Bugfix/Check actual value when deregistering pybind11 instance (#2252)

* Add tests demonstrating the problem with deregistering pybind11 instances

* Fix deregistering of different pybind11 instance from internals

Co-authored-by: Yannick Jadoul <yannick.jadoul@belgacom.net>
Co-authored-by: Blistic <wots_wot@hotmail.com>
This commit is contained in:
Riyaz Haque 2020-10-02 10:06:04 -07:00 committed by GitHub
parent b9d00273ee
commit 2b6b98e28f
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3 changed files with 26 additions and 1 deletions

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@ -258,7 +258,7 @@ inline bool deregister_instance_impl(void *ptr, instance *self) {
auto &registered_instances = get_internals().registered_instances; auto &registered_instances = get_internals().registered_instances;
auto range = registered_instances.equal_range(ptr); auto range = registered_instances.equal_range(ptr);
for (auto it = range.first; it != range.second; ++it) { for (auto it = range.first; it != range.second; ++it) {
if (Py_TYPE(self) == Py_TYPE(it->second)) { if (self == it->second) {
registered_instances.erase(it); registered_instances.erase(it);
return true; return true;
} }

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@ -420,6 +420,16 @@ TEST_SUBMODULE(class_, m) {
py::class_<PyPrintDestructor>(m, "PyPrintDestructor") py::class_<PyPrintDestructor>(m, "PyPrintDestructor")
.def(py::init<>()) .def(py::init<>())
.def("throw_something", &PyPrintDestructor::throw_something); .def("throw_something", &PyPrintDestructor::throw_something);
struct SamePointer {};
static SamePointer samePointer;
py::class_<SamePointer, std::unique_ptr<SamePointer, py::nodelete>>(m, "SamePointer")
.def(py::init([]() { return &samePointer; }))
.def("__del__", [](SamePointer&) { py::print("__del__ called"); });
struct Empty {};
py::class_<Empty>(m, "Empty")
.def(py::init<>());
} }
template <int N> class BreaksBase { public: template <int N> class BreaksBase { public:

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@ -368,3 +368,18 @@ def test_non_final_final():
def test_exception_rvalue_abort(): def test_exception_rvalue_abort():
with pytest.raises(RuntimeError): with pytest.raises(RuntimeError):
m.PyPrintDestructor().throw_something() m.PyPrintDestructor().throw_something()
# https://github.com/pybind/pybind11/issues/1568
def test_multiple_instances_with_same_pointer(capture):
n = 100
instances = [m.SamePointer() for _ in range(n)]
for i in range(n):
# We need to reuse the same allocated memory for with a different type,
# to ensure the bug in `deregister_instance_impl` is detected. Otherwise
# `Py_TYPE(self) == Py_TYPE(it->second)` will still succeed, even though
# the `instance` is already deleted.
instances[i] = m.Empty()
# No assert: if this does not trigger the error
# pybind11_fail("pybind11_object_dealloc(): Tried to deallocate unregistered instance!");
# and just completes without crashing, we're good.