Merge Add Mixin that allows refresh_from_db. Clse #246

Author: kmmbvnr

django_fsm/__init__.py

@@ -471,6 +471,32 @@ def set_state(self, instance, state):
         instance.__dict__[self.attname] = self.to_python(state)
 
 
+class FSMModelMixin(object):
+    """
+    Mixin that allows refresh_from_db for models with fsm protected fields
+    """
+
+    def _get_protected_fsm_fields(self):
+        def is_fsm_and_protected(f):
+            return isinstance(f, FSMFieldMixin) and f.protected
+        protected_fields = filter(is_fsm_and_protected, self._meta.concrete_fields)
+        return {f.attname for f in protected_fields}
+
+    def refresh_from_db(self, *args, **kwargs):
+        fields = kwargs.pop("fields", None)
+
+        # Use provided fields, if not set then reload all non-deferred fields.0
+        if not fields:
+            deferred_fields = self.get_deferred_fields()
+            protected_fields = self._get_protected_fsm_fields()
+            skipped_fields = deferred_fields.union(protected_fields)
+
+            fields = [f.attname for f in self._meta.concrete_fields
+                      if f.attname not in skipped_fields]
+
+        kwargs['fields'] = fields
+        super(FSMModelMixin, self).refresh_from_db(*args, **kwargs)
+
 class ConcurrentTransitionMixin(object):
     """
     Protects a Model from undesirable effects caused by concurrently executed transitions,

django_fsm/tests/test_protected_fields.py

@@ -0,0 +1,44 @@
+import unittest
+
+import django
+from django.db import models
+from django.test import TestCase
+
+from django_fsm import FSMField, FSMModelMixin, transition
+
+
+class RefreshableProtectedAccessModel(models.Model):
+    status = FSMField(default='new', protected=True)
+
+    @transition(field=status, source='new', target='published')
+    def publish(self):
+        pass
+
+    class Meta:
+        app_label = 'django_fsm'
+
+
+class RefreshableModel(FSMModelMixin, RefreshableProtectedAccessModel):
+    pass
+
+
+class TestDirectAccessModels(TestCase):
+    def test_no_direct_access(self):
+        instance = RefreshableProtectedAccessModel()
+        self.assertEqual(instance.status, 'new')
+
+        def try_change():
+            instance.status = 'change'
+
+        self.assertRaises(AttributeError, try_change)
+
+        instance.publish()
+        instance.save()
+        self.assertEqual(instance.status, 'published')
+
+    @unittest.skipIf(django.VERSION < (1, 8), "Django introduced refresh_from_db in 1.8")
+    def test_refresh_from_db(self):
+        instance = RefreshableModel()
+        instance.save()
+
+        instance.refresh_from_db()

tox.ini

@@ -5,8 +5,8 @@ envlist =
     # py33-dj{16,18}
     py{34,35,36}-dj{18,19,110,111}
     py{36,37}-dj{20,21}
-    py{37,38,39}-dj{22,30,31,32}
-    py{38,39,310}-dj{40,41}
+    py{37,38}-dj{22,30,31,32}
+    py{38,310}-dj{40,41}
 skipsdist = True
 
 [testenv]