Do not send RST_STREAM when UnprocessedRequestException is raised

[minwoox]

Motivation:
When an UnprocessedRequestException is raised, the client should not send an RST_STREAM.

Modifications:

• Updated the Http2ResponseDecoder to avoid sending RST_STREAM when UnprocessedRequestException occurs.

Result:

• The client does not send an RST_STREAM when an UnprocessedRequestException is raised.

[github-actions]

🔍 Build Scan® (commit: c1a3632)

Job name	Status	Build Scan®
build-ubicloud-standard-16-jdk-8	✅	https://ge.armeria.dev/s/etthsfdyne6f6
build-ubicloud-standard-16-jdk-21-snapshot-blockhound	✅	https://ge.armeria.dev/s/5rc74utjmubga
build-ubicloud-standard-16-jdk-17-min-java-17-coverage	✅	https://ge.armeria.dev/s/4l3lppuypftzc
build-ubicloud-standard-16-jdk-17-min-java-11	❌ (failure)	https://ge.armeria.dev/s/3l6ev7vt3x4r2
build-ubicloud-standard-16-jdk-17-leak	✅	https://ge.armeria.dev/s/np5ha37pvspsa
build-ubicloud-standard-16-jdk-11	✅	https://ge.armeria.dev/s/rl4tov5zmicwa
build-macos-latest-jdk-21	✅	https://ge.armeria.dev/s/jotsckc5setto

[ikhoon]

We may not need to send RST_STREAM when the stream was closed or a RST_STREAM was received before. I was wondering if our logic already handles the cases.

armeria/core/src/main/java/com/linecorp/armeria/client/Http2ResponseDecoder.java

Lines 138 to 150 in e08527d

	if (res.isOpen()) {
	if (!goAwayHandler.receivedGoAway()) {
	res.close(newClosedStreamException(channel()));
	return;
	}
	final int lastStreamId = conn.local().lastStreamKnownByPeer();
	if (stream.id() > lastStreamId) {
	res.close(UnprocessedRequestException.of(GoAwayReceivedException.get()));
	} else {
	res.close(newClosedStreamException(channel()));
	}
	}

armeria/core/src/main/java/com/linecorp/armeria/client/Http2ResponseDecoder.java

Line 314 in e08527d

res.close(cause);

[minwoox]

I think Netty handles those cases:
https://github.com/netty/netty/blob/4.1/codec-http2/src/main/java/io/netty/handler/codec/http2/Http2ConnectionHandler.java#L808-L810
The problem that I fixed is that it tries to send RST_STREAM even though the stream was removed. Let me also add that condition to prevent the situation.

[ikhoon]

Netty seems to send another RST_STREAM by encoder.writeRstStream() when the client receives an RST_STREAM or the connection is closed.

My suggestion is:

if (cause instanceof UnprocessedRequestException || 
    cause instanceof ClosedStreamException) {
   return;
}

[minwoox]

Thanks addressed. 👍

[ikhoon]

Thanks!