Do not let a StockItem be deleted if child items exist

InvenTree/stock/models.py

@@ -376,10 +376,14 @@ class StockItem(MPTTModel):
     def can_delete(self):
         """ Can this stock item be deleted? It can NOT be deleted under the following circumstances:
 
+        - Has child StockItems
         - Has a serial number and is tracked
         - Is installed inside another StockItem
         """
 
+        if self.child_count > 0:
+            return False
+
         if self.part.trackable and self.serial is not None:
             return False
 

InvenTree/stock/templates/stock/item_base.html

@@ -43,15 +43,21 @@
                 <button type='button' class='btn btn-default btn-glyph' id='stock-edit' title='Edit stock item'>
                     <span class='glyphicon glyphicon-edit'/>
                 </button>
+                {% if item.can_delete %}
                 <button type='button' class='btn btn-default btn-glyph' id='stock-delete' title='Edit stock item'>
                     <span class='glyphicon glyphicon-trash'/>
                 </button>
+                {% endif %}
             </div>
         </p>
         {% if item.serialized %}
         <div class='alert alert-block alert-info'>
             {% trans "This stock item is serialized - it has a unique serial number and the quantity cannot be adjusted." %}
         </div>
+        {% elif item.child_count > 0 %}
+        <div class='alert alert-block alert-warning'>
+            {% trans "This stock item cannot be deleted as it has child items" %}
+        </div>
         {% elif item.delete_on_deplete %}
         <div class='alert alert-block alert-warning'>
             {% trans "This stock item will be automatically deleted when all stock is depleted." %}