Fix FieldDescriptor default value bug. Close #49.

tests/test_replies.py

@@ -102,3 +102,13 @@ def test_music_reply_properties(self):
         self.assertEqual('test', reply.description)
         self.assertEqual('http://www.qq.com', reply.music_url)
         self.assertTrue(reply.hq_music_url is None)
+
+    def test_multi_article_reply(self):
+        from wechatpy.replies import ArticlesReply
+
+        article = {'title': 'test', 'url': 'http://www.qq.com'}
+
+        r1 = ArticlesReply()
+        r1.add_article(article)
+        r2 = ArticlesReply()
+        self.assertTrue(r1.render() != r2.render())

wechatpy/fields.py

@@ -10,6 +10,8 @@
 """
 from __future__ import absolute_import, unicode_literals
 import base64
+import copy
+
 import six
 
 from wechatpy.utils import to_text, to_binary, ObjectDict
@@ -25,8 +27,8 @@ def __get__(self, instance, instance_type=None):
         if instance is not None:
             value = instance._data.get(self.attr_name)
             if value is None:
-                instance._data[self.attr_name] = self.field.default
-                value = self.field.default
+                value = copy.deepcopy(self.field.default)
+                instance._data[self.attr_name] = value
             if isinstance(value, dict):
                 value = ObjectDict(value)
             if value and not isinstance(value, (dict, list, tuple)) and \