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Fixed #19069 -- Improved the error message when trying to query a swapped model. 

Thanks to Preston Holmes for the suggestion.
This commit is contained in:
Russell Keith-Magee 2012-10-06 14:21:57 +08:00
parent 12f39be508
commit cc337a74f1
3 changed files with 201 additions and 17 deletions
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37
django/db/models/manager.py
View File

@ -13,7 +13,11 @@ def ensure_default_manager(sender, **kwargs):
_default_manager if it's not a subclass of Manager).
"""
cls = sender
if cls._meta.abstract or cls._meta.swapped:
if cls._meta.abstract:
setattr(cls, 'objects', AbstractManagerDescriptor(cls))
return
elif cls._meta.swapped:
setattr(cls, 'objects', SwappedManagerDescriptor(cls))
return
if not getattr(cls, '_default_manager', None):
# Create the default manager, if needed.
@ -58,7 +62,12 @@ class Manager(object):
# TODO: Use weakref because of possible memory leak / circular reference.
self.model = model
# Only contribute the manager if the model is concrete
if not model._meta.abstract and not model._meta.swapped:
if model._meta.abstract:
setattr(model, name, AbstractManagerDescriptor(model))
elif model._meta.swapped:
setattr(model, name, SwappedManagerDescriptor(model))
else:
# if not model._meta.abstract and not model._meta.swapped:
setattr(model, name, ManagerDescriptor(self))
if not getattr(model, '_default_manager', None) or self.creation_counter < model._default_manager.creation_counter:
model._default_manager = self
@ -224,6 +233,30 @@ class ManagerDescriptor(object):
return self.manager
class AbstractManagerDescriptor(object):
# This class provides a better error message when you try to access a
# manager on an abstract model.
def __init__(self, model):
self.model = model
def __get__(self, instance, type=None):
raise AttributeError("Manager isn't available; %s is abstract" % (
self.model._meta.object_name,
))
class SwappedManagerDescriptor(object):
# This class provides a better error message when you try to access a
# manager on a swapped model.
def __init__(self, model):
self.model = model
def __get__(self, instance, type=None):
raise AttributeError("Manager isn't available; %s has been swapped for '%s'" % (
self.model._meta.object_name, self.model._meta.swapped
))
class EmptyManager(Manager):
def get_query_set(self):
return self.get_empty_query_set()

13
tests/regressiontests/managers_regress/models.py
View File

@ -10,14 +10,17 @@ class OnlyFred(models.Manager):
def get_query_set(self):
return super(OnlyFred, self).get_query_set().filter(name='fred')
class OnlyBarney(models.Manager):
def get_query_set(self):
return super(OnlyBarney, self).get_query_set().filter(name='barney')
class Value42(models.Manager):
def get_query_set(self):
return super(Value42, self).get_query_set().filter(value=42)
class AbstractBase1(models.Model):
name = models.CharField(max_length=50)
@ -29,6 +32,7 @@ class AbstractBase1(models.Model):
manager2 = OnlyBarney()
objects = models.Manager()
class AbstractBase2(models.Model):
value = models.IntegerField()
@ -38,6 +42,7 @@ class AbstractBase2(models.Model):
# Custom manager
restricted = Value42()
# No custom manager on this class to make sure the default case doesn't break.
class AbstractBase3(models.Model):
comment = models.CharField(max_length=50)
@ -45,6 +50,7 @@ class AbstractBase3(models.Model):
class Meta:
abstract = True
@python_2_unicode_compatible
class Parent(models.Model):
name = models.CharField(max_length=50)
@ -54,6 +60,7 @@ class Parent(models.Model):
def __str__(self):
return self.name
# Managers from base classes are inherited and, if no manager is specified
# *and* the parent has a manager specified, the first one (in the MRO) will
# become the default.
@ -64,6 +71,7 @@ class Child1(AbstractBase1):
def __str__(self):
return self.data
@python_2_unicode_compatible
class Child2(AbstractBase1, AbstractBase2):
data = models.CharField(max_length=25)
@ -71,6 +79,7 @@ class Child2(AbstractBase1, AbstractBase2):
def __str__(self):
return self.data
@python_2_unicode_compatible
class Child3(AbstractBase1, AbstractBase3):
data = models.CharField(max_length=25)
@ -78,6 +87,7 @@ class Child3(AbstractBase1, AbstractBase3):
def __str__(self):
return self.data
@python_2_unicode_compatible
class Child4(AbstractBase1):
data = models.CharField(max_length=25)
@ -89,6 +99,7 @@ class Child4(AbstractBase1):
def __str__(self):
return self.data
@python_2_unicode_compatible
class Child5(AbstractBase3):
name = models.CharField(max_length=25)
@ -99,10 +110,12 @@ class Child5(AbstractBase3):
def __str__(self):
return self.name
# Will inherit managers from AbstractBase1, but not Child4.
class Child6(Child4):
value = models.IntegerField()
# Will not inherit default manager from parent.
class Child7(Parent):
pass

168
tests/regressiontests/managers_regress/tests.py
View File

@ -1,26 +1,42 @@
from __future__ import absolute_import
import copy
from django.conf import settings
from django.db import models
from django.db.models.loading import cache
from django.test import TestCase
from django.test.utils import override_settings
from .models import Child1, Child2, Child3, Child4, Child5, Child6, Child7
from .models import (
Child1,
Child2,
Child3,
Child4,
Child5,
Child6,
Child7,
AbstractBase1,
AbstractBase2,
AbstractBase3,
)
class ManagersRegressionTests(TestCase):
def test_managers(self):
a1 = Child1.objects.create(name='fred', data='a1')
a2 = Child1.objects.create(name='barney', data='a2')
b1 = Child2.objects.create(name='fred', data='b1', value=1)
b2 = Child2.objects.create(name='barney', data='b2', value=42)
c1 = Child3.objects.create(name='fred', data='c1', comment='yes')
c2 = Child3.objects.create(name='barney', data='c2', comment='no')
d1 = Child4.objects.create(name='fred', data='d1')
d2 = Child4.objects.create(name='barney', data='d2')
e1 = Child5.objects.create(name='fred', comment='yes')
e2 = Child5.objects.create(name='barney', comment='no')
f1 = Child6.objects.create(name='fred', data='f1', value=42)
f2 = Child6.objects.create(name='barney', data='f2', value=42)
g1 = Child7.objects.create(name='fred')
g2 = Child7.objects.create(name='barney')
Child1.objects.create(name='fred', data='a1')
Child1.objects.create(name='barney', data='a2')
Child2.objects.create(name='fred', data='b1', value=1)
Child2.objects.create(name='barney', data='b2', value=42)
Child3.objects.create(name='fred', data='c1', comment='yes')
Child3.objects.create(name='barney', data='c2', comment='no')
Child4.objects.create(name='fred', data='d1')
Child4.objects.create(name='barney', data='d2')
Child5.objects.create(name='fred', comment='yes')
Child5.objects.create(name='barney', comment='no')
Child6.objects.create(name='fred', data='f1', value=42)
Child6.objects.create(name='barney', data='f2', value=42)
Child7.objects.create(name='fred')
Child7.objects.create(name='barney')
self.assertQuerysetEqual(Child1.manager1.all(), ["<Child1: a1>"])
self.assertQuerysetEqual(Child1.manager2.all(), ["<Child1: a2>"])
@ -54,3 +70,125 @@ class ManagersRegressionTests(TestCase):
"<Child7: fred>"
]
)
def test_abstract_manager(self):
# Accessing the manager on an abstract model should
# raise an attribute error with an appropriate message.
try:
AbstractBase3.objects.all()
self.fail('Should raise an AttributeError')
except AttributeError as e:
# This error message isn't ideal, but if the model is abstract and
# a lot of the class instantiation logic isn't invoked; if the
# manager is implied, then we don't get a hook to install the
# error-raising manager.
self.assertEqual(str(e), "type object 'AbstractBase3' has no attribute 'objects'")
def test_custom_abstract_manager(self):
# Accessing the manager on an abstract model with an custom
# manager should raise an attribute error with an appropriate
# message.
try:
AbstractBase2.restricted.all()
self.fail('Should raise an AttributeError')
except AttributeError as e:
self.assertEqual(str(e), "Manager isn't available; AbstractBase2 is abstract")
def test_explicit_abstract_manager(self):
# Accessing the manager on an abstract model with an explicit
# manager should raise an attribute error with an appropriate
# message.
try:
AbstractBase1.objects.all()
self.fail('Should raise an AttributeError')
except AttributeError as e:
self.assertEqual(str(e), "Manager isn't available; AbstractBase1 is abstract")
def test_swappable_manager(self):
try:
# This test adds dummy models to the app cache. These
# need to be removed in order to prevent bad interactions
# with the flush operation in other tests.
old_app_models = copy.deepcopy(cache.app_models)
old_app_store = copy.deepcopy(cache.app_store)
settings.TEST_SWAPPABLE_MODEL = 'managers_regress.Parent'
class SwappableModel(models.Model):
class Meta:
swappable = 'TEST_SWAPPABLE_MODEL'
# Accessing the manager on a swappable model should
# raise an attribute error with a helpful message
try:
SwappableModel.objects.all()
self.fail('Should raise an AttributeError')
except AttributeError as e:
self.assertEqual(str(e), "Manager isn't available; SwappableModel has been swapped for 'managers_regress.Parent'")
finally:
del settings.TEST_SWAPPABLE_MODEL
cache.app_models = old_app_models
cache.app_store = old_app_store
def test_custom_swappable_manager(self):
try:
# This test adds dummy models to the app cache. These
# need to be removed in order to prevent bad interactions
# with the flush operation in other tests.
old_app_models = copy.deepcopy(cache.app_models)
old_app_store = copy.deepcopy(cache.app_store)
settings.TEST_SWAPPABLE_MODEL = 'managers_regress.Parent'
class SwappableModel(models.Model):
stuff = models.Manager()
class Meta:
swappable = 'TEST_SWAPPABLE_MODEL'
# Accessing the manager on a swappable model with an
# explicit manager should raise an attribute error with a
# helpful message
try:
SwappableModel.stuff.all()
self.fail('Should raise an AttributeError')
except AttributeError as e:
self.assertEqual(str(e), "Manager isn't available; SwappableModel has been swapped for 'managers_regress.Parent'")
finally:
del settings.TEST_SWAPPABLE_MODEL
cache.app_models = old_app_models
cache.app_store = old_app_store
def test_explicit_swappable_manager(self):
try:
# This test adds dummy models to the app cache. These
# need to be removed in order to prevent bad interactions
# with the flush operation in other tests.
old_app_models = copy.deepcopy(cache.app_models)
old_app_store = copy.deepcopy(cache.app_store)
settings.TEST_SWAPPABLE_MODEL = 'managers_regress.Parent'
class SwappableModel(models.Model):
objects = models.Manager()
class Meta:
swappable = 'TEST_SWAPPABLE_MODEL'
# Accessing the manager on a swappable model with an
# explicit manager should raise an attribute error with a
# helpful message
try:
SwappableModel.objects.all()
self.fail('Should raise an AttributeError')
except AttributeError as e:
self.assertEqual(str(e), "Manager isn't available; SwappableModel has been swapped for 'managers_regress.Parent'")
finally:
del settings.TEST_SWAPPABLE_MODEL
cache.app_models = old_app_models
cache.app_store = old_app_store