[smart_holder] return value policies allowed for shared_ptr

include/pybind11/detail/smart_holder_type_casters.h

@@ -623,11 +623,16 @@ struct smart_holder_type_caster<std::shared_ptr<T>> : smart_holder_type_caster_l
     static constexpr auto name = _<std::shared_ptr<T>>();
 
     static handle cast(const std::shared_ptr<T> &src, return_value_policy policy, handle parent) {
-        if (policy != return_value_policy::automatic
-            && policy != return_value_policy::reference_internal
-            && policy != return_value_policy::automatic_reference) {
-            // SMART_HOLDER_WIP: IMPROVABLE: Error message.
-            throw cast_error("Invalid return_value_policy for shared_ptr.");
+        switch (policy) {
+            case return_value_policy::automatic: break;
+            case return_value_policy::automatic_reference: break;
+            case return_value_policy::take_ownership:
+                throw cast_error("Invalid return_value_policy for shared_ptr (take_ownership).");
+            case return_value_policy::copy: break;
+            case return_value_policy::move: break;
+            case return_value_policy::reference:
+                throw cast_error("Invalid return_value_policy for shared_ptr (reference).");
+            case return_value_policy::reference_internal: break;
         }
         if (!src)
             return none().release();

tests/CMakeLists.txt

@@ -106,6 +106,7 @@ set(PYBIND11_TEST_FILES
     test_class_sh_disowning_mi.cpp
     test_class_sh_factory_constructors.cpp
     test_class_sh_inheritance.cpp
+    test_class_sh_shared_ptr_copy_move.cpp
     test_class_sh_trampoline_basic.cpp
     test_class_sh_trampoline_self_life_support.cpp
     test_class_sh_trampoline_shared_ptr_cpp_arg.cpp

tests/test_class_sh_shared_ptr_copy_move.cpp

@@ -0,0 +1,114 @@
+#include "pybind11_tests.h"
+
+#include <pybind11/smart_holder.h>
+
+#include <memory>
+#include <string>
+#include <vector>
+
+namespace pybind11_tests {
+namespace {
+
+const std::string fooNames[] = {"ShPtr_", "SmHld_"};
+
+template <int SerNo>
+struct Foo {
+    std::string history;
+    Foo(const std::string &history_) : history(history_) {}
+    Foo(const Foo &other) : history(other.history + "_CpCtor") {}
+    Foo(Foo &&other) noexcept : history(other.history + "_MvCtor") {}
+    Foo &operator=(const Foo &other) {
+        history = other.history + "_OpEqLv";
+        return *this;
+    }
+    Foo &operator=(Foo &&other) noexcept {
+        history = other.history + "_OpEqRv";
+        return *this;
+    }
+    std::string get_history() const { return "Foo" + fooNames[SerNo] + history; }
+};
+
+using FooShPtr = Foo<0>;
+using FooSmHld = Foo<1>;
+
+struct Outer {
+    std::shared_ptr<FooShPtr> ShPtr;
+    std::shared_ptr<FooSmHld> SmHld;
+    Outer()
+        : ShPtr(std::make_shared<FooShPtr>("Outer")), SmHld(std::make_shared<FooSmHld>("Outer")) {}
+    std::shared_ptr<FooShPtr> getShPtr() const { return ShPtr; }
+    std::shared_ptr<FooSmHld> getSmHld() const { return SmHld; }
+};
+
+} // namespace
+} // namespace pybind11_tests
+
+PYBIND11_TYPE_CASTER_BASE_HOLDER(pybind11_tests::FooShPtr,
+                                 std::shared_ptr<pybind11_tests::FooShPtr>)
+PYBIND11_SMART_HOLDER_TYPE_CASTERS(pybind11_tests::FooSmHld)
+
+namespace pybind11_tests {
+namespace {
+
+TEST_SUBMODULE(class_sh_shared_ptr_copy_move, m) {
+    namespace py = pybind11;
+
+    py::class_<FooShPtr, std::shared_ptr<FooShPtr>>(m, "FooShPtr")
+        .def("get_history", &FooShPtr::get_history);
+    py::classh<FooSmHld>(m, "FooSmHld").def("get_history", &FooSmHld::get_history);
+
+    auto outer = py::class_<Outer>(m, "Outer").def(py::init());
+#define MAKE_PROP(PropTyp)                                                                        \
+    MAKE_PROP_FOO(ShPtr, PropTyp)                                                                 \
+    MAKE_PROP_FOO(SmHld, PropTyp)
+
+#define MAKE_PROP_FOO(FooTyp, PropTyp)                                                            \
+    .def_##PropTyp(#FooTyp "_" #PropTyp "_default", &Outer::FooTyp)                               \
+        .def_##PropTyp(                                                                           \
+            #FooTyp "_" #PropTyp "_copy", &Outer::FooTyp, py::return_value_policy::copy)          \
+        .def_##PropTyp(                                                                           \
+            #FooTyp "_" #PropTyp "_move", &Outer::FooTyp, py::return_value_policy::move)
+    outer MAKE_PROP(readonly) MAKE_PROP(readwrite);
+#undef MAKE_PROP_FOO
+
+#define MAKE_PROP_FOO(FooTyp, PropTyp)                                                            \
+    .def_##PropTyp(#FooTyp "_property_" #PropTyp "_default", &Outer::FooTyp)                      \
+        .def_property_##PropTyp(#FooTyp "_property_" #PropTyp "_copy",                            \
+                                &Outer::get##FooTyp,                                              \
+                                py::return_value_policy::copy)                                    \
+        .def_property_##PropTyp(#FooTyp "_property_" #PropTyp "_move",                            \
+                                &Outer::get##FooTyp,                                              \
+                                py::return_value_policy::move)
+    outer MAKE_PROP(readonly);
+#undef MAKE_PROP_FOO
+#undef MAKE_PROP
+
+    m.def("test_ShPtr_copy", []() {
+        auto o = std::make_shared<FooShPtr>("copy");
+        auto l = py::list();
+        l.append(o);
+        return l;
+    });
+    m.def("test_SmHld_copy", []() {
+        auto o = std::make_shared<FooSmHld>("copy");
+        auto l = py::list();
+        l.append(o);
+        return l;
+    });
+
+    m.def("test_ShPtr_move", []() {
+        auto o = std::make_shared<FooShPtr>("move");
+        auto l = py::list();
+        l.append(std::move(o));
+        return l;
+    });
+    m.def("test_SmHld_move", []() {
+        auto o = std::make_shared<FooSmHld>("move");
+        auto l = py::list();
+        l.append(std::move(o));
+        return l;
+    });
+}
+
+} // namespace
+} // namespace pybind11_tests

tests/test_class_sh_shared_ptr_copy_move.py

@@ -0,0 +1,41 @@
+# -*- coding: utf-8 -*-
+
+from pybind11_tests import class_sh_shared_ptr_copy_move as m
+
+
+def test_shptr_copy():
+    txt = m.test_ShPtr_copy()[0].get_history()
+    assert txt == "FooShPtr_copy"
+
+
+def test_smhld_copy():
+    txt = m.test_SmHld_copy()[0].get_history()
+    assert txt == "FooSmHld_copy"
+
+
+def test_shptr_move():
+    txt = m.test_ShPtr_move()[0].get_history()
+    assert txt == "FooShPtr_move"
+
+
+def test_smhld_move():
+    txt = m.test_SmHld_move()[0].get_history()
+    assert txt == "FooSmHld_move"
+
+
+def _check_property(foo_typ, prop_typ, policy):
+    o = m.Outer()
+    name = "{}_{}_{}".format(foo_typ, prop_typ, policy)
+    history = "Foo{}_Outer".format(foo_typ)
+    f = getattr(o, name)
+    assert f.get_history() == history
+    # and try again to check that o did not get changed
+    f = getattr(o, name)
+    assert f.get_history() == history
+
+
+def test_properties():
+    for prop_typ in ("readonly", "readwrite", "property_readonly"):
+        for foo_typ in ("ShPtr", "SmHld"):
+            for policy in ("default", "copy", "move"):
+                _check_property(foo_typ, prop_typ, policy)