Make CREATE_MISSING_FLAGS logic universal (#400) (#427)

Before CREATE_MISSING_FLAGS was only respected when `is_active(request)` method was used, now any check against a flag (calling `get(name)`) will trigger the automatic creation of the `Flag` model.

waffle/models.py

@@ -56,6 +56,13 @@ def get_from_db(cls, name):
         objects = cls.objects
         if get_setting('READ_FROM_WRITE_DB'):
             objects = objects.using(router.db_for_write(cls))
+
+        if get_setting('CREATE_MISSING_FLAGS'):
+            flag, _created = objects.get_or_create(
+                name=name, defaults={'everyone': get_setting('FLAG_DEFAULT')}
+            )
+            return flag
+
         return objects.get(name=name)
 
     @classmethod
@@ -247,16 +254,6 @@ def is_active(self, request):
             log_level = get_setting('LOG_MISSING_FLAGS')
             if log_level:
                 logger.log(log_level, 'Flag %s not found', self.name)
-            if get_setting('CREATE_MISSING_FLAGS'):
-                flag, _created = get_waffle_flag_model().objects.get_or_create(
-                    name=self.name,
-                    defaults={
-                        'everyone': get_setting('FLAG_DEFAULT')
-                    }
-                )
-                cache = get_cache()
-                cache.set(self._cache_key(self.name), flag)
-
             return get_setting('FLAG_DEFAULT')
 
         if get_setting('OVERRIDE'):

waffle/tests/test_waffle.py

@@ -441,6 +441,16 @@ def test_flag_created_dynamically_default_false(self):
     def test_flag_created_dynamically_default_true(self):
         self.assert_flag_dynamically_created_with_value(True)
 
+    @override_settings(WAFFLE_CREATE_MISSING_FLAGS=True)
+    @override_settings(WAFFLE_FLAG_DEFAULT=True)
+    def test_flag_created_dynamically_upon_retrieval(self):
+        FLAG_NAME = 'myflag'
+        flag_model = waffle.get_waffle_flag_model()
+        flag = flag_model.get(FLAG_NAME)
+
+        assert flag.is_active(get())
+        assert flag_model.objects.filter(name=FLAG_NAME).exists()
+
     @mock.patch('waffle.models.logger')
     def test_no_logging_missing_flag_by_default(self, mock_logger):
         request = get()