DefaultHttp2ConnectionDecoder notifies frame listener before connection of GOAWAYS (#10009)

Motivation:

Users of the DefaultHttp2ConnectionDecodcer are notified of inbound GoAwayFrames
after the connection has already closed any ignored streams, potentially
losing the signal that some streams may have been ignored by the peer and
are thus retryable.

Modifications:

Reorder the notifications of the frame and connection listeners to
propagate the frame first, giving the frame listeners the opportunity to
clean up ignored streams in their own way.

Result:
Fixes #9986

codec-http2/src/main/java/io/netty/handler/codec/http2/DefaultHttp2ConnectionDecoder.java

@@ -214,8 +214,8 @@ public class DefaultHttp2ConnectionDecoder implements Http2ConnectionDecoder {
 
     void onGoAwayRead0(ChannelHandlerContext ctx, int lastStreamId, long errorCode, ByteBuf debugData)
             throws Http2Exception {
-        connection.goAwayReceived(lastStreamId, errorCode, debugData);
         listener.onGoAwayRead(ctx, lastStreamId, errorCode, debugData);
+        connection.goAwayReceived(lastStreamId, errorCode, debugData);
     }
 
     void onUnknownFrame0(ChannelHandlerContext ctx, byte frameType, int streamId, Http2Flags flags,

codec-http2/src/test/java/io/netty/handler/codec/http2/Http2ConnectionRoundtripTest.java

@@ -52,6 +52,8 @@ import java.io.ByteArrayOutputStream;
 import java.util.Random;
 import java.util.concurrent.CountDownLatch;
 import java.util.concurrent.ExecutionException;
+import java.util.concurrent.atomic.AtomicBoolean;
+import java.util.concurrent.atomic.AtomicInteger;
 import java.util.concurrent.atomic.AtomicReference;
 
 import static io.netty.buffer.Unpooled.EMPTY_BUFFER;
@@ -945,47 +947,33 @@ public class Http2ConnectionRoundtripTest {
     }
 
     @Test
-    public void createStreamSynchronouslyAfterGoAwayReceivedShouldFailLocally() throws Exception {
+    public void listenerIsNotifiedOfGoawayBeforeStreamsAreRemovedFromTheConnection() throws Exception {
         bootstrapEnv(1, 1, 2, 1, 1);
 
-        final CountDownLatch clientGoAwayLatch = new CountDownLatch(1);
-        doAnswer(new Answer<Void>() {
-            @Override
-            public Void answer(InvocationOnMock invocationOnMock) throws Throwable {
-                clientGoAwayLatch.countDown();
-                return null;
-            }
-        }).when(clientListener).onGoAwayRead(any(ChannelHandlerContext.class), anyInt(), anyLong(), any(ByteBuf.class));
-
         // We want both sides to do graceful shutdown during the test.
         setClientGracefulShutdownTime(10000);
         setServerGracefulShutdownTime(10000);
 
-        final Http2Headers headers = dummyHeaders();
+        final AtomicReference<Http2Stream.State> clientStream3State = new AtomicReference<Http2Stream.State>();
-        final AtomicReference<ChannelFuture> clientWriteAfterGoAwayFutureRef = new AtomicReference<ChannelFuture>();
+        final CountDownLatch clientGoAwayLatch = new CountDownLatch(1);
-        final CountDownLatch clientWriteAfterGoAwayLatch = new CountDownLatch(1);
         doAnswer(new Answer<Void>() {
             @Override
             public Void answer(InvocationOnMock invocationOnMock) throws Throwable {
-                ChannelFuture f = http2Client.encoder().writeHeaders(ctx(), 5, headers, 0, (short) 16, false, 0,
+                clientStream3State.set(http2Client.connection().stream(3).state());
-                        true, newPromise());
+                clientGoAwayLatch.countDown();
-                clientWriteAfterGoAwayFutureRef.set(f);
-                f.addListener(new ChannelFutureListener() {
-                    @Override
-                    public void operationComplete(ChannelFuture future) throws Exception {
-                        clientWriteAfterGoAwayLatch.countDown();
-                    }
-                });
-                http2Client.flush(ctx());
                 return null;
             }
         }).when(clientListener).onGoAwayRead(any(ChannelHandlerContext.class), anyInt(), anyLong(), any(ByteBuf.class));
 
+        // Create a single stream by sending a HEADERS frame to the server.
+        final Http2Headers headers = dummyHeaders();
         runInChannel(clientChannel, new Http2Runnable() {
             @Override
             public void run() throws Http2Exception {
+                http2Client.encoder().writeHeaders(ctx(), 1, headers, 0, (short) 16, false, 0,
+                    false, newPromise());
                 http2Client.encoder().writeHeaders(ctx(), 3, headers, 0, (short) 16, false, 0,
-                        true, newPromise());
+                    false, newPromise());
                 http2Client.flush(ctx());
             }
         });
@@ -998,24 +986,38 @@ public class Http2ConnectionRoundtripTest {
         runInChannel(serverChannel, new Http2Runnable() {
             @Override
             public void run() throws Http2Exception {
-                http2Server.encoder().writeGoAway(serverCtx(), 3, NO_ERROR.code(), EMPTY_BUFFER, serverNewPromise());
+                http2Server.encoder().writeGoAway(serverCtx(), 1, NO_ERROR.code(), EMPTY_BUFFER, serverNewPromise());
                 http2Server.flush(serverCtx());
             }
         });
 
-        // Wait for the client's write operation to complete.
+        // wait for the client to receive the GO_AWAY.
-        assertTrue(clientWriteAfterGoAwayLatch.await(DEFAULT_AWAIT_TIMEOUT_SECONDS, SECONDS));
+        assertTrue(clientGoAwayLatch.await(DEFAULT_AWAIT_TIMEOUT_SECONDS, SECONDS));
+        verify(clientListener).onGoAwayRead(any(ChannelHandlerContext.class), eq(1), eq(NO_ERROR.code()),
+            any(ByteBuf.class));
+        assertEquals(Http2Stream.State.OPEN, clientStream3State.get());
 
-        ChannelFuture clientWriteAfterGoAwayFuture = clientWriteAfterGoAwayFutureRef.get();
+        // Make sure that stream 3 has been closed which is true if it's gone.
-        assertNotNull(clientWriteAfterGoAwayFuture);
+        final CountDownLatch probeStreamCount = new CountDownLatch(1);
-        Throwable clientCause = clientWriteAfterGoAwayFuture.cause();
+        final AtomicBoolean stream3Exists = new AtomicBoolean();
-        assertThat(clientCause, is(instanceOf(Http2Exception.StreamException.class)));
+        final AtomicInteger streamCount = new AtomicInteger();
-        assertEquals(Http2Error.REFUSED_STREAM.code(), ((Http2Exception.StreamException) clientCause).error().code());
+        runInChannel(this.clientChannel, new Http2Runnable() {
+            @Override
+            public void run() throws Http2Exception {
+                stream3Exists.set(http2Client.connection().stream(3) != null);
+                streamCount.set(http2Client.connection().numActiveStreams());
+                probeStreamCount.countDown();
+            }
+        });
+        // The stream should be closed right after
+        assertTrue(probeStreamCount.await(DEFAULT_AWAIT_TIMEOUT_SECONDS, SECONDS));
+        assertEquals(1, streamCount.get());
+        assertFalse(stream3Exists.get());
 
         // Wait for the server to receive a GO_AWAY, but this is expected to timeout!
         assertFalse(goAwayLatch.await(1, SECONDS));
         verify(serverListener, never()).onGoAwayRead(any(ChannelHandlerContext.class), anyInt(), anyLong(),
-                any(ByteBuf.class));
+            any(ByteBuf.class));
 
         // Shutdown shouldn't wait for the server to close streams
         setClientGracefulShutdownTime(0);