[#963] Fix invalid free-up of messages if they are only passed-throught in HttpContentEncoder and HttpContentDecoder

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

@@ -114,6 +114,15 @@ public abstract class HttpContentDecoder extends MessageToMessageDecoder<Object>
         return msg;
     }
 
+    @Override
+    protected void freeInboundMessage(Object msg) throws Exception {
+        if (decoder == null) {
+            // if the decoder was null we returned the original message so we are not allowed to free it
+            return;
+        }
+        super.freeInboundMessage(msg);
+    }
+
     private Object[] decodeContent(HttpMessage header, HttpContent c) {
         ByteBuf newContent = Unpooled.buffer();
         ByteBuf content = c.data();

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

@@ -161,6 +161,20 @@ public abstract class HttpContentEncoder extends MessageToMessageCodec<HttpMessa
         return null;
     }
 
+    @Override
+    protected void freeOutboundMessage(Object msg) throws Exception {
+        if (encoder == null) {
+            // if the decoder was null we returned the original message so we are not allowed to free it
+            return;
+        }
+        super.freeOutboundMessage(msg);
+    }
+
+    @Override
+    protected void freeInboundMessage(HttpMessage msg) throws Exception {
+        // not free it as it is only passed through
+    }
+
     private Object[] encodeContent(HttpMessage header, HttpContent c) {
         ByteBuf newContent = Unpooled.buffer();
         ByteBuf content = c.data();