From fe5427fc23b0a54c586c3d3a905043ab996847e1 Mon Sep 17 00:00:00 2001
From: "Ralf W. Grosse-Kunstleve" <rwgk@google.com>
Date: Mon, 11 Jan 2021 20:34:23 -0800
Subject: [PATCH] Adding rvalue_ref, renaming const_value_ref to lvalue_ref &
 removing const.

---
 include/pybind11/smart_holder_poc.h  | 12 ++++++--
 tests/core/smart_holder_poc_test.cpp | 42 ++++++++++++++++++++--------
 2 files changed, 40 insertions(+), 14 deletions(-)

diff --git a/include/pybind11/smart_holder_poc.h b/include/pybind11/smart_holder_poc.h
index 4d14409cf..f3374f103 100644
--- a/include/pybind11/smart_holder_poc.h
+++ b/include/pybind11/smart_holder_poc.h
@@ -158,13 +158,21 @@ struct smart_holder {
   }
 
   template <typename T>
-  const T& const_value_ref() const {
-    static const char* context = "const_value_ref";
+  T& lvalue_ref() const {
+    static const char* context = "lvalue_ref";
     ensure_compatible_rtti_held<T>(context);
     ensure_has_pointee(context);
     return *static_cast<T*>(vptr.get());
   }
 
+  template <typename T>
+  T&& rvalue_ref() const {
+    static const char* context = "rvalue_ref";
+    ensure_compatible_rtti_held<T>(context);
+    ensure_has_pointee(context);
+    return std::move(*static_cast<T*>(vptr.get()));
+  }
+
   template <typename T>
   static smart_holder from_raw_ptr_take_ownership(T* raw_ptr) {
     smart_holder hld;
diff --git a/tests/core/smart_holder_poc_test.cpp b/tests/core/smart_holder_poc_test.cpp
index 9aebba62f..e696d9e53 100644
--- a/tests/core/smart_holder_poc_test.cpp
+++ b/tests/core/smart_holder_poc_test.cpp
@@ -7,6 +7,15 @@ using pybindit::memory::smart_holder;
 
 namespace helpers {
 
+struct movable_int {
+  int valu;
+  movable_int(int v) : valu{v} {}
+  movable_int(movable_int&& other) {
+    valu = other.valu;
+    other.valu = 91;
+  }
+};
+
 template <typename T>
 struct functor_builtin_delete {
   void operator()(T* ptr) { delete ptr; }
@@ -23,10 +32,20 @@ TEST_CASE("from_raw_ptr_unowned+as_raw_ptr_unowned", "[S]") {
   REQUIRE(*hld.as_raw_ptr_unowned<int>() == 19);
 }
 
-TEST_CASE("from_raw_ptr_unowned+const_value_ref", "[S]") {
+TEST_CASE("from_raw_ptr_unowned+lvalue_ref", "[S]") {
   static int value = 19;
   auto hld = smart_holder::from_raw_ptr_unowned(&value);
-  REQUIRE(hld.const_value_ref<int>() == 19);
+  REQUIRE(hld.lvalue_ref<int>() == 19);
+}
+
+TEST_CASE("from_raw_ptr_unowned+rvalue_ref", "[S]") {
+  helpers::movable_int orig(19);
+  {
+    auto hld = smart_holder::from_raw_ptr_unowned(&orig);
+    helpers::movable_int othr(hld.rvalue_ref<helpers::movable_int>());
+    REQUIRE(othr.valu == 19);
+    REQUIRE(orig.valu == 91);
+  }
 }
 
 TEST_CASE("from_raw_ptr_unowned+as_raw_ptr_release_ownership", "[E]") {
@@ -61,10 +80,10 @@ TEST_CASE("from_raw_ptr_unowned+as_shared_ptr", "[S]") {
   REQUIRE(*hld.as_shared_ptr<int>() == 19);
 }
 
-TEST_CASE("from_raw_ptr_take_ownership+const_value_ref", "[S]") {
+TEST_CASE("from_raw_ptr_take_ownership+lvalue_ref", "[S]") {
   auto hld = smart_holder::from_raw_ptr_take_ownership(new int(19));
   REQUIRE(hld.has_pointee());
-  REQUIRE(hld.const_value_ref<int>() == 19);
+  REQUIRE(hld.lvalue_ref<int>() == 19);
 }
 
 TEST_CASE("from_raw_ptr_take_ownership+as_raw_ptr_release_ownership1", "[S]") {
@@ -114,11 +133,11 @@ TEST_CASE("from_raw_ptr_take_ownership+as_shared_ptr", "[S]") {
   REQUIRE(*new_owner == 19);
 }
 
-TEST_CASE("from_unique_ptr+const_value_ref", "[S]") {
+TEST_CASE("from_unique_ptr+lvalue_ref", "[S]") {
   std::unique_ptr<int> orig_owner(new int(19));
   auto hld = smart_holder::from_unique_ptr(std::move(orig_owner));
   REQUIRE(orig_owner.get() == nullptr);
-  REQUIRE(hld.const_value_ref<int>() == 19);
+  REQUIRE(hld.lvalue_ref<int>() == 19);
 }
 
 TEST_CASE("from_unique_ptr+as_raw_ptr_release_ownership1", "[S]") {
@@ -180,12 +199,12 @@ TEST_CASE("from_unique_ptr+as_shared_ptr", "[S]") {
   REQUIRE(*new_owner == 19);
 }
 
-TEST_CASE("from_unique_ptr_with_deleter+const_value_ref", "[S]") {
+TEST_CASE("from_unique_ptr_with_deleter+lvalue_ref", "[S]") {
   std::unique_ptr<int, helpers::functor_builtin_delete<int>> orig_owner(
       new int(19));
   auto hld = smart_holder::from_unique_ptr_with_deleter(std::move(orig_owner));
   REQUIRE(orig_owner.get() == nullptr);
-  REQUIRE(hld.const_value_ref<int>() == 19);
+  REQUIRE(hld.lvalue_ref<int>() == 19);
 }
 
 TEST_CASE("from_unique_ptr_with_deleter+as_raw_ptr_release_ownership", "[E]") {
@@ -242,10 +261,10 @@ TEST_CASE("from_unique_ptr_with_deleter+as_shared_ptr", "[S]") {
   REQUIRE(*new_owner == 19);
 }
 
-TEST_CASE("from_shared_ptr+const_value_ref", "[S]") {
+TEST_CASE("from_shared_ptr+lvalue_ref", "[S]") {
   std::shared_ptr<int> orig_owner(new int(19));
   auto hld = smart_holder::from_shared_ptr(orig_owner);
-  REQUIRE(hld.const_value_ref<int>() == 19);
+  REQUIRE(hld.lvalue_ref<int>() == 19);
 }
 
 TEST_CASE("from_shared_ptr+as_raw_ptr_release_ownership", "[E]") {
@@ -296,6 +315,5 @@ TEST_CASE("error_incompatible_type", "[E]") {
 TEST_CASE("error_disowned_holder", "[E]") {
   auto hld = smart_holder::from_raw_ptr_take_ownership(new int(19));
   hld.as_unique_ptr<int>();
-  REQUIRE_THROWS_WITH(hld.const_value_ref<int>(),
-                      "Disowned holder (const_value_ref).");
+  REQUIRE_THROWS_WITH(hld.lvalue_ref<int>(), "Disowned holder (lvalue_ref).");
 }