io.netty.util.IllegalReferenceCountException: refCnt: 0, decrement: 1 when refreshing a page

[gastaldi]

Describe the bug
When refreshing a page that is already processing something, the following error appears in the logs:

2020-07-26 21:59:17,015 WARN  [io.net.cha.AbstractChannelHandlerContext] (vert.x-eventloop-thread-8) Failed to mark a promise as failure because it has failed already: DefaultChannelPromise@3e14144f(failure: java.nio.channels.ClosedChannelException), unnotified cause: java.nio.channels.ClosedChannelException
	at io.netty.channel.AbstractChannel$AbstractUnsafe.newClosedChannelException(AbstractChannel.java:957)
	at io.netty.channel.AbstractChannel$AbstractUnsafe.write(AbstractChannel.java:865)
	at io.netty.channel.DefaultChannelPipeline$HeadContext.write(DefaultChannelPipeline.java:1367)
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:717)
	at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:764)
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:790)
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:758)
	at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:767)
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:790)
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:758)
	at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:767)
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:790)
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:758)
	at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:767)
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:790)
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:758)
	at io.vertx.core.net.impl.ConnectionBase.write(ConnectionBase.java:124)
	at io.vertx.core.net.impl.ConnectionBase.lambda$queueForWrite$2(ConnectionBase.java:215)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Thread.java:834)
: io.netty.util.IllegalReferenceCountException: refCnt: 0, decrement: 1
	at io.netty.util.internal.ReferenceCountUpdater.toLiveRealRefCnt(ReferenceCountUpdater.java:74)
	at io.netty.util.internal.ReferenceCountUpdater.release(ReferenceCountUpdater.java:138)
	at io.netty.buffer.AbstractReferenceCountedByteBuf.release(AbstractReferenceCountedByteBuf.java:100)
	at io.vertx.core.http.impl.AssembledHttpResponse.release(AssembledHttpResponse.java:159)
	at io.netty.util.ReferenceCountUtil.release(ReferenceCountUtil.java:88)
	at io.netty.channel.AbstractChannel$AbstractUnsafe.write(AbstractChannel.java:867)
	at io.netty.channel.DefaultChannelPipeline$HeadContext.write(DefaultChannelPipeline.java:1367)
	at io.netty.channel.AbstractChannelHandlerContext.invokeWrite0(AbstractChannelHandlerContext.java:717)
	at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:764)
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:790)
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:758)
	at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:767)
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:790)
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:758)
	at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:767)
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:790)
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:758)
	at io.netty.channel.AbstractChannelHandlerContext.invokeWriteAndFlush(AbstractChannelHandlerContext.java:767)
	at io.netty.channel.AbstractChannelHandlerContext.write(AbstractChannelHandlerContext.java:790)
	at io.netty.channel.AbstractChannelHandlerContext.writeAndFlush(AbstractChannelHandlerContext.java:758)
	at io.vertx.core.net.impl.ConnectionBase.write(ConnectionBase.java:124)
	at io.vertx.core.net.impl.ConnectionBase.lambda$queueForWrite$2(ConnectionBase.java:215)
	at io.netty.util.concurrent.AbstractEventExecutor.safeExecute(AbstractEventExecutor.java:164)
	at io.netty.util.concurrent.SingleThreadEventExecutor.runAllTasks(SingleThreadEventExecutor.java:472)
	at io.netty.channel.nio.NioEventLoop.run(NioEventLoop.java:500)
	at io.netty.util.concurrent.SingleThreadEventExecutor$4.run(SingleThreadEventExecutor.java:989)
	at io.netty.util.internal.ThreadExecutorMap$2.run(ThreadExecutorMap.java:74)
	at io.netty.util.concurrent.FastThreadLocalRunnable.run(FastThreadLocalRunnable.java:30)
	at java.base/java.lang.Thread.run(Thread.java:834)

Expected behavior
No error in the logs

Actual behavior
Error (although harmless) appears in the logs

To Reproduce
Steps to reproduce the behavior:

1. Clone https://github.com/gastaldi/quarkus-backports/tree/graphql
2. Go to http://localhost:8080/backports/1.1.0.Final/
3. Before the page is rendered, hit refresh in your browser. You should see the error in the logs

Configuration
Create an .env file in the project root with the following content:

BACKPORTS_TOKEN=<YOUR_GITHUB_TOKEN>

Environment (please complete the following information):

• Output of uname -a or ver: Fedora 32

• Output of java -version:
  openjdk version "11.0.6" 2020-01-14
  OpenJDK Runtime Environment 18.9 (build 11.0.6+10)
  OpenJDK 64-Bit Server VM 18.9 (build 11.0.6+10, mixed mode)

• GraalVM version (if different from Java): Not used

• Quarkus version or git rev: 1.6.1.Final

• Build tool (ie. output of mvnw --version or gradlew --version):

Apache Maven 3.6.3 (cecedd343002696d0abb50b32b541b8a6ba2883f)
Maven home: /home/ggastald/.m2/wrapper/dists/apache-maven-3.6.3-bin/1iopthnavndlasol9gbrbg6bf2/apache-maven-3.6.3
Java version: 11.0.6, vendor: Oracle Corporation, runtime: /home/ggastald/.sdkman/candidates/java/11.0.6-open
Default locale: en_US, platform encoding: UTF-8
OS name: "linux", version: "5.7.8-200.fc32.x86_64", arch: "amd64", family: "unix"

Additional Context

It happens with quarkus:dev and with java -jar too

[gastaldi]

@stuartwdouglas any clue?