pybind11/tests/test_multiple_inheritance.cpp

/*
    tests/test_multiple_inheritance.cpp -- multiple inheritance,
    implicit MI casts

    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>

    All rights reserved. Use of this source code is governed by a
    BSD-style license that can be found in the LICENSE file.
*/

#include "constructor_stats.h"
#include "pybind11_tests.h"

namespace {

// Many bases for testing that multiple inheritance from many classes (i.e. requiring extra
// space for holder constructed flags) works.
template <int N>
struct BaseN {
    explicit BaseN(int i) : i(i) {}
    int i;
};

// test_mi_static_properties
struct Vanilla {
    std::string vanilla() { return "Vanilla"; };
};
struct WithStatic1 {
    static std::string static_func1() { return "WithStatic1"; };
    static int static_value1;
};
struct WithStatic2 {
    static std::string static_func2() { return "WithStatic2"; };
    static int static_value2;
};
struct VanillaStaticMix1 : Vanilla, WithStatic1, WithStatic2 {
    static std::string static_func() { return "VanillaStaticMix1"; }
    static int static_value;
};
struct VanillaStaticMix2 : WithStatic1, Vanilla, WithStatic2 {
    static std::string static_func() { return "VanillaStaticMix2"; }
    static int static_value;
};
int WithStatic1::static_value1 = 1;
int WithStatic2::static_value2 = 2;
int VanillaStaticMix1::static_value = 12;
int VanillaStaticMix2::static_value = 12;

// test_multiple_inheritance_virtbase
struct Base1a {
    explicit Base1a(int i) : i(i) {}
    int foo() const { return i; }
    int i;
};
struct Base2a {
    explicit Base2a(int i) : i(i) {}
    int bar() const { return i; }
    int i;
};
struct Base12a : Base1a, Base2a {
    Base12a(int i, int j) : Base1a(i), Base2a(j) {}
};

// test_mi_unaligned_base
// test_mi_base_return
struct I801B1 {
    int a = 1;
    I801B1() = default;
    I801B1(const I801B1 &) = default;
    virtual ~I801B1() = default;
};
struct I801B2 {
    int b = 2;
    I801B2() = default;
    I801B2(const I801B2 &) = default;
    virtual ~I801B2() = default;
};
struct I801C : I801B1, I801B2 {};
struct I801D : I801C {}; // Indirect MI

} // namespace

namespace TrampolineNesting {
class ChainBaseA {
public:
    ChainBaseA() = default;
    ChainBaseA(const ChainBaseA &) = default;
    ChainBaseA(ChainBaseA &&) = default;
    virtual ~ChainBaseA() = default;
    virtual int resultA() { return 1; }
};
class ChainChildA : public ChainBaseA {
public:
    using ChainBaseA::ChainBaseA;
    int resultA() override { return 2; }
};
class ChainBaseB {
public:
    ChainBaseB() = default;
    ChainBaseB(const ChainBaseB &) = default;
    ChainBaseB(ChainBaseB &&) = default;
    virtual ~ChainBaseB() = default;
    virtual std::string resultB() { return "A"; }
};
class ChainChildB : public ChainBaseB {
public:
    using ChainBaseB::ChainBaseB;
    std::string resultB() override { return "B"; }
};
class Joined : public ChainChildA, public ChainChildB {
public:
    Joined() = default;
    Joined(const Joined &) = default;
    Joined(Joined &&) = default;
};

template <class Base = ChainBaseA>
class TrampolineA : public Base {
public:
    using Base::Base;
    int resultA() override { PYBIND11_OVERLOAD(int, Base, resultA, ); }
};
template <class Base = ChainBaseB, class PyBase = Base>
class TrampolineB : public PyBase {
public:
    using PyBase::PyBase;
    std::string resultB() override { PYBIND11_OVERLOAD(std::string, Base, resultB, ); }
};
template <class Base = Joined>
class TrampolineJoined : public TrampolineB<Base, TrampolineA<Base>> {
public:
    using TrampolineB<Base, TrampolineA<Base>>::TrampolineB;
};
} // namespace TrampolineNesting

TEST_SUBMODULE(multiple_inheritance, m) {
    // Please do not interleave `struct` and `class` definitions with bindings code,
    // but implement `struct`s and `class`es in the anonymous namespace above.
    // This helps keeping the smart_holder branch in sync with master.

    // test_multiple_inheritance_mix1
    // test_multiple_inheritance_mix2
    struct Base1 {
        explicit Base1(int i) : i(i) {}
        int foo() const { return i; }
        int i;
    };
    py::class_<Base1> b1(m, "Base1");
    b1.def(py::init<int>()).def("foo", &Base1::foo);

    struct Base2 {
        explicit Base2(int i) : i(i) {}
        int bar() const { return i; }
        int i;
    };
    py::class_<Base2> b2(m, "Base2");
    b2.def(py::init<int>()).def("bar", &Base2::bar);

    // test_multiple_inheritance_cpp
    struct Base12 : Base1, Base2 {
        Base12(int i, int j) : Base1(i), Base2(j) {}
    };
    struct MIType : Base12 {
        MIType(int i, int j) : Base12(i, j) {}
    };
    py::class_<Base12, Base1, Base2>(m, "Base12");
    py::class_<MIType, Base12>(m, "MIType").def(py::init<int, int>());

    // test_multiple_inheritance_python_many_bases
#define PYBIND11_BASEN(N)                                                                         \
    py::class_<BaseN<(N)>>(m, "BaseN" #N).def(py::init<int>()).def("f" #N, [](BaseN<N> &b) {      \
        return b.i + (N);                                                                         \
    })
    PYBIND11_BASEN(1);
    PYBIND11_BASEN(2);
    PYBIND11_BASEN(3);
    PYBIND11_BASEN(4);
    PYBIND11_BASEN(5);
    PYBIND11_BASEN(6);
    PYBIND11_BASEN(7);
    PYBIND11_BASEN(8);
    PYBIND11_BASEN(9);
    PYBIND11_BASEN(10);
    PYBIND11_BASEN(11);
    PYBIND11_BASEN(12);
    PYBIND11_BASEN(13);
    PYBIND11_BASEN(14);
    PYBIND11_BASEN(15);
    PYBIND11_BASEN(16);
    PYBIND11_BASEN(17);

    // Uncommenting this should result in a compile time failure (MI can only be specified via
    // template parameters because pybind has to know the types involved; see discussion in #742
    // for details).
    //    struct Base12v2 : Base1, Base2 {
    //        Base12v2(int i, int j) : Base1(i), Base2(j) { }
    //    };
    //    py::class_<Base12v2>(m, "Base12v2", b1, b2)
    //        .def(py::init<int, int>());

    // test_multiple_inheritance_virtbase
    // Test the case where not all base classes are specified, and where pybind11 requires the
    // py::multiple_inheritance flag to perform proper casting between types.
    py::class_<Base1a, std::shared_ptr<Base1a>>(m, "Base1a")
        .def(py::init<int>())
        .def("foo", &Base1a::foo);

    py::class_<Base2a, std::shared_ptr<Base2a>>(m, "Base2a")
        .def(py::init<int>())
        .def("bar", &Base2a::bar);

    py::class_<Base12a, /* Base1 missing */ Base2a, std::shared_ptr<Base12a>>(
        m, "Base12a", py::multiple_inheritance())
        .def(py::init<int, int>());

    m.def("bar_base2a", [](Base2a *b) { return b->bar(); });
    m.def("bar_base2a_sharedptr", [](const std::shared_ptr<Base2a> &b) { return b->bar(); });

    // test_mi_unaligned_base
    // test_mi_base_return
    // Issue #801: invalid casting to derived type with MI bases
    // Unregistered classes:
    struct I801B3 {
        int c = 3;
        virtual ~I801B3() = default;
    };
    struct I801E : I801B3, I801D {};

    py::class_<I801B1, std::shared_ptr<I801B1>>(m, "I801B1")
        .def(py::init<>())
        .def_readonly("a", &I801B1::a);
    py::class_<I801B2, std::shared_ptr<I801B2>>(m, "I801B2")
        .def(py::init<>())
        .def_readonly("b", &I801B2::b);
    py::class_<I801C, I801B1, I801B2, std::shared_ptr<I801C>>(m, "I801C").def(py::init<>());
    py::class_<I801D, I801C, std::shared_ptr<I801D>>(m, "I801D").def(py::init<>());

    // Two separate issues here: first, we want to recognize a pointer to a base type as being a
    // known instance even when the pointer value is unequal (i.e. due to a non-first
    // multiple-inheritance base class):
    m.def("i801b1_c", [](I801C *c) { return static_cast<I801B1 *>(c); });
    m.def("i801b2_c", [](I801C *c) { return static_cast<I801B2 *>(c); });
    m.def("i801b1_d", [](I801D *d) { return static_cast<I801B1 *>(d); });
    m.def("i801b2_d", [](I801D *d) { return static_cast<I801B2 *>(d); });

    // Second, when returned a base class pointer to a derived instance, we cannot assume that the
    // pointer is `reinterpret_cast`able to the derived pointer because, like above, the base class
    // pointer could be offset.
    m.def("i801c_b1", []() -> I801B1 * { return new I801C(); });
    m.def("i801c_b2", []() -> I801B2 * { return new I801C(); });
    m.def("i801d_b1", []() -> I801B1 * { return new I801D(); });
    m.def("i801d_b2", []() -> I801B2 * { return new I801D(); });

    // Return a base class pointer to a pybind-registered type when the actual derived type
    // isn't pybind-registered (and uses multiple-inheritance to offset the pybind base)
    m.def("i801e_c", []() -> I801C * { return new I801E(); });
    m.def("i801e_b2", []() -> I801B2 * { return new I801E(); });

    // test_mi_static_properties
    py::class_<Vanilla>(m, "Vanilla").def(py::init<>()).def("vanilla", &Vanilla::vanilla);

    py::class_<WithStatic1>(m, "WithStatic1")
        .def(py::init<>())
        .def_static("static_func1", &WithStatic1::static_func1)
        .def_readwrite_static("static_value1", &WithStatic1::static_value1);

    py::class_<WithStatic2>(m, "WithStatic2")
        .def(py::init<>())
        .def_static("static_func2", &WithStatic2::static_func2)
        .def_readwrite_static("static_value2", &WithStatic2::static_value2);

    py::class_<VanillaStaticMix1, Vanilla, WithStatic1, WithStatic2>(m, "VanillaStaticMix1")
        .def(py::init<>())
        .def_static("static_func", &VanillaStaticMix1::static_func)
        .def_readwrite_static("static_value", &VanillaStaticMix1::static_value);

    py::class_<VanillaStaticMix2, WithStatic1, Vanilla, WithStatic2>(m, "VanillaStaticMix2")
        .def(py::init<>())
        .def_static("static_func", &VanillaStaticMix2::static_func)
        .def_readwrite_static("static_value", &VanillaStaticMix2::static_value);

    struct WithDict {};
    struct VanillaDictMix1 : Vanilla, WithDict {};
    struct VanillaDictMix2 : WithDict, Vanilla {};
    py::class_<WithDict>(m, "WithDict", py::dynamic_attr()).def(py::init<>());
    py::class_<VanillaDictMix1, Vanilla, WithDict>(m, "VanillaDictMix1").def(py::init<>());
    py::class_<VanillaDictMix2, WithDict, Vanilla>(m, "VanillaDictMix2").def(py::init<>());

    // test_diamond_inheritance
    // Issue #959: segfault when constructing diamond inheritance instance
    // All of these have int members so that there will be various unequal pointers involved.
    struct B {
        int b;
        B() = default;
        B(const B &) = default;
        virtual ~B() = default;
    };
    struct C0 : public virtual B {
        int c0;
    };
    struct C1 : public virtual B {
        int c1;
    };
    struct D : public C0, public C1 {
        int d;
    };
    py::class_<B>(m, "B").def("b", [](B *self) { return self; });
    py::class_<C0, B>(m, "C0").def("c0", [](C0 *self) { return self; });
    py::class_<C1, B>(m, "C1").def("c1", [](C1 *self) { return self; });
    py::class_<D, C0, C1>(m, "D").def(py::init<>());

    // test_pr3635_diamond_*
    // - functions are get_{base}_{var}, return {var}
    struct MVB {
        MVB() = default;
        MVB(const MVB &) = default;
        virtual ~MVB() = default;

        int b = 1;
        int get_b_b() const { return b; }
    };
    struct MVC : virtual MVB {
        int c = 2;
        int get_c_b() const { return b; }
        int get_c_c() const { return c; }
    };
    struct MVD0 : virtual MVC {
        int d0 = 3;
        int get_d0_b() const { return b; }
        int get_d0_c() const { return c; }
        int get_d0_d0() const { return d0; }
    };
    struct MVD1 : virtual MVC {
        int d1 = 4;
        int get_d1_b() const { return b; }
        int get_d1_c() const { return c; }
        int get_d1_d1() const { return d1; }
    };
    struct MVE : virtual MVD0, virtual MVD1 {
        int e = 5;
        int get_e_b() const { return b; }
        int get_e_c() const { return c; }
        int get_e_d0() const { return d0; }
        int get_e_d1() const { return d1; }
        int get_e_e() const { return e; }
    };
    struct MVF : virtual MVE {
        int f = 6;
        int get_f_b() const { return b; }
        int get_f_c() const { return c; }
        int get_f_d0() const { return d0; }
        int get_f_d1() const { return d1; }
        int get_f_e() const { return e; }
        int get_f_f() const { return f; }
    };
    py::class_<MVB>(m, "MVB")
        .def(py::init<>())
        .def("get_b_b", &MVB::get_b_b)
        .def_readwrite("b", &MVB::b);
    py::class_<MVC, MVB>(m, "MVC")
        .def(py::init<>())
        .def("get_c_b", &MVC::get_c_b)
        .def("get_c_c", &MVC::get_c_c)
        .def_readwrite("c", &MVC::c);
    py::class_<MVD0, MVC>(m, "MVD0")
        .def(py::init<>())
        .def("get_d0_b", &MVD0::get_d0_b)
        .def("get_d0_c", &MVD0::get_d0_c)
        .def("get_d0_d0", &MVD0::get_d0_d0)
        .def_readwrite("d0", &MVD0::d0);
    py::class_<MVD1, MVC>(m, "MVD1")
        .def(py::init<>())
        .def("get_d1_b", &MVD1::get_d1_b)
        .def("get_d1_c", &MVD1::get_d1_c)
        .def("get_d1_d1", &MVD1::get_d1_d1)
        .def_readwrite("d1", &MVD1::d1);
    py::class_<MVE, MVD0, MVD1>(m, "MVE")
        .def(py::init<>())
        .def("get_e_b", &MVE::get_e_b)
        .def("get_e_c", &MVE::get_e_c)
        .def("get_e_d0", &MVE::get_e_d0)
        .def("get_e_d1", &MVE::get_e_d1)
        .def("get_e_e", &MVE::get_e_e)
        .def_readwrite("e", &MVE::e);
    py::class_<MVF, MVE>(m, "MVF")
        .def(py::init<>())
        .def("get_f_b", &MVF::get_f_b)
        .def("get_f_c", &MVF::get_f_c)
        .def("get_f_d0", &MVF::get_f_d0)
        .def("get_f_d1", &MVF::get_f_d1)
        .def("get_f_e", &MVF::get_f_e)
        .def("get_f_f", &MVF::get_f_f)
        .def_readwrite("f", &MVF::f);

    namespace TN = TrampolineNesting;

    py::class_<TN::ChainBaseA, TN::TrampolineA<>>(m, "ChainBaseA")
        .def(py::init<>())
        .def("resultA", &TN::ChainBaseA::resultA);
    py::class_<TN::ChainChildA, TN::ChainBaseA, TN::TrampolineA<TN::ChainChildA>>(m, "ChainChildA")
        .def(py::init<>());
    py::class_<TN::ChainBaseB, TN::TrampolineB<>>(m, "ChainBaseB")
        .def(py::init<>())
        .def("resultB", &TN::ChainBaseB::resultB);
    py::class_<TN::ChainChildB, TN::ChainBaseB, TN::TrampolineB<TN::ChainChildB>>(m, "ChainChildB")
        .def(py::init<>());
    py::class_<TN::Joined, TN::ChainBaseA, TN::ChainBaseB, TN::TrampolineJoined<>>(m, "Joined")
        .def(py::init<>());
}