Fixed #13328 -- Ensured that querysets on models with callable defaults can be pickled. No, really this time. Thanks to Alex for his help brainstorming the solution.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@13013 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/backends/creation.py

@@ -73,9 +73,6 @@ class BaseDatabaseCreation(object):
                 else:
                     field_output.extend(ref_output)
             table_output.append(' '.join(field_output))
-        if opts.order_with_respect_to:
-            table_output.append(style.SQL_FIELD(qn('_order')) + ' ' + \
-                style.SQL_COLTYPE(models.IntegerField().db_type(connection=self.connection)))
         for field_constraints in opts.unique_together:
             table_output.append(style.SQL_KEYWORD('UNIQUE') + ' (%s)' % \
                 ", ".join([style.SQL_FIELD(qn(opts.get_field(f).column)) for f in field_constraints]))

django/db/models/base.py

@@ -504,6 +504,13 @@ class Model(object):
                 else:
                     record_exists = False
             if not pk_set or not record_exists:
+                if meta.order_with_respect_to:
+                    # If this is a model with an order_with_respect_to
+                    # autopopulate the _order field
+                    field = meta.order_with_respect_to
+                    order_value = manager.using(using).filter(**{field.name: getattr(self, field.attname)}).count()
+                    setattr(self, '_order', order_value)
+
                 if not pk_set:
                     if force_update:
                         raise ValueError("Cannot force an update in save() with no primary key.")
@@ -513,9 +520,6 @@ class Model(object):
                     values = [(f, f.get_db_prep_save(raw and getattr(self, f.attname) or f.pre_save(self, True), connection=connection))
                         for f in meta.local_fields]
 
-                if meta.order_with_respect_to:
-                    field = meta.order_with_respect_to
-                    values.append((meta.get_field_by_name('_order')[0], manager.using(using).filter(**{field.name: getattr(self, field.attname)}).count()))
                 record_exists = False
 
                 update_pk = bool(meta.has_auto_field and not pk_set)

django/db/models/fields/__init__.py

@@ -132,22 +132,6 @@ class Field(object):
         memodict[id(self)] = obj
         return obj
 
-    def __getstate__(self):
-        "Don't try to pickle a callable default value"
-        obj_dict = self.__dict__.copy()
-        del obj_dict['default']
-        return obj_dict
-
-    def __setstate__(self, data):
-        "When unpickling, restore the callable default"
-        self.__dict__.update(data)
-
-        # Restore the default
-        try:
-            self.default = self.model._meta.get_field(self.name).default
-        except FieldDoesNotExist:
-            self.default = NOT_PROVIDED
-
     def to_python(self, value):
         """
         Converts the input value into the expected Python data type, raising

django/db/models/fields/proxy.py

@@ -11,9 +11,7 @@ class OrderWrt(fields.IntegerField):
     Meta.order_with_respect_to is specified.
     """
 
-    def __init__(self, model, *args, **kwargs):
+    def __init__(self, *args, **kwargs):
+        kwargs['name'] = '_order'
+        kwargs['editable'] = False
         super(OrderWrt, self).__init__(*args, **kwargs)
-        self.model = model
-        self.attname = '_order'
-        self.column = '_order'
-        self.name = '_order'

django/db/models/options.py

@@ -108,7 +108,7 @@ class Options(object):
         if self.order_with_respect_to:
             self.order_with_respect_to = self.get_field(self.order_with_respect_to)
             self.ordering = ('_order',)
-            self._order = OrderWrt(model)
+            model.add_to_class('_order', OrderWrt())
         else:
             self.order_with_respect_to = None
 
@@ -330,8 +330,6 @@ class Options(object):
             cache[f.name] = (f, model, True, True)
         for f, model in self.get_fields_with_model():
             cache[f.name] = (f, model, True, False)
-        if self.order_with_respect_to:
-            cache['_order'] = self._order, None, True, False
         if app_cache_ready():
             self._name_map = cache
         return cache

django/db/models/sql/where.py

@@ -270,6 +270,30 @@ class Constraint(object):
     def __init__(self, alias, col, field):
         self.alias, self.col, self.field = alias, col, field
 
+    def __getstate__(self):
+        """Save the state of the Constraint for pickling.
+
+        Fields aren't necessarily pickleable, because they can have
+        callable default values. So, instead of pickling the field
+        store a reference so we can restore it manually
+        """
+        obj_dict = self.__dict__.copy()
+        if self.field:
+            obj_dict['model'] = self.field.model
+            obj_dict['field_name'] = self.field.name
+        del obj_dict['field']
+        return obj_dict
+
+    def __setstate__(self, data):
+        """Restore the constraint """
+        model = data.pop('model', None)
+        field_name = data.pop('field_name', None)
+        self.__dict__.update(data)
+        if model is not None:
+            self.field = model._meta.get_field(field_name)
+        else:
+            self.field = None
+
     def prepare(self, lookup_type, value):
         if self.field:
             return self.field.get_prep_lookup(lookup_type, value)

tests/regressiontests/queryset_pickle/models.py

@@ -2,11 +2,22 @@ import datetime
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
 
+def standalone_number(self):
+    return 1
+
 class Numbers(object):
+    @staticmethod
+    def get_static_number(self):
+        return 2
 
     @classmethod
-    def get_number(self):
-        return 2
+    def get_class_number(self):
+        return 3
+
+    def get_member_number(self):
+        return 4
+
+nn = Numbers()
 
 class Group(models.Model):
     name = models.CharField(_('name'), max_length=100)
@@ -17,4 +28,7 @@ class Event(models.Model):
 class Happening(models.Model):
     when = models.DateTimeField(blank=True, default=datetime.datetime.now)
     name = models.CharField(blank=True, max_length=100, default=lambda:"test")
-    number = models.IntegerField(blank=True, default=Numbers.get_number)
+    number1 = models.IntegerField(blank=True, default=standalone_number)
+    number2 = models.IntegerField(blank=True, default=Numbers.get_static_number)
+    number3 = models.IntegerField(blank=True, default=Numbers.get_class_number)
+    number4 = models.IntegerField(blank=True, default=nn.get_member_number)

tests/regressiontests/queryset_pickle/tests.py

@@ -23,5 +23,14 @@ class PickleabilityTestCase(TestCase):
     def test_lambda_as_default(self):
         self.assert_pickles(Happening.objects.filter(name="test"))
 
-    def test_callable_as_default(self):
-        self.assert_pickles(Happening.objects.filter(number=1))
+    def test_standalone_method_as_default(self):
+        self.assert_pickles(Happening.objects.filter(number1=1))
+
+    def test_staticmethod_as_default(self):
+        self.assert_pickles(Happening.objects.filter(number2=1))
+
+    def test_classmethod_as_default(self):
+        self.assert_pickles(Happening.objects.filter(number2=1))
+
+    def test_membermethod_as_default(self):
+        self.assert_pickles(Happening.objects.filter(number2=1))