id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
1204	"""gzip_vary"" will add a duplicate Vary header if a PHP page also adds a Vary header"	RichardBradley@…		"I have a PHP app served by nginx, and I'd like to enable gzip output compression.

I have turned on the ""gzip"" and ""gzip_vary"" settings:

{{{
/etc/nginx/nginx.conf:    gzip  on;
/etc/nginx/nginx.conf:    gzip_vary on;
/etc/nginx/nginx.conf:    gzip_disable ""msie6"";
}}}

My PHP app already adds a Vary header. 

== Observed Behaviour ==

Unfortunately this causes `nginx` to add a duplicate Vary header:

{{{
HTTP/1.1 200 OK
Server: nginx
Content-Type: text/html; charset=UTF-8
Transfer-Encoding: chunked
Connection: keep-alive
Vary: Accept-Encoding
Cache-Control: max-age=300, public
Vary: Accept-Encoding,X-Cookie-ckps_language
Content-language: en-GB
Date: Mon, 13 Feb 2017 15:20:39 GMT
}}}

== Expected Behaviour ==

I believe that `nginx` should merge the ""Vary"" header added by `gzip_vary` with any `Vary` headers produced by hosted apps.

== Previous reports of this bug ==

See also:
 * http://serverfault.com/questions/821310/nginx-gzip-vary-header-together-with-existing-vary-headers
 * https://forum.nginx.org/read.php?2,240322,240322#msg-240322
"	defect	closed	major		nginx-core	1.10.x	duplicate	gzip,gzip_vary		"Linux ip-10-56-38-16.eu-west-1.compute.internal 2.6.32-642.13.1.el6.x86_64 #1 SMP Wed Jan 11 20:56:24 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
"	"nginx version: nginx/1.10.2
built by gcc 4.4.7 20120313 (Red Hat 4.4.7-17) (GCC)
built with OpenSSL 1.0.1e-fips 11 Feb 2013
TLS SNI support enabled
configure arguments: --prefix=/usr/share/nginx --sbin-path=/usr/sbin/nginx --modules-path=/usr/lib64/nginx/modules --conf-path=/etc/nginx/nginx.conf --error-log-path=/var/log/nginx/error.log --http-log-path=/var/log/nginx/access.log --http-client-body-temp-path=/var/lib/nginx/tmp/client_body --http-proxy-temp-path=/var/lib/nginx/tmp/proxy --http-fastcgi-temp-path=/var/lib/nginx/tmp/fastcgi --http-uwsgi-temp-path=/var/lib/nginx/tmp/uwsgi --http-scgi-temp-path=/var/lib/nginx/tmp/scgi --pid-path=/var/run/nginx.pid --lock-path=/var/lock/subsys/nginx --user=nginx --group=nginx --with-file-aio --with-ipv6 --with-http_ssl_module --with-http_v2_module --with-http_realip_module --with-http_addition_module --with-http_xslt_module=dynamic --with-http_image_filter_module=dynamic --with-http_geoip_module=dynamic --with-http_sub_module --with-http_dav_module --with-http_flv_module --with-http_mp4_module --with-http_gunzip_module --with-http_gzip_static_module --with-http_random_index_module --with-http_secure_link_module --with-http_degradation_module --with-http_slice_module --with-http_stub_status_module --with-http_perl_module=dynamic --with-mail=dynamic --with-mail_ssl_module --with-pcre --with-pcre-jit --with-stream=dynamic --with-stream_ssl_module --with-debug --with-cc-opt='-O2 -g -pipe -Wall -Wp,-D_FORTIFY_SOURCE=2 -fexceptions -fstack-protector --param=ssp-buffer-size=4 -m64 -mtune=generic' --with-ld-opt=' -Wl,-E'"