| import gc |
| import sys |
| import unittest |
| import UserList |
| import weakref |
| import operator |
| |
| from test import test_support |
| |
| # Used in ReferencesTestCase.test_ref_created_during_del() . |
| ref_from_del = None |
| |
| class C: |
| def method(self): |
| pass |
| |
| |
| class Callable: |
| bar = None |
| |
| def __call__(self, x): |
| self.bar = x |
| |
| |
| def create_function(): |
| def f(): pass |
| return f |
| |
| def create_bound_method(): |
| return C().method |
| |
| def create_unbound_method(): |
| return C.method |
| |
| |
| class Object: |
| def __init__(self, arg): |
| self.arg = arg |
| def __repr__(self): |
| return "<Object %r>" % self.arg |
| def __eq__(self, other): |
| if isinstance(other, Object): |
| return self.arg == other.arg |
| return NotImplemented |
| def __ne__(self, other): |
| if isinstance(other, Object): |
| return self.arg != other.arg |
| return NotImplemented |
| def __hash__(self): |
| return hash(self.arg) |
| |
| class RefCycle: |
| def __init__(self): |
| self.cycle = self |
| |
| |
| class TestBase(unittest.TestCase): |
| |
| def setUp(self): |
| self.cbcalled = 0 |
| |
| def callback(self, ref): |
| self.cbcalled += 1 |
| |
| |
| class ReferencesTestCase(TestBase): |
| |
| def test_basic_ref(self): |
| self.check_basic_ref(C) |
| self.check_basic_ref(create_function) |
| self.check_basic_ref(create_bound_method) |
| self.check_basic_ref(create_unbound_method) |
| |
| # Just make sure the tp_repr handler doesn't raise an exception. |
| # Live reference: |
| o = C() |
| wr = weakref.ref(o) |
| repr(wr) |
| # Dead reference: |
| del o |
| repr(wr) |
| |
| def test_basic_callback(self): |
| self.check_basic_callback(C) |
| self.check_basic_callback(create_function) |
| self.check_basic_callback(create_bound_method) |
| self.check_basic_callback(create_unbound_method) |
| |
| def test_multiple_callbacks(self): |
| o = C() |
| ref1 = weakref.ref(o, self.callback) |
| ref2 = weakref.ref(o, self.callback) |
| del o |
| self.assertTrue(ref1() is None, |
| "expected reference to be invalidated") |
| self.assertTrue(ref2() is None, |
| "expected reference to be invalidated") |
| self.assertTrue(self.cbcalled == 2, |
| "callback not called the right number of times") |
| |
| def test_multiple_selfref_callbacks(self): |
| # Make sure all references are invalidated before callbacks are called |
| # |
| # What's important here is that we're using the first |
| # reference in the callback invoked on the second reference |
| # (the most recently created ref is cleaned up first). This |
| # tests that all references to the object are invalidated |
| # before any of the callbacks are invoked, so that we only |
| # have one invocation of _weakref.c:cleanup_helper() active |
| # for a particular object at a time. |
| # |
| def callback(object, self=self): |
| self.ref() |
| c = C() |
| self.ref = weakref.ref(c, callback) |
| ref1 = weakref.ref(c, callback) |
| del c |
| |
| def test_proxy_ref(self): |
| o = C() |
| o.bar = 1 |
| ref1 = weakref.proxy(o, self.callback) |
| ref2 = weakref.proxy(o, self.callback) |
| del o |
| |
| def check(proxy): |
| proxy.bar |
| |
| self.assertRaises(weakref.ReferenceError, check, ref1) |
| self.assertRaises(weakref.ReferenceError, check, ref2) |
| self.assertRaises(weakref.ReferenceError, bool, weakref.proxy(C())) |
| self.assertTrue(self.cbcalled == 2) |
| |
| def check_basic_ref(self, factory): |
| o = factory() |
| ref = weakref.ref(o) |
| self.assertTrue(ref() is not None, |
| "weak reference to live object should be live") |
| o2 = ref() |
| self.assertTrue(o is o2, |
| "<ref>() should return original object if live") |
| |
| def check_basic_callback(self, factory): |
| self.cbcalled = 0 |
| o = factory() |
| ref = weakref.ref(o, self.callback) |
| del o |
| self.assertTrue(self.cbcalled == 1, |
| "callback did not properly set 'cbcalled'") |
| self.assertTrue(ref() is None, |
| "ref2 should be dead after deleting object reference") |
| |
| def test_ref_reuse(self): |
| o = C() |
| ref1 = weakref.ref(o) |
| # create a proxy to make sure that there's an intervening creation |
| # between these two; it should make no difference |
| proxy = weakref.proxy(o) |
| ref2 = weakref.ref(o) |
| self.assertTrue(ref1 is ref2, |
| "reference object w/out callback should be re-used") |
| |
| o = C() |
| proxy = weakref.proxy(o) |
| ref1 = weakref.ref(o) |
| ref2 = weakref.ref(o) |
| self.assertTrue(ref1 is ref2, |
| "reference object w/out callback should be re-used") |
| self.assertTrue(weakref.getweakrefcount(o) == 2, |
| "wrong weak ref count for object") |
| del proxy |
| self.assertTrue(weakref.getweakrefcount(o) == 1, |
| "wrong weak ref count for object after deleting proxy") |
| |
| def test_proxy_reuse(self): |
| o = C() |
| proxy1 = weakref.proxy(o) |
| ref = weakref.ref(o) |
| proxy2 = weakref.proxy(o) |
| self.assertTrue(proxy1 is proxy2, |
| "proxy object w/out callback should have been re-used") |
| |
| def test_basic_proxy(self): |
| o = C() |
| self.check_proxy(o, weakref.proxy(o)) |
| |
| L = UserList.UserList() |
| p = weakref.proxy(L) |
| self.assertFalse(p, "proxy for empty UserList should be false") |
| p.append(12) |
| self.assertEqual(len(L), 1) |
| self.assertTrue(p, "proxy for non-empty UserList should be true") |
| with test_support.check_py3k_warnings(): |
| p[:] = [2, 3] |
| self.assertEqual(len(L), 2) |
| self.assertEqual(len(p), 2) |
| self.assertIn(3, p, "proxy didn't support __contains__() properly") |
| p[1] = 5 |
| self.assertEqual(L[1], 5) |
| self.assertEqual(p[1], 5) |
| L2 = UserList.UserList(L) |
| p2 = weakref.proxy(L2) |
| self.assertEqual(p, p2) |
| ## self.assertEqual(repr(L2), repr(p2)) |
| L3 = UserList.UserList(range(10)) |
| p3 = weakref.proxy(L3) |
| with test_support.check_py3k_warnings(): |
| self.assertEqual(L3[:], p3[:]) |
| self.assertEqual(L3[5:], p3[5:]) |
| self.assertEqual(L3[:5], p3[:5]) |
| self.assertEqual(L3[2:5], p3[2:5]) |
| |
| def test_proxy_unicode(self): |
| # See bug 5037 |
| class C(object): |
| def __str__(self): |
| return "string" |
| def __unicode__(self): |
| return u"unicode" |
| instance = C() |
| self.assertIn("__unicode__", dir(weakref.proxy(instance))) |
| self.assertEqual(unicode(weakref.proxy(instance)), u"unicode") |
| |
| def test_proxy_index(self): |
| class C: |
| def __index__(self): |
| return 10 |
| o = C() |
| p = weakref.proxy(o) |
| self.assertEqual(operator.index(p), 10) |
| |
| def test_proxy_div(self): |
| class C: |
| def __floordiv__(self, other): |
| return 42 |
| def __ifloordiv__(self, other): |
| return 21 |
| o = C() |
| p = weakref.proxy(o) |
| self.assertEqual(p // 5, 42) |
| p //= 5 |
| self.assertEqual(p, 21) |
| |
| # The PyWeakref_* C API is documented as allowing either NULL or |
| # None as the value for the callback, where either means "no |
| # callback". The "no callback" ref and proxy objects are supposed |
| # to be shared so long as they exist by all callers so long as |
| # they are active. In Python 2.3.3 and earlier, this guarantee |
| # was not honored, and was broken in different ways for |
| # PyWeakref_NewRef() and PyWeakref_NewProxy(). (Two tests.) |
| |
| def test_shared_ref_without_callback(self): |
| self.check_shared_without_callback(weakref.ref) |
| |
| def test_shared_proxy_without_callback(self): |
| self.check_shared_without_callback(weakref.proxy) |
| |
| def check_shared_without_callback(self, makeref): |
| o = Object(1) |
| p1 = makeref(o, None) |
| p2 = makeref(o, None) |
| self.assertTrue(p1 is p2, "both callbacks were None in the C API") |
| del p1, p2 |
| p1 = makeref(o) |
| p2 = makeref(o, None) |
| self.assertTrue(p1 is p2, "callbacks were NULL, None in the C API") |
| del p1, p2 |
| p1 = makeref(o) |
| p2 = makeref(o) |
| self.assertTrue(p1 is p2, "both callbacks were NULL in the C API") |
| del p1, p2 |
| p1 = makeref(o, None) |
| p2 = makeref(o) |
| self.assertTrue(p1 is p2, "callbacks were None, NULL in the C API") |
| |
| def test_callable_proxy(self): |
| o = Callable() |
| ref1 = weakref.proxy(o) |
| |
| self.check_proxy(o, ref1) |
| |
| self.assertTrue(type(ref1) is weakref.CallableProxyType, |
| "proxy is not of callable type") |
| ref1('twinkies!') |
| self.assertTrue(o.bar == 'twinkies!', |
| "call through proxy not passed through to original") |
| ref1(x='Splat.') |
| self.assertTrue(o.bar == 'Splat.', |
| "call through proxy not passed through to original") |
| |
| # expect due to too few args |
| self.assertRaises(TypeError, ref1) |
| |
| # expect due to too many args |
| self.assertRaises(TypeError, ref1, 1, 2, 3) |
| |
| def check_proxy(self, o, proxy): |
| o.foo = 1 |
| self.assertTrue(proxy.foo == 1, |
| "proxy does not reflect attribute addition") |
| o.foo = 2 |
| self.assertTrue(proxy.foo == 2, |
| "proxy does not reflect attribute modification") |
| del o.foo |
| self.assertTrue(not hasattr(proxy, 'foo'), |
| "proxy does not reflect attribute removal") |
| |
| proxy.foo = 1 |
| self.assertTrue(o.foo == 1, |
| "object does not reflect attribute addition via proxy") |
| proxy.foo = 2 |
| self.assertTrue( |
| o.foo == 2, |
| "object does not reflect attribute modification via proxy") |
| del proxy.foo |
| self.assertTrue(not hasattr(o, 'foo'), |
| "object does not reflect attribute removal via proxy") |
| |
| def test_proxy_deletion(self): |
| # Test clearing of SF bug #762891 |
| class Foo: |
| result = None |
| def __delitem__(self, accessor): |
| self.result = accessor |
| g = Foo() |
| f = weakref.proxy(g) |
| del f[0] |
| self.assertEqual(f.result, 0) |
| |
| def test_proxy_bool(self): |
| # Test clearing of SF bug #1170766 |
| class List(list): pass |
| lyst = List() |
| self.assertEqual(bool(weakref.proxy(lyst)), bool(lyst)) |
| |
| def test_getweakrefcount(self): |
| o = C() |
| ref1 = weakref.ref(o) |
| ref2 = weakref.ref(o, self.callback) |
| self.assertTrue(weakref.getweakrefcount(o) == 2, |
| "got wrong number of weak reference objects") |
| |
| proxy1 = weakref.proxy(o) |
| proxy2 = weakref.proxy(o, self.callback) |
| self.assertTrue(weakref.getweakrefcount(o) == 4, |
| "got wrong number of weak reference objects") |
| |
| del ref1, ref2, proxy1, proxy2 |
| self.assertTrue(weakref.getweakrefcount(o) == 0, |
| "weak reference objects not unlinked from" |
| " referent when discarded.") |
| |
| # assumes ints do not support weakrefs |
| self.assertTrue(weakref.getweakrefcount(1) == 0, |
| "got wrong number of weak reference objects for int") |
| |
| def test_getweakrefs(self): |
| o = C() |
| ref1 = weakref.ref(o, self.callback) |
| ref2 = weakref.ref(o, self.callback) |
| del ref1 |
| self.assertTrue(weakref.getweakrefs(o) == [ref2], |
| "list of refs does not match") |
| |
| o = C() |
| ref1 = weakref.ref(o, self.callback) |
| ref2 = weakref.ref(o, self.callback) |
| del ref2 |
| self.assertTrue(weakref.getweakrefs(o) == [ref1], |
| "list of refs does not match") |
| |
| del ref1 |
| self.assertTrue(weakref.getweakrefs(o) == [], |
| "list of refs not cleared") |
| |
| # assumes ints do not support weakrefs |
| self.assertTrue(weakref.getweakrefs(1) == [], |
| "list of refs does not match for int") |
| |
| def test_newstyle_number_ops(self): |
| class F(float): |
| pass |
| f = F(2.0) |
| p = weakref.proxy(f) |
| self.assertTrue(p + 1.0 == 3.0) |
| self.assertTrue(1.0 + p == 3.0) # this used to SEGV |
| |
| def test_callbacks_protected(self): |
| # Callbacks protected from already-set exceptions? |
| # Regression test for SF bug #478534. |
| class BogusError(Exception): |
| pass |
| data = {} |
| def remove(k): |
| del data[k] |
| def encapsulate(): |
| f = lambda : () |
| data[weakref.ref(f, remove)] = None |
| raise BogusError |
| try: |
| encapsulate() |
| except BogusError: |
| pass |
| else: |
| self.fail("exception not properly restored") |
| try: |
| encapsulate() |
| except BogusError: |
| pass |
| else: |
| self.fail("exception not properly restored") |
| |
| def test_sf_bug_840829(self): |
| # "weakref callbacks and gc corrupt memory" |
| # subtype_dealloc erroneously exposed a new-style instance |
| # already in the process of getting deallocated to gc, |
| # causing double-deallocation if the instance had a weakref |
| # callback that triggered gc. |
| # If the bug exists, there probably won't be an obvious symptom |
| # in a release build. In a debug build, a segfault will occur |
| # when the second attempt to remove the instance from the "list |
| # of all objects" occurs. |
| |
| import gc |
| |
| class C(object): |
| pass |
| |
| c = C() |
| wr = weakref.ref(c, lambda ignore: gc.collect()) |
| del c |
| |
| # There endeth the first part. It gets worse. |
| del wr |
| |
| c1 = C() |
| c1.i = C() |
| wr = weakref.ref(c1.i, lambda ignore: gc.collect()) |
| |
| c2 = C() |
| c2.c1 = c1 |
| del c1 # still alive because c2 points to it |
| |
| # Now when subtype_dealloc gets called on c2, it's not enough just |
| # that c2 is immune from gc while the weakref callbacks associated |
| # with c2 execute (there are none in this 2nd half of the test, btw). |
| # subtype_dealloc goes on to call the base classes' deallocs too, |
| # so any gc triggered by weakref callbacks associated with anything |
| # torn down by a base class dealloc can also trigger double |
| # deallocation of c2. |
| del c2 |
| |
| def test_callback_in_cycle_1(self): |
| import gc |
| |
| class J(object): |
| pass |
| |
| class II(object): |
| def acallback(self, ignore): |
| self.J |
| |
| I = II() |
| I.J = J |
| I.wr = weakref.ref(J, I.acallback) |
| |
| # Now J and II are each in a self-cycle (as all new-style class |
| # objects are, since their __mro__ points back to them). I holds |
| # both a weak reference (I.wr) and a strong reference (I.J) to class |
| # J. I is also in a cycle (I.wr points to a weakref that references |
| # I.acallback). When we del these three, they all become trash, but |
| # the cycles prevent any of them from getting cleaned up immediately. |
| # Instead they have to wait for cyclic gc to deduce that they're |
| # trash. |
| # |
| # gc used to call tp_clear on all of them, and the order in which |
| # it does that is pretty accidental. The exact order in which we |
| # built up these things manages to provoke gc into running tp_clear |
| # in just the right order (I last). Calling tp_clear on II leaves |
| # behind an insane class object (its __mro__ becomes NULL). Calling |
| # tp_clear on J breaks its self-cycle, but J doesn't get deleted |
| # just then because of the strong reference from I.J. Calling |
| # tp_clear on I starts to clear I's __dict__, and just happens to |
| # clear I.J first -- I.wr is still intact. That removes the last |
| # reference to J, which triggers the weakref callback. The callback |
| # tries to do "self.J", and instances of new-style classes look up |
| # attributes ("J") in the class dict first. The class (II) wants to |
| # search II.__mro__, but that's NULL. The result was a segfault in |
| # a release build, and an assert failure in a debug build. |
| del I, J, II |
| gc.collect() |
| |
| def test_callback_in_cycle_2(self): |
| import gc |
| |
| # This is just like test_callback_in_cycle_1, except that II is an |
| # old-style class. The symptom is different then: an instance of an |
| # old-style class looks in its own __dict__ first. 'J' happens to |
| # get cleared from I.__dict__ before 'wr', and 'J' was never in II's |
| # __dict__, so the attribute isn't found. The difference is that |
| # the old-style II doesn't have a NULL __mro__ (it doesn't have any |
| # __mro__), so no segfault occurs. Instead it got: |
| # test_callback_in_cycle_2 (__main__.ReferencesTestCase) ... |
| # Exception exceptions.AttributeError: |
| # "II instance has no attribute 'J'" in <bound method II.acallback |
| # of <?.II instance at 0x00B9B4B8>> ignored |
| |
| class J(object): |
| pass |
| |
| class II: |
| def acallback(self, ignore): |
| self.J |
| |
| I = II() |
| I.J = J |
| I.wr = weakref.ref(J, I.acallback) |
| |
| del I, J, II |
| gc.collect() |
| |
| def test_callback_in_cycle_3(self): |
| import gc |
| |
| # This one broke the first patch that fixed the last two. In this |
| # case, the objects reachable from the callback aren't also reachable |
| # from the object (c1) *triggering* the callback: you can get to |
| # c1 from c2, but not vice-versa. The result was that c2's __dict__ |
| # got tp_clear'ed by the time the c2.cb callback got invoked. |
| |
| class C: |
| def cb(self, ignore): |
| self.me |
| self.c1 |
| self.wr |
| |
| c1, c2 = C(), C() |
| |
| c2.me = c2 |
| c2.c1 = c1 |
| c2.wr = weakref.ref(c1, c2.cb) |
| |
| del c1, c2 |
| gc.collect() |
| |
| def test_callback_in_cycle_4(self): |
| import gc |
| |
| # Like test_callback_in_cycle_3, except c2 and c1 have different |
| # classes. c2's class (C) isn't reachable from c1 then, so protecting |
| # objects reachable from the dying object (c1) isn't enough to stop |
| # c2's class (C) from getting tp_clear'ed before c2.cb is invoked. |
| # The result was a segfault (C.__mro__ was NULL when the callback |
| # tried to look up self.me). |
| |
| class C(object): |
| def cb(self, ignore): |
| self.me |
| self.c1 |
| self.wr |
| |
| class D: |
| pass |
| |
| c1, c2 = D(), C() |
| |
| c2.me = c2 |
| c2.c1 = c1 |
| c2.wr = weakref.ref(c1, c2.cb) |
| |
| del c1, c2, C, D |
| gc.collect() |
| |
| def test_callback_in_cycle_resurrection(self): |
| import gc |
| |
| # Do something nasty in a weakref callback: resurrect objects |
| # from dead cycles. For this to be attempted, the weakref and |
| # its callback must also be part of the cyclic trash (else the |
| # objects reachable via the callback couldn't be in cyclic trash |
| # to begin with -- the callback would act like an external root). |
| # But gc clears trash weakrefs with callbacks early now, which |
| # disables the callbacks, so the callbacks shouldn't get called |
| # at all (and so nothing actually gets resurrected). |
| |
| alist = [] |
| class C(object): |
| def __init__(self, value): |
| self.attribute = value |
| |
| def acallback(self, ignore): |
| alist.append(self.c) |
| |
| c1, c2 = C(1), C(2) |
| c1.c = c2 |
| c2.c = c1 |
| c1.wr = weakref.ref(c2, c1.acallback) |
| c2.wr = weakref.ref(c1, c2.acallback) |
| |
| def C_went_away(ignore): |
| alist.append("C went away") |
| wr = weakref.ref(C, C_went_away) |
| |
| del c1, c2, C # make them all trash |
| self.assertEqual(alist, []) # del isn't enough to reclaim anything |
| |
| gc.collect() |
| # c1.wr and c2.wr were part of the cyclic trash, so should have |
| # been cleared without their callbacks executing. OTOH, the weakref |
| # to C is bound to a function local (wr), and wasn't trash, so that |
| # callback should have been invoked when C went away. |
| self.assertEqual(alist, ["C went away"]) |
| # The remaining weakref should be dead now (its callback ran). |
| self.assertEqual(wr(), None) |
| |
| del alist[:] |
| gc.collect() |
| self.assertEqual(alist, []) |
| |
| def test_callbacks_on_callback(self): |
| import gc |
| |
| # Set up weakref callbacks *on* weakref callbacks. |
| alist = [] |
| def safe_callback(ignore): |
| alist.append("safe_callback called") |
| |
| class C(object): |
| def cb(self, ignore): |
| alist.append("cb called") |
| |
| c, d = C(), C() |
| c.other = d |
| d.other = c |
| callback = c.cb |
| c.wr = weakref.ref(d, callback) # this won't trigger |
| d.wr = weakref.ref(callback, d.cb) # ditto |
| external_wr = weakref.ref(callback, safe_callback) # but this will |
| self.assertTrue(external_wr() is callback) |
| |
| # The weakrefs attached to c and d should get cleared, so that |
| # C.cb is never called. But external_wr isn't part of the cyclic |
| # trash, and no cyclic trash is reachable from it, so safe_callback |
| # should get invoked when the bound method object callback (c.cb) |
| # -- which is itself a callback, and also part of the cyclic trash -- |
| # gets reclaimed at the end of gc. |
| |
| del callback, c, d, C |
| self.assertEqual(alist, []) # del isn't enough to clean up cycles |
| gc.collect() |
| self.assertEqual(alist, ["safe_callback called"]) |
| self.assertEqual(external_wr(), None) |
| |
| del alist[:] |
| gc.collect() |
| self.assertEqual(alist, []) |
| |
| def test_gc_during_ref_creation(self): |
| self.check_gc_during_creation(weakref.ref) |
| |
| def test_gc_during_proxy_creation(self): |
| self.check_gc_during_creation(weakref.proxy) |
| |
| def check_gc_during_creation(self, makeref): |
| thresholds = gc.get_threshold() |
| gc.set_threshold(1, 1, 1) |
| gc.collect() |
| class A: |
| pass |
| |
| def callback(*args): |
| pass |
| |
| referenced = A() |
| |
| a = A() |
| a.a = a |
| a.wr = makeref(referenced) |
| |
| try: |
| # now make sure the object and the ref get labeled as |
| # cyclic trash: |
| a = A() |
| weakref.ref(referenced, callback) |
| |
| finally: |
| gc.set_threshold(*thresholds) |
| |
| def test_ref_created_during_del(self): |
| # Bug #1377858 |
| # A weakref created in an object's __del__() would crash the |
| # interpreter when the weakref was cleaned up since it would refer to |
| # non-existent memory. This test should not segfault the interpreter. |
| class Target(object): |
| def __del__(self): |
| global ref_from_del |
| ref_from_del = weakref.ref(self) |
| |
| w = Target() |
| |
| def test_init(self): |
| # Issue 3634 |
| # <weakref to class>.__init__() doesn't check errors correctly |
| r = weakref.ref(Exception) |
| self.assertRaises(TypeError, r.__init__, 0, 0, 0, 0, 0) |
| # No exception should be raised here |
| gc.collect() |
| |
| def test_classes(self): |
| # Check that both old-style classes and new-style classes |
| # are weakrefable. |
| class A(object): |
| pass |
| class B: |
| pass |
| l = [] |
| weakref.ref(int) |
| a = weakref.ref(A, l.append) |
| A = None |
| gc.collect() |
| self.assertEqual(a(), None) |
| self.assertEqual(l, [a]) |
| b = weakref.ref(B, l.append) |
| B = None |
| gc.collect() |
| self.assertEqual(b(), None) |
| self.assertEqual(l, [a, b]) |
| |
| def test_equality(self): |
| # Alive weakrefs defer equality testing to their underlying object. |
| x = Object(1) |
| y = Object(1) |
| z = Object(2) |
| a = weakref.ref(x) |
| b = weakref.ref(y) |
| c = weakref.ref(z) |
| d = weakref.ref(x) |
| # Note how we directly test the operators here, to stress both |
| # __eq__ and __ne__. |
| self.assertTrue(a == b) |
| self.assertFalse(a != b) |
| self.assertFalse(a == c) |
| self.assertTrue(a != c) |
| self.assertTrue(a == d) |
| self.assertFalse(a != d) |
| del x, y, z |
| gc.collect() |
| for r in a, b, c: |
| # Sanity check |
| self.assertIs(r(), None) |
| # Dead weakrefs compare by identity: whether `a` and `d` are the |
| # same weakref object is an implementation detail, since they pointed |
| # to the same original object and didn't have a callback. |
| # (see issue #16453). |
| self.assertFalse(a == b) |
| self.assertTrue(a != b) |
| self.assertFalse(a == c) |
| self.assertTrue(a != c) |
| self.assertEqual(a == d, a is d) |
| self.assertEqual(a != d, a is not d) |
| |
| def test_hashing(self): |
| # Alive weakrefs hash the same as the underlying object |
| x = Object(42) |
| y = Object(42) |
| a = weakref.ref(x) |
| b = weakref.ref(y) |
| self.assertEqual(hash(a), hash(42)) |
| del x, y |
| gc.collect() |
| # Dead weakrefs: |
| # - retain their hash is they were hashed when alive; |
| # - otherwise, cannot be hashed. |
| self.assertEqual(hash(a), hash(42)) |
| self.assertRaises(TypeError, hash, b) |
| |
| def test_trashcan_16602(self): |
| # Issue #16602: when a weakref's target was part of a long |
| # deallocation chain, the trashcan mechanism could delay clearing |
| # of the weakref and make the target object visible from outside |
| # code even though its refcount had dropped to 0. A crash ensued. |
| class C(object): |
| def __init__(self, parent): |
| if not parent: |
| return |
| wself = weakref.ref(self) |
| def cb(wparent): |
| o = wself() |
| self.wparent = weakref.ref(parent, cb) |
| |
| d = weakref.WeakKeyDictionary() |
| root = c = C(None) |
| for n in range(100): |
| d[c] = c = C(c) |
| del root |
| gc.collect() |
| |
| |
| class SubclassableWeakrefTestCase(TestBase): |
| |
| def test_subclass_refs(self): |
| class MyRef(weakref.ref): |
| def __init__(self, ob, callback=None, value=42): |
| self.value = value |
| super(MyRef, self).__init__(ob, callback) |
| def __call__(self): |
| self.called = True |
| return super(MyRef, self).__call__() |
| o = Object("foo") |
| mr = MyRef(o, value=24) |
| self.assertTrue(mr() is o) |
| self.assertTrue(mr.called) |
| self.assertEqual(mr.value, 24) |
| del o |
| self.assertTrue(mr() is None) |
| self.assertTrue(mr.called) |
| |
| def test_subclass_refs_dont_replace_standard_refs(self): |
| class MyRef(weakref.ref): |
| pass |
| o = Object(42) |
| r1 = MyRef(o) |
| r2 = weakref.ref(o) |
| self.assertTrue(r1 is not r2) |
| self.assertEqual(weakref.getweakrefs(o), [r2, r1]) |
| self.assertEqual(weakref.getweakrefcount(o), 2) |
| r3 = MyRef(o) |
| self.assertEqual(weakref.getweakrefcount(o), 3) |
| refs = weakref.getweakrefs(o) |
| self.assertEqual(len(refs), 3) |
| self.assertTrue(r2 is refs[0]) |
| self.assertIn(r1, refs[1:]) |
| self.assertIn(r3, refs[1:]) |
| |
| def test_subclass_refs_dont_conflate_callbacks(self): |
| class MyRef(weakref.ref): |
| pass |
| o = Object(42) |
| r1 = MyRef(o, id) |
| r2 = MyRef(o, str) |
| self.assertTrue(r1 is not r2) |
| refs = weakref.getweakrefs(o) |
| self.assertIn(r1, refs) |
| self.assertIn(r2, refs) |
| |
| def test_subclass_refs_with_slots(self): |
| class MyRef(weakref.ref): |
| __slots__ = "slot1", "slot2" |
| def __new__(type, ob, callback, slot1, slot2): |
| return weakref.ref.__new__(type, ob, callback) |
| def __init__(self, ob, callback, slot1, slot2): |
| self.slot1 = slot1 |
| self.slot2 = slot2 |
| def meth(self): |
| return self.slot1 + self.slot2 |
| o = Object(42) |
| r = MyRef(o, None, "abc", "def") |
| self.assertEqual(r.slot1, "abc") |
| self.assertEqual(r.slot2, "def") |
| self.assertEqual(r.meth(), "abcdef") |
| self.assertFalse(hasattr(r, "__dict__")) |
| |
| def test_subclass_refs_with_cycle(self): |
| # Bug #3110 |
| # An instance of a weakref subclass can have attributes. |
| # If such a weakref holds the only strong reference to the object, |
| # deleting the weakref will delete the object. In this case, |
| # the callback must not be called, because the ref object is |
| # being deleted. |
| class MyRef(weakref.ref): |
| pass |
| |
| # Use a local callback, for "regrtest -R::" |
| # to detect refcounting problems |
| def callback(w): |
| self.cbcalled += 1 |
| |
| o = C() |
| r1 = MyRef(o, callback) |
| r1.o = o |
| del o |
| |
| del r1 # Used to crash here |
| |
| self.assertEqual(self.cbcalled, 0) |
| |
| # Same test, with two weakrefs to the same object |
| # (since code paths are different) |
| o = C() |
| r1 = MyRef(o, callback) |
| r2 = MyRef(o, callback) |
| r1.r = r2 |
| r2.o = o |
| del o |
| del r2 |
| |
| del r1 # Used to crash here |
| |
| self.assertEqual(self.cbcalled, 0) |
| |
| |
| class MappingTestCase(TestBase): |
| |
| COUNT = 10 |
| |
| def check_len_cycles(self, dict_type, cons): |
| N = 20 |
| items = [RefCycle() for i in range(N)] |
| dct = dict_type(cons(o) for o in items) |
| # Keep an iterator alive |
| it = dct.iteritems() |
| try: |
| next(it) |
| except StopIteration: |
| pass |
| del items |
| gc.collect() |
| n1 = len(dct) |
| del it |
| gc.collect() |
| n2 = len(dct) |
| # one item may be kept alive inside the iterator |
| self.assertIn(n1, (0, 1)) |
| self.assertEqual(n2, 0) |
| |
| def test_weak_keyed_len_cycles(self): |
| self.check_len_cycles(weakref.WeakKeyDictionary, lambda k: (k, 1)) |
| |
| def test_weak_valued_len_cycles(self): |
| self.check_len_cycles(weakref.WeakValueDictionary, lambda k: (1, k)) |
| |
| def check_len_race(self, dict_type, cons): |
| # Extended sanity checks for len() in the face of cyclic collection |
| self.addCleanup(gc.set_threshold, *gc.get_threshold()) |
| for th in range(1, 100): |
| N = 20 |
| gc.collect(0) |
| gc.set_threshold(th, th, th) |
| items = [RefCycle() for i in range(N)] |
| dct = dict_type(cons(o) for o in items) |
| del items |
| # All items will be collected at next garbage collection pass |
| it = dct.iteritems() |
| try: |
| next(it) |
| except StopIteration: |
| pass |
| n1 = len(dct) |
| del it |
| n2 = len(dct) |
| self.assertGreaterEqual(n1, 0) |
| self.assertLessEqual(n1, N) |
| self.assertGreaterEqual(n2, 0) |
| self.assertLessEqual(n2, n1) |
| |
| def test_weak_keyed_len_race(self): |
| self.check_len_race(weakref.WeakKeyDictionary, lambda k: (k, 1)) |
| |
| def test_weak_valued_len_race(self): |
| self.check_len_race(weakref.WeakValueDictionary, lambda k: (1, k)) |
| |
| def test_weak_values(self): |
| # |
| # This exercises d.copy(), d.items(), d[], del d[], len(d). |
| # |
| dict, objects = self.make_weak_valued_dict() |
| for o in objects: |
| self.assertTrue(weakref.getweakrefcount(o) == 1, |
| "wrong number of weak references to %r!" % o) |
| self.assertTrue(o is dict[o.arg], |
| "wrong object returned by weak dict!") |
| items1 = dict.items() |
| items2 = dict.copy().items() |
| items1.sort() |
| items2.sort() |
| self.assertTrue(items1 == items2, |
| "cloning of weak-valued dictionary did not work!") |
| del items1, items2 |
| self.assertTrue(len(dict) == self.COUNT) |
| del objects[0] |
| self.assertTrue(len(dict) == (self.COUNT - 1), |
| "deleting object did not cause dictionary update") |
| del objects, o |
| self.assertTrue(len(dict) == 0, |
| "deleting the values did not clear the dictionary") |
| # regression on SF bug #447152: |
| dict = weakref.WeakValueDictionary() |
| self.assertRaises(KeyError, dict.__getitem__, 1) |
| dict[2] = C() |
| self.assertRaises(KeyError, dict.__getitem__, 2) |
| |
| def test_weak_keys(self): |
| # |
| # This exercises d.copy(), d.items(), d[] = v, d[], del d[], |
| # len(d), in d. |
| # |
| dict, objects = self.make_weak_keyed_dict() |
| for o in objects: |
| self.assertTrue(weakref.getweakrefcount(o) == 1, |
| "wrong number of weak references to %r!" % o) |
| self.assertTrue(o.arg is dict[o], |
| "wrong object returned by weak dict!") |
| items1 = dict.items() |
| items2 = dict.copy().items() |
| self.assertTrue(set(items1) == set(items2), |
| "cloning of weak-keyed dictionary did not work!") |
| del items1, items2 |
| self.assertTrue(len(dict) == self.COUNT) |
| del objects[0] |
| self.assertTrue(len(dict) == (self.COUNT - 1), |
| "deleting object did not cause dictionary update") |
| del objects, o |
| self.assertTrue(len(dict) == 0, |
| "deleting the keys did not clear the dictionary") |
| o = Object(42) |
| dict[o] = "What is the meaning of the universe?" |
| self.assertIn(o, dict) |
| self.assertNotIn(34, dict) |
| |
| def test_weak_keyed_iters(self): |
| dict, objects = self.make_weak_keyed_dict() |
| self.check_iters(dict) |
| |
| # Test keyrefs() |
| refs = dict.keyrefs() |
| self.assertEqual(len(refs), len(objects)) |
| objects2 = list(objects) |
| for wr in refs: |
| ob = wr() |
| self.assertIn(ob, dict) |
| self.assertEqual(ob.arg, dict[ob]) |
| objects2.remove(ob) |
| self.assertEqual(len(objects2), 0) |
| |
| # Test iterkeyrefs() |
| objects2 = list(objects) |
| self.assertEqual(len(list(dict.iterkeyrefs())), len(objects)) |
| for wr in dict.iterkeyrefs(): |
| ob = wr() |
| self.assertIn(ob, dict) |
| self.assertEqual(ob.arg, dict[ob]) |
| objects2.remove(ob) |
| self.assertEqual(len(objects2), 0) |
| |
| def test_weak_valued_iters(self): |
| dict, objects = self.make_weak_valued_dict() |
| self.check_iters(dict) |
| |
| # Test valuerefs() |
| refs = dict.valuerefs() |
| self.assertEqual(len(refs), len(objects)) |
| objects2 = list(objects) |
| for wr in refs: |
| ob = wr() |
| self.assertEqual(ob, dict[ob.arg]) |
| self.assertEqual(ob.arg, dict[ob.arg].arg) |
| objects2.remove(ob) |
| self.assertEqual(len(objects2), 0) |
| |
| # Test itervaluerefs() |
| objects2 = list(objects) |
| self.assertEqual(len(list(dict.itervaluerefs())), len(objects)) |
| for wr in dict.itervaluerefs(): |
| ob = wr() |
| self.assertEqual(ob, dict[ob.arg]) |
| self.assertEqual(ob.arg, dict[ob.arg].arg) |
| objects2.remove(ob) |
| self.assertEqual(len(objects2), 0) |
| |
| def check_iters(self, dict): |
| # item iterator: |
| items = dict.items() |
| for item in dict.iteritems(): |
| items.remove(item) |
| self.assertTrue(len(items) == 0, "iteritems() did not touch all items") |
| |
| # key iterator, via __iter__(): |
| keys = dict.keys() |
| for k in dict: |
| keys.remove(k) |
| self.assertTrue(len(keys) == 0, "__iter__() did not touch all keys") |
| |
| # key iterator, via iterkeys(): |
| keys = dict.keys() |
| for k in dict.iterkeys(): |
| keys.remove(k) |
| self.assertTrue(len(keys) == 0, "iterkeys() did not touch all keys") |
| |
| # value iterator: |
| values = dict.values() |
| for v in dict.itervalues(): |
| values.remove(v) |
| self.assertTrue(len(values) == 0, |
| "itervalues() did not touch all values") |
| |
| def test_make_weak_keyed_dict_from_dict(self): |
| o = Object(3) |
| dict = weakref.WeakKeyDictionary({o:364}) |
| self.assertTrue(dict[o] == 364) |
| |
| def test_make_weak_keyed_dict_from_weak_keyed_dict(self): |
| o = Object(3) |
| dict = weakref.WeakKeyDictionary({o:364}) |
| dict2 = weakref.WeakKeyDictionary(dict) |
| self.assertTrue(dict[o] == 364) |
| |
| def make_weak_keyed_dict(self): |
| dict = weakref.WeakKeyDictionary() |
| objects = map(Object, range(self.COUNT)) |
| for o in objects: |
| dict[o] = o.arg |
| return dict, objects |
| |
| def make_weak_valued_dict(self): |
| dict = weakref.WeakValueDictionary() |
| objects = map(Object, range(self.COUNT)) |
| for o in objects: |
| dict[o.arg] = o |
| return dict, objects |
| |
| def check_popitem(self, klass, key1, value1, key2, value2): |
| weakdict = klass() |
| weakdict[key1] = value1 |
| weakdict[key2] = value2 |
| self.assertTrue(len(weakdict) == 2) |
| k, v = weakdict.popitem() |
| self.assertTrue(len(weakdict) == 1) |
| if k is key1: |
| self.assertTrue(v is value1) |
| else: |
| self.assertTrue(v is value2) |
| k, v = weakdict.popitem() |
| self.assertTrue(len(weakdict) == 0) |
| if k is key1: |
| self.assertTrue(v is value1) |
| else: |
| self.assertTrue(v is value2) |
| |
| def test_weak_valued_dict_popitem(self): |
| self.check_popitem(weakref.WeakValueDictionary, |
| "key1", C(), "key2", C()) |
| |
| def test_weak_keyed_dict_popitem(self): |
| self.check_popitem(weakref.WeakKeyDictionary, |
| C(), "value 1", C(), "value 2") |
| |
| def check_setdefault(self, klass, key, value1, value2): |
| self.assertTrue(value1 is not value2, |
| "invalid test" |
| " -- value parameters must be distinct objects") |
| weakdict = klass() |
| o = weakdict.setdefault(key, value1) |
| self.assertIs(o, value1) |
| self.assertIn(key, weakdict) |
| self.assertIs(weakdict.get(key), value1) |
| self.assertIs(weakdict[key], value1) |
| |
| o = weakdict.setdefault(key, value2) |
| self.assertIs(o, value1) |
| self.assertIn(key, weakdict) |
| self.assertIs(weakdict.get(key), value1) |
| self.assertIs(weakdict[key], value1) |
| |
| def test_weak_valued_dict_setdefault(self): |
| self.check_setdefault(weakref.WeakValueDictionary, |
| "key", C(), C()) |
| |
| def test_weak_keyed_dict_setdefault(self): |
| self.check_setdefault(weakref.WeakKeyDictionary, |
| C(), "value 1", "value 2") |
| |
| def check_update(self, klass, dict): |
| # |
| # This exercises d.update(), len(d), d.keys(), in d, |
| # d.get(), d[]. |
| # |
| weakdict = klass() |
| weakdict.update(dict) |
| self.assertEqual(len(weakdict), len(dict)) |
| for k in weakdict.keys(): |
| self.assertIn(k, dict, |
| "mysterious new key appeared in weak dict") |
| v = dict.get(k) |
| self.assertIs(v, weakdict[k]) |
| self.assertIs(v, weakdict.get(k)) |
| for k in dict.keys(): |
| self.assertIn(k, weakdict, |
| "original key disappeared in weak dict") |
| v = dict[k] |
| self.assertIs(v, weakdict[k]) |
| self.assertIs(v, weakdict.get(k)) |
| |
| def test_weak_valued_dict_update(self): |
| self.check_update(weakref.WeakValueDictionary, |
| {1: C(), 'a': C(), C(): C()}) |
| |
| def test_weak_keyed_dict_update(self): |
| self.check_update(weakref.WeakKeyDictionary, |
| {C(): 1, C(): 2, C(): 3}) |
| |
| def test_weak_keyed_delitem(self): |
| d = weakref.WeakKeyDictionary() |
| o1 = Object('1') |
| o2 = Object('2') |
| d[o1] = 'something' |
| d[o2] = 'something' |
| self.assertTrue(len(d) == 2) |
| del d[o1] |
| self.assertTrue(len(d) == 1) |
| self.assertTrue(d.keys() == [o2]) |
| |
| def test_weak_valued_delitem(self): |
| d = weakref.WeakValueDictionary() |
| o1 = Object('1') |
| o2 = Object('2') |
| d['something'] = o1 |
| d['something else'] = o2 |
| self.assertTrue(len(d) == 2) |
| del d['something'] |
| self.assertTrue(len(d) == 1) |
| self.assertTrue(d.items() == [('something else', o2)]) |
| |
| def test_weak_keyed_bad_delitem(self): |
| d = weakref.WeakKeyDictionary() |
| o = Object('1') |
| # An attempt to delete an object that isn't there should raise |
| # KeyError. It didn't before 2.3. |
| self.assertRaises(KeyError, d.__delitem__, o) |
| self.assertRaises(KeyError, d.__getitem__, o) |
| |
| # If a key isn't of a weakly referencable type, __getitem__ and |
| # __setitem__ raise TypeError. __delitem__ should too. |
| self.assertRaises(TypeError, d.__delitem__, 13) |
| self.assertRaises(TypeError, d.__getitem__, 13) |
| self.assertRaises(TypeError, d.__setitem__, 13, 13) |
| |
| def test_weak_keyed_cascading_deletes(self): |
| # SF bug 742860. For some reason, before 2.3 __delitem__ iterated |
| # over the keys via self.data.iterkeys(). If things vanished from |
| # the dict during this (or got added), that caused a RuntimeError. |
| |
| d = weakref.WeakKeyDictionary() |
| mutate = False |
| |
| class C(object): |
| def __init__(self, i): |
| self.value = i |
| def __hash__(self): |
| return hash(self.value) |
| def __eq__(self, other): |
| if mutate: |
| # Side effect that mutates the dict, by removing the |
| # last strong reference to a key. |
| del objs[-1] |
| return self.value == other.value |
| |
| objs = [C(i) for i in range(4)] |
| for o in objs: |
| d[o] = o.value |
| del o # now the only strong references to keys are in objs |
| # Find the order in which iterkeys sees the keys. |
| objs = d.keys() |
| # Reverse it, so that the iteration implementation of __delitem__ |
| # has to keep looping to find the first object we delete. |
| objs.reverse() |
| |
| # Turn on mutation in C.__eq__. The first time thru the loop, |
| # under the iterkeys() business the first comparison will delete |
| # the last item iterkeys() would see, and that causes a |
| # RuntimeError: dictionary changed size during iteration |
| # when the iterkeys() loop goes around to try comparing the next |
| # key. After this was fixed, it just deletes the last object *our* |
| # "for o in obj" loop would have gotten to. |
| mutate = True |
| count = 0 |
| for o in objs: |
| count += 1 |
| del d[o] |
| self.assertEqual(len(d), 0) |
| self.assertEqual(count, 2) |
| |
| from test import mapping_tests |
| |
| class WeakValueDictionaryTestCase(mapping_tests.BasicTestMappingProtocol): |
| """Check that WeakValueDictionary conforms to the mapping protocol""" |
| __ref = {"key1":Object(1), "key2":Object(2), "key3":Object(3)} |
| type2test = weakref.WeakValueDictionary |
| def _reference(self): |
| return self.__ref.copy() |
| |
| class WeakKeyDictionaryTestCase(mapping_tests.BasicTestMappingProtocol): |
| """Check that WeakKeyDictionary conforms to the mapping protocol""" |
| __ref = {Object("key1"):1, Object("key2"):2, Object("key3"):3} |
| type2test = weakref.WeakKeyDictionary |
| def _reference(self): |
| return self.__ref.copy() |
| |
| libreftest = """ Doctest for examples in the library reference: weakref.rst |
| |
| >>> import weakref |
| >>> class Dict(dict): |
| ... pass |
| ... |
| >>> obj = Dict(red=1, green=2, blue=3) # this object is weak referencable |
| >>> r = weakref.ref(obj) |
| >>> print r() is obj |
| True |
| |
| >>> import weakref |
| >>> class Object: |
| ... pass |
| ... |
| >>> o = Object() |
| >>> r = weakref.ref(o) |
| >>> o2 = r() |
| >>> o is o2 |
| True |
| >>> del o, o2 |
| >>> print r() |
| None |
| |
| >>> import weakref |
| >>> class ExtendedRef(weakref.ref): |
| ... def __init__(self, ob, callback=None, **annotations): |
| ... super(ExtendedRef, self).__init__(ob, callback) |
| ... self.__counter = 0 |
| ... for k, v in annotations.iteritems(): |
| ... setattr(self, k, v) |
| ... def __call__(self): |
| ... '''Return a pair containing the referent and the number of |
| ... times the reference has been called. |
| ... ''' |
| ... ob = super(ExtendedRef, self).__call__() |
| ... if ob is not None: |
| ... self.__counter += 1 |
| ... ob = (ob, self.__counter) |
| ... return ob |
| ... |
| >>> class A: # not in docs from here, just testing the ExtendedRef |
| ... pass |
| ... |
| >>> a = A() |
| >>> r = ExtendedRef(a, foo=1, bar="baz") |
| >>> r.foo |
| 1 |
| >>> r.bar |
| 'baz' |
| >>> r()[1] |
| 1 |
| >>> r()[1] |
| 2 |
| >>> r()[0] is a |
| True |
| |
| |
| >>> import weakref |
| >>> _id2obj_dict = weakref.WeakValueDictionary() |
| >>> def remember(obj): |
| ... oid = id(obj) |
| ... _id2obj_dict[oid] = obj |
| ... return oid |
| ... |
| >>> def id2obj(oid): |
| ... return _id2obj_dict[oid] |
| ... |
| >>> a = A() # from here, just testing |
| >>> a_id = remember(a) |
| >>> id2obj(a_id) is a |
| True |
| >>> del a |
| >>> try: |
| ... id2obj(a_id) |
| ... except KeyError: |
| ... print 'OK' |
| ... else: |
| ... print 'WeakValueDictionary error' |
| OK |
| |
| """ |
| |
| __test__ = {'libreftest' : libreftest} |
| |
| def test_main(): |
| test_support.run_unittest( |
| ReferencesTestCase, |
| MappingTestCase, |
| WeakValueDictionaryTestCase, |
| WeakKeyDictionaryTestCase, |
| SubclassableWeakrefTestCase, |
| ) |
| test_support.run_doctest(sys.modules[__name__]) |
| |
| |
| if __name__ == "__main__": |
| test_main() |
