Fix async Python functors invoking from multiple C++ threads (#1587) (#1595)
* Fix async Python functors invoking from multiple C++ threads (#1587)
Ensure GIL is held during functor destruction.
* Add async Python callbacks test that runs in separate Python thread
diff --git a/tests/test_callbacks.cpp b/tests/test_callbacks.cpp
index 273eacc..71b88c4 100644
--- a/tests/test_callbacks.cpp
+++ b/tests/test_callbacks.cpp
@@ -10,6 +10,7 @@
#include "pybind11_tests.h"
#include "constructor_stats.h"
#include <pybind11/functional.h>
+#include <thread>
int dummy_function(int i) { return i + 1; }
@@ -146,4 +147,22 @@
py::class_<CppBoundMethodTest>(m, "CppBoundMethodTest")
.def(py::init<>())
.def("triple", [](CppBoundMethodTest &, int val) { return 3 * val; });
+
+ // test async Python callbacks
+ using callback_f = std::function<void(int)>;
+ m.def("test_async_callback", [](callback_f f, py::list work) {
+ // make detached thread that calls `f` with piece of work after a little delay
+ auto start_f = [f](int j) {
+ auto invoke_f = [f, j] {
+ std::this_thread::sleep_for(std::chrono::milliseconds(50));
+ f(j);
+ };
+ auto t = std::thread(std::move(invoke_f));
+ t.detach();
+ };
+
+ // spawn worker threads
+ for (auto i : work)
+ start_f(py::cast<int>(i));
+ });
}