Add missing validation rule.

main/inc/lib/formvalidator/Rule/CompareDateTimeText.php

@@ -0,0 +1,27 @@
+<?php
+/* For licensing terms, see /license.txt */
+
+/**
+ * QuickForm rule to compare 2 dates
+ */
+class HTML_QuickForm_Rule_CompareDateTimeText extends HTML_QuickForm_Rule_Compare
+{
+    /**
+     * Validate 2 dates
+     * @param string $operator The operator to use (default '==')
+     * @return boolean True if the 2 given dates match the operator
+     */
+    function validate($values, $operator = null) {
+    	$datetime1 = api_strtotime($values[0]);
+        $datetime2 = api_strtotime($values[1]);
+
+        if (strpos($operator, 'allow_empty') !== false) {
+            $operator = str_replace('allow_empty', '', $operator);
+            if (!$datetime2 || empty($datetime2)) {
+                return true;
+            }
+        }
+		$result =  parent::validate(array($datetime1, $datetime2), $operator);
+        return $result;
+    }
+}

main/inc/lib/pear/HTML/QuickForm/RuleRegistry.php

@@ -151,7 +151,8 @@ class HTML_QuickForm_RuleRegistry
             'compare_fields' => 'HTML_QuickForm_Compare_Fields',
             'html' => 'HTML_QuickForm_Rule_HTML',
             'CAPTCHA' => 'HTML_QuickForm_Rule_CAPTCHA',
-            'date' => 'HTML_QuickForm_Rule_Date'
+            'date' => 'HTML_QuickForm_Rule_Date',
+            'compare_datetime_text' => 'HTML_QuickForm_Rule_CompareDateTimeText'
         );
 
         $class = $rules[$ruleName];