Ensure mtime update is triggered for Django

aiida/backends/tests/orm/implementation/test_nodes.py

@@ -126,6 +126,14 @@ def test_creation_with_time(self):
         self.assertEqual(node.ctime, ctime)
         self.assertEqual(node.mtime, mtime)
 
+    def test_mtime(self):
+        """Test the `mtime` is automatically updated when a database field is updated."""
+        node = self.node.store()
+        node_mtime = node.mtime
+
+        node.label = 'changed label'
+        self.assertTrue(node.mtime > node_mtime)
+
     def test_clone(self):
         """Test the `clone` method."""
         node = self.node.store()

aiida/orm/implementation/django/utils.py

@@ -77,6 +77,10 @@ def _flush(self, fields=None):
         """ If the user is stored then save the current value """
         if self.is_saved():
             try:
+                # Manually append the `mtime` to fields to update, because when using the `update_fields` keyword of the
+                # `save` method, the `auto_now` property of `mtime` column is not triggered
+                if self._is_model_field('mtime'):
+                    fields.add('mtime')
                 self._model.save(update_fields=fields)
             except django.db.IntegrityError as e:
                 # Convert to one of our exceptions