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Fixed #21840 -- Moved dunder methods from SimpleLazyObject to LazyObj…

…ect.

This commit also added tests for LazyObject and refactored
the testsuite of SimpleLazyObject so that it can share
test cases with LazyObject.
commit 61917aa08b4ab2bc35f3ffe87b7693bd8b58e205 1 parent 4b4c704
@bmispelon bmispelon authored
View
116 django/utils/functional.py
@@ -265,9 +265,62 @@ def _setup(self):
"""
raise NotImplementedError('subclasses of LazyObject must provide a _setup() method')
+ # Because we have messed with __class__ below, we confuse pickle as to what
+ # class we are pickling. It also appears to stop __reduce__ from being
+ # called. So, we define __getstate__ in a way that cooperates with the way
+ # that pickle interprets this class. This fails when the wrapped class is
+ # a builtin, but it is better than nothing.
+ def __getstate__(self):
+ if self._wrapped is empty:
+ self._setup()
+ return self._wrapped.__dict__
+
+ # Python 3.3 will call __reduce__ when pickling; this method is needed
+ # to serialize and deserialize correctly.
+ @classmethod
+ def __newobj__(cls, *args):
+ return cls.__new__(cls, *args)
+
+ def __reduce_ex__(self, proto):
+ if proto >= 2:
+ # On Py3, since the default protocol is 3, pickle uses the
+ # ``__newobj__`` method (& more efficient opcodes) for writing.
+ return (self.__newobj__, (self.__class__,), self.__getstate__())
+ else:
+ # On Py2, the default protocol is 0 (for back-compat) & the above
+ # code fails miserably (see regression test). Instead, we return
+ # exactly what's returned if there's no ``__reduce__`` method at
+ # all.
+ return (copyreg._reconstructor, (self.__class__, object, None), self.__getstate__())
+
+ def __deepcopy__(self, memo):
+ if self._wrapped is empty:
+ # We have to use type(self), not self.__class__, because the
+ # latter is proxied.
+ result = type(self)()
+ memo[id(self)] = result
+ return result
+ return copy.deepcopy(self._wrapped, memo)
+
+ if six.PY3:
+ __bytes__ = new_method_proxy(bytes)
+ __str__ = new_method_proxy(str)
+ __bool__ = new_method_proxy(bool)
+ else:
+ __str__ = new_method_proxy(str)
+ __unicode__ = new_method_proxy(unicode)
+ __nonzero__ = new_method_proxy(bool)
+
# Introspection support
__dir__ = new_method_proxy(dir)
+ # Need to pretend to be the wrapped class, for the sake of objects that
+ # care about this (especially in equality tests)
+ __class__ = property(new_method_proxy(operator.attrgetter("__class__")))
+ __eq__ = new_method_proxy(operator.eq)
+ __ne__ = new_method_proxy(operator.ne)
+ __hash__ = new_method_proxy(hash)
+
# Dictionary methods support
__getitem__ = new_method_proxy(operator.getitem)
__setitem__ = new_method_proxy(operator.setitem)
@@ -303,51 +356,6 @@ def __init__(self, func):
def _setup(self):
self._wrapped = self._setupfunc()
- if six.PY3:
- __bytes__ = new_method_proxy(bytes)
- __str__ = new_method_proxy(str)
- else:
- __str__ = new_method_proxy(str)
- __unicode__ = new_method_proxy(unicode)
-
- def __deepcopy__(self, memo):
- if self._wrapped is empty:
- # We have to use SimpleLazyObject, not self.__class__, because the
- # latter is proxied.
- result = SimpleLazyObject(self._setupfunc)
- memo[id(self)] = result
- return result
- else:
- return copy.deepcopy(self._wrapped, memo)
-
- # Because we have messed with __class__ below, we confuse pickle as to what
- # class we are pickling. It also appears to stop __reduce__ from being
- # called. So, we define __getstate__ in a way that cooperates with the way
- # that pickle interprets this class. This fails when the wrapped class is
- # a builtin, but it is better than nothing.
- def __getstate__(self):
- if self._wrapped is empty:
- self._setup()
- return self._wrapped.__dict__
-
- # Python 3.3 will call __reduce__ when pickling; this method is needed
- # to serialize and deserialize correctly.
- @classmethod
- def __newobj__(cls, *args):
- return cls.__new__(cls, *args)
-
- def __reduce_ex__(self, proto):
- if proto >= 2:
- # On Py3, since the default protocol is 3, pickle uses the
- # ``__newobj__`` method (& more efficient opcodes) for writing.
- return (self.__newobj__, (self.__class__,), self.__getstate__())
- else:
- # On Py2, the default protocol is 0 (for back-compat) & the above
- # code fails miserably (see regression test). Instead, we return
- # exactly what's returned if there's no ``__reduce__`` method at
- # all.
- return (copyreg._reconstructor, (self.__class__, object, None), self.__getstate__())
-
# Return a meaningful representation of the lazy object for debugging
# without evaluating the wrapped object.
def __repr__(self):
@@ -355,16 +363,16 @@ def __repr__(self):
repr_attr = self._setupfunc
else:
repr_attr = self._wrapped
- return '<SimpleLazyObject: %r>' % repr_attr
+ return '<%s: %r>' % (type(self).__name__, repr_attr)
- # Need to pretend to be the wrapped class, for the sake of objects that
- # care about this (especially in equality tests)
- __class__ = property(new_method_proxy(operator.attrgetter("__class__")))
- __eq__ = new_method_proxy(operator.eq)
- __ne__ = new_method_proxy(operator.ne)
- __hash__ = new_method_proxy(hash)
- __bool__ = new_method_proxy(bool) # Python 3
- __nonzero__ = __bool__ # Python 2
+ def __deepcopy__(self, memo):
+ if self._wrapped is empty:
+ # We have to use type(self), not self.__class__, because the
+ # latter is proxied.
+ result = SimpleLazyObject(self._setupfunc)
+ memo[id(self)] = result
+ return result
+ return copy.deepcopy(self._wrapped, memo)
class lazy_property(property):
View
275 tests/utils_tests/test_lazyobject.py
@@ -0,0 +1,275 @@
+from __future__ import unicode_literals
+
+import copy
+import pickle
+import sys
+from unittest import TestCase
+
+from django.utils import six
+from django.utils.functional import LazyObject, SimpleLazyObject, empty
+
+
+class Foo(object):
+ """
+ A simple class with just one attribute.
+ """
+ foo = 'bar'
+
+ def __eq__(self, other):
+ return self.foo == other.foo
+
+
+class LazyObjectTestCase(TestCase):
+ def lazy_wrap(self, wrapped_object):
+ """
+ Wrap the given object into a LazyObject
+ """
+ class AdHocLazyObject(LazyObject):
+ def _setup(self):
+ self._wrapped = wrapped_object
+
+ return AdHocLazyObject()
+
+ def test_getattr(self):
+ obj = self.lazy_wrap(Foo())
+ self.assertEqual(obj.foo, 'bar')
+
+ def test_setattr(self):
+ obj = self.lazy_wrap(Foo())
+ obj.foo = 'BAR'
+ obj.bar = 'baz'
+ self.assertEqual(obj.foo, 'BAR')
+ self.assertEqual(obj.bar, 'baz')
+
+ def test_setattr2(self):
+ # Same as test_setattr but in reversed order
+ obj = self.lazy_wrap(Foo())
+ obj.bar = 'baz'
+ obj.foo = 'BAR'
+ self.assertEqual(obj.foo, 'BAR')
+ self.assertEqual(obj.bar, 'baz')
+
+ def test_delattr(self):
+ obj = self.lazy_wrap(Foo())
+ obj.bar = 'baz'
+ self.assertEqual(obj.bar, 'baz')
+ del obj.bar
+ with self.assertRaises(AttributeError):
+ obj.bar
+
+ def test_cmp(self):
+ obj1 = self.lazy_wrap('foo')
+ obj2 = self.lazy_wrap('bar')
+ obj3 = self.lazy_wrap('foo')
+ self.assertEqual(obj1, 'foo')
+ self.assertEqual(obj1, obj3)
+ self.assertNotEqual(obj1, obj2)
+ self.assertNotEqual(obj1, 'bar')
+
+ def test_bytes(self):
+ obj = self.lazy_wrap(b'foo')
+ self.assertEqual(bytes(obj), b'foo')
+
+ def test_text(self):
+ obj = self.lazy_wrap('foo')
+ self.assertEqual(six.text_type(obj), 'foo')
+
+ def test_bool(self):
+ # Refs #21840
+ for f in [False, 0, (), {}, [], None, set()]:
+ self.assertFalse(self.lazy_wrap(f))
+ for t in [True, 1, (1,), {1: 2}, [1], object(), {1}]:
+ self.assertTrue(t)
+
+ def test_dir(self):
+ obj = self.lazy_wrap('foo')
+ self.assertEqual(dir(obj), dir('foo'))
+
+ def test_len(self):
+ for seq in ['asd', [1, 2, 3], {'a': 1, 'b': 2, 'c': 3}]:
+ obj = self.lazy_wrap(seq)
+ self.assertEqual(len(obj), 3)
+
+ def test_class(self):
+ self.assertIsInstance(self.lazy_wrap(42), int)
+
+ class Bar(Foo):
+ pass
+
+ self.assertIsInstance(self.lazy_wrap(Bar()), Foo)
+
+ def test_hash(self):
+ obj = self.lazy_wrap('foo')
+ d = {}
+ d[obj] = 'bar'
+ self.assertIn('foo', d)
+ self.assertEqual(d['foo'], 'bar')
+
+ def test_contains(self):
+ test_data = [
+ ('c', 'abcde'),
+ (2, [1, 2, 3]),
+ ('a', {'a': 1, 'b': 2, 'c': 3}),
+ (2, {1, 2, 3}),
+ ]
+ for needle, haystack in test_data:
+ self.assertIn(needle, self.lazy_wrap(haystack))
+
+ # __contains__ doesn't work when the haystack is a string and the needle a LazyObject
+ for needle_haystack in test_data[1:]:
+ self.assertIn(self.lazy_wrap(needle), haystack)
+ self.assertIn(self.lazy_wrap(needle), self.lazy_wrap(haystack))
+
+ def test_getitem(self):
+ obj_list = self.lazy_wrap([1, 2, 3])
+ obj_dict = self.lazy_wrap({'a': 1, 'b': 2, 'c': 3})
+
+ self.assertEqual(obj_list[0], 1)
+ self.assertEqual(obj_list[-1], 3)
+ self.assertEqual(obj_list[1:2], [2])
+
+ self.assertEqual(obj_dict['b'], 2)
+
+ with self.assertRaises(IndexError):
+ obj_list[3]
+
+ with self.assertRaises(KeyError):
+ obj_dict['f']
+
+ def test_setitem(self):
+ obj_list = self.lazy_wrap([1, 2, 3])
+ obj_dict = self.lazy_wrap({'a': 1, 'b': 2, 'c': 3})
+
+ obj_list[0] = 100
+ self.assertEqual(obj_list, [100, 2, 3])
+ obj_list[1:2] = [200, 300, 400]
+ self.assertEqual(obj_list, [100, 200, 300, 400, 3])
+
+ obj_dict['a'] = 100
+ obj_dict['d'] = 400
+ self.assertEqual(obj_dict, {'a': 100, 'b': 2, 'c': 3, 'd': 400})
+
+ def test_delitem(self):
+ obj_list = self.lazy_wrap([1, 2, 3])
+ obj_dict = self.lazy_wrap({'a': 1, 'b': 2, 'c': 3})
+
+ del obj_list[-1]
+ del obj_dict['c']
+ self.assertEqual(obj_list, [1, 2])
+ self.assertEqual(obj_dict, {'a': 1, 'b': 2})
+
+ with self.assertRaises(IndexError):
+ del obj_list[3]
+
+ with self.assertRaises(KeyError):
+ del obj_dict['f']
+
+ def test_iter(self):
+ # LazyObjects don't actually implements __iter__ but you can still
+ # iterate over them because they implement __getitem__
+ obj = self.lazy_wrap([1, 2, 3])
+ for expected, actual in zip([1, 2, 3], obj):
+ self.assertEqual(expected, actual)
+
+ def test_pickle(self):
+ # See ticket #16563
+ obj = self.lazy_wrap(Foo())
+ pickled = pickle.dumps(obj)
+ unpickled = pickle.loads(pickled)
+ self.assertIsInstance(unpickled, Foo)
+ self.assertEqual(unpickled, obj)
+ self.assertEqual(unpickled.foo, obj.foo)
+
+ def test_deepcopy(self):
+ # Check that we *can* do deep copy, and that it returns the right
+ # objects.
+
+ l = [1, 2, 3]
+
+ obj = self.lazy_wrap(l)
+ len(l) # forces evaluation
+ obj2 = copy.deepcopy(obj)
+
+ self.assertIsInstance(obj2, list)
+ self.assertEqual(obj2, [1, 2, 3])
+
+ def test_deepcopy_no_evaluation(self):
+ # copying doesn't force evaluation
+
+ l = [1, 2, 3]
+
+ obj = self.lazy_wrap(l)
+ obj2 = copy.deepcopy(obj)
+
+ # Copying shouldn't force evaluation
+ self.assertIs(obj._wrapped, empty)
+ self.assertIs(obj2._wrapped, empty)
+
+
+class SimpleLazyObjectTestCase(LazyObjectTestCase):
+ # By inheriting from LazyObjectTestCase and redefining the lazy_wrap()
+ # method which all testcases use, we get to make sure all behaviors
+ # tested in the parent testcase also apply to SimpleLazyObject.
+ def lazy_wrap(self, wrapped_object):
+ return SimpleLazyObject(lambda: wrapped_object)
+
+ def test_repr(self):
+ # First, for an unevaluated SimpleLazyObject
+ obj = self.lazy_wrap(42)
+ # __repr__ contains __repr__ of setup function and does not evaluate
+ # the SimpleLazyObject
+ self.assertRegexpMatches(repr(obj), '^<SimpleLazyObject:')
+ self.assertIs(obj._wrapped, empty) # make sure evaluation hasn't been triggered
+
+ self.assertEqual(obj, 42) # evaluate the lazy object
+ self.assertIsInstance(obj._wrapped, int)
+ self.assertEqual(repr(obj), '<SimpleLazyObject: 42>')
+
+ def test_trace(self):
+ # See ticket #19456
+ old_trace_func = sys.gettrace()
+ try:
+ def trace_func(frame, event, arg):
+ frame.f_locals['self'].__class__
+ if old_trace_func is not None:
+ old_trace_func(frame, event, arg)
+ sys.settrace(trace_func)
+ self.lazy_wrap(None)
+ finally:
+ sys.settrace(old_trace_func)
+
+ def test_none(self):
+ i = [0]
+
+ def f():
+ i[0] += 1
+ return None
+
+ x = SimpleLazyObject(f)
+ self.assertEqual(str(x), "None")
+ self.assertEqual(i, [1])
+ self.assertEqual(str(x), "None")
+ self.assertEqual(i, [1])
+
+ def test_dict(self):
+ # See ticket #18447
+ lazydict = SimpleLazyObject(lambda: {'one': 1})
+ self.assertEqual(lazydict['one'], 1)
+ lazydict['one'] = -1
+ self.assertEqual(lazydict['one'], -1)
+ self.assertTrue('one' in lazydict)
+ self.assertFalse('two' in lazydict)
+ self.assertEqual(len(lazydict), 1)
+ del lazydict['one']
+ with self.assertRaises(KeyError):
+ lazydict['one']
+
+ def test_list_set(self):
+ lazy_list = SimpleLazyObject(lambda: [1, 2, 3, 4, 5])
+ lazy_set = SimpleLazyObject(lambda: set([1, 2, 3, 4]))
+ self.assertTrue(1 in lazy_list)
+ self.assertTrue(1 in lazy_set)
+ self.assertFalse(6 in lazy_list)
+ self.assertFalse(6 in lazy_set)
+ self.assertEqual(len(lazy_list), 5)
+ self.assertEqual(len(lazy_set), 4)
View
176 tests/utils_tests/test_simplelazyobject.py
@@ -1,184 +1,14 @@
from __future__ import unicode_literals
-import copy
import pickle
-import sys
-from unittest import TestCase
from django.contrib.auth.models import User
-from django.test import TestCase as DjangoTestCase
+from django.test import TestCase
from django.utils import six
-from django.utils.functional import SimpleLazyObject, empty
+from django.utils.functional import SimpleLazyObject
-class _ComplexObject(object):
- def __init__(self, name):
- self.name = name
-
- def __eq__(self, other):
- return self.name == other.name
-
- def __hash__(self):
- return hash(self.name)
-
- if six.PY3:
- def __bytes__(self):
- return ("I am _ComplexObject(%r)" % self.name).encode("utf-8")
-
- def __str__(self):
- return self.name
-
- else:
- def __str__(self):
- return b"I am _ComplexObject(%r)" % str(self.name)
-
- def __unicode__(self):
- return self.name
-
- def __repr__(self):
- return "_ComplexObject(%r)" % self.name
-
-
-complex_object = lambda: _ComplexObject("joe")
-
-
-class TestUtilsSimpleLazyObject(TestCase):
- """
- Tests for SimpleLazyObject
- """
- # Note that concrete use cases for SimpleLazyObject are also found in the
- # auth context processor tests (unless the implementation of that function
- # is changed).
-
- def test_equality(self):
- self.assertEqual(complex_object(), SimpleLazyObject(complex_object))
- self.assertEqual(SimpleLazyObject(complex_object), complex_object())
-
- def test_hash(self):
- # hash() equality would not be true for many objects, but it should be
- # for _ComplexObject
- self.assertEqual(hash(complex_object()),
- hash(SimpleLazyObject(complex_object)))
-
- def test_repr(self):
- # First, for an unevaluated SimpleLazyObject
- x = SimpleLazyObject(complex_object)
- # __repr__ contains __repr__ of setup function and does not evaluate
- # the SimpleLazyObject
- self.assertEqual("<SimpleLazyObject: %r>" % complex_object, repr(x))
- self.assertEqual(empty, x._wrapped)
-
- # Second, for an evaluated SimpleLazyObject
- x.name # evaluate
- self.assertIsInstance(x._wrapped, _ComplexObject)
- # __repr__ contains __repr__ of wrapped object
- self.assertEqual("<SimpleLazyObject: %r>" % x._wrapped, repr(x))
-
- def test_bytes(self):
- self.assertEqual(b"I am _ComplexObject('joe')",
- bytes(SimpleLazyObject(complex_object)))
-
- def test_text(self):
- self.assertEqual("joe", six.text_type(SimpleLazyObject(complex_object)))
-
- def test_class(self):
- # This is important for classes that use __class__ in things like
- # equality tests.
- self.assertEqual(_ComplexObject, SimpleLazyObject(complex_object).__class__)
-
- def test_deepcopy(self):
- # Check that we *can* do deep copy, and that it returns the right
- # objects.
-
- # First, for an unevaluated SimpleLazyObject
- s = SimpleLazyObject(complex_object)
- self.assertIs(s._wrapped, empty)
- s2 = copy.deepcopy(s)
- # something has gone wrong is s is evaluated
- self.assertIs(s._wrapped, empty)
- self.assertEqual(s2, complex_object())
-
- # Second, for an evaluated SimpleLazyObject
- s.name # evaluate
- self.assertIsNot(s._wrapped, empty)
- s3 = copy.deepcopy(s)
- self.assertEqual(s3, complex_object())
-
- def test_none(self):
- i = [0]
-
- def f():
- i[0] += 1
- return None
-
- x = SimpleLazyObject(f)
- self.assertEqual(str(x), "None")
- self.assertEqual(i, [1])
- self.assertEqual(str(x), "None")
- self.assertEqual(i, [1])
-
- def test_bool(self):
- x = SimpleLazyObject(lambda: 3)
- self.assertTrue(x)
- x = SimpleLazyObject(lambda: 0)
- self.assertFalse(x)
-
- def test_pickle_complex(self):
- # See ticket #16563
- x = SimpleLazyObject(complex_object)
- pickled = pickle.dumps(x)
- unpickled = pickle.loads(pickled)
- self.assertEqual(unpickled, x)
- self.assertEqual(six.text_type(unpickled), six.text_type(x))
- self.assertEqual(unpickled.name, x.name)
-
- def test_dict(self):
- # See ticket #18447
- lazydict = SimpleLazyObject(lambda: {'one': 1})
- self.assertEqual(lazydict['one'], 1)
- lazydict['one'] = -1
- self.assertEqual(lazydict['one'], -1)
- self.assertTrue('one' in lazydict)
- self.assertFalse('two' in lazydict)
- self.assertEqual(len(lazydict), 1)
- del lazydict['one']
- with self.assertRaises(KeyError):
- lazydict['one']
-
- def test_trace(self):
- # See ticket #19456
- old_trace_func = sys.gettrace()
- try:
- def trace_func(frame, event, arg):
- frame.f_locals['self'].__class__
- if old_trace_func is not None:
- old_trace_func(frame, event, arg)
- sys.settrace(trace_func)
- SimpleLazyObject(None)
- finally:
- sys.settrace(old_trace_func)
-
- def test_not_equal(self):
- lazy1 = SimpleLazyObject(lambda: 2)
- lazy2 = SimpleLazyObject(lambda: 2)
- lazy3 = SimpleLazyObject(lambda: 3)
- self.assertEqual(lazy1, lazy2)
- self.assertNotEqual(lazy1, lazy3)
- self.assertTrue(lazy1 != lazy3)
- self.assertFalse(lazy1 != lazy2)
-
- def test_list_set(self):
- lazy_list = SimpleLazyObject(lambda: [1, 2, 3, 4, 5])
- lazy_set = SimpleLazyObject(lambda: set([1, 2, 3, 4]))
- self.assertTrue(1 in lazy_list)
- self.assertTrue(1 in lazy_set)
- self.assertFalse(6 in lazy_list)
- self.assertFalse(6 in lazy_set)
- self.assertEqual(len(lazy_list), 5)
- self.assertEqual(len(lazy_set), 4)
-
-
-class TestUtilsSimpleLazyObjectDjangoTestCase(DjangoTestCase):
+class TestUtilsSimpleLazyObjectDjangoTestCase(TestCase):
def test_pickle_py2_regression(self):
# See ticket #20212
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