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	These never failed in 2.3, and the tests confirm it. They still blow up in the 2.2 branch, despite that all the gc-vs-__del__ fixes from 2.3 have been backported (and this is expected -- 2.2 needs more work than 2.3 needed).
		
			
				
	
	
		
			419 lines
		
	
	
	
		
			10 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
			
		
		
	
	
			419 lines
		
	
	
	
		
			10 KiB
		
	
	
	
		
			Python
		
	
	
	
	
	
from test.test_support import verify, verbose, TestFailed, vereq
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import sys
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import gc
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def expect(actual, expected, name):
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    if actual != expected:
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        raise TestFailed, "test_%s: actual %r, expected %r" % (
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            name, actual, expected)
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def expect_nonzero(actual, name):
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    if actual == 0:
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        raise TestFailed, "test_%s: unexpected zero" % name
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def run_test(name, thunk):
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    if verbose:
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        print "testing %s..." % name,
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    thunk()
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    if verbose:
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        print "ok"
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def test_list():
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    l = []
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    l.append(l)
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    gc.collect()
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    del l
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    expect(gc.collect(), 1, "list")
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def test_dict():
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    d = {}
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    d[1] = d
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    gc.collect()
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    del d
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    expect(gc.collect(), 1, "dict")
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def test_tuple():
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    # since tuples are immutable we close the loop with a list
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    l = []
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    t = (l,)
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    l.append(t)
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    gc.collect()
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    del t
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    del l
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    expect(gc.collect(), 2, "tuple")
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def test_class():
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    class A:
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        pass
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    A.a = A
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    gc.collect()
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    del A
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    expect_nonzero(gc.collect(), "class")
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def test_newstyleclass():
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    class A(object):
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        pass
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    gc.collect()
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    del A
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    expect_nonzero(gc.collect(), "staticclass")
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def test_instance():
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    class A:
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        pass
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    a = A()
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    a.a = a
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    gc.collect()
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    del a
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    expect_nonzero(gc.collect(), "instance")
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def test_newinstance():
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    class A(object):
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        pass
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    a = A()
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    a.a = a
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    gc.collect()
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    del a
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    expect_nonzero(gc.collect(), "newinstance")
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    class B(list):
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        pass
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    class C(B, A):
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        pass
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    a = C()
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    a.a = a
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    gc.collect()
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    del a
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    expect_nonzero(gc.collect(), "newinstance(2)")
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    del B, C
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    expect_nonzero(gc.collect(), "newinstance(3)")
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    A.a = A()
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    del A
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    expect_nonzero(gc.collect(), "newinstance(4)")
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    expect(gc.collect(), 0, "newinstance(5)")
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def test_method():
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    # Tricky: self.__init__ is a bound method, it references the instance.
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    class A:
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        def __init__(self):
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            self.init = self.__init__
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    a = A()
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    gc.collect()
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    del a
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    expect_nonzero(gc.collect(), "method")
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def test_finalizer():
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    # A() is uncollectable if it is part of a cycle, make sure it shows up
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    # in gc.garbage.
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    class A:
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        def __del__(self): pass
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    class B:
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        pass
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    a = A()
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    a.a = a
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    id_a = id(a)
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    b = B()
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    b.b = b
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    gc.collect()
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    del a
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    del b
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    expect_nonzero(gc.collect(), "finalizer")
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    for obj in gc.garbage:
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        if id(obj) == id_a:
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            del obj.a
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            break
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    else:
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        raise TestFailed, "didn't find obj in garbage (finalizer)"
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    gc.garbage.remove(obj)
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def test_finalizer_newclass():
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    # A() is uncollectable if it is part of a cycle, make sure it shows up
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    # in gc.garbage.
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    class A(object):
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        def __del__(self): pass
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    class B(object):
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        pass
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    a = A()
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    a.a = a
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    id_a = id(a)
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    b = B()
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    b.b = b
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    gc.collect()
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    del a
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    del b
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    expect_nonzero(gc.collect(), "finalizer")
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    for obj in gc.garbage:
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        if id(obj) == id_a:
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            del obj.a
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            break
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    else:
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        raise TestFailed, "didn't find obj in garbage (finalizer)"
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    gc.garbage.remove(obj)
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def test_function():
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    # Tricky: f -> d -> f, code should call d.clear() after the exec to
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    # break the cycle.
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    d = {}
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    exec("def f(): pass\n") in d
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    gc.collect()
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    del d
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    expect(gc.collect(), 2, "function")
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def test_frame():
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    def f():
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        frame = sys._getframe()
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    gc.collect()
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    f()
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    expect(gc.collect(), 1, "frame")
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def test_saveall():
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    # Verify that cyclic garbage like lists show up in gc.garbage if the
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    # SAVEALL option is enabled.
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    # First make sure we don't save away other stuff that just happens to
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    # be waiting for collection.
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    gc.collect()
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    vereq(gc.garbage, []) # if this fails, someone else created immortal trash
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    L = []
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    L.append(L)
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    id_L = id(L)
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    debug = gc.get_debug()
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    gc.set_debug(debug | gc.DEBUG_SAVEALL)
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    del L
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    gc.collect()
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    gc.set_debug(debug)
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    vereq(len(gc.garbage), 1)
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    obj = gc.garbage.pop()
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    vereq(id(obj), id_L)
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def test_del():
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    # __del__ methods can trigger collection, make this to happen
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    thresholds = gc.get_threshold()
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    gc.enable()
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    gc.set_threshold(1)
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    class A:
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        def __del__(self):
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            dir(self)
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    a = A()
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    del a
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    gc.disable()
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    gc.set_threshold(*thresholds)
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def test_del_newclass():
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    # __del__ methods can trigger collection, make this to happen
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    thresholds = gc.get_threshold()
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    gc.enable()
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    gc.set_threshold(1)
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    class A(object):
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        def __del__(self):
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            dir(self)
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    a = A()
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    del a
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    gc.disable()
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    gc.set_threshold(*thresholds)
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class Ouch:
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    n = 0
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    def __del__(self):
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        Ouch.n = Ouch.n + 1
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        if Ouch.n % 17 == 0:
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            gc.collect()
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def test_trashcan():
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    # "trashcan" is a hack to prevent stack overflow when deallocating
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    # very deeply nested tuples etc.  It works in part by abusing the
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    # type pointer and refcount fields, and that can yield horrible
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    # problems when gc tries to traverse the structures.
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    # If this test fails (as it does in 2.0, 2.1 and 2.2), it will
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    # most likely die via segfault.
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    # Note:  In 2.3 the possibility for compiling without cyclic gc was
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    # removed, and that in turn allows the trashcan mechanism to work
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    # via much simpler means (e.g., it never abuses the type pointer or
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    # refcount fields anymore).  Since it's much less likely to cause a
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    # problem now, the various constants in this expensive (we force a lot
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    # of full collections) test are cut back from the 2.2 version.
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    gc.enable()
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    N = 150
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    for count in range(2):
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        t = []
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        for i in range(N):
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            t = [t, Ouch()]
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        u = []
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        for i in range(N):
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            u = [u, Ouch()]
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        v = {}
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        for i in range(N):
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            v = {1: v, 2: Ouch()}
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    gc.disable()
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class Boom:
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    def __getattr__(self, someattribute):
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        del self.attr
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        raise AttributeError
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def test_boom():
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    a = Boom()
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    b = Boom()
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    a.attr = b
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    b.attr = a
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    gc.collect()
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    garbagelen = len(gc.garbage)
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    del a, b
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    # a<->b are in a trash cycle now.  Collection will invoke Boom.__getattr__
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    # (to see whether a and b have __del__ methods), and __getattr__ deletes
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    # the internal "attr" attributes as a side effect.  That causes the
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    # trash cycle to get reclaimed via refcounts falling to 0, thus mutating
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    # the trash graph as a side effect of merely asking whether __del__
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    # exists.  This used to (before 2.3b1) crash Python.  Now __getattr__
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    # isn't called.
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    expect(gc.collect(), 4, "boom")
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    expect(len(gc.garbage), garbagelen, "boom")
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class Boom2:
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    def __init__(self):
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        self.x = 0
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    def __getattr__(self, someattribute):
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        self.x += 1
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        if self.x > 1:
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            del self.attr
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        raise AttributeError
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def test_boom2():
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    a = Boom2()
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    b = Boom2()
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    a.attr = b
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    b.attr = a
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    gc.collect()
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    garbagelen = len(gc.garbage)
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    del a, b
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    # Much like test_boom(), except that __getattr__ doesn't break the
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    # cycle until the second time gc checks for __del__.  As of 2.3b1,
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    # there isn't a second time, so this simply cleans up the trash cycle.
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    # We expect a, b, a.__dict__ and b.__dict__ (4 objects) to get reclaimed
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    # this way.
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    expect(gc.collect(), 4, "boom2")
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    expect(len(gc.garbage), garbagelen, "boom2")
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# boom__new and boom2_new are exactly like boom and boom2, except use
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# new-style classes.
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class Boom_New(object):
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    def __getattr__(self, someattribute):
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        del self.attr
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        raise AttributeError
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def test_boom_new():
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    a = Boom_New()
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    b = Boom_New()
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    a.attr = b
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    b.attr = a
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    gc.collect()
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    garbagelen = len(gc.garbage)
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    del a, b
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    expect(gc.collect(), 4, "boom_new")
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    expect(len(gc.garbage), garbagelen, "boom_new")
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class Boom2_New(object):
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    def __init__(self):
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        self.x = 0
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    def __getattr__(self, someattribute):
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        self.x += 1
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        if self.x > 1:
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            del self.attr
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        raise AttributeError
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def test_boom2_new():
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    a = Boom2_New()
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    b = Boom2_New()
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    a.attr = b
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    b.attr = a
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    gc.collect()
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    garbagelen = len(gc.garbage)
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    del a, b
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    expect(gc.collect(), 4, "boom2_new")
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    expect(len(gc.garbage), garbagelen, "boom2_new")
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def test_get_referents():
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    alist = [1, 3, 5]
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    got = gc.get_referents(alist)
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    got.sort()
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    expect(got, alist, "get_referents")
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    atuple = tuple(alist)
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    got = gc.get_referents(atuple)
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    got.sort()
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    expect(got, alist, "get_referents")
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    adict = {1: 3, 5: 7}
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    expected = [1, 3, 5, 7]
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    got = gc.get_referents(adict)
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    got.sort()
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    expect(got, expected, "get_referents")
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    got = gc.get_referents([1, 2], {3: 4}, (0, 0, 0))
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    got.sort()
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    expect(got, [0, 0] + range(5), "get_referents")
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    expect(gc.get_referents(1, 'a', 4j), [], "get_referents")
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def test_all():
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    gc.collect() # Delete 2nd generation garbage
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    run_test("lists", test_list)
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    run_test("dicts", test_dict)
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    run_test("tuples", test_tuple)
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    run_test("classes", test_class)
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    run_test("new style classes", test_newstyleclass)
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    run_test("instances", test_instance)
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    run_test("new instances", test_newinstance)
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    run_test("methods", test_method)
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    run_test("functions", test_function)
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    run_test("frames", test_frame)
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    run_test("finalizers", test_finalizer)
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    run_test("finalizers (new class)", test_finalizer_newclass)
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    run_test("__del__", test_del)
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    run_test("__del__ (new class)", test_del_newclass)
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    run_test("saveall", test_saveall)
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    run_test("trashcan", test_trashcan)
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    run_test("boom", test_boom)
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    run_test("boom2", test_boom2)
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    run_test("boom_new", test_boom_new)
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    run_test("boom2_new", test_boom2_new)
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    run_test("get_referents", test_get_referents)
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def test():
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    if verbose:
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        print "disabling automatic collection"
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    enabled = gc.isenabled()
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    gc.disable()
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    verify(not gc.isenabled())
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    debug = gc.get_debug()
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    gc.set_debug(debug & ~gc.DEBUG_LEAK) # this test is supposed to leak
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    try:
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        test_all()
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    finally:
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        gc.set_debug(debug)
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        # test gc.enable() even if GC is disabled by default
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        if verbose:
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            print "restoring automatic collection"
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        # make sure to always test gc.enable()
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        gc.enable()
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        verify(gc.isenabled())
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        if not enabled:
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            gc.disable()
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test()
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