From ce302b7977c4adada5cfa6a129636d653491aace Mon Sep 17 00:00:00 2001
From: Dean Chen <862469039@qq.com>
Date: Sun, 6 Sep 2026 21:32:14 +0500
Subject: [PATCH] Tests: empty HTTP/2 upstream response keepalive.

Check buffered and unbuffered empty responses, including HEAD, 204,
and 304. Verify that control acknowledgements reach the upstream before
the next request, and that GOAWAY and partial frames prevent reuse.

See https://github.com/nginx/nginx/issues/1726.
---
 proxy_h2_keepalive_empty.t | 165 +++++++++++++++++++++++++++++++++++++
 1 file changed, 165 insertions(+)
 create mode 100644 proxy_h2_keepalive_empty.t

diff --git a/proxy_h2_keepalive_empty.t b/proxy_h2_keepalive_empty.t
new file mode 100644
index 00000000..028dcc98
--- /dev/null
+++ b/proxy_h2_keepalive_empty.t
@@ -0,0 +1,165 @@
+#!/usr/bin/perl
+
+# Tests for HTTP/2 upstream keepalive with empty responses and control frames.
+
+###############################################################################
+
+use warnings;
+use strict;
+
+use Test::More;
+use IO::Socket::INET;
+
+BEGIN { use FindBin; chdir($FindBin::Bin); }
+
+use lib 'lib';
+use Test::Nginx;
+use Test::Nginx::HTTP2;
+
+###############################################################################
+
+select STDERR; $| = 1;
+select STDOUT; $| = 1;
+
+my $t = Test::Nginx->new()->has(qw/http http_v2 proxy upstream_keepalive/)
+	->write_file_expand('nginx.conf', <<'EOF');
+
+%%TEST_GLOBALS%%
+
+daemon off;
+
+events {
+}
+
+http {
+    %%TEST_GLOBALS_HTTP%%
+
+    upstream backend {
+        server 127.0.0.1:8081;
+        keepalive 1;
+        keepalive_requests 2;
+    }
+
+    server {
+        listen       127.0.0.1:8080;
+        server_name  localhost;
+
+        proxy_http_version 2;
+
+        location / {
+            proxy_pass http://backend;
+        }
+
+        location /unbuffered/ {
+            proxy_pass http://backend;
+            proxy_buffering off;
+        }
+    }
+}
+
+EOF
+
+$t->run_daemon(\&http_daemon);
+$t->waitforsocket('127.0.0.1:' . port(8081));
+$t->try_run('no proxy_http_version 2')->plan(40);
+
+###############################################################################
+
+# Each pair starts on a fresh upstream connection.  SETTINGS and PING are sent
+# together with the response, so their acknowledgements are still queued when
+# the END_STREAM header is parsed.
+
+for my $mode ('buffered', 'unbuffered') {
+	for my $response ('200', '204', '304', 'HEAD') {
+		my $status = $response eq 'HEAD' ? 200 : $response;
+		my $uri = "/$mode/$response";
+		my $r = $response eq 'HEAD' ? http_head($uri) : http_get($uri);
+		like($r, qr/ $status .*X-Connection: \d+/si,
+			"$mode $response response");
+		my ($connection) = $r =~ /X-Connection: (\d+)/i;
+		$connection = -1 unless defined $connection;
+
+		$r = $response eq 'HEAD' ? http_head($uri) : http_get($uri);
+		like($r, qr/X-Connection: $connection\r?\n/i,
+			"$mode $response keepalive");
+		like($r, qr/X-Settings-Acks: 1\r?\n/i,
+			"$mode $response settings ack before reuse");
+		like($r, qr/X-Ping-Acks: 1\r?\n/i,
+			"$mode $response ping ack before reuse");
+	}
+}
+
+# Neither GOAWAY nor an incomplete frame after the response permits reuse.
+
+for my $mode ('buffered', 'unbuffered') {
+	for my $response ('goaway', 'partial') {
+		my $uri = "/$mode/$response";
+		my $r = http_get($uri);
+		like($r, qr/ 200 .*X-Connection: \d+/si,
+			"$mode $response response");
+		my ($connection) = $r =~ /X-Connection: (\d+)/i;
+		$connection = -1 unless defined $connection;
+
+		like(http_get($uri),
+			qr/ 200 .*X-Connection: (?!$connection\r?\n)\d+/si,
+			"$mode $response not reused");
+	}
+}
+
+###############################################################################
+
+sub http_daemon {
+	my $server = IO::Socket::INET->new(
+		Proto => 'tcp',
+		LocalAddr => '127.0.0.1:' . port(8081),
+		Listen => 5,
+		Reuse => 1
+	) or die "Can't create listening socket: $!";
+
+	my $connection = 0;
+
+	while (my $client = $server->accept()) {
+		$client->autoflush(1);
+		$client->sysread(my $preface, 24) or next;
+		$connection++;
+
+		my $c = Test::Nginx::HTTP2->new(1, socket => $client,
+			pure => 1, preface => '');
+		my ($settings, $pings, $requests) = (0, 0, 0);
+
+		while (1) {
+			my $frames = $c->read(all => [{ type => 'HEADERS' }]);
+			$settings += grep {
+				$_->{type} eq 'SETTINGS' && $_->{flags} == 1
+			} @$frames;
+			$pings += grep {
+				$_->{type} eq 'PING' && $_->{flags} == 1
+			} @$frames;
+
+			my ($frame) = grep { $_->{type} eq 'HEADERS' } @$frames;
+			last unless $frame;
+			my ($response) = $frame->{headers}{':path'} =~ m|([^/]+)$|;
+			my $status = $response =~ /^\d+$/ ? $response : 200;
+			my $length = $response eq 'HEAD' || $status == 304 ? 100 : 0;
+			my @headers = (
+				{ name => ':status', value => $status },
+				{ name => 'x-connection', value => $connection, mode => 4 },
+				{ name => 'x-settings-acks', value => $settings, mode => 4 },
+				{ name => 'x-ping-acks', value => $pings, mode => 4 }
+			);
+			push @headers, { name => 'content-length', value => $length }
+				unless $status == 204;
+
+			$c->start_chain();
+			$c->h2_settings(0);
+			$c->h2_settings(1) unless $requests++;
+			$c->h2_ping('12345678');
+			$c->h2_goaway(0, $frame->{sid}, 0) if $response eq 'goaway';
+			$c->new_stream({ headers => \@headers }, $frame->{sid});
+			$c->raw_write(pack('x2C2', 8, 6)) if $response eq 'partial';
+			$c->send_chain();
+		}
+	}
+}
+
+###############################################################################