djc · JonathanWylie · Mar 15, 2016 · Mar 16, 2016 · Mar 16, 2016 · Mar 16, 2016
diff --git a/.idea/vcs.xml b/.idea/vcs.xml
diff --git a/couchdb/mapping.py b/couchdb/mapping.py
@@ -94,7 +94,11 @@ def __get__(self, instance, owner):
         value = instance._data.get(self.name)
         if value is not None:
             value = self._to_python(value)
-        elif self.default is not None:
+        return value
+
+    def get_default(self):
+        value = None
+        if self.default is not None:
             default = self.default
             if callable(default):
                 default = default()
@@ -139,7 +143,8 @@ def __init__(self, **values):
             if attrname in values:
                 setattr(self, attrname, values.pop(attrname))
             else:
-                setattr(self, attrname, getattr(self, attrname))
+                field = getattr(self.__class__, attrname)
+                setattr(self, attrname, field.get_default())
 
     def __iter__(self):
         return iter(self._data)
@@ -177,8 +182,43 @@ def build(cls, **d):
 
     @classmethod
     def wrap(cls, data):
+        """ Wrap the data object with cls, so that any data changes are made to
+        the data object
+
+        cls may define schema for data that is not in data yet,
+            eg a document is saved to the DB
+            the document schema is changed to contain another kind of data
+            load the old document with the new schema
+            we want to be able to
+                write the data for the new schema
+                get a default value for the new schema
+
+        :param data: A dictionary object of data
+        :return: an instance of class which provides a nice interface to the
+            information in the data object
+        """
+        instance = cls(**data)
+        data.update(instance._data)
+        instance._data = data
+        return instance
+
         instance = cls()
+
+        def add_defaults(default_values, data_dict):
+            for key, defaultValue in default_values.items():
+                if key not in data_dict:
+                    data_dict[key] = defaultValue
+                if isinstance(defaultValue, dict):
+                    add_defaults(defaultValue, data_dict[key])
+                # # If it is a list of DictField then the DictField schema may have updated
+                # if isinstance(defaultValue, list) and :
+
+
+
+        # Recursively set the defaults if they are not in the doc already
+        add_defaults(instance._data, data)
         instance._data = data
+
         return instance
 
     def _to_python(self, value):
@@ -465,6 +505,8 @@ def _to_python(self, value):
         return value
 
     def _to_json(self, value):
+        # Make sure it is the right format (it might have come from wrap)
+        value = self._to_python(value)
         if isinstance(value, datetime):
             value = value.date()
         return value.isoformat()
@@ -493,6 +535,8 @@ def _to_python(self, value):
         return value
 
     def _to_json(self, value):
+        # Make sure it is the right format (it might have come from wrap)
+        value = self._to_python(value)
         if isinstance(value, struct_time):
             value = datetime.utcfromtimestamp(timegm(value))
         elif not isinstance(value, datetime):
@@ -522,6 +566,8 @@ def _to_python(self, value):
         return value
 
     def _to_json(self, value):
+        # Make sure it is the right format (it might have come from wrap)
+        value = self._to_python(value)
         if isinstance(value, datetime):
             value = value.time()
         return value.replace(microsecond=0).isoformat()
@@ -611,7 +657,7 @@ class ListField(Field):
     >>> comment['content']
     u'Bla bla'
     >>> comment['time'] #doctest: +ELLIPSIS
-    u'...T...Z'
+    '...T...Z'
 
     >>> del server['python-tests']
     """

diff --git a/couchdb/tests/mapping.py b/couchdb/tests/mapping.py
@@ -6,6 +6,7 @@
 # This software is licensed as described in the file COPYING, which
 # you should have received as part of this distribution.
 
+import copy
 from decimal import Decimal
 import unittest
 
@@ -250,6 +251,161 @@ def test_query(self):
         self.assertEqual(type(results.rows[0]), self.Item)
 
 
+class TestWrap(testutil.TempDatabaseMixin, unittest.TestCase):
+
+    def test_simple_schema_change(self):
+        my_mapping = mapping.Mapping.build(
+            name=mapping.TextField(),
+        )
+        my_instance = my_mapping.wrap({})
+        my_instance.name = 'Harry'
+
+        data = copy.copy(my_instance._data)
+
+        my_new_mapping = mapping.Mapping.build(
+            name=mapping.TextField(),
+            age=mapping.IntegerField(),
+        )
+
+        instance = my_new_mapping.wrap(data)
+        instance.age = 32
+        assert data['age'] == 32
+
+    def test_defaults_for_new_schema_should_be_set(self):
+        my_mapping = mapping.Mapping.build(
+            name=mapping.TextField(),
+        )
+        my_instance = my_mapping.wrap({})
+        my_instance.name = 'Harry'
+
+        data = copy.copy(my_instance._data)
+
+        my_new_mapping = mapping.Mapping.build(
+            name=mapping.TextField(),
+            address=mapping.DictField(mapping.Mapping.build(
+                number=mapping.IntegerField(default=1),
+                street=mapping.TextField(default='street')
+            )),
+            pets=mapping.ListField(mapping.TextField(), default=[])
+        )
+
+        my_new_instance = my_new_mapping.wrap(data)
+
+        assert data['pets'] == []
+        assert data['address']['number'] == 1
+        assert data['address']['street'] == 'street'
+        assert my_new_instance.address.number == 1
+        assert my_new_instance.address.street == 'street'
+
+    def test_defaults_for_new_schema_should_be_set_more_complex(self):
+        my_mapping = mapping.Mapping.build(
+            name=mapping.TextField(),
+        )
+        my_instance = my_mapping.wrap({})
+        my_instance.name = 'Harry'
+
+        data = copy.copy(my_instance._data)
+
+        my_new_mapping = mapping.Mapping.build(
+            name=mapping.TextField(),
+            address=mapping.DictField(mapping.Mapping.build(
+                number=mapping.IntegerField(default=1),
+                street=mapping.TextField(default='street')
+            )),
+            pets=mapping.ListField(mapping.TextField(), default=[])
+        )
+
+        my_new_instance = my_new_mapping.wrap(data)
+
+        assert data['pets'] == []
+        assert data['address']['number'] == 1
+        assert data['address']['street'] == 'street'
+        assert my_new_instance.address.number == 1
+        assert my_new_instance.address.street == 'street'
+
+        data = copy.copy(my_new_instance._data)
+
+        my_newer_mapping = mapping.Mapping.build(
+            name=mapping.TextField(),
+            address=mapping.DictField(mapping.Mapping.build(
+                number=mapping.IntegerField(default=1),
+                street=mapping.TextField(default='street'),
+                cars=mapping.ListField(
+                    mapping.DictField(
+                        mapping.Mapping.build(
+                            registration=mapping.TextField()
+                        )
+                    )
+                )
+            )),
+            pets=mapping.ListField(mapping.TextField(), default=[])
+        )
+
+        my_newer_instance = my_newer_mapping.wrap(data)
+
+        assert data['address']['cars'] == []
+        my_newer_instance.address.cars.append({"registration": "AJ54 VSE"})
+        assert data['address']['cars'] == [{"registration": "AJ54 VSE"}]
+        assert my_newer_instance.address.cars[0].registration == "AJ54 VSE"
+
+        data = copy.copy(my_newer_instance._data)
+
+        my_newest_mapping = mapping.Mapping.build(
+            name=mapping.TextField(),
+            address=mapping.DictField(mapping.Mapping.build(
+                number=mapping.IntegerField(default=1),
+                street=mapping.TextField(default='street'),
+                cars=mapping.ListField(
+                    mapping.DictField(
+                        mapping.Mapping.build(
+                            registration=mapping.TextField(),
+                            wheels=mapping.IntegerField(default=4)
+                        )
+                    )
+                )
+            )),
+            pets=mapping.ListField(mapping.TextField(), default=[])
+        )
+
+        my_newest_instance = my_newest_mapping.wrap(data)
+
+        assert data['address']['cars'] == [{"registration": "AJ54 VSE", "wheels": 4}]
+        assert my_newest_instance.address.cars[0].wheels == 4
+
+    def test_can_set_new_schema_data(self):
+        my_mapping = mapping.Mapping.build(
+            name=mapping.TextField(),
+        )
+        my_instance = my_mapping.wrap({})
+        my_instance.name = 'Sherlock'
+
+        data = copy.copy(my_instance._data)
+
+        my_new_mapping = mapping.Mapping.build(
+            name=mapping.TextField(),
+            address=mapping.DictField(mapping.Mapping.build(
+                number=mapping.TextField(),
+                street=mapping.TextField()
+            )),
+            pets=mapping.ListField(mapping.TextField(), default=[]),
+        )
+
+        my_new_instance = my_new_mapping.wrap(data)
+
+        my_new_instance.pets.append('dog')
+        my_new_instance.pets.append('cat')
+        my_new_instance.address.number = '221B'
+        my_new_instance.address.street = 'Baker Street'
+
+        assert data['address']['number'] == '221B'
+        assert data['address']['street'] == 'Baker Street'
+        assert data['pets'] == ['dog', 'cat']
+        assert my_new_instance.address.number == '221B'
+        assert my_new_instance.address.street == 'Baker Street'
+        assert my_new_instance.pets[0] == 'dog'
+        assert my_new_instance.pets[1] == 'cat'
+
+
 def suite():
     suite = unittest.TestSuite()
     suite.addTest(testutil.doctest_suite(mapping))