Bug fix: trampoline_self_life_support CpCtor, MvCtor. (#2947)

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Ralf W. Grosse-Kunstleve 2021-04-13 05:34:46 -07:00 committed by GitHub
parent 6c922614ed
commit 8efd5e3820
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4 changed files with 132 additions and 6 deletions

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@ -22,6 +22,8 @@ PYBIND11_NAMESPACE_END(detail)
struct trampoline_self_life_support {
detail::value_and_holder v_h;
trampoline_self_life_support() = default;
void activate_life_support(const detail::value_and_holder &v_h_) {
Py_INCREF((PyObject *) v_h_.inst);
v_h = v_h_;
@ -46,12 +48,14 @@ struct trampoline_self_life_support {
}
}
// Some compilers complain about implicitly defined versions of some of the following:
trampoline_self_life_support() = default;
trampoline_self_life_support(const trampoline_self_life_support &) = default;
trampoline_self_life_support(trampoline_self_life_support &&) = default;
trampoline_self_life_support &operator=(const trampoline_self_life_support &) = default;
trampoline_self_life_support &operator=(trampoline_self_life_support &&) = default;
// For the next two, the default implementations generate undefined behavior (ASAN failures
// manually verified). The reason is that v_h needs to be kept default-initialized.
trampoline_self_life_support(const trampoline_self_life_support &) {}
trampoline_self_life_support(trampoline_self_life_support &&) {}
// These should never be needed (please provide test cases if you think they are).
trampoline_self_life_support &operator=(const trampoline_self_life_support &) = delete;
trampoline_self_life_support &operator=(trampoline_self_life_support &&) = delete;
};
PYBIND11_NAMESPACE_END(PYBIND11_NAMESPACE)

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@ -107,6 +107,7 @@ set(PYBIND11_TEST_FILES
test_class_sh_factory_constructors.cpp
test_class_sh_inheritance.cpp
test_class_sh_trampoline_basic.cpp
test_class_sh_trampoline_self_life_support.cpp
test_class_sh_trampoline_shared_ptr_cpp_arg.cpp
test_class_sh_trampoline_unique_ptr.cpp
test_class_sh_unique_ptr_member.cpp

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@ -0,0 +1,84 @@
// Copyright (c) 2021 The Pybind Development Team.
// All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.
#include "pybind11/smart_holder.h"
#include "pybind11/trampoline_self_life_support.h"
#include "pybind11_tests.h"
#include <memory>
#include <string>
namespace {
struct Big5 { // Also known as "rule of five".
std::string history;
explicit Big5(std::string history_start) : history{history_start} {}
Big5(const Big5 &other) { history = other.history + "_CpCtor"; }
Big5(Big5 &&other) { history = other.history + "_MvCtor"; }
Big5 &operator=(const Big5 &other) {
history = other.history + "_OpEqLv";
return *this;
}
Big5 &operator=(Big5 &&other) {
history = other.history + "_OpEqRv";
return *this;
}
virtual ~Big5() = default;
protected:
Big5() : history{"DefaultConstructor"} {}
};
struct Big5Trampoline : Big5, py::trampoline_self_life_support {
using Big5::Big5;
};
} // namespace
PYBIND11_SMART_HOLDER_TYPE_CASTERS(Big5)
TEST_SUBMODULE(class_sh_trampoline_self_life_support, m) {
py::classh<Big5, Big5Trampoline>(m, "Big5")
.def(py::init<std::string>())
.def_readonly("history", &Big5::history);
m.def("action", [](std::unique_ptr<Big5> obj, int action_id) {
py::object o2 = py::none();
// This is very unusual, but needed to directly exercise the trampoline_self_life_support
// CpCtor, MvCtor, operator= lvalue, operator= rvalue.
auto obj_trampoline = dynamic_cast<Big5Trampoline *>(obj.get());
if (obj_trampoline != nullptr) {
switch (action_id) {
case 0: { // CpCtor
std::unique_ptr<Big5> cp(new Big5Trampoline(*obj_trampoline));
o2 = py::cast(std::move(cp));
} break;
case 1: { // MvCtor
std::unique_ptr<Big5> mv(new Big5Trampoline(std::move(*obj_trampoline)));
o2 = py::cast(std::move(mv));
} break;
case 2: { // operator= lvalue
std::unique_ptr<Big5> lv(new Big5Trampoline);
*lv = *obj_trampoline;
o2 = py::cast(std::move(lv));
} break;
case 3: { // operator= rvalue
std::unique_ptr<Big5> rv(new Big5Trampoline);
*rv = std::move(*obj_trampoline);
o2 = py::cast(std::move(rv));
} break;
default:
break;
}
}
py::object o1 = py::cast(std::move(obj));
return py::make_tuple(o1, o2);
});
}

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@ -0,0 +1,37 @@
# -*- coding: utf-8 -*-
import pytest
import pybind11_tests.class_sh_trampoline_self_life_support as m
class PyBig5(m.Big5):
pass
def test_m_big5():
obj = m.Big5("Seed")
assert obj.history == "Seed"
o1, o2 = m.action(obj, 0)
assert o1 is not obj
assert o1.history == "Seed"
with pytest.raises(ValueError) as excinfo:
obj.history
assert "Python instance was disowned" in str(excinfo.value)
assert o2 is None
@pytest.mark.parametrize(
"action_id, expected_history",
[
(0, "Seed_CpCtor"),
(1, "Seed_MvCtor"),
(2, "Seed_OpEqLv"),
(3, "Seed_OpEqRv"),
],
)
def test_py_big5(action_id, expected_history):
obj = PyBig5("Seed")
assert obj.history == "Seed"
o1, o2 = m.action(obj, action_id)
assert o1 is obj
assert o2.history == expected_history