Range filter: fixed duplicate last buffers. In ngx_http_range_singlepart_body() special buffers where passed unmodified, including ones after the end of the range. As such, if the last buffer of a response was sent separately as a special buffer, two buffers with b->last_buf set were present in the response. In particular, this might result in a duplicate final chunk when using chunked transfer encoding (normally range filter and chunked transfer encoding are not used together, but this may happen if there are trailers in the response). This also likely to cause problems in HTTP/2. Fix is to skip all special buffers after we've sent the last part of the range requested. These special buffers are not meaningful anyway, since we set b->last_buf in the buffer with the last part of the range, and everything is expected to be flushed due to it. Additionally, ngx_http_next_body_filter() is now called even if no buffers are to be passed to it. This ensures that various write events are properly propagated through the filter chain. In particular, this fixes test failures observed with the above change and aio enabled.

fastcgi_param  SCRIPT_FILENAME    $document_root$fastcgi_script_name;
fastcgi_param  QUERY_STRING       $query_string;
fastcgi_param  REQUEST_METHOD     $request_method;
fastcgi_param  CONTENT_TYPE       $content_type;
fastcgi_param  CONTENT_LENGTH     $content_length;

fastcgi_param  SCRIPT_NAME        $fastcgi_script_name;
fastcgi_param  REQUEST_URI        $request_uri;
fastcgi_param  DOCUMENT_URI       $document_uri;
fastcgi_param  DOCUMENT_ROOT      $document_root;
fastcgi_param  SERVER_PROTOCOL    $server_protocol;
fastcgi_param  REQUEST_SCHEME     $scheme;
fastcgi_param  HTTPS              $https if_not_empty;

fastcgi_param  GATEWAY_INTERFACE  CGI/1.1;
fastcgi_param  SERVER_SOFTWARE    nginx/$nginx_version;

fastcgi_param  REMOTE_ADDR        $remote_addr;
fastcgi_param  REMOTE_PORT        $remote_port;
fastcgi_param  SERVER_ADDR        $server_addr;
fastcgi_param  SERVER_PORT        $server_port;
fastcgi_param  SERVER_NAME        $server_name;

# PHP only, required if PHP was built with --enable-force-cgi-redirect
fastcgi_param  REDIRECT_STATUS    200;