pybind11/tests/test_thread.cpp
Laramie Leavitt 0e599589fe
Fix thread safety for pybind11 loader_life_support (#3237)
* Fix thread safety for pybind11 loader_life_support

Fixes issue: https://github.com/pybind/pybind11/issues/2765

This converts the vector of PyObjects to either a single void* or
a per-thread void* depending on the WITH_THREAD define.

The new field is used by each thread to construct a stack
of loader_life_support frames that can extend the life of python
objects.

The pointer is updated when the loader_life_support object is allocated
(which happens before a call) as well as on release.

Each loader_life_support maintains a set of PyObject references
that need to be lifetime extended; this is done by storing them
in a c++ std::unordered_set and clearing the references when the
method completes.

* Also update the internals version as the internal struct is no longer compatible

* Add test demonstrating threading works correctly.

It may be appropriate to run this under msan/tsan/etc.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Update test to use lifetime-extended references rather than
std::string_view, as that's a C++ 17 feature.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Make loader_life_support members private

* Update version to dev2

* Update test to use python threading rather than concurrent.futures

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* Remove unnecessary env in test

* Remove unnecessary pytest in test

* Use native C++ thread_local in place of python per-thread data structures to retain compatability

* clang-format test_thread.cpp

* Add a note about debugging the py::cast() error

* thread_test.py now propagates exceptions on join() calls.

* [pre-commit.ci] auto fixes from pre-commit.com hooks

for more information, see https://pre-commit.ci

* remove unused sys / merge

* Update include order in test_thread.cpp

* Remove spurious whitespace

* Update comment / whitespace.

* Address review comments

* lint cleanup

* Fix test IntStruct constructor.

* Add explicit to constructor

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>
Co-authored-by: Aaron Gokaslan <skylion.aaron@gmail.com>
2021-09-10 12:29:21 -04:00

67 lines
1.8 KiB
C++

/*
tests/test_thread.cpp -- call pybind11 bound methods in threads
Copyright (c) 2021 Laramie Leavitt (Google LLC) <lar@google.com>
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/cast.h>
#include <pybind11/pybind11.h>
#include <chrono>
#include <thread>
#include "pybind11_tests.h"
namespace py = pybind11;
namespace {
struct IntStruct {
explicit IntStruct(int v) : value(v) {};
~IntStruct() { value = -value; }
IntStruct(const IntStruct&) = default;
IntStruct& operator=(const IntStruct&) = default;
int value;
};
} // namespace
TEST_SUBMODULE(thread, m) {
py::class_<IntStruct>(m, "IntStruct").def(py::init([](const int i) { return IntStruct(i); }));
// implicitly_convertible uses loader_life_support when an implicit
// conversion is required in order to lifetime extend the reference.
//
// This test should be run with ASAN for better effectiveness.
py::implicitly_convertible<int, IntStruct>();
m.def("test", [](int expected, const IntStruct &in) {
{
py::gil_scoped_release release;
std::this_thread::sleep_for(std::chrono::milliseconds(5));
}
if (in.value != expected) {
throw std::runtime_error("Value changed!!");
}
});
m.def(
"test_no_gil",
[](int expected, const IntStruct &in) {
std::this_thread::sleep_for(std::chrono::milliseconds(5));
if (in.value != expected) {
throw std::runtime_error("Value changed!!");
}
},
py::call_guard<py::gil_scoped_release>());
// NOTE: std::string_view also uses loader_life_support to ensure that
// the string contents remain alive, but that's a C++ 17 feature.
}