Upstream: added check if a response is complete. Checks were added to both buffered and unbuffered code paths to detect and complain if a response is incomplete. Appropriate error codes are now passed to ngx_http_upstream_finalize_request(). With this change in unbuffered mode we now use u->length set to -1 as an indicator that EOF is allowed per protocol and used to indicate response end (much like its with p->length in buffered mode). Proxy module was changed to set u->length to 1 (instead of previously used -1) in case of chunked transfer encoding used to comply with the above.

--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -1542,7 +1542,7 @@ ngx_http_proxy_input_filter_init(void *d
         u->pipe->length = 3; /* "0" LF LF */
 
         u->input_filter = ngx_http_proxy_non_buffered_chunked_filter;
-        u->length = -1;
+        u->length = 1;
 
     } else if (u->headers_in.content_length_n == 0) {
         /* empty body: special case as filter won't be called */