test_potentially_slicing_shared_ptr.cpp,py (for smart_holder only)

Author: rwgk

tests/CMakeLists.txt

@@ -130,11 +130,9 @@ set(PYBIND11_TEST_FILES
     test_class_sh_trampoline_shared_from_this
     test_class_sh_trampoline_shared_ptr_cpp_arg
     test_class_sh_trampoline_unique_ptr
-    test_class_sh_trampoline_weak_ptr
     test_class_sh_unique_ptr_custom_deleter
     test_class_sh_unique_ptr_member
     test_class_sh_virtual_py_cpp_mix
-    test_class_sp_trampoline_weak_ptr
     test_const_name
     test_constants_and_functions
     test_copy_move
@@ -163,6 +161,7 @@ set(PYBIND11_TEST_FILES
     test_opaque_types
     test_operator_overloading
     test_pickling
+    test_potentially_slicing_shared_ptr
     test_python_multiple_inheritance
     test_pytypes
     test_sequences_and_iterators

tests/test_class_sh_trampoline_weak_ptr.cpp

@@ -7,7 +7,7 @@
 #include <memory>
 
 namespace pybind11_tests {
-namespace class_sp_trampoline_weak_ptr {
+namespace potentially_slicing_shared_ptr {
 
 struct VirtBase {
     virtual ~VirtBase() = default;
@@ -17,66 +17,69 @@ struct VirtBase {
 struct PyVirtBase : VirtBase, py::trampoline_self_life_support {
     using VirtBase::VirtBase;
     int get_code() override { PYBIND11_OVERRIDE(int, VirtBase, get_code); }
-
-    ~PyVirtBase() override {
-        fflush(stderr);
-        printf("\nLOOOK ~PyVirtBase()\n");
-        fflush(stdout);
-    }
 };
 
-struct WpOwner {
-    void set_wp(const std::shared_ptr<VirtBase> &sp) { wp = sp; }
+std::shared_ptr<VirtBase> rtrn_obj_cast_shared_ptr(py::handle obj) {
+    return obj.cast<std::shared_ptr<VirtBase>>();
+}
+
+std::shared_ptr<VirtBase> rtrn_potentially_slicing_shared_ptr(py::handle obj) {
+    return py::potentially_slicing_shared_ptr<VirtBase>(obj);
+}
+
+struct SpOwner {
+    void set_sp(const std::shared_ptr<VirtBase> &sp_) { sp = sp_; }
 
     int get_code() {
-        auto sp = wp.lock();
         if (!sp) {
-            return -999;
+            return -888;
         }
         return sp->get_code();
     }
 
 private:
-    std::weak_ptr<VirtBase> wp;
+    std::shared_ptr<VirtBase> sp;
 };
 
-struct SpOwner {
-    void set_sp(const std::shared_ptr<VirtBase> &sp_) { sp = sp_; }
+struct WpOwner {
+    void set_wp(const std::shared_ptr<VirtBase> &sp) { wp = sp; }
 
     int get_code() {
+        auto sp = wp.lock();
         if (!sp) {
-            return -888;
+            return -999;
         }
         return sp->get_code();
     }
 
 private:
-    std::shared_ptr<VirtBase> sp;
+    std::weak_ptr<VirtBase> wp;
 };
 
-std::shared_ptr<VirtBase> pass_through_sp_VirtBase(const std::shared_ptr<VirtBase> &sp) {
-    return sp;
-}
-
-} // namespace class_sp_trampoline_weak_ptr
+} // namespace potentially_slicing_shared_ptr
 } // namespace pybind11_tests
 
-using namespace pybind11_tests::class_sp_trampoline_weak_ptr;
+using namespace pybind11_tests::potentially_slicing_shared_ptr;
 
-TEST_SUBMODULE(class_sp_trampoline_weak_ptr, m) {
-    py::class_<VirtBase, std::shared_ptr<VirtBase>, PyVirtBase>(m, "VirtBase")
+TEST_SUBMODULE(potentially_slicing_shared_ptr, m) {
+    py::classh<VirtBase, PyVirtBase>(m, "VirtBase")
         .def(py::init<>())
         .def("get_code", &VirtBase::get_code);
 
-    py::class_<WpOwner>(m, "WpOwner")
-        .def(py::init<>())
-        .def("set_wp", &WpOwner::set_wp)
-        .def("get_code", &WpOwner::get_code);
+    m.def("rtrn_obj_cast_shared_ptr", rtrn_obj_cast_shared_ptr);
+    m.def("rtrn_potentially_slicing_shared_ptr", rtrn_potentially_slicing_shared_ptr);
 
-    py::class_<SpOwner>(m, "SpOwner")
+    py::classh<SpOwner>(m, "SpOwner")
         .def(py::init<>())
         .def("set_sp", &SpOwner::set_sp)
         .def("get_code", &SpOwner::get_code);
 
-    m.def("pass_through_sp_VirtBase", pass_through_sp_VirtBase);
+    py::classh<WpOwner>(m, "WpOwner")
+        .def(py::init<>())
+        .def("set_wp", &WpOwner::set_wp)
+        .def("set_wp_potentially_slicing",
+             [](WpOwner &self, py::handle obj) {
+                 self.set_wp(py::potentially_slicing_shared_ptr<VirtBase>(obj));
+             })
+        .def("get_code", &WpOwner::get_code);
 }