NULL is short way
diff --git a/src/http/ngx_http_variables.c b/src/http/ngx_http_variables.c
index 48b46f0..1201458 100644
--- a/src/http/ngx_http_variables.c
+++ b/src/http/ngx_http_variables.c
@@ -367,7 +367,7 @@
     r->variables[index].valid = 0;
     r->variables[index].not_found = 1;
 
-    return &r->variables[index];
+    return NULL;
 }