Save.php: add specific error message for missing slaveId Definition.

extension/qfq/qfq/Constants.php

@@ -158,6 +158,7 @@ const ERROR_MISSING_CONFIG_INI_VALUE = 1070;
 const ERROR_SENDMAIL = 1071;
 const ERROR_SENDMAIL_MISSING_VALUE = 1072;
 const ERROR_OVERWRITE_RECORD_ID = 1073;
+const ERROR_MISSING_SLAVE_ID_DEFINITION = 1074;
 
 // Subrecord
 const ERROR_SUBRECORD_MISSING_COLUMN_ID = 1100;

extension/qfq/qfq/Save.php

@@ -384,6 +384,10 @@ class Save {
         $flagUpdateSlaveId = false;
         $flagSlaveDeleted = false;
 
+        if(!isset($fe[FE_SLAVE_ID])) {
+            throw new UserFormException("Missing 'slaveId'-definition", ERROR_MISSING_SLAVE_ID_DEFINITION);
+        }
+
         // Get the slaveId
         $slaveId = Support::falseEmptyToZero($this->evaluate->parse($fe[FE_SLAVE_ID]));
         // Store the slaveId: it's used and replaced in the update statement.