id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	uname	nginx_version
32	expires header not set correctly using '@' format	time4tea.myopenid.com	somebody	"If upstream does not send last-modified header, @ style expiry times will be interpreted as (now + time)

(from r1.0.8)

ngx_http_headers_filter_module.c line 266
the bug is that the expires header is not set correctly when using @
and it is the case that it is not set correctly, but you will only see the bug if upstream does not set a last-modified header
 if (conf->expires == NGX_HTTP_EXPIRES_ACCESS
        || r->headers_out.last_modified_time == -1)
    {
its the || condition that causes the problem


confirmed on #nginx by PiotrSikora
"	defect	new	minor		nginx-core	1.0.x		expires