diff --git a/include/pybind11/detail/class.h b/include/pybind11/detail/class.h index 677c36ef39..94825a88e1 100644 --- a/include/pybind11/detail/class.h +++ b/include/pybind11/detail/class.h @@ -189,12 +189,10 @@ extern "C" inline PyObject *pybind11_meta_call(PyObject *type, PyObject *args, P return nullptr; } - // This must be a pybind11 instance - auto *instance = reinterpret_cast(self); - // Ensure that the base __init__ function(s) were called - for (const auto &vh : values_and_holders(instance)) { - if (!vh.holder_constructed()) { + values_and_holders vhs(self); + for (const auto &vh : vhs) { + if (!vh.holder_constructed() && !vhs.is_redundant_value_and_holder(vh)) { PyErr_Format(PyExc_TypeError, "%.200s.__init__() must be called when overriding __init__", get_fully_qualified_tp_name(vh.type->type).c_str()); diff --git a/include/pybind11/detail/type_caster_base.h b/include/pybind11/detail/type_caster_base.h index 77999abe32..14992be41d 100644 --- a/include/pybind11/detail/type_caster_base.h +++ b/include/pybind11/detail/type_caster_base.h @@ -102,8 +102,22 @@ class loader_life_support { inline std::pair all_type_info_get_cache(PyTypeObject *type); +// Band-aid workaround to fix a subtle but serious bug in a minimalistic fashion. See PR #4762. +inline void all_type_info_add_base_most_derived_first(std::vector &bases, + type_info *addl_base) { + for (auto it = bases.begin(); it != bases.end(); it++) { + type_info *existing_base = *it; + if (PyType_IsSubtype(addl_base->type, existing_base->type) != 0) { + bases.insert(it, addl_base); + return; + } + } + bases.push_back(addl_base); +} + // Populates a just-created cache entry. PYBIND11_NOINLINE void all_type_info_populate(PyTypeObject *t, std::vector &bases) { + assert(bases.empty()); std::vector check; for (handle parent : reinterpret_borrow(t->tp_bases)) { check.push_back((PyTypeObject *) parent.ptr()); @@ -136,7 +150,7 @@ PYBIND11_NOINLINE void all_type_info_populate(PyTypeObject *t, std::vectortp_bases) { @@ -322,18 +336,29 @@ struct values_and_holders { explicit values_and_holders(instance *inst) : inst{inst}, tinfo(all_type_info(Py_TYPE(inst))) {} + explicit values_and_holders(PyObject *obj) + : inst{nullptr}, tinfo(all_type_info(Py_TYPE(obj))) { + if (!tinfo.empty()) { + inst = reinterpret_cast(obj); + } + } + struct iterator { private: instance *inst = nullptr; const type_vec *types = nullptr; value_and_holder curr; friend struct values_and_holders; - iterator(instance *inst, const type_vec *tinfo) - : inst{inst}, types{tinfo}, - curr(inst /* instance */, - types->empty() ? nullptr : (*types)[0] /* type info */, - 0, /* vpos: (non-simple types only): the first vptr comes first */ - 0 /* index */) {} + iterator(instance *inst, const type_vec *tinfo) : inst{inst}, types{tinfo} { + if (inst != nullptr) { + assert(!types->empty()); + curr = value_and_holder( + inst /* instance */, + (*types)[0] /* type info */, + 0, /* vpos: (non-simple types only): the first vptr comes first */ + 0 /* index */); + } + } // Past-the-end iterator: explicit iterator(size_t end) : curr(end) {} @@ -364,6 +389,16 @@ struct values_and_holders { } size_t size() { return tinfo.size(); } + + // Band-aid workaround to fix a subtle but serious bug in a minimalistic fashion. See PR #4762. + bool is_redundant_value_and_holder(const value_and_holder &vh) { + for (size_t i = 0; i < vh.index; i++) { + if (PyType_IsSubtype(tinfo[i]->type, tinfo[vh.index]->type) != 0) { + return true; + } + } + return false; + } }; /** diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt index e8cff2ead5..906bef4a6f 100644 --- a/tests/CMakeLists.txt +++ b/tests/CMakeLists.txt @@ -165,6 +165,7 @@ set(PYBIND11_TEST_FILES test_opaque_types test_operator_overloading test_pickling + test_python_multiple_inheritance test_pytypes test_return_value_policy_override test_sequences_and_iterators diff --git a/tests/test_class.py b/tests/test_class.py index ee7467cf8b..73a48309e8 100644 --- a/tests/test_class.py +++ b/tests/test_class.py @@ -1,3 +1,5 @@ +from unittest import mock + import pytest import env @@ -203,6 +205,18 @@ def __init__(self): assert msg(exc_info.value) == expected +@pytest.mark.parametrize( + "mock_return_value", [None, (1, 2, 3), m.Pet("Polly", "parrot"), m.Dog("Molly")] +) +def test_mock_new(mock_return_value): + with mock.patch.object( + m.Pet, "__new__", return_value=mock_return_value + ) as mock_new: + obj = m.Pet("Noname", "Nospecies") + assert obj is mock_return_value + mock_new.assert_called_once_with(m.Pet, "Noname", "Nospecies") + + def test_automatic_upcasting(): assert type(m.return_class_1()).__name__ == "DerivedClass1" assert type(m.return_class_2()).__name__ == "DerivedClass2" diff --git a/tests/test_python_multiple_inheritance.cpp b/tests/test_python_multiple_inheritance.cpp new file mode 100644 index 0000000000..6899171585 --- /dev/null +++ b/tests/test_python_multiple_inheritance.cpp @@ -0,0 +1,45 @@ +#include "pybind11_tests.h" + +namespace test_python_multiple_inheritance { + +// Copied from: +// https://github.com/google/clif/blob/5718e4d0807fd3b6a8187dde140069120b81ecef/clif/testing/python_multiple_inheritance.h + +struct CppBase { + explicit CppBase(int value) : base_value(value) {} + int get_base_value() const { return base_value; } + void reset_base_value(int new_value) { base_value = new_value; } + +private: + int base_value; +}; + +struct CppDrvd : CppBase { + explicit CppDrvd(int value) : CppBase(value), drvd_value(value * 3) {} + int get_drvd_value() const { return drvd_value; } + void reset_drvd_value(int new_value) { drvd_value = new_value; } + + int get_base_value_from_drvd() const { return get_base_value(); } + void reset_base_value_from_drvd(int new_value) { reset_base_value(new_value); } + +private: + int drvd_value; +}; + +} // namespace test_python_multiple_inheritance + +TEST_SUBMODULE(python_multiple_inheritance, m) { + using namespace test_python_multiple_inheritance; + + py::class_(m, "CppBase") + .def(py::init()) + .def("get_base_value", &CppBase::get_base_value) + .def("reset_base_value", &CppBase::reset_base_value); + + py::class_(m, "CppDrvd") + .def(py::init()) + .def("get_drvd_value", &CppDrvd::get_drvd_value) + .def("reset_drvd_value", &CppDrvd::reset_drvd_value) + .def("get_base_value_from_drvd", &CppDrvd::get_base_value_from_drvd) + .def("reset_base_value_from_drvd", &CppDrvd::reset_base_value_from_drvd); +} diff --git a/tests/test_python_multiple_inheritance.py b/tests/test_python_multiple_inheritance.py new file mode 100644 index 0000000000..3bddd67dfb --- /dev/null +++ b/tests/test_python_multiple_inheritance.py @@ -0,0 +1,35 @@ +# Adapted from: +# https://github.com/google/clif/blob/5718e4d0807fd3b6a8187dde140069120b81ecef/clif/testing/python/python_multiple_inheritance_test.py + +from pybind11_tests import python_multiple_inheritance as m + + +class PC(m.CppBase): + pass + + +class PPCC(PC, m.CppDrvd): + pass + + +def test_PC(): + d = PC(11) + assert d.get_base_value() == 11 + d.reset_base_value(13) + assert d.get_base_value() == 13 + + +def test_PPCC(): + d = PPCC(11) + assert d.get_drvd_value() == 33 + d.reset_drvd_value(55) + assert d.get_drvd_value() == 55 + + assert d.get_base_value() == 11 + assert d.get_base_value_from_drvd() == 11 + d.reset_base_value(20) + assert d.get_base_value() == 20 + assert d.get_base_value_from_drvd() == 20 + d.reset_base_value_from_drvd(30) + assert d.get_base_value() == 30 + assert d.get_base_value_from_drvd() == 30