Fix application of keep_alive policy to constructors (regression)

This commit is contained in:
Dean Moldovan 2017-09-04 13:49:19 +02:00
parent fbab29c73a
commit 7939f4b3fe
6 changed files with 53 additions and 5 deletions

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@ -191,6 +191,17 @@ container:
py::class_<List>(m, "List")
.def("append", &List::append, py::keep_alive<1, 2>());
For consistency, the argument indexing is identical for constructors. Index
``1`` still refers to the implicit ``this`` pointer, i.e. the object which is
being constructed. Index ``0`` refers to the return type which is presumed to
be ``void`` when a constructor is viewed like a function. The following example
ties the lifetime of the constructor element to the constructed object:
.. code-block:: cpp
py::class_<Nurse>(m, "Nurse")
.def(py::init<Patient &>(), py::keep_alive<1, 2>());
.. note::
``keep_alive`` is analogous to the ``with_custodian_and_ward`` (if Nurse,

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@ -11,6 +11,12 @@ v2.3.0 (Not yet released)
* TBD
v2.2.1 (Not yet released)
-----------------------------------------------------
* Fixed a regression where the ``py::keep_alive`` policy could not be applied
to constructors. `#1065 <https://github.com/pybind/pybind11/pull/1065>`_.
v2.2.0 (August 31, 2017)
-----------------------------------------------------

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@ -1800,6 +1800,9 @@ struct function_call {
/// The parent, if any
handle parent;
/// If this is a call to an initializer, this argument contains `self`
handle init_self;
};

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@ -511,6 +511,7 @@ protected:
if (self_value_and_holder)
self_value_and_holder.type->dealloc(self_value_and_holder);
call.init_self = PyTuple_GET_ITEM(args_in, 0);
call.args.push_back(reinterpret_cast<PyObject *>(&self_value_and_holder));
call.args_convert.push_back(false);
++args_copied;
@ -1457,10 +1458,17 @@ inline void keep_alive_impl(handle nurse, handle patient) {
}
PYBIND11_NOINLINE inline void keep_alive_impl(size_t Nurse, size_t Patient, function_call &call, handle ret) {
keep_alive_impl(
Nurse == 0 ? ret : Nurse <= call.args.size() ? call.args[Nurse - 1] : handle(),
Patient == 0 ? ret : Patient <= call.args.size() ? call.args[Patient - 1] : handle()
);
auto get_arg = [&](size_t n) {
if (n == 0)
return ret;
else if (n == 1 && call.init_self)
return call.init_self;
else if (n <= call.args.size())
return call.args[n - 1];
return handle();
};
keep_alive_impl(get_arg(Nurse), get_arg(Patient));
}
inline std::pair<decltype(internals::registered_types_py)::iterator, bool> all_type_info_get_cache(PyTypeObject *type) {

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@ -32,7 +32,7 @@ bool DependentGuard::enabled = false;
TEST_SUBMODULE(call_policies, m) {
// Parent/Child are used in:
// test_keep_alive_argument, test_keep_alive_return_value, test_alive_gc_derived,
// test_alive_gc_multi_derived, test_return_none
// test_alive_gc_multi_derived, test_return_none, test_keep_alive_constructor
class Child {
public:
Child() { py::print("Allocating child."); }
@ -51,6 +51,7 @@ TEST_SUBMODULE(call_policies, m) {
};
py::class_<Parent>(m, "Parent")
.def(py::init<>())
.def(py::init([](Child *) { return new Parent(); }), py::keep_alive<1, 2>())
.def("addChild", &Parent::addChild)
.def("addChildKeepAlive", &Parent::addChild, py::keep_alive<1, 2>())
.def("returnChild", &Parent::returnChild)

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@ -156,6 +156,25 @@ def test_return_none(capture):
assert capture == "Releasing parent."
def test_keep_alive_constructor(capture):
n_inst = ConstructorStats.detail_reg_inst()
with capture:
p = m.Parent(m.Child())
assert ConstructorStats.detail_reg_inst() == n_inst + 2
assert capture == """
Allocating child.
Allocating parent.
"""
with capture:
del p
assert ConstructorStats.detail_reg_inst() == n_inst
assert capture == """
Releasing parent.
Releasing child.
"""
def test_call_guard():
assert m.unguarded_call() == "unguarded"
assert m.guarded_call() == "guarded"