From b80a1a077c1f146aeae3e52e53a2bc66bf262bd9 Mon Sep 17 00:00:00 2001
From: Norman Maurer <norman_maurer@apple.com>
Date: Sat, 9 Apr 2016 22:25:28 +0200
Subject: [PATCH] We need to ensure we correct reset decoder in decodeLast() to
 not produce multiple LastHttpContent instances.

Motivation:

We missed to reset the decoder when asked for it in HttpObjectDecoder and so sometimes could produce more then one LastHttpContent in a sequence during channelInactive.

This did show up as AssertionError:

22:22:35.499 [nioEventLoopGroup-3-1] WARN  i.n.channel.DefaultChannelPipeline - An exceptionCaught() event was fired, and it reached at the tail of the pipeline. It usually means the last handler in the pipeline did not handle the exception.
java.lang.AssertionError: null
	at io.netty.handler.codec.http.HttpObjectAggregator.decode(HttpObjectAggregator.java:205) ~[classes/:na]
	at io.netty.handler.codec.http.HttpObjectAggregator.decode(HttpObjectAggregator.java:57) ~[classes/:na]
	at io.netty.handler.codec.MessageToMessageDecoder.channelRead(MessageToMessageDecoder.java:89) ~[classes/:na]
	at io.netty.channel.AbstractChannelHandlerContext.invokeChannelRead(AbstractChannelHandlerContext.java:292) [classes/:na]
	at io.netty.channel.AbstractChannelHandlerContext.fireChannelRead(AbstractChannelHandlerContext.java:278) [classes/:na]
	at io.netty.channel.CombinedChannelDuplexHandler$DelegatingChannelHandlerContext.fireChannelRead(CombinedChannelDuplexHandler.java:428) [classes/:na]
	at io.netty.handler.codec.ByteToMessageDecoder.fireChannelRead(ByteToMessageDecoder.java:277) [classes/:na]
	at io.netty.handler.codec.ByteToMessageDecoder.channelInputClosed(ByteToMessageDecoder.java:343) [classes/:na]
	at io.netty.handler.codec.ByteToMessageDecoder.channelInactive(ByteToMessageDecoder.java:309) [classes/:na]
	at io.netty.handler.codec.http.HttpClientCodec$Decoder.channelInactive(HttpClientCodec.java:228) [classes/:na]
	at io.netty.channel.CombinedChannelDuplexHandler.channelInactive(CombinedChannelDuplexHandler.java:213) [classes/:na]
        ...

Modifications:

Correctly reset decoder.

Result:

Correctly only produce one LastHttpContent per sequence.
---
 .../java/io/netty/handler/codec/http/HttpObjectDecoder.java  | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java b/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java
index c79a0ed627..bb39f9c1b4 100644
--- a/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java
+++ b/codec-http/src/main/java/io/netty/handler/codec/http/HttpObjectDecoder.java
@@ -402,6 +402,11 @@ public abstract class HttpObjectDecoder extends ByteToMessageDecoder {
     protected void decodeLast(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {
         super.decodeLast(ctx, in, out);
 
+        if (resetRequested) {
+            // If a reset was requested by decodeLast() we need to do it now otherwise we may produce a
+            // LastHttpContent while there was already one.
+            resetNow();
+        }
         // Handle the last unfinished message.
         if (message != null) {
             boolean chunked = HttpHeaders.isTransferEncodingChunked(message);