# HG changeset patch
# User Roman Arutyunyan <arut@nginx.com>
# Date 1441282161 -10800
# Node ID 50169ef2f3feb96ed3a29c1af4fc42cdc8a6691f
# Parent  2797b4347a2af4e8fd46dc5d1def5083813f38f1
Upstream: fixed cache send error handling.

The value of NGX_ERROR, returned from filter handlers, was treated as a generic
upstream error and changed to NGX_HTTP_INTERNAL_SERVER_ERROR before calling
ngx_http_finalize_request().  This resulted in "header already sent" alert
if header was already sent in filter handlers.

The problem appeared in 54e9b83d00f0 (1.7.5).

diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -530,15 +530,24 @@ ngx_http_upstream_init_request(ngx_http_
 
         r->write_event_handler = ngx_http_request_empty_handler;
 
-        if (rc == NGX_DONE) {
-            return;
-        }
-
         if (rc == NGX_ERROR) {
             ngx_http_finalize_request(r, NGX_HTTP_INTERNAL_SERVER_ERROR);
             return;
         }
 
+        if (rc == NGX_OK) {
+            rc = ngx_http_upstream_cache_send(r, u);
+
+            if (rc == NGX_DONE) {
+                return;
+            }
+
+            if (rc == NGX_HTTP_UPSTREAM_INVALID_HEADER) {
+                rc = NGX_DECLINED;
+                r->cached = 0;
+            }
+        }
+
         if (rc != NGX_DECLINED) {
             ngx_http_finalize_request(r, rc);
             return;
@@ -833,13 +842,7 @@ ngx_http_upstream_cache(ngx_http_request
 
     case NGX_OK:
 
-        rc = ngx_http_upstream_cache_send(r, u);
-
-        if (rc != NGX_HTTP_UPSTREAM_INVALID_HEADER) {
-            return rc;
-        }
-
-        break;
+        return NGX_OK;
 
     case NGX_HTTP_CACHE_STALE: