Fixed background update with "if". Cloned subrequests should inherit r->content_handler. This way they will be able to use the same location configuration as the original request if there are "if" directives in the configuration. Without r->content_handler inherited, the following configuration tries to access a static file in the update request: location / { set $true 1; if ($true) { # nothing } proxy_pass http://backend; proxy_cache one; proxy_cache_use_stale updating; proxy_cache_background_update on; } See http://mailman.nginx.org/pipermail/nginx/2017-February/053019.html for initial report.

--- a/src/http/ngx_http_core_module.c
+++ b/src/http/ngx_http_core_module.c
@@ -2571,6 +2571,7 @@ ngx_http_subrequest(ngx_http_request_t *
         sr->method_name = r->method_name;
         sr->loc_conf = r->loc_conf;
         sr->valid_location = r->valid_location;
+        sr->content_handler = r->content_handler;
         sr->phase_handler = r->phase_handler;
         sr->write_event_handler = ngx_http_core_run_phases;