[PATCH 08 of 31] Fix double content when return is used in error_page redirection

[Maxim Dounin]

# HG changeset patch
# User Maxim Dounin <mdounin at mdounin.ru>
# Date 1309178892 -14400
# Node ID 2f56387eb87fdbf3212540211381ea972c4a75e3
# Parent  0ec754a289a69cea6b147a1744e277175658a772
Fix double content when return is used in error_page redirection.

Test case:

   location / {
       error_page 405 /nope;
       return 405;
   }

   location /nope {
       return 200;
   }

This is expected to return 405 with empty body, but in 0.8.42+ will return
builtin 405 error page as well (though not counted in Content-Length, thus
breaking protocol).

Note that this patch also changes behaviour for "return 302 ..." and
"rewrite ... redirect" used as error handler.  E.g.

    location / {
        error_page 405 /redirect;
        return 405;
    }

    location /redirect {
        rewrite ^ http://example.com/;
    }

will actually return redirect to "http://example.com/" instead of builtin 405
error page with meaningless Location header.  This looks like correct change
and it's in line with what happens on e.g. directory redirects in error
handlers.

diff --git a/src/http/modules/ngx_http_rewrite_module.c b/src/http/modules/ngx_http_rewrite_module.c
--- a/src/http/modules/ngx_http_rewrite_module.c
+++ b/src/http/modules/ngx_http_rewrite_module.c
@@ -167,8 +167,8 @@ ngx_http_rewrite_handler(ngx_http_reques
         code(e);
     }
 
-    if (e->status == NGX_DECLINED) {
-        return NGX_DECLINED;
+    if (e->status < NGX_HTTP_BAD_REQUEST) {
+        return e->status;
     }
 
     if (r->err_status == 0) {