,7 @@ public abstract class Http2MultiplexTest<C extends Http2FrameCodec> {
     public void callUnsafeCloseMultipleTimes() {
         LastInboundHandler inboundHandler = new LastInboundHandler();
         Http2StreamChannel childChannel = newInboundStream(3, false, inboundHandler);
-        childChannel.unsafe().close(childChannel.voidPromise());
+        childChannel.unsafe().close(childChannel.newPromise());
 
         ChannelPromise promise = childChannel.newPromise();
         childChannel.unsafe().close(promise);

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2TestUtil.java

@@ -438,51 +438,6 @@ public final class Http2TestUtil {
         }
     }
 
-    static ChannelPromise newVoidPromise(final Channel channel) {
-        return new DefaultChannelPromise(channel, ImmediateEventExecutor.INSTANCE) {
-            @Override
-            public ChannelPromise addListener(
-                    GenericFutureListener<? extends Future<? super Void>> listener) {
-                throw new AssertionFailedError();
-            }
-
-            @Override
-            public ChannelPromise addListeners(
-                    GenericFutureListener<? extends Future<? super Void>>... listeners) {
-                throw new AssertionFailedError();
-            }
-
-            @Override
-            public boolean isVoid() {
-                return true;
-            }
-
-            @Override
-            public boolean tryFailure(Throwable cause) {
-                channel().pipeline().fireExceptionCaught(cause);
-                return true;
-            }
-
-            @Override
-            public ChannelPromise setFailure(Throwable cause) {
-                tryFailure(cause);
-                return this;
-            }
-
-            @Override
-            public ChannelPromise unvoid() {
-                ChannelPromise promise =
-                        new DefaultChannelPromise(channel, ImmediateEventExecutor.INSTANCE);
-                promise.addListener((ChannelFutureListener) future -> {
-                    if (!future.isSuccess()) {
-                        channel().pipeline().fireExceptionCaught(future.cause());
-                    }
-                });
-                return promise;
-            }
-        };
-    }
-
     static final class TestStreamByteDistributorStreamState implements StreamByteDistributor.StreamState {
         private final Http2Stream stream;
         boolean isWriteAllowed;

codec-memcache/src/main/java/io/netty/handler/codec/memcache/binary/BinaryMemcacheClientCodec.java

@@ -291,10 +291,6 @@ public final class BinaryMemcacheClientCodec extends
                 public ChannelFuture newFailedFuture(Throwable cause) {
                     return ctx.newFailedFuture(cause);
                 }
-
-                public ChannelPromise voidPromise() {
-                    return ctx.voidPromise();
-                }
             };
         }
 

codec/src/main/java/io/netty/handler/codec/ByteToMessageDecoder.java

@@ -744,10 +744,5 @@ public abstract class ByteToMessageDecoder extends ChannelHandlerAdapter {
         public ChannelFuture newFailedFuture(Throwable cause) {
             return ctx.newFailedFuture(cause);
         }
-
-        @Override
-        public ChannelPromise voidPromise() {
-            return ctx.voidPromise();
-        }
     }
 }

codec/src/main/java/io/netty/handler/codec/MessageToMessageEncoder.java

@@ -109,13 +109,7 @@ public abstract class MessageToMessageEncoder<I> extends ChannelHandlerAdapter {
                     if (sizeMinusOne == 0) {
                         ctx.write(out.getUnsafe(0), promise);
                     } else if (sizeMinusOne > 0) {
-                        // Check if we can use a voidPromise for our extra writes to reduce GC-Pressure
+                        writePromiseCombiner(ctx, out, promise);
-                        // See https://github.com/netty/netty/issues/2525
-                        if (promise == ctx.voidPromise()) {
-                            writeVoidPromise(ctx, out);
-                        } else {
-                            writePromiseCombiner(ctx, out, promise);
-                        }
                     }
                 } finally {
                     out.recycle();
@@ -124,13 +118,6 @@ public abstract class MessageToMessageEncoder<I> extends ChannelHandlerAdapter {
         }
     }
 
-    private static void writeVoidPromise(ChannelHandlerContext ctx, CodecOutputList out) {
-        final ChannelPromise voidPromise = ctx.voidPromise();
-        for (int i = 0; i < out.size(); i++) {
-            ctx.write(out.getUnsafe(i), voidPromise);
-        }
-    }
-
     private static void writePromiseCombiner(ChannelHandlerContext ctx, CodecOutputList out, ChannelPromise promise) {
         final PromiseCombiner combiner = new PromiseCombiner(ctx.executor());
         for (int i = 0; i < out.size(); i++) {

handler/src/main/java/io/netty/handler/ssl/SslHandler.java

@@ -784,10 +784,6 @@ public class SslHandler extends ByteToMessageDecoder {
 
     private void wrapAndFlush(ChannelHandlerContext ctx) throws SSLException {
         if (pendingUnencryptedWrites.isEmpty()) {
-            // It's important to NOT use a voidPromise here as the user
-            // may want to add a ChannelFutureListener to the ChannelPromise later.
-            //
-            // See https://github.com/netty/netty/issues/3364
             pendingUnencryptedWrites.add(Unpooled.EMPTY_BUFFER, ctx.newPromise());
         }
         if (!handshakePromise.isDone()) {

handler/src/main/java/io/netty/handler/timeout/IdleStateHandler.java

@@ -300,7 +300,7 @@ public class IdleStateHandler implements ChannelHandler {
     public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
         // Allow writing with void promise if handler is only configured for read timeout events.
         if (writerIdleTimeNanos > 0 || allIdleTimeNanos > 0) {
-            ctx.write(msg, promise.unvoid()).addListener(writeListener);
+            ctx.write(msg, promise).addListener(writeListener);
         } else {
             ctx.write(msg, promise);
         }

handler/src/main/java/io/netty/handler/timeout/WriteTimeoutHandler.java

@@ -106,7 +106,6 @@ public class WriteTimeoutHandler implements ChannelHandler {
     @Override
     public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
         if (timeoutNanos > 0) {
-            promise = promise.unvoid();
             scheduleTimeout(ctx, promise);
         }
         ctx.write(msg, promise);

microbench/src/main/java/io/netty/handler/codec/http2/Http2FrameWriterDataBenchmark.java

@@ -101,14 +101,14 @@ public class Http2FrameWriterDataBenchmark extends AbstractMicrobenchmark {
     @Benchmark
     @BenchmarkMode(Mode.AverageTime)
     public void newWriter() {
-        writer.writeData(ctx, 3, payload.retain(), padding, true, ctx.voidPromise());
+        writer.writeData(ctx, 3, payload.retain(), padding, true, ctx.newPromise());
         ctx.flush();
     }
 
     @Benchmark
     @BenchmarkMode(Mode.AverageTime)
     public void oldWriter() {
-        oldWriter.writeData(ctx, 3, payload.retain(), padding, true, ctx.voidPromise());
+        oldWriter.writeData(ctx, 3, payload.retain(), padding, true, ctx.newPromise());
         ctx.flush();
     }
 

microbench/src/main/java/io/netty/microbench/channel/EmbeddedChannelHandlerContext.java

@@ -316,9 +316,4 @@ public abstract class EmbeddedChannelHandlerContext implements ChannelHandlerCon
     public final ChannelFuture newFailedFuture(Throwable cause) {
         return channel().newFailedFuture(cause);
     }
-
-    @Override
-    public final ChannelPromise voidPromise() {
-        return channel().voidPromise();
-    }
 }

microbench/src/main/java/io/netty/microbench/channel/epoll/EpollSocketChannelBenchmark.java

@@ -63,7 +63,7 @@ public class EpollSocketChannelBenchmark extends AbstractMicrobenchmark {
                         @Override
                         public void channelRead(ChannelHandlerContext ctx, Object msg) {
                             if (msg instanceof ByteBuf) {
-                                ctx.writeAndFlush(msg, ctx.voidPromise());
+                                ctx.writeAndFlush(msg);
                             } else {
                                 throw new AssertionError();
                             }
@@ -110,7 +110,7 @@ public class EpollSocketChannelBenchmark extends AbstractMicrobenchmark {
                             throw new IllegalStateException();
                         }
                         lastWritePromise = promise;
-                        ctx.write(msg, ctx.voidPromise());
+                        ctx.write(msg);
                     }
                 });
             }

microbench/src/main/java/io/netty/microbench/handler/ssl/AbstractSslHandlerThroughputBenchmark.java

@@ -87,7 +87,7 @@ public abstract class AbstractSslHandlerThroughputBenchmark extends AbstractSslH
         for (int i = 0; i < numWrites; ++i) {
             ByteBuf wrapSrcBuffer = this.wrapSrcBuffer.retainedSlice();
 
-            clientSslHandler.write(clientCtx, wrapSrcBuffer, clientCtx.voidPromise());
+            clientSslHandler.write(clientCtx, wrapSrcBuffer, clientCtx.newPromise());
         }
         clientSslHandler.flush(clientCtx);
         return clientCtx.cumulation().retainedSlice();

microbench/src/main/java/io/netty/microbench/http/HttpObjectEncoderBenchmark.java

@@ -66,9 +66,6 @@ public class HttpObjectEncoderBenchmark extends AbstractMicrobenchmark {
     @Param({ "true", "false" })
     public boolean pooledAllocator;
 
-    @Param({ "true", "false" })
-    public boolean voidPromise;
-
     @Setup(Level.Trial)
     public void setup() {
         byte[] bytes = new byte[256];
@@ -121,6 +118,6 @@ public class HttpObjectEncoderBenchmark extends AbstractMicrobenchmark {
     }
 
     private ChannelPromise newPromise() {
-        return voidPromise ? context.voidPromise() : context.newPromise();
+        return context.newPromise();
     }
 }

microbench/src/main/java/io/netty/microbench/redis/RedisEncoderBenchmark.java

@@ -56,9 +56,6 @@ public class RedisEncoderBenchmark extends AbstractMicrobenchmark {
     @Param({ "true", "false" })
     public boolean pooledAllocator;
 
-    @Param({ "true", "false" })
-    public boolean voidPromise;
-
     @Param({ "50", "200", "1000" })
     public int arraySize;
 
@@ -96,6 +93,6 @@ public class RedisEncoderBenchmark extends AbstractMicrobenchmark {
     }
 
     private ChannelPromise newPromise() {
-        return voidPromise ? context.voidPromise() : context.newPromise();
+        return context.newPromise();
     }
 }

microbench/src/main/java/io/netty/microbench/stomp/StompEncoderBenchmark.java

@@ -58,9 +58,6 @@ public class StompEncoderBenchmark extends AbstractMicrobenchmark {
     @Param({ "true", "false" })
     public boolean pooledAllocator;
 
-    @Param({ "true", "false" })
-    public boolean voidPromise;
-
     @Param
     public ExampleStompHeadersSubframe.HeadersType headersType;
 
@@ -100,7 +97,7 @@ public class StompEncoderBenchmark extends AbstractMicrobenchmark {
     }
 
     private ChannelPromise newPromise() {
-        return voidPromise? context.voidPromise() : context.newPromise();
+        return context.newPromise();
     }
 
     @Override

resolver-dns/src/main/java/io/netty/resolver/dns/DnsNameResolver.java

@@ -1230,7 +1230,6 @@ public class DnsNameResolver extends InetNameResolver {
             boolean flush,
             ChannelPromise writePromise,
             Promise<AddressedEnvelope<? extends DnsResponse, InetSocketAddress>> promise) {
-        assert !writePromise.isVoid();
 
         final Promise<AddressedEnvelope<DnsResponse, InetSocketAddress>> castPromise = cast(
                 requireNonNull(promise, "promise"));

testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketEchoTest.java

@@ -34,7 +34,6 @@ import org.junit.jupiter.api.TestInfo;
 import org.junit.jupiter.api.Timeout;
 
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotEquals;
 
 public class SocketEchoTest extends AbstractSocketTest {
 
@@ -52,7 +51,7 @@ public class SocketEchoTest extends AbstractSocketTest {
     }
 
     public void testSimpleEcho(ServerBootstrap sb, Bootstrap cb) throws Throwable {
-        testSimpleEcho0(sb, cb, false, true);
+        testSimpleEcho0(sb, cb, true);
     }
 
     @Test
@@ -62,29 +61,11 @@ public class SocketEchoTest extends AbstractSocketTest {
     }
 
     public void testSimpleEchoNotAutoRead(ServerBootstrap sb, Bootstrap cb) throws Throwable {
-        testSimpleEcho0(sb, cb, false, false);
+        testSimpleEcho0(sb, cb, false);
-    }
-
-    @Test//(timeout = 30000)
-    public void testSimpleEchoWithVoidPromise(TestInfo testInfo) throws Throwable {
-        run(testInfo, this::testSimpleEchoWithVoidPromise);
-    }
-
-    public void testSimpleEchoWithVoidPromise(ServerBootstrap sb, Bootstrap cb) throws Throwable {
-        testSimpleEcho0(sb, cb, true, true);
-    }
-
-    @Test//(timeout = 30000)
-    public void testSimpleEchoWithVoidPromiseNotAutoRead(TestInfo testInfo) throws Throwable {
-        run(testInfo, this::testSimpleEchoWithVoidPromiseNotAutoRead);
-    }
-
-    public void testSimpleEchoWithVoidPromiseNotAutoRead(ServerBootstrap sb, Bootstrap cb) throws Throwable {
-        testSimpleEcho0(sb, cb, true, false);
     }
 
     private static void testSimpleEcho0(
-            ServerBootstrap sb, Bootstrap cb, boolean voidPromise, boolean autoRead)
+            ServerBootstrap sb, Bootstrap cb, boolean autoRead)
             throws Throwable {
 
         final EchoHandler sh = new EchoHandler(autoRead);
@@ -107,11 +88,7 @@ public class SocketEchoTest extends AbstractSocketTest {
         for (int i = 0; i < data.length;) {
             int length = Math.min(random.nextInt(1024 * 64), data.length - i);
             ByteBuf buf = Unpooled.wrappedBuffer(data, i, length);
-            if (voidPromise) {
+            cc.writeAndFlush(buf);
-                assertEquals(cc.voidPromise(), cc.writeAndFlush(buf, cc.voidPromise()));
-            } else {
-                assertNotEquals(cc.voidPromise(), cc.writeAndFlush(buf));
-            }
             i += length;
         }
 

testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketFileRegionTest.java

@@ -43,7 +43,6 @@ import java.util.concurrent.atomic.AtomicReference;
 import static org.hamcrest.CoreMatchers.is;
 import static org.hamcrest.MatcherAssert.assertThat;
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotEquals;
 
 public class SocketFileRegionTest extends AbstractSocketTest {
 
@@ -68,39 +67,21 @@ public class SocketFileRegionTest extends AbstractSocketTest {
         run(testInfo, this::testFileRegionNotAutoRead);
     }
 
-    @Test
-    public void testFileRegionVoidPromise(TestInfo testInfo) throws Throwable {
-        run(testInfo, this::testFileRegionVoidPromise);
-    }
-
-    @Test
-    public void testFileRegionVoidPromiseNotAutoRead(TestInfo testInfo) throws Throwable {
-        run(testInfo, this::testFileRegionVoidPromiseNotAutoRead);
-    }
-
     @Test
     public void testFileRegionCountLargerThenFile(TestInfo testInfo) throws Throwable {
         run(testInfo, this::testFileRegionCountLargerThenFile);
     }
 
     public void testFileRegion(ServerBootstrap sb, Bootstrap cb) throws Throwable {
-        testFileRegion0(sb, cb, false, true, true);
+        testFileRegion0(sb, cb, true, true);
     }
 
     public void testCustomFileRegion(ServerBootstrap sb, Bootstrap cb) throws Throwable {
-        testFileRegion0(sb, cb, false, true, false);
+        testFileRegion0(sb, cb, true, false);
-    }
-
-    public void testFileRegionVoidPromise(ServerBootstrap sb, Bootstrap cb) throws Throwable {
-        testFileRegion0(sb, cb, true, true, true);
     }
 
     public void testFileRegionNotAutoRead(ServerBootstrap sb, Bootstrap cb) throws Throwable {
-        testFileRegion0(sb, cb, false, false, true);
+        testFileRegion0(sb, cb, false, true);
-    }
-
-    public void testFileRegionVoidPromiseNotAutoRead(ServerBootstrap sb, Bootstrap cb) throws Throwable {
-        testFileRegion0(sb, cb, true, false, true);
     }
 
     public void testFileRegionCountLargerThenFile(ServerBootstrap sb, Bootstrap cb) throws Throwable {
@@ -132,7 +113,7 @@ public class SocketFileRegionTest extends AbstractSocketTest {
     }
 
     private static void testFileRegion0(
-            ServerBootstrap sb, Bootstrap cb, boolean voidPromise, final boolean autoRead, boolean defaultFileRegion)
+            ServerBootstrap sb, Bootstrap cb, final boolean autoRead, boolean defaultFileRegion)
             throws Throwable {
         sb.childOption(ChannelOption.AUTO_READ, autoRead);
         cb.option(ChannelOption.AUTO_READ, autoRead);
@@ -198,15 +179,9 @@ public class SocketFileRegionTest extends AbstractSocketTest {
         //
         // See https://github.com/netty/netty/issues/2769
         //     https://github.com/netty/netty/issues/2964
-        if (voidPromise) {
+        cc.write(Unpooled.wrappedBuffer(data, 0, bufferSize));
-            assertEquals(cc.voidPromise(), cc.write(Unpooled.wrappedBuffer(data, 0, bufferSize), cc.voidPromise()));
+        cc.write(emptyRegion);
-            assertEquals(cc.voidPromise(), cc.write(emptyRegion, cc.voidPromise()));
+        cc.writeAndFlush(region);
-            assertEquals(cc.voidPromise(), cc.writeAndFlush(region, cc.voidPromise()));
-        } else {
-            assertNotEquals(cc.voidPromise(), cc.write(Unpooled.wrappedBuffer(data, 0, bufferSize)));
-            assertNotEquals(cc.voidPromise(), cc.write(emptyRegion));
-            assertNotEquals(cc.voidPromise(), cc.writeAndFlush(region));
-        }
 
         while (sh.counter < data.length) {
             if (sh.exception.get() != null) {

testsuite/src/main/java/io/netty/testsuite/transport/socket/SocketGatheringWriteTest.java

@@ -42,7 +42,6 @@ import java.util.concurrent.atomic.AtomicReference;
 import static io.netty.buffer.Unpooled.compositeBuffer;
 import static io.netty.buffer.Unpooled.wrappedBuffer;
 import static org.junit.jupiter.api.Assertions.assertEquals;
-import static org.junit.jupiter.api.Assertions.assertNotEquals;
 import static org.junit.jupiter.api.Assertions.assertTrue;
 
 public class SocketGatheringWriteTest extends AbstractSocketTest {
@@ -143,7 +142,6 @@ public class SocketGatheringWriteTest extends AbstractSocketTest {
         }
 
         ChannelFuture cf = cc.writeAndFlush(Unpooled.EMPTY_BUFFER);
-        assertNotEquals(cc.voidPromise(), cf);
         try {
             assertTrue(cf.await(60000));
             cf.sync();

transport-native-epoll/src/main/java/io/netty/channel/epoll/AbstractEpollChannel.java

@@ -489,7 +489,7 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
                 clearFlag(Native.EPOLLRDHUP);
             } catch (IOException e) {
                 pipeline().fireExceptionCaught(e);
-                close(voidPromise());
+                close(newPromise());
             }
         }
 
@@ -513,7 +513,7 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
                     clearEpollIn();
                     pipeline().fireUserEventTriggered(ChannelInputShutdownEvent.INSTANCE);
                 } else {
-                    close(voidPromise());
+                    close(newPromise());
                 }
             } else if (!rdHup) {
                 inputClosedSeenErrorOnRead = true;
@@ -523,7 +523,7 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
 
         private void fireEventAndClose(Object evt) {
             pipeline().fireUserEventTriggered(evt);
-            close(voidPromise());
+            close(newPromise());
         }
 
         @Override
@@ -574,7 +574,7 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
                 // When this happens there is something completely wrong with either the filedescriptor or epoll,
                 // so fire the exception through the pipeline and close the Channel.
                 pipeline().fireExceptionCaught(e);
-                unsafe().close(unsafe().voidPromise());
+                unsafe().close(newPromise());
             }
         }
 
@@ -605,7 +605,7 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
                             if (connectPromise != null && !connectPromise.isDone()
                                     && connectPromise.tryFailure(new ConnectTimeoutException(
                                     "connection timed out: " + remoteAddress))) {
-                                close(voidPromise());
+                                close(newPromise());
                             }
                         }, connectTimeoutMillis, TimeUnit.MILLISECONDS);
                     }
@@ -616,7 +616,7 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
                                 connectTimeoutFuture.cancel(false);
                             }
                             connectPromise = null;
-                            close(voidPromise());
+                            close(newPromise());
                         }
                     });
                 }
@@ -649,7 +649,7 @@ abstract class AbstractEpollChannel extends AbstractChannel implements UnixChann
 
             // If a user cancelled the connection attempt, close the channel, which is followed by channelInactive().
             if (!promiseSet) {
-                close(voidPromise());
+                close(newPromise());
             }
         }
 

transport-native-epoll/src/main/java/io/netty/channel/epoll/EpollDomainSocketChannel.java

@@ -168,7 +168,7 @@ public final class EpollDomainSocketChannel extends AbstractEpollStreamChannel i
                     case 0:
                         break readLoop;
                     case -1:
-                        close(voidPromise());
+                        close(newPromise());
                         return;
                     default:
                         allocHandle.incMessagesRead(1);

transport-native-epoll/src/main/java/io/netty/channel/epoll/EpollHandler.java

@@ -375,7 +375,7 @@ public class EpollHandler implements IoHandler {
         AbstractEpollChannel[] localChannels = channels.values().toArray(new AbstractEpollChannel[0]);
 
         for (AbstractEpollChannel ch: localChannels) {
-            ch.unsafe().close(ch.unsafe().voidPromise());
+            ch.unsafe().close(ch.newPromise());
         }
     }
 

transport-native-kqueue/src/main/java/io/netty/channel/kqueue/AbstractKQueueChannel.java

@@ -460,7 +460,7 @@ abstract class AbstractKQueueChannel extends AbstractChannel implements UnixChan
                     }
                     pipeline().fireUserEventTriggered(ChannelInputShutdownEvent.INSTANCE);
                 } else {
-                    close(voidPromise());
+                    close(newPromise());
                 }
             } else if (!readEOF) {
                 inputClosedSeenErrorOnRead = true;
@@ -520,13 +520,13 @@ abstract class AbstractKQueueChannel extends AbstractChannel implements UnixChan
                 // When this happens there is something completely wrong with either the filedescriptor or epoll,
                 // so fire the exception through the pipeline and close the Channel.
                 pipeline().fireExceptionCaught(e);
-                unsafe().close(unsafe().voidPromise());
+                unsafe().close(newPromise());
             }
         }
 
         private void fireEventAndClose(Object evt) {
             pipeline().fireUserEventTriggered(evt);
-            close(voidPromise());
+            close(newPromise());
         }
 
         @Override
@@ -556,7 +556,7 @@ abstract class AbstractKQueueChannel extends AbstractChannel implements UnixChan
                             if (connectPromise != null && !connectPromise.isDone()
                                     && connectPromise.tryFailure(new ConnectTimeoutException(
                                     "connection timed out: " + remoteAddress))) {
-                                close(voidPromise());
+                                close(newPromise());
                             }
                         }, connectTimeoutMillis, TimeUnit.MILLISECONDS);
                     }
@@ -567,7 +567,7 @@ abstract class AbstractKQueueChannel extends AbstractChannel implements UnixChan
                                 connectTimeoutFuture.cancel(false);
                             }
                             connectPromise = null;
-                            close(voidPromise());
+                            close(newPromise());
                         }
                     });
                 }
@@ -600,7 +600,7 @@ abstract class AbstractKQueueChannel extends AbstractChannel implements UnixChan
 
             // If a user cancelled the connection attempt, close the channel, which is followed by channelInactive().
             if (!promiseSet) {
-                close(voidPromise());
+                close(newPromise());
             }
         }
 

transport-native-kqueue/src/main/java/io/netty/channel/kqueue/KQueueDomainSocketChannel.java

@@ -163,7 +163,7 @@ public final class KQueueDomainSocketChannel extends AbstractKQueueStreamChannel
                             break readLoop;
                         case -1:
                             allocHandle.lastBytesRead(-1);
-                            close(voidPromise());
+                            close(newPromise());
                             return;
                         default:
                             allocHandle.lastBytesRead(1);

transport-native-kqueue/src/main/java/io/netty/channel/kqueue/KQueueHandler.java

@@ -342,7 +342,7 @@ public final class KQueueHandler implements IoHandler {
         AbstractKQueueChannel[] localChannels = channels.values().toArray(new AbstractKQueueChannel[0]);
 
         for (AbstractKQueueChannel ch: localChannels) {
-            ch.unsafe().close(ch.unsafe().voidPromise());
+            ch.unsafe().close(ch.newPromise());
         }
     }
 

transport/src/main/java/io/netty/channel/AbstractChannel.java

@@ -52,7 +52,6 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
     private final Unsafe unsafe;
     private final ChannelPipeline pipeline;
     private final ChannelFuture succeedFuture;
-    private final VoidChannelPromise unsafeVoidPromise = new VoidChannelPromise(this, false);
     private final CloseFuture closeFuture;
 
     private volatile SocketAddress localAddress;
@@ -438,11 +437,6 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
         return strVal;
     }
 
-    @Override
-    public final ChannelPromise voidPromise() {
-        return pipeline.voidPromise();
-    }
-
     protected final void readIfIsAutoRead() {
         if (config().isAutoRead()) {
             read();
@@ -679,7 +673,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
                 if (closeFuture.isDone()) {
                     // Closed already.
                     safeSetSuccess(promise);
-                } else if (!(promise instanceof VoidChannelPromise)) { // Only needed if no VoidChannelPromise.
+                } else {
                     // This means close() was called before so we just register a listener and return
                     closeFuture.addListener((ChannelFutureListener) future -> promise.setSuccess());
                 }
@@ -740,7 +734,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
         }
 
         private void fireChannelInactiveAndDeregister(final boolean wasActive) {
-            deregister(voidPromise(), wasActive && !isActive());
+            deregister(newPromise(), wasActive && !isActive());
         }
 
         @Override
@@ -825,7 +819,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
                 doBeginRead();
             } catch (final Exception e) {
                 invokeLater(() -> pipeline.fireExceptionCaught(e));
-                close(voidPromise());
+                close(newPromise());
             }
         }
 
@@ -936,13 +930,13 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
                  * may still return {@code true} even if the channel should be closed as result of the exception.
                  */
                 initialCloseCause = t;
-                close(voidPromise(), t, newClosedChannelException(t, "flush0()"), false);
+                close(newPromise(), t, newClosedChannelException(t, "flush0()"), false);
             } else {
                 try {
-                    shutdownOutput(voidPromise(), t);
+                    shutdownOutput(newPromise(), t);
                 } catch (Throwable t2) {
                     initialCloseCause = t;
-                    close(voidPromise(), t2, newClosedChannelException(t, "flush0()"), false);
+                    close(newPromise(), t2, newClosedChannelException(t, "flush0()"), false);
                 }
             }
         }
@@ -956,13 +950,6 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
             return exception;
         }
 
-        @Override
-        public final ChannelPromise voidPromise() {
-            assertEventLoop();
-
-            return unsafeVoidPromise;
-        }
-
         protected final boolean ensureOpen(ChannelPromise promise) {
             if (isOpen()) {
                 return true;
@@ -976,7 +963,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
          * Marks the specified {@code promise} as success.  If the {@code promise} is done already, log a message.
          */
         protected final void safeSetSuccess(ChannelPromise promise) {
-            if (!(promise instanceof VoidChannelPromise) && !promise.trySuccess()) {
+            if (!promise.trySuccess()) {
                 logger.warn("Failed to mark a promise as success because it is done already: {}", promise);
             }
         }
@@ -985,7 +972,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
          * Marks the specified {@code promise} as failure.  If the {@code promise} is done already, log a message.
          */
         protected final void safeSetFailure(ChannelPromise promise, Throwable cause) {
-            if (!(promise instanceof VoidChannelPromise) && !promise.tryFailure(cause)) {
+            if (!promise.tryFailure(cause)) {
                 logger.warn("Failed to mark a promise as failure because it's done already: {}", promise, cause);
             }
         }
@@ -994,7 +981,7 @@ public abstract class AbstractChannel extends DefaultAttributeMap implements Cha
             if (isOpen()) {
                 return;
             }
-            close(voidPromise());
+            close(newPromise());
         }
 
         private void invokeLater(Runnable task) {

transport/src/main/java/io/netty/channel/AbstractCoalescingBufferQueue.java

@@ -54,7 +54,7 @@ public abstract class AbstractCoalescingBufferQueue {
      * @param promise to complete when all the bytes have been consumed and written, can be void.
      */
     public final void addFirst(ByteBuf buf, ChannelPromise promise) {
-        addFirst(buf, toChannelFutureListener(promise));
+        addFirst(buf, (ChannelFutureListener) new DelegatingChannelPromiseNotifier(promise));
     }
 
     private void addFirst(ByteBuf buf, ChannelFutureListener listener) {
@@ -81,7 +81,7 @@ public abstract class AbstractCoalescingBufferQueue {
     public final void add(ByteBuf buf, ChannelPromise promise) {
         // buffers are added before promises so that we naturally 'consume' the entire buffer during removal
         // before we complete it's promise.
-        add(buf, toChannelFutureListener(promise));
+        add(buf, (ChannelFutureListener) new DelegatingChannelPromiseNotifier(promise));
     }
 
     /**
@@ -230,7 +230,10 @@ public abstract class AbstractCoalescingBufferQueue {
                 if (entry == null) {
                     if (previousBuf != null) {
                         decrementReadableBytes(previousBuf.readableBytes());
-                        ctx.write(previousBuf, ctx.voidPromise());
+                        // If the write fails we want to at least propagate the exception through the ChannelPipeline
+                        // as otherwise the user will not be made aware of the failure at all.
+                        ctx.write(previousBuf).addListener(
+                                ChannelFutureListener.FIRE_EXCEPTION_ON_FAILURE);
                     }
                     break;
                 }
@@ -238,7 +241,10 @@ public abstract class AbstractCoalescingBufferQueue {
                 if (entry instanceof ByteBufConvertible) {
                     if (previousBuf != null) {
                         decrementReadableBytes(previousBuf.readableBytes());
-                        ctx.write(previousBuf, ctx.voidPromise());
+                        // If the write fails we want to at least propagate the exception through the ChannelPipeline
+                        // as otherwise the user will not be made aware of the failure at all.
+                        ctx.write(previousBuf).addListener(
+                                ChannelFutureListener.FIRE_EXCEPTION_ON_FAILURE);
                     }
                     previousBuf = ((ByteBufConvertible) entry).asByteBuf();
                 } else if (entry instanceof ChannelPromise) {
@@ -380,8 +386,4 @@ public abstract class AbstractCoalescingBufferQueue {
             tracker.decrementPendingOutboundBytes(decrement);
         }
     }
-
-    private static ChannelFutureListener toChannelFutureListener(ChannelPromise promise) {
-        return promise.isVoid() ? null : new DelegatingChannelPromiseNotifier(promise);
-    }
 }

transport/src/main/java/io/netty/channel/Channel.java

@@ -203,7 +203,6 @@ public interface Channel extends AttributeMap, ChannelOutboundInvoker, Comparabl
      *   <li>{@link #closeForcibly()}</li>
      *   <li>{@link #register(ChannelPromise)}</li>
      *   <li>{@link #deregister(ChannelPromise)}</li>
-     *   <li>{@link #voidPromise()}</li>
      * </ul>
      */
     interface Unsafe {
@@ -287,13 +286,6 @@ public interface Channel extends AttributeMap, ChannelOutboundInvoker, Comparabl
          */
         void flush();
 
-        /**
-         * Return a special ChannelPromise which can be reused and passed to the operations in {@link Unsafe}.
-         * It will never be notified of a success or error and so is only a placeholder for operations
-         * that take a {@link ChannelPromise} as argument but for which you not want to get notified.
-         */
-        ChannelPromise voidPromise();
-
         /**
          * Returns the {@link ChannelOutboundBuffer} of the {@link Channel} where the pending write requests are stored.
          */

transport/src/main/java/io/netty/channel/ChannelFuture.java

@@ -193,20 +193,4 @@ public interface ChannelFuture extends Future<Void> {
 
     @Override
     ChannelFuture awaitUninterruptibly();
-
-    /**
-     * Returns {@code true} if this {@link ChannelFuture} is a void future and so not allow to call any of the
-     * following methods:
-     * <ul>
-     *     <li>{@link #addListener(GenericFutureListener)}</li>
-     *     <li>{@link #addListeners(GenericFutureListener[])}</li>
-     *     <li>{@link #await()}</li>
-     *     <li>{@link #await(long, TimeUnit)} ()}</li>
-     *     <li>{@link #await(long)} ()}</li>
-     *     <li>{@link #awaitUninterruptibly()}</li>
-     *     <li>{@link #sync()}</li>
-     *     <li>{@link #syncUninterruptibly()}</li>
-     * </ul>
-     */
-    boolean isVoid();
 }

transport/src/main/java/io/netty/channel/ChannelOutboundBuffer.java

@@ -702,15 +702,11 @@ public final class ChannelOutboundBuffer {
     }
 
     private static void safeSuccess(ChannelPromise promise) {
-        // Only log if the given promise is not of type VoidChannelPromise as trySuccess(...) is expected to return
+        PromiseNotificationUtil.trySuccess(promise, null, logger);
-        // false.
-        PromiseNotificationUtil.trySuccess(promise, null, promise instanceof VoidChannelPromise ? null : logger);
     }
 
     private static void safeFail(ChannelPromise promise, Throwable cause) {
-        // Only log if the given promise is not of type VoidChannelPromise as tryFailure(...) is expected to return
+        PromiseNotificationUtil.tryFailure(promise, cause, logger);
-        // false.
-        PromiseNotificationUtil.tryFailure(promise, cause, promise instanceof VoidChannelPromise ? null : logger);
     }
 
     @Deprecated

transport/src/main/java/io/netty/channel/ChannelOutboundInvoker.java

@@ -279,20 +279,4 @@ public interface ChannelOutboundInvoker {
      * every call of blocking methods will just return without blocking.
      */
     ChannelFuture newFailedFuture(Throwable cause);
-
-    /**
-     * Return a special ChannelPromise which can be reused for different operations.
-     * <p>
-     * It's only supported to use
-     * it for {@link ChannelOutboundInvoker#write(Object, ChannelPromise)}.
-     * </p>
-     * <p>
-     * Be aware that the returned {@link ChannelPromise} will not support most operations and should only be used
-     * if you want to save an object allocation for every write operation. You will not be able to detect if the
-     * operation  was complete, only if it failed as the implementation will call
-     * {@link ChannelPipeline#fireExceptionCaught(Throwable)} in this case.
-     * </p>
-     * <strong>Be aware this is an expert feature and should be used with care!</strong>
-     */
-    ChannelPromise voidPromise();
 }

transport/src/main/java/io/netty/channel/ChannelProgressivePromise.java

@@ -59,7 +59,4 @@ public interface ChannelProgressivePromise extends ProgressivePromise<Void>, Cha
 
     @Override
     ChannelProgressivePromise setProgress(long progress, long total);
-
-    @Override
-    ChannelProgressivePromise unvoid();
 }

transport/src/main/java/io/netty/channel/ChannelPromise.java

@@ -60,9 +60,4 @@ public interface ChannelPromise extends ChannelFuture, Promise<Void> {
 
     @Override
     ChannelPromise awaitUninterruptibly();
-
-    /**
-     * Returns a new {@link ChannelPromise} if {@link #isVoid()} returns {@code true} otherwise itself.
-     */
-    ChannelPromise unvoid();
 }

transport/src/main/java/io/netty/channel/CombinedChannelDuplexHandler.java

@@ -558,11 +558,6 @@ public class CombinedChannelDuplexHandler<I extends ChannelHandler, O extends Ch
             return ctx.newFailedFuture(cause);
         }
 
-        @Override
-        public ChannelPromise voidPromise() {
-            return ctx.voidPromise();
-        }
-
         @Override
         public <T> Attribute<T> attr(AttributeKey<T> key) {
             return ctx.channel().attr(key);

transport/src/main/java/io/netty/channel/CompleteChannelFuture.java

@@ -104,9 +104,4 @@ abstract class CompleteChannelFuture extends CompleteFuture<Void> implements Cha
     public Void getNow() {
         return null;
     }
-
-    @Override
-    public boolean isVoid() {
-        return false;
-    }
 }

transport/src/main/java/io/netty/channel/DefaultChannelHandlerContext.java

@@ -456,7 +456,7 @@ final class DefaultChannelHandlerContext implements ChannelHandlerContext, Resou
     @Override
     public ChannelFuture bind(final SocketAddress localAddress, final ChannelPromise promise) {
         requireNonNull(localAddress, "localAddress");
-        if (isNotValidPromise(promise, false)) {
+        if (isNotValidPromise(promise)) {
             // cancelled
             return promise;
         }
@@ -496,7 +496,7 @@ final class DefaultChannelHandlerContext implements ChannelHandlerContext, Resou
     public ChannelFuture connect(
             final SocketAddress remoteAddress, final SocketAddress localAddress, final ChannelPromise promise) {
         requireNonNull(remoteAddress, "remoteAddress");
-        if (isNotValidPromise(promise, false)) {
+        if (isNotValidPromise(promise)) {
             // cancelled
             return promise;
         }
@@ -535,7 +535,7 @@ final class DefaultChannelHandlerContext implements ChannelHandlerContext, Resou
             return close(promise);
         }
 
-        if (isNotValidPromise(promise, false)) {
+        if (isNotValidPromise(promise)) {
             // cancelled
             return promise;
         }
@@ -568,7 +568,7 @@ final class DefaultChannelHandlerContext implements ChannelHandlerContext, Resou
 
     @Override
     public ChannelFuture close(final ChannelPromise promise) {
-        if (isNotValidPromise(promise, false)) {
+        if (isNotValidPromise(promise)) {
             // cancelled
             return promise;
         }
@@ -601,7 +601,7 @@ final class DefaultChannelHandlerContext implements ChannelHandlerContext, Resou
 
     @Override
     public ChannelFuture register(final ChannelPromise promise) {
-        if (isNotValidPromise(promise, false)) {
+        if (isNotValidPromise(promise)) {
             // cancelled
             return promise;
         }
@@ -634,7 +634,7 @@ final class DefaultChannelHandlerContext implements ChannelHandlerContext, Resou
 
     @Override
     public ChannelFuture deregister(final ChannelPromise promise) {
-        if (isNotValidPromise(promise, false)) {
+        if (isNotValidPromise(promise)) {
             // cancelled
             return promise;
         }
@@ -733,7 +733,10 @@ final class DefaultChannelHandlerContext implements ChannelHandlerContext, Resou
             findAndInvokeFlush();
         } else {
             Tasks tasks = invokeTasks();
-            safeExecute(executor, tasks.invokeFlushTask, channel().voidPromise(), null);
+            safeExecute(executor, tasks.invokeFlushTask,
+                    // If flush throws we want to at least propagate the exception through the ChannelPipeline
+                    // as otherwise the user will not be made aware of the failure at all.
+                    newPromise().addListener(ChannelFutureListener.FIRE_EXCEPTION_ON_FAILURE), null);
         }
 
         return this;
@@ -768,7 +771,7 @@ final class DefaultChannelHandlerContext implements ChannelHandlerContext, Resou
     private void write(Object msg, boolean flush, ChannelPromise promise) {
         requireNonNull(msg, "msg");
         try {
-            if (isNotValidPromise(promise, true)) {
+            if (isNotValidPromise(promise)) {
                 ReferenceCountUtil.release(msg);
                 // cancelled
                 return;
@@ -815,9 +818,7 @@ final class DefaultChannelHandlerContext implements ChannelHandlerContext, Resou
     }
 
     private static void notifyOutboundHandlerException(Throwable cause, ChannelPromise promise) {
-        // Only log if the given promise is not of type VoidChannelPromise as tryFailure(...) is expected to return
+        PromiseNotificationUtil.tryFailure(promise, cause, logger);
-        // false.
-        PromiseNotificationUtil.tryFailure(promise, cause, promise instanceof VoidChannelPromise ? null : logger);
     }
 
     @Override
@@ -840,7 +841,7 @@ final class DefaultChannelHandlerContext implements ChannelHandlerContext, Resou
         return pipeline().newFailedFuture(cause);
     }
 
-    private boolean isNotValidPromise(ChannelPromise promise, boolean allowVoidPromise) {
+    private boolean isNotValidPromise(ChannelPromise promise) {
         requireNonNull(promise, "promise");
 
         if (promise.isDone()) {
@@ -863,11 +864,6 @@ final class DefaultChannelHandlerContext implements ChannelHandlerContext, Resou
             return false;
         }
 
-        if (!allowVoidPromise && promise instanceof VoidChannelPromise) {
-            throw new IllegalArgumentException(
-                    StringUtil.simpleClassName(VoidChannelPromise.class) + " not allowed for this operation");
-        }
-
         if (promise instanceof AbstractChannel.CloseFuture) {
             throw new IllegalArgumentException(
                     StringUtil.simpleClassName(AbstractChannel.CloseFuture.class) + " not allowed in a pipeline");
@@ -897,11 +893,6 @@ final class DefaultChannelHandlerContext implements ChannelHandlerContext, Resou
         return ctx;
     }
 
-    @Override
-    public ChannelPromise voidPromise() {
-        return channel().voidPromise();
-    }
-
     boolean setAddComplete() {
         // Ensure we never update when the handlerState is REMOVE_COMPLETE already.
         // oldState is usually ADD_PENDING but can also be REMOVE_COMPLETE when an EventExecutor is used that is not
@@ -977,7 +968,9 @@ final class DefaultChannelHandlerContext implements ChannelHandlerContext, Resou
                     ReferenceCountUtil.release(msg);
                 }
             } finally {
-                promise.setFailure(cause);
+                if (promise != null) {
+                    promise.setFailure(cause);
+                }
             }
             return false;
         }

transport/src/main/java/io/netty/channel/DefaultChannelPipeline.java

@@ -68,7 +68,6 @@ public class DefaultChannelPipeline implements ChannelPipeline {
 
     private final Channel channel;
     private final ChannelFuture succeededFuture;
-    private final VoidChannelPromise voidPromise;
     private final boolean touch = ResourceLeakDetector.isEnabled();
     private final List<DefaultChannelHandlerContext> handlers = new ArrayList<>(4);
 
@@ -77,7 +76,6 @@ public class DefaultChannelPipeline implements ChannelPipeline {
     public DefaultChannelPipeline(Channel channel) {
         this.channel = requireNonNull(channel, "channel");
         succeededFuture = new SucceededChannelFuture(channel, channel.eventLoop());
-        voidPromise =  new VoidChannelPromise(channel, true);
 
         tail = new DefaultChannelHandlerContext(this, TAIL_NAME, TAIL_HANDLER);
         head = new DefaultChannelHandlerContext(this, HEAD_NAME, HEAD_HANDLER);
@@ -953,11 +951,6 @@ public class DefaultChannelPipeline implements ChannelPipeline {
         return new FailedChannelFuture(channel(), executor(), cause);
     }
 
-    @Override
-    public final ChannelPromise voidPromise() {
-        return voidPromise;
-    }
-
     /**
      * Called once a {@link Throwable} hit the end of the {@link ChannelPipeline} without been handled by the user
      * in {@link ChannelHandler#exceptionCaught(ChannelHandlerContext, Throwable)}.

transport/src/main/java/io/netty/channel/DefaultChannelProgressivePromise.java

@@ -158,14 +158,4 @@ public class DefaultChannelProgressivePromise
             super.checkDeadLock();
         }
     }
-
-    @Override
-    public ChannelProgressivePromise unvoid() {
-        return this;
-    }
-
-    @Override
-    public boolean isVoid() {
-        return false;
-    }
 }

transport/src/main/java/io/netty/channel/DefaultChannelPromise.java

@@ -149,14 +149,4 @@ public class DefaultChannelPromise extends DefaultPromise<Void> implements Chann
             super.checkDeadLock();
         }
     }
-
-    @Override
-    public ChannelPromise unvoid() {
-        return this;
-    }
-
-    @Override
-    public boolean isVoid() {
-        return false;
-    }
 }

transport/src/main/java/io/netty/channel/DelegatingChannelPromiseNotifier.java

@@ -37,7 +37,7 @@ public final class DelegatingChannelPromiseNotifier implements ChannelPromise, C
     private final boolean logNotifyFailure;
 
     public DelegatingChannelPromiseNotifier(ChannelPromise delegate) {
-        this(delegate, !(delegate instanceof VoidChannelPromise));
+        this(delegate, true);
     }
 
     public DelegatingChannelPromiseNotifier(ChannelPromise delegate, boolean logNotifyFailure) {
@@ -143,16 +143,6 @@ public final class DelegatingChannelPromiseNotifier implements ChannelPromise, C
         return this;
     }
 
-    @Override
-    public boolean isVoid() {
-        return delegate.isVoid();
-    }
-
-    @Override
-    public ChannelPromise unvoid() {
-        return isVoid() ? new DelegatingChannelPromiseNotifier(delegate.unvoid()) : this;
-    }
-
     @Override
     public boolean await(long timeout, TimeUnit unit) throws InterruptedException {
         return delegate.await(timeout, unit);

transport/src/main/java/io/netty/channel/PendingWriteQueue.java

@@ -141,9 +141,7 @@ public final class PendingWriteQueue {
                     Object msg = write.msg;
                     ChannelPromise promise = write.promise;
                     recycle(write, false);
-                    if (!(promise instanceof VoidChannelPromise)) {
+                    combiner.add(promise);
-                        combiner.add(promise);
-                    }
                     ctx.write(msg, promise);
                     write = next;
                 }
@@ -276,7 +274,7 @@ public final class PendingWriteQueue {
     }
 
     private static void safeFail(ChannelPromise promise, Throwable cause) {
-        if (!(promise instanceof VoidChannelPromise) && !promise.tryFailure(cause)) {
+        if (!promise.tryFailure(cause)) {
             logger.warn("Failed to mark a promise as failure because it's done already: {}", promise, cause);
         }
     }

transport/src/main/java/io/netty/channel/VoidChannelPromise.java

@@ -1,241 +0,0 @@
-/*
- * Copyright 2012 The Netty Project
- *
- * The Netty Project licenses this file to you under the Apache License,
- * version 2.0 (the "License"); you may not use this file except in compliance
- * with the License. You may obtain a copy of the License at:
- *
- *   https://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
- * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
- * License for the specific language governing permissions and limitations
- * under the License.
- */
-package io.netty.channel;
-
-import static java.util.Objects.requireNonNull;
-
-import io.netty.util.concurrent.EventExecutor;
-import io.netty.util.concurrent.Future;
-import io.netty.util.concurrent.GenericFutureListener;
-import io.netty.util.internal.UnstableApi;
-
-import java.util.concurrent.TimeUnit;
-
-@UnstableApi
-public final class VoidChannelPromise implements ChannelPromise {
-
-    private final Channel channel;
-    // Will be null if we should not propagate exceptions through the pipeline on failure case.
-    private final ChannelFutureListener fireExceptionListener;
-
-    /**
-     * Creates a new instance.
-     *
-     * @param channel the {@link Channel} associated with this future
-     */
-    public VoidChannelPromise(final Channel channel, boolean fireException) {
-        requireNonNull(channel, "channel");
-        this.channel = channel;
-        if (fireException) {
-            fireExceptionListener = future -> {
-                Throwable cause = future.cause();
-                if (cause != null) {
-                    fireException0(cause);
-                }
-            };
-        } else {
-            fireExceptionListener = null;
-        }
-    }
-
-    @Override
-    public EventExecutor executor() {
-        return channel.eventLoop();
-    }
-
-    @Override
-    public VoidChannelPromise addListener(GenericFutureListener<? extends Future<? super Void>> listener) {
-        fail();
-        return this;
-    }
-
-    @Override
-    public VoidChannelPromise addListeners(GenericFutureListener<? extends Future<? super Void>>... listeners) {
-        fail();
-        return this;
-    }
-
-    @Override
-    public VoidChannelPromise removeListener(GenericFutureListener<? extends Future<? super Void>> listener) {
-        // NOOP
-        return this;
-    }
-
-    @Override
-    public VoidChannelPromise removeListeners(GenericFutureListener<? extends Future<? super Void>>... listeners) {
-        // NOOP
-        return this;
-    }
-
-    @Override
-    public VoidChannelPromise await() throws InterruptedException {
-        if (Thread.interrupted()) {
-            throw new InterruptedException();
-        }
-        return this;
-    }
-
-    @Override
-    public boolean await(long timeout, TimeUnit unit) {
-        fail();
-        return false;
-    }
-
-    @Override
-    public boolean await(long timeoutMillis) {
-        fail();
-        return false;
-    }
-
-    @Override
-    public VoidChannelPromise awaitUninterruptibly() {
-        fail();
-        return this;
-    }
-
-    @Override
-    public boolean awaitUninterruptibly(long timeout, TimeUnit unit) {
-        fail();
-        return false;
-    }
-
-    @Override
-    public boolean awaitUninterruptibly(long timeoutMillis) {
-        fail();
-        return false;
-    }
-
-    @Override
-    public Channel channel() {
-        return channel;
-    }
-
-    @Override
-    public boolean isDone() {
-        return false;
-    }
-
-    @Override
-    public boolean isSuccess() {
-        return false;
-    }
-
-    @Override
-    public boolean setUncancellable() {
-        return true;
-    }
-
-    @Override
-    public boolean isCancellable() {
-        return false;
-    }
-
-    @Override
-    public boolean isCancelled() {
-        return false;
-    }
-
-    @Override
-    public Throwable cause() {
-        return null;
-    }
-
-    @Override
-    public VoidChannelPromise sync() {
-        fail();
-        return this;
-    }
-
-    @Override
-    public VoidChannelPromise syncUninterruptibly() {
-        fail();
-        return this;
-    }
-    @Override
-    public VoidChannelPromise setFailure(Throwable cause) {
-        fireException0(cause);
-        return this;
-    }
-
-    @Override
-    public VoidChannelPromise setSuccess() {
-        return this;
-    }
-
-    @Override
-    public boolean tryFailure(Throwable cause) {
-        fireException0(cause);
-        return false;
-    }
-
-    /**
-     * {@inheritDoc}
-     *
-     * @param mayInterruptIfRunning this value has no effect in this implementation.
-     */
-    @Override
-    public boolean cancel(boolean mayInterruptIfRunning) {
-        return false;
-    }
-
-    @Override
-    public boolean trySuccess() {
-        return false;
-    }
-
-    private static void fail() {
-        throw new IllegalStateException("void future");
-    }
-
-    @Override
-    public VoidChannelPromise setSuccess(Void result) {
-        return this;
-    }
-
-    @Override
-    public boolean trySuccess(Void result) {
-        return false;
-    }
-
-    @Override
-    public Void getNow() {
-        return null;
-    }
-
-    @Override
-    public ChannelPromise unvoid() {
-        ChannelPromise promise = new DefaultChannelPromise(channel);
-        if (fireExceptionListener != null) {
-            promise.addListener(fireExceptionListener);
-        }
-        return promise;
-    }
-
-    @Override
-    public boolean isVoid() {
-        return true;
-    }
-
-    private void fireException0(Throwable cause) {
-        // Only fire the exception if the channel is open and registered
-        // if not the pipeline is not setup and so it would hit the tail
-        // of the pipeline.
-        // See https://github.com/netty/netty/issues/1517
-        if (fireExceptionListener != null && channel.isRegistered()) {
-            channel.pipeline().fireExceptionCaught(cause);
-        }
-    }
-}

transport/src/main/java/io/netty/channel/embedded/EmbeddedChannel.java

@@ -342,7 +342,7 @@ public class EmbeddedChannel extends AbstractChannel {
             p.fireChannelRead(m);
         }
 
-        flushInbound(false, voidPromise());
+        flushInbound(false, null);
         return isNotEmpty(inboundMessages);
     }
 
@@ -366,7 +366,8 @@ public class EmbeddedChannel extends AbstractChannel {
         if (checkOpen(true)) {
             pipeline().fireChannelRead(msg);
         }
-        return checkException(promise);
+        checkException(promise);
+        return promise;
     }
 
     /**
@@ -375,7 +376,7 @@ public class EmbeddedChannel extends AbstractChannel {
      * @see #flushOutbound()
      */
     public EmbeddedChannel flushInbound() {
-        flushInbound(true, voidPromise());
+        flushInbound(true, null);
         return this;
     }
 
@@ -386,7 +387,8 @@ public class EmbeddedChannel extends AbstractChannel {
           runPendingTasks();
       }
 
-      return checkException(promise);
+      checkException(promise);
+      return promise;
     }
 
     /**
@@ -450,7 +452,8 @@ public class EmbeddedChannel extends AbstractChannel {
         if (checkOpen(true)) {
             return write(msg, promise);
         }
-        return checkException(promise);
+        checkException(promise);
+        return promise;
     }
 
     /**
@@ -462,7 +465,7 @@ public class EmbeddedChannel extends AbstractChannel {
         if (checkOpen(true)) {
             flushOutbound0();
         }
-        checkException(voidPromise());
+        checkException(null);
         return this;
     }
 
@@ -640,26 +643,27 @@ public class EmbeddedChannel extends AbstractChannel {
     /**
      * Checks for the presence of an {@link Exception}.
      */
-    private ChannelFuture checkException(ChannelPromise promise) {
+    private void checkException(ChannelPromise promise) {
-      Throwable t = lastException;
+        Throwable t = lastException;
-      if (t != null) {
+        if (t != null) {
-        lastException = null;
+            lastException = null;
 
-        if (promise.isVoid()) {
+            if (promise == null) {
-            PlatformDependent.throwException(t);
+                PlatformDependent.throwException(t);
+                return;
+            }
+
+            promise.setFailure(t);
+        } else if (promise != null) {
+            promise.setSuccess();
         }
-
-        return promise.setFailure(t);
-      }
-
-      return promise.setSuccess();
     }
 
     /**
      * Check if there was any {@link Throwable} received and if so rethrow it.
      */
     public void checkException() {
-      checkException(voidPromise());
+        checkException(null);
     }
 
     /**
@@ -848,11 +852,6 @@ public class EmbeddedChannel extends AbstractChannel {
                 mayRunPendingTasks();
             }
 
-            @Override
-            public ChannelPromise voidPromise() {
-                return EmbeddedUnsafe.this.voidPromise();
-            }
-
             @Override
             public ChannelOutboundBuffer outboundBuffer() {
                 return EmbeddedUnsafe.this.outboundBuffer();

transport/src/main/java/io/netty/channel/group/ChannelGroup.java

@@ -132,22 +132,6 @@ public interface ChannelGroup extends Set<Channel>, Comparable<ChannelGroup> {
      */
     ChannelGroupFuture write(Object message, ChannelMatcher matcher);
 
-    /**
-     * Writes the specified {@code message} to all {@link Channel}s in this
-     * group that are matched by the given {@link ChannelMatcher}. If the specified {@code message} is an instance of
-     * {@link ByteBuf}, it is automatically
-     * {@linkplain ByteBuf#duplicate() duplicated} to avoid a race
-     * condition. The same is true for {@link ByteBufHolder}. Please note that this operation is asynchronous as
-     * {@link Channel#write(Object)} is.
-     *
-     * If {@code voidPromise} is {@code true} {@link Channel#voidPromise()} is used for the writes and so the same
-     * restrictions to the returned {@link ChannelGroupFuture} apply as to a void promise.
-     *
-     * @return the {@link ChannelGroupFuture} instance that notifies when
-     *         the operation is done for all channels
-     */
-    ChannelGroupFuture write(Object message, ChannelMatcher matcher, boolean voidPromise);
-
     /**
      * Flush all {@link Channel}s in this
      * group. If the specified {@code messages} are an instance of
@@ -191,12 +175,6 @@ public interface ChannelGroup extends Set<Channel>, Comparable<ChannelGroup> {
      */
     ChannelGroupFuture writeAndFlush(Object message, ChannelMatcher matcher);
 
-    /**
-     * Shortcut for calling {@link #write(Object, ChannelMatcher, boolean)} and {@link #flush()} and only act on
-     * {@link Channel}s that are matched by the {@link ChannelMatcher}.
-     */
-    ChannelGroupFuture writeAndFlush(Object message, ChannelMatcher matcher, boolean voidPromise);
-
     /**
      * @deprecated Use {@link #writeAndFlush(Object, ChannelMatcher)} instead.
      */

transport/src/main/java/io/netty/channel/group/DefaultChannelGroup.java

@@ -246,31 +246,16 @@ public class DefaultChannelGroup extends AbstractSet<Channel> implements Channel
 
     @Override
     public ChannelGroupFuture write(Object message, ChannelMatcher matcher) {
-        return write(message, matcher, false);
-    }
-
-    @Override
-    public ChannelGroupFuture write(Object message, ChannelMatcher matcher, boolean voidPromise) {
         requireNonNull(message, "message");
         requireNonNull(matcher, "matcher");
 
-        final ChannelGroupFuture future;
+        Map<Channel, ChannelFuture> futures = new LinkedHashMap<>(nonServerChannels.size());
-        if (voidPromise) {
+        for (Channel c: nonServerChannels.values()) {
-            for (Channel c: nonServerChannels.values()) {
+            if (matcher.matches(c)) {
-                if (matcher.matches(c)) {
+                futures.put(c, c.write(safeDuplicate(message)));
-                    c.write(safeDuplicate(message), c.voidPromise());
-                }
             }
-            future = voidFuture;
-        } else {
-            Map<Channel, ChannelFuture> futures = new LinkedHashMap<>(nonServerChannels.size());
-            for (Channel c: nonServerChannels.values()) {
-                if (matcher.matches(c)) {
-                    futures.put(c, c.write(safeDuplicate(message)));
-                }
-            }
-            future = new DefaultChannelGroupFuture(this, futures, executor);
         }
+        final ChannelGroupFuture future = new DefaultChannelGroupFuture(this, futures, executor);
         ReferenceCountUtil.release(message);
         return future;
     }
@@ -380,30 +365,15 @@ public class DefaultChannelGroup extends AbstractSet<Channel> implements Channel
 
     @Override
     public ChannelGroupFuture writeAndFlush(Object message, ChannelMatcher matcher) {
-        return writeAndFlush(message, matcher, false);
-    }
-
-    @Override
-    public ChannelGroupFuture writeAndFlush(Object message, ChannelMatcher matcher, boolean voidPromise) {
         requireNonNull(message, "message");
 
-        final ChannelGroupFuture future;
+        Map<Channel, ChannelFuture> futures = new LinkedHashMap<>(nonServerChannels.size());
-        if (voidPromise) {
+        for (Channel c: nonServerChannels.values()) {
-            for (Channel c: nonServerChannels.values()) {
+            if (matcher.matches(c)) {
-                if (matcher.matches(c)) {
+                futures.put(c, c.writeAndFlush(safeDuplicate(message)));
-                    c.writeAndFlush(safeDuplicate(message), c.voidPromise());
-                }
             }
-            future = voidFuture;
-        } else {
-            Map<Channel, ChannelFuture> futures = new LinkedHashMap<>(nonServerChannels.size());
-            for (Channel c: nonServerChannels.values()) {
-                if (matcher.matches(c)) {
-                    futures.put(c, c.writeAndFlush(safeDuplicate(message)));
-                }
-            }
-            future = new DefaultChannelGroupFuture(this, futures, executor);
         }
+        final ChannelGroupFuture future = new DefaultChannelGroupFuture(this, futures, executor);
         ReferenceCountUtil.release(message);
         return future;
     }

transport/src/main/java/io/netty/channel/local/LocalChannel.java

@@ -217,7 +217,7 @@ public class LocalChannel extends AbstractChannel {
 
     private void tryClose(boolean isActive) {
         if (isActive) {
-            unsafe().close(unsafe().voidPromise());
+            unsafe().close(newPromise());
         } else {
             releaseInboundBuffers();
 
@@ -419,7 +419,7 @@ public class LocalChannel extends AbstractChannel {
                     doBind(localAddress);
                 } catch (Throwable t) {
                     safeSetFailure(promise, t);
-                    close(voidPromise());
+                    close(newPromise());
                     return;
                 }
             }
@@ -428,7 +428,7 @@ public class LocalChannel extends AbstractChannel {
             if (!(boundChannel instanceof LocalServerChannel)) {
                 Exception cause = new ConnectException("connection refused: " + remoteAddress);
                 safeSetFailure(promise, cause);
-                close(voidPromise());
+                close(newPromise());
                 return;
             }
 
@@ -472,5 +472,10 @@ public class LocalChannel extends AbstractChannel {
         @Override
         public void deregister0() {
         }
+
+        @Override
+        public ChannelPromise newPromise() {
+            return LocalChannel.this.newPromise();
+        }
     }
 }

transport/src/main/java/io/netty/channel/local/LocalChannelUnsafe.java

@@ -16,8 +16,10 @@
 package io.netty.channel.local;
 
 import io.netty.channel.Channel;
+import io.netty.channel.ChannelPromise;
 
 interface LocalChannelUnsafe extends Channel.Unsafe {
     void register0();
     void deregister0();
+    ChannelPromise newPromise();
 }

transport/src/main/java/io/netty/channel/local/LocalHandler.java

@@ -75,7 +75,7 @@ public final class LocalHandler implements IoHandler {
     @Override
     public void prepareToDestroy() {
         for (LocalChannelUnsafe unsafe : registeredChannels) {
-            unsafe.close(unsafe.voidPromise());
+            unsafe.close(unsafe.newPromise());
         }
         registeredChannels.clear();
     }

transport/src/main/java/io/netty/channel/local/LocalServerChannel.java

@@ -171,5 +171,10 @@ public class LocalServerChannel extends AbstractServerChannel {
         @Override
         public void deregister0() {
         }
+
+        @Override
+        public ChannelPromise newPromise() {
+            return LocalServerChannel.this.newPromise();
+        }
     }
 }

transport/src/main/java/io/netty/channel/nio/AbstractNioByteChannel.java

@@ -102,7 +102,7 @@ public abstract class AbstractNioByteChannel extends AbstractNioChannel {
                     shutdownInput();
                     pipeline.fireUserEventTriggered(ChannelInputShutdownEvent.INSTANCE);
                 } else {
-                    close(voidPromise());
+                    close(newPromise());
                 }
             } else {
                 inputClosedSeenErrorOnRead = true;

transport/src/main/java/io/netty/channel/nio/AbstractNioChannel.java

@@ -243,7 +243,7 @@ public abstract class AbstractNioChannel extends AbstractChannel {
                             if (connectPromise != null && !connectPromise.isDone()
                                     && connectPromise.tryFailure(new ConnectTimeoutException(
                                     "connection timed out: " + remoteAddress))) {
-                                close(voidPromise());
+                                close(newPromise());
                             }
                         }, connectTimeoutMillis, TimeUnit.MILLISECONDS);
                     }
@@ -254,7 +254,7 @@ public abstract class AbstractNioChannel extends AbstractChannel {
                                 connectTimeoutFuture.cancel(false);
                             }
                             connectPromise = null;
-                            close(voidPromise());
+                            close(newPromise());
                         }
                     });
                 }
@@ -286,7 +286,7 @@ public abstract class AbstractNioChannel extends AbstractChannel {
 
             // If a user cancelled the connection attempt, close the channel, which is followed by channelInactive().
             if (!promiseSet) {
-                close(voidPromise());
+                close(newPromise());
             }
         }
 

transport/src/main/java/io/netty/channel/nio/AbstractNioMessageChannel.java

@@ -110,7 +110,7 @@ public abstract class AbstractNioMessageChannel extends AbstractNioChannel {
                 if (closed) {
                     inputShutdown = true;
                     if (isOpen()) {
-                        close(voidPromise());
+                        close(newPromise());
                     }
                 } else {
                     readIfIsAutoRead();

transport/src/main/java/io/netty/channel/nio/NioHandler.java

@@ -329,7 +329,7 @@ public final class NioHandler implements IoHandler {
                 logger.warn("Failed to re-register a Channel to the new Selector.", e);
                 if (a instanceof AbstractNioChannel) {
                     AbstractNioChannel ch = (AbstractNioChannel) a;
-                    ch.unsafe().close(ch.unsafe().voidPromise());
+                    ch.unsafe().close(ch.newPromise());
                 } else {
                     @SuppressWarnings("unchecked")
                     NioTask<SelectableChannel> task = (NioTask<SelectableChannel>) a;
@@ -573,7 +573,7 @@ public final class NioHandler implements IoHandler {
         if (!k.isValid()) {
 
             // close the channel if the key is not valid anymore
-            unsafe.close(unsafe.voidPromise());
+            unsafe.close(ch.newPromise());
             return;
         }
 
@@ -603,7 +603,7 @@ public final class NioHandler implements IoHandler {
                 unsafe.read();
             }
         } catch (CancelledKeyException ignored) {
-            unsafe.close(unsafe.voidPromise());
+            unsafe.close(ch.newPromise());
         }
     }
 
@@ -651,7 +651,7 @@ public final class NioHandler implements IoHandler {
         }
 
         for (AbstractNioChannel ch: channels) {
-            ch.unsafe().close(ch.unsafe().voidPromise());
+            ch.unsafe().close(ch.newPromise());
         }
     }
 

transport/src/test/java/io/netty/channel/ChannelOutboundBufferTest.java

@@ -58,7 +58,7 @@ public class ChannelOutboundBufferTest {
 
         ByteBuf buf = copiedBuffer("buf1", CharsetUtil.US_ASCII);
         ByteBuffer nioBuf = buf.internalNioBuffer(buf.readerIndex(), buf.readableBytes());
-        buffer.addMessage(buf, buf.readableBytes(), channel.voidPromise());
+        buffer.addMessage(buf, buf.readableBytes(), channel.newPromise());
         assertEquals(0, buffer.nioBufferCount(), "Should still be 0 as not flushed yet");
         buffer.addFlush();
         ByteBuffer[] buffers = buffer.nioBuffers();
@@ -82,7 +82,7 @@ public class ChannelOutboundBufferTest {
 
         ByteBuf buf = directBuffer().writeBytes("buf1".getBytes(CharsetUtil.US_ASCII));
         for (int i = 0; i < 64; i++) {
-            buffer.addMessage(buf.copy(), buf.readableBytes(), channel.voidPromise());
+            buffer.addMessage(buf.copy(), buf.readableBytes(), channel.newPromise());
         }
         assertEquals(0, buffer.nioBufferCount(), "Should still be 0 as not flushed yet");
         buffer.addFlush();
@@ -106,7 +106,7 @@ public class ChannelOutboundBufferTest {
         for (int i = 0; i < 65; i++) {
             comp.addComponent(true, buf.copy());
         }
-        buffer.addMessage(comp, comp.readableBytes(), channel.voidPromise());
+        buffer.addMessage(comp, comp.readableBytes(), channel.newPromise());
 
         assertEquals(0, buffer.nioBufferCount(), "Should still be 0 as not flushed yet");
         buffer.addFlush();
@@ -135,7 +135,7 @@ public class ChannelOutboundBufferTest {
             comp.addComponent(true, buf.copy());
         }
         assertEquals(65, comp.nioBufferCount());
-        buffer.addMessage(comp, comp.readableBytes(), channel.voidPromise());
+        buffer.addMessage(comp, comp.readableBytes(), channel.newPromise());
         assertEquals(0, buffer.nioBufferCount(), "Should still be 0 as not flushed yet");
         buffer.addFlush();
         final int maxCount = 10;    // less than comp.nioBufferCount()

transport/src/test/java/io/netty/channel/CoalescingBufferQueueTest.java

@@ -58,7 +58,7 @@ public class CoalescingBufferQueueTest {
             mouseSuccess = future.isSuccess();
         };
         emptyPromise = newPromise();
-        voidPromise = channel.voidPromise();
+        voidPromise = channel.newPromise();
 
         cat = Unpooled.wrappedBuffer("cat".getBytes(CharsetUtil.US_ASCII));
         mouse = Unpooled.wrappedBuffer("mouse".getBytes(CharsetUtil.US_ASCII));

transport/src/test/java/io/netty/channel/DefaultChannelPipelineTest.java

@@ -743,19 +743,6 @@ public class DefaultChannelPipelineTest {
         }
     }
 
-    @Test
-    public void testUnexpectedVoidChannelPromise() throws Exception {
-        ChannelPipeline pipeline = newLocalChannel().pipeline();
-        pipeline.channel().register().sync();
-
-        try {
-            ChannelPromise promise = new VoidChannelPromise(pipeline.channel(), false);
-            assertThrows(IllegalArgumentException.class, () -> pipeline.close(promise));
-        } finally {
-            pipeline.close();
-        }
-    }
-
     @Test
     public void testUnexpectedVoidChannelPromiseCloseFuture() throws Exception {
         ChannelPipeline pipeline = newLocalChannel().pipeline();
@@ -1183,36 +1170,6 @@ public class DefaultChannelPipelineTest {
         pipeline.addBefore("test", null, newHandler());
     }
 
-    @Test
-    @Timeout(value = 3000, unit = TimeUnit.MILLISECONDS)
-    public void testVoidPromiseNotify() throws Throwable {
-        EventLoopGroup defaultGroup = new MultithreadEventLoopGroup(1, LocalHandler.newFactory());
-        EventLoop eventLoop1 = defaultGroup.next();
-        ChannelPipeline pipeline1 = new LocalChannel(eventLoop1).pipeline();
-
-        final Promise<Throwable> promise = eventLoop1.newPromise();
-        final Exception exception = new IllegalArgumentException();
-        try {
-            pipeline1.channel().register().syncUninterruptibly();
-            pipeline1.addLast(new ChannelHandler() {
-                @Override
-                public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) throws Exception {
-                    throw exception;
-                }
-
-                @Override
-                public void exceptionCaught(ChannelHandlerContext ctx, Throwable cause) {
-                    promise.setSuccess(cause);
-                }
-            });
-            pipeline1.write("test", pipeline1.voidPromise());
-            assertSame(exception, promise.syncUninterruptibly().getNow());
-        } finally {
-            pipeline1.channel().close().syncUninterruptibly();
-            defaultGroup.shutdownGracefully();
-        }
-    }
-
     // Test for https://github.com/netty/netty/issues/8676.
     @Test
     public void testHandlerRemovedOnlyCalledWhenHandlerAddedCalled() throws Exception {

transport/src/test/java/io/netty/channel/PendingWriteQueueTest.java

@@ -267,32 +267,6 @@ public class PendingWriteQueueTest {
         assertEquals(3L, (long) channel.readOutbound());
     }
 
-    @Test
-    public void testRemoveAndWriteAllWithVoidPromise() {
-        EmbeddedChannel channel = new EmbeddedChannel(new ChannelHandler() {
-            @Override
-            public void write(ChannelHandlerContext ctx, Object msg, ChannelPromise promise) {
-                // Convert to writeAndFlush(...) so the promise will be notified by the transport.
-                ctx.writeAndFlush(msg, promise);
-            }
-        }, new ChannelHandler() { });
-
-        final PendingWriteQueue queue = new PendingWriteQueue(channel.pipeline().lastContext());
-
-        ChannelPromise promise = channel.newPromise();
-        channel.eventLoop().execute(() -> {
-            queue.add(1L, promise);
-            queue.add(2L, channel.voidPromise());
-            queue.removeAndWriteAll();
-        });
-
-        assertTrue(channel.finish());
-        assertTrue(promise.isDone());
-        assertTrue(promise.isSuccess());
-        assertEquals(1L, (long) channel.readOutbound());
-        assertEquals(2L, (long) channel.readOutbound());
-    }
-
     @Disabled("Need to verify and think about if the assumptions made by this test are valid at all.")
     @Test
     public void testRemoveAndFailAllReentrantWrite() {