Fixed bug where an empty list stored in ContentItem.used_on_pages_dat…

…a was being ignored.

- Fixes sub issue of Issue django-fiber#47: Query count reduction

fiber/models.py

@@ -63,7 +63,7 @@ def set_used_on_pages_json(self):
         self.save()
 
     def get_used_on_pages_json(self):
-        if not self.used_on_pages_data:
+        if self.used_on_pages_data is None:
             self.set_used_on_pages_json()
 
         return simplejson.dumps(self.used_on_pages_data)

fiber/utils/json.py

@@ -54,7 +54,7 @@ def formfield(self, **kwargs):
         return super(JSONField, self).formfield(form_class=JSONFormField, **kwargs)
 
     def to_python(self, value):
-        if not value:
+        if value is None:
             return None
         try:
             if isinstance(value, basestring):
@@ -64,7 +64,7 @@ def to_python(self, value):
         return value
 
     def _get_json_value(self, value):
-        if not value:
+        if value is None:
             return ''
         elif isinstance(value, basestring):
             return value
@@ -75,7 +75,7 @@ def get_prep_value(self, value, *args, **kwargs):
         return self._get_json_value(value)
 
     def get_db_prep_save(self, value, *args, **kwargs):
-        if not value:
+        if value is None:
             return None
         if isinstance(value, dict):
             value = json.dumps(value)