Hardcopy of pybind11 instead of using git submodules (#552)

* removed pybind as submodule
* added hardcopy of pybind11 2.10.0
* rename pybind11 folder to avoid conflicts when changing branch

Co-authored-by: Dhanya Thattil <dhanya.thattil@psi.ch>

libs/pybind/tests/test_call_policies.cpp

@@ -0,0 +1,115 @@
+/*
+    tests/test_call_policies.cpp -- keep_alive and call_guard
+
+    Copyright (c) 2016 Wenzel Jakob <wenzel.jakob@epfl.ch>
+
+    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_tests.h"
+
+struct CustomGuard {
+    static bool enabled;
+
+    CustomGuard() { enabled = true; }
+    ~CustomGuard() { enabled = false; }
+
+    static const char *report_status() { return enabled ? "guarded" : "unguarded"; }
+};
+bool CustomGuard::enabled = false;
+
+struct DependentGuard {
+    static bool enabled;
+
+    DependentGuard() { enabled = CustomGuard::enabled; }
+    ~DependentGuard() { enabled = false; }
+
+    static const char *report_status() { return enabled ? "guarded" : "unguarded"; }
+};
+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_keep_alive_constructor
+    class Child {
+    public:
+        Child() { py::print("Allocating child."); }
+        Child(const Child &) = default;
+        Child(Child &&) = default;
+        ~Child() { py::print("Releasing child."); }
+    };
+    py::class_<Child>(m, "Child").def(py::init<>());
+
+    class Parent {
+    public:
+        Parent() { py::print("Allocating parent."); }
+        Parent(const Parent &parent) = default;
+        ~Parent() { py::print("Releasing parent."); }
+        void addChild(Child *) {}
+        Child *returnChild() { return new Child(); }
+        Child *returnNullChild() { return nullptr; }
+        static Child *staticFunction(Parent *) { return new Child(); }
+    };
+    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)
+        .def("returnChildKeepAlive", &Parent::returnChild, py::keep_alive<1, 0>())
+        .def("returnNullChildKeepAliveChild", &Parent::returnNullChild, py::keep_alive<1, 0>())
+        .def("returnNullChildKeepAliveParent", &Parent::returnNullChild, py::keep_alive<0, 1>())
+        .def_static("staticFunction", &Parent::staticFunction, py::keep_alive<1, 0>());
+
+    m.def(
+        "free_function", [](Parent *, Child *) {}, py::keep_alive<1, 2>());
+    m.def(
+        "invalid_arg_index", [] {}, py::keep_alive<0, 1>());
+
+#if !defined(PYPY_VERSION)
+    // test_alive_gc
+    class ParentGC : public Parent {
+    public:
+        using Parent::Parent;
+    };
+    py::class_<ParentGC, Parent>(m, "ParentGC", py::dynamic_attr()).def(py::init<>());
+#endif
+
+    // test_call_guard
+    m.def("unguarded_call", &CustomGuard::report_status);
+    m.def("guarded_call", &CustomGuard::report_status, py::call_guard<CustomGuard>());
+
+    m.def(
+        "multiple_guards_correct_order",
+        []() {
+            return CustomGuard::report_status() + std::string(" & ")
+                   + DependentGuard::report_status();
+        },
+        py::call_guard<CustomGuard, DependentGuard>());
+
+    m.def(
+        "multiple_guards_wrong_order",
+        []() {
+            return DependentGuard::report_status() + std::string(" & ")
+                   + CustomGuard::report_status();
+        },
+        py::call_guard<DependentGuard, CustomGuard>());
+
+#if defined(WITH_THREAD) && !defined(PYPY_VERSION)
+    // `py::call_guard<py::gil_scoped_release>()` should work in PyPy as well,
+    // but it's unclear how to test it without `PyGILState_GetThisThreadState`.
+    auto report_gil_status = []() {
+        auto is_gil_held = false;
+        if (auto *tstate = py::detail::get_thread_state_unchecked()) {
+            is_gil_held = (tstate == PyGILState_GetThisThreadState());
+        }
+
+        return is_gil_held ? "GIL held" : "GIL released";
+    };
+
+    m.def("with_gil", report_gil_status);
+    m.def("without_gil", report_gil_status, py::call_guard<py::gil_scoped_release>());
+#endif
+}