From 640aec1debd8106c2909997714df0b19dae8829e Mon Sep 17 00:00:00 2001
From: Coleman Watts <coleman@civicrm.org>
Date: Mon, 1 May 2017 14:30:19 -0400
Subject: [PATCH] CRM-20327 - Avoid api chaining errors when replacing value
 with operators

---
 api/api.php | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/api/api.php b/api/api.php
index 1675d9d1aa..5c432630a8 100644
--- a/api/api.php
+++ b/api/api.php
@@ -136,6 +136,10 @@ function _civicrm_api_replace_variables(&$params, &$parentResult, $separator = '
     elseif (is_array($value) && is_string(reset($value)) && substr(reset($value), 0, 6) == '$value') {
       $key = key($value);
       $value[$key] = _civicrm_api_replace_variable($value[$key], $parentResult, $separator);
+      // A null value with an operator will cause an error, so remove it.
+      if ($value[$key] === NULL) {
+        $value = '';
+      }
     }
   }
 }
-- 
2.25.1