Fixes #23, don't allow transition on unsaved model

django_states/model_methods.py

@@ -132,6 +132,9 @@ def test_transition(si_self, transition, user=None):
             if not machine.has_transition(transition):
                 raise UnknownTransition(self, transition)
 
+            if not self.pk:
+                raise ValueError("Unsaved model instance %r cannot be used in make_transition." % self)
+
             t = machine.get_transitions(transition)
 
             if getattr(self, field) not in t.from_states:
@@ -162,6 +165,10 @@ def make_transition(si_self, transition, user=None, **kwargs):
             # Transition name should be known
             if not machine.has_transition(transition):
                 raise UnknownTransition(self, transition)
+
+            if not self.pk:
+                raise ValueError("Unsaved model instance %r cannot be used in make_transition." % self)
+
             t = machine.get_transitions(transition)
 
             _state_log_model = getattr(self, '_%s_log_model' % field, None)

django_states/tests.py

@@ -541,3 +541,11 @@ def test_statelog(self):
         # We should also be able to find this via
         self.assertEqual(test.get_state_transitions().count(), 1)
         self.assertEqual(len(test.get_public_state_transitions()), 1)
+
+    def test_statelog_unsaved(self):
+        test = DjangoStateLogClass(field1=42, field2="Hello world?")
+        # Try to make transition on unsaved model
+        with self.assertRaises(ValueError):
+            test.get_state_info().test_transition('start_step_1', user=self.superuser)
+        with self.assertRaises(ValueError):
+            test.get_state_info().make_transition('start_step_1', user=self.superuser)