pybind11/tests/test_smart_ptr.py

import pytest
from pybind11_tests import ConstructorStats


def test_smart_ptr(capture):
    # Object1
    from pybind11_tests import (MyObject1, make_object_1, make_object_2,
                                print_object_1, print_object_2, print_object_3, print_object_4)

    for i, o in enumerate([make_object_1(), make_object_2(), MyObject1(3)], start=1):
        assert o.getRefCount() == 1
        with capture:
            print_object_1(o)
            print_object_2(o)
            print_object_3(o)
            print_object_4(o)
        assert capture == "MyObject1[{i}]\n".format(i=i) * 4

    from pybind11_tests import (make_myobject1_1, make_myobject1_2,
                                print_myobject1_1, print_myobject1_2,
                                print_myobject1_3, print_myobject1_4)

    for i, o in enumerate([make_myobject1_1(), make_myobject1_2(), MyObject1(6), 7], start=4):
        print(o)
        with capture:
            if not isinstance(o, int):
                print_object_1(o)
                print_object_2(o)
                print_object_3(o)
                print_object_4(o)
            print_myobject1_1(o)
            print_myobject1_2(o)
            print_myobject1_3(o)
            print_myobject1_4(o)
        assert capture == "MyObject1[{i}]\n".format(i=i) * (4 if isinstance(o, int) else 8)

    cstats = ConstructorStats.get(MyObject1)
    assert cstats.alive() == 0
    expected_values = ['MyObject1[{}]'.format(i) for i in range(1, 7)] + ['MyObject1[7]'] * 4
    assert cstats.values() == expected_values
    assert cstats.default_constructions == 0
    assert cstats.copy_constructions == 0
    # assert cstats.move_constructions >= 0 # Doesn't invoke any
    assert cstats.copy_assignments == 0
    assert cstats.move_assignments == 0

    # Object2
    from pybind11_tests import (MyObject2, make_myobject2_1, make_myobject2_2,
                                make_myobject3_1, make_myobject3_2,
                                print_myobject2_1, print_myobject2_2,
                                print_myobject2_3, print_myobject2_4)

    for i, o in zip([8, 6, 7], [MyObject2(8), make_myobject2_1(), make_myobject2_2()]):
        print(o)
        with capture:
            print_myobject2_1(o)
            print_myobject2_2(o)
            print_myobject2_3(o)
            print_myobject2_4(o)
        assert capture == "MyObject2[{i}]\n".format(i=i) * 4

    cstats = ConstructorStats.get(MyObject2)
    assert cstats.alive() == 1
    o = None
    assert cstats.alive() == 0
    assert cstats.values() == ['MyObject2[8]', 'MyObject2[6]', 'MyObject2[7]']
    assert cstats.default_constructions == 0
    assert cstats.copy_constructions == 0
    # assert cstats.move_constructions >= 0 # Doesn't invoke any
    assert cstats.copy_assignments == 0
    assert cstats.move_assignments == 0

    # Object3
    from pybind11_tests import (MyObject3, print_myobject3_1, print_myobject3_2,
                                print_myobject3_3, print_myobject3_4)

    for i, o in zip([9, 8, 9], [MyObject3(9), make_myobject3_1(), make_myobject3_2()]):
        print(o)
        with capture:
            print_myobject3_1(o)
            print_myobject3_2(o)
            print_myobject3_3(o)
            print_myobject3_4(o)
        assert capture == "MyObject3[{i}]\n".format(i=i) * 4

    cstats = ConstructorStats.get(MyObject3)
    assert cstats.alive() == 1
    o = None
    assert cstats.alive() == 0
    assert cstats.values() == ['MyObject3[9]', 'MyObject3[8]', 'MyObject3[9]']
    assert cstats.default_constructions == 0
    assert cstats.copy_constructions == 0
    # assert cstats.move_constructions >= 0 # Doesn't invoke any
    assert cstats.copy_assignments == 0
    assert cstats.move_assignments == 0

    # Object and ref
    from pybind11_tests import Object, cstats_ref

    cstats = ConstructorStats.get(Object)
    assert cstats.alive() == 0
    assert cstats.values() == []
    assert cstats.default_constructions == 10
    assert cstats.copy_constructions == 0
    # assert cstats.move_constructions >= 0 # Doesn't invoke any
    assert cstats.copy_assignments == 0
    assert cstats.move_assignments == 0

    cstats = cstats_ref()
    assert cstats.alive() == 0
    assert cstats.values() == ['from pointer'] * 10
    assert cstats.default_constructions == 30
    assert cstats.copy_constructions == 12
    # assert cstats.move_constructions >= 0 # Doesn't invoke any
    assert cstats.copy_assignments == 30
    assert cstats.move_assignments == 0


def test_smart_ptr_refcounting():
    from pybind11_tests import test_object1_refcounting
    assert test_object1_refcounting()


def test_unique_nodelete():
    from pybind11_tests import MyObject4
    o = MyObject4(23)
    assert o.value == 23
    cstats = ConstructorStats.get(MyObject4)
    assert cstats.alive() == 1
    del o
    cstats = ConstructorStats.get(MyObject4)
    assert cstats.alive() == 1  # Leak, but that's intentional


def test_large_holder():
    from pybind11_tests import MyObject5
    o = MyObject5(5)
    assert o.value == 5
    cstats = ConstructorStats.get(MyObject5)
    assert cstats.alive() == 1
    del o
    assert cstats.alive() == 0


def test_shared_ptr_and_references():
    from pybind11_tests.smart_ptr import SharedPtrRef, A

    s = SharedPtrRef()
    stats = ConstructorStats.get(A)
    assert stats.alive() == 2

    ref = s.ref  # init_holder_helper(holder_ptr=false, owned=false)
    assert stats.alive() == 2
    assert s.set_ref(ref)
    with pytest.raises(RuntimeError) as excinfo:
        assert s.set_holder(ref)
    assert "Unable to cast from non-held to held instance" in str(excinfo.value)

    copy = s.copy  # init_holder_helper(holder_ptr=false, owned=true)
    assert stats.alive() == 3
    assert s.set_ref(copy)
    assert s.set_holder(copy)

    holder_ref = s.holder_ref  # init_holder_helper(holder_ptr=true, owned=false)
    assert stats.alive() == 3
    assert s.set_ref(holder_ref)
    assert s.set_holder(holder_ref)

    holder_copy = s.holder_copy  # init_holder_helper(holder_ptr=true, owned=true)
    assert stats.alive() == 3
    assert s.set_ref(holder_copy)
    assert s.set_holder(holder_copy)

    del ref, copy, holder_ref, holder_copy, s
    assert stats.alive() == 0


def test_shared_ptr_from_this_and_references():
    from pybind11_tests.smart_ptr import SharedFromThisRef, B, SharedFromThisVirt

    s = SharedFromThisRef()
    stats = ConstructorStats.get(B)
    assert stats.alive() == 2

    ref = s.ref  # init_holder_helper(holder_ptr=false, owned=false, bad_wp=false)
    assert stats.alive() == 2
    assert s.set_ref(ref)
    assert s.set_holder(ref)  # std::enable_shared_from_this can create a holder from a reference

    bad_wp = s.bad_wp  # init_holder_helper(holder_ptr=false, owned=false, bad_wp=true)
    assert stats.alive() == 2
    assert s.set_ref(bad_wp)
    with pytest.raises(RuntimeError) as excinfo:
        assert s.set_holder(bad_wp)
    assert "Unable to cast from non-held to held instance" in str(excinfo.value)

    copy = s.copy  # init_holder_helper(holder_ptr=false, owned=true, bad_wp=false)
    assert stats.alive() == 3
    assert s.set_ref(copy)
    assert s.set_holder(copy)

    holder_ref = s.holder_ref  # init_holder_helper(holder_ptr=true, owned=false, bad_wp=false)
    assert stats.alive() == 3
    assert s.set_ref(holder_ref)
    assert s.set_holder(holder_ref)

    holder_copy = s.holder_copy  # init_holder_helper(holder_ptr=true, owned=true, bad_wp=false)
    assert stats.alive() == 3
    assert s.set_ref(holder_copy)
    assert s.set_holder(holder_copy)

    del ref, bad_wp, copy, holder_ref, holder_copy, s
    assert stats.alive() == 0

    z = SharedFromThisVirt.get()
    y = SharedFromThisVirt.get()
    assert y is z


def test_move_only_holder():
    from pybind11_tests.smart_ptr import TypeWithMoveOnlyHolder

    a = TypeWithMoveOnlyHolder.make()
    stats = ConstructorStats.get(TypeWithMoveOnlyHolder)
    assert stats.alive() == 1
    del a
    assert stats.alive() == 0


def test_smart_ptr_from_default():
    from pybind11_tests.smart_ptr import HeldByDefaultHolder

    instance = HeldByDefaultHolder()
    with pytest.raises(RuntimeError) as excinfo:
        HeldByDefaultHolder.load_shared_ptr(instance)
    assert "Unable to load a custom holder type from a default-holder instance" in str(excinfo)


def test_shared_ptr_gc():
    """#187: issue involving std::shared_ptr<> return value policy & garbage collection"""
    from pybind11_tests.smart_ptr import ElementList, ElementA

    el = ElementList()
    for i in range(10):
        el.add(ElementA(i))
    pytest.gc_collect()
    for i, v in enumerate(el.get()):
        assert i == v.value()