Use `PyGILState_GetThisThreadState` when using gil_scoped_acquire. (#1211)
This avoids GIL deadlocking when pybind11 tries to acquire the GIL in a thread that already acquired it using standard Python API (e.g. when running from a Python thread).
diff --git a/tests/test_gil_scoped.py b/tests/test_gil_scoped.py
new file mode 100644
index 0000000..5e70243
--- /dev/null
+++ b/tests/test_gil_scoped.py
@@ -0,0 +1,80 @@
+import multiprocessing
+import threading
+from pybind11_tests import gil_scoped as m
+
+
+def _run_in_process(target, *args, **kwargs):
+ """Runs target in process and returns its exitcode after 1s (None if still alive)."""
+ process = multiprocessing.Process(target=target, args=args, kwargs=kwargs)
+ process.daemon = True
+ try:
+ process.start()
+ # Do not need to wait much, 1s should be more than enough.
+ process.join(timeout=1)
+ return process.exitcode
+ finally:
+ if process.is_alive():
+ process.terminate()
+
+
+def _python_to_cpp_to_python():
+ """Calls different C++ functions that come back to Python."""
+ class ExtendedVirtClass(m.VirtClass):
+ def virtual_func(self):
+ pass
+
+ def pure_virtual_func(self):
+ pass
+
+ extended = ExtendedVirtClass()
+ m.test_callback_py_obj(lambda: None)
+ m.test_callback_std_func(lambda: None)
+ m.test_callback_virtual_func(extended)
+ m.test_callback_pure_virtual_func(extended)
+
+
+def _python_to_cpp_to_python_from_threads(num_threads, parallel=False):
+ """Calls different C++ functions that come back to Python, from Python threads."""
+ threads = []
+ for _ in range(num_threads):
+ thread = threading.Thread(target=_python_to_cpp_to_python)
+ thread.daemon = True
+ thread.start()
+ if parallel:
+ threads.append(thread)
+ else:
+ thread.join()
+ for thread in threads:
+ thread.join()
+
+
+def test_python_to_cpp_to_python_from_thread():
+ """Makes sure there is no GIL deadlock when running in a thread.
+
+ It runs in a separate process to be able to stop and assert if it deadlocks.
+ """
+ assert _run_in_process(_python_to_cpp_to_python_from_threads, 1) == 0
+
+
+def test_python_to_cpp_to_python_from_thread_multiple_parallel():
+ """Makes sure there is no GIL deadlock when running in a thread multiple times in parallel.
+
+ It runs in a separate process to be able to stop and assert if it deadlocks.
+ """
+ assert _run_in_process(_python_to_cpp_to_python_from_threads, 8, parallel=True) == 0
+
+
+def test_python_to_cpp_to_python_from_thread_multiple_sequential():
+ """Makes sure there is no GIL deadlock when running in a thread multiple times sequentially.
+
+ It runs in a separate process to be able to stop and assert if it deadlocks.
+ """
+ assert _run_in_process(_python_to_cpp_to_python_from_threads, 8, parallel=False) == 0
+
+
+def test_python_to_cpp_to_python_from_process():
+ """Makes sure there is no GIL deadlock when using processes.
+
+ This test is for completion, but it was never an issue.
+ """
+ assert _run_in_process(_python_to_cpp_to_python) == 0