orm: Crash if accessing non-existent magic property

include/class.dynamic_forms.php

@@ -494,7 +494,7 @@ class DynamicFormEntry extends VerySimpleModel {
     function getForm() {
         if (!isset($this->_form)) {
             $this->_form = DynamicForm::lookup($this->get('form_id'));
-            if ($this->id)
+            if (isset($this->id))
                 $this->_form->data($this);
         }
         return $this->_form;

include/class.orm.php

@@ -16,6 +16,8 @@
     vim: expandtab sw=4 ts=4 sts=4:
 **********************************************************************/
 
+class OrmException extends Exception {}
+
 class VerySimpleModel {
     static $meta = array(
         'table' => false,
@@ -46,6 +48,13 @@ class VerySimpleModel {
             $v = $this->ht[$field] = $class::lookup($this->ht[$j['local']]);
             return $v;
         }
+        throw new OrmException(sprintf('%s: %s: Field not defined',
+            get_class($this), $field));
+    }
+
+    function __isset($field) {
+        return array_key_exists($field, $this->ht)
+            || isset(static::$meta['joins'][$field]);
     }
 
     function set($field, $value) {
@@ -86,7 +95,8 @@ class VerySimpleModel {
         // Construct related lists
         if (isset(static::$meta['joins'])) {
             foreach (static::$meta['joins'] as $name => $j) {
-                if (isset($j['list']) && $j['list']) {
+                if (isset($this->{$j['local']})
+                        && isset($j['list']) && $j['list']) {
                     $fkey = $j['fkey'];
                     $this->{$name} = new InstrumentedList(
                         // Send Model, Foriegn-Field, Local-Id