Allow std::nullptr_t for all Scopable types (this was an oversight …

…in the API).

In rare instances classes may want to have uninitialized members that reside on the stack. Previously, the base declaration will call the constructor with no arguments, but this API provides for declaring members with "LocalObject<kClass> obj{nullptr};" syntax.

#274

PiperOrigin-RevId: 617944956

implementation/global_object_test.cc

@@ -43,6 +43,17 @@ using ::testing::InSequence;
 using ::testing::Return;
 using ::testing::StrEq;
 
+TEST_F(JniTest, GlobalObject_AllowsNullPtrT) {
+  static constexpr Class kClass{"kClass"};
+  EXPECT_CALL(*env_, NewLocalRef).Times(0);
+  EXPECT_CALL(*env_, NewGlobalRef).Times(0);
+  EXPECT_CALL(*env_, DeleteLocalRef).Times(0);
+  EXPECT_CALL(*env_, DeleteGlobalRef).Times(0);
+
+  GlobalObject<kClass> obj{nullptr};
+  EXPECT_EQ(jobject{obj}, nullptr);
+}
+
 TEST_F(JniTest, GlobalObject_CallsNewAndDeleteOnNewObject) {
   static constexpr Class kClass{"kClass"};
 
@@ -65,7 +76,7 @@ TEST_F(JniTest, GlobalObject_ConstructsFromNonStandardConstructor) {
 
   GlobalObject<kClass> global_object{1.f, 2.f};
 
-  EXPECT_NE(jobject{global_object}, nullptr);
+  EXPECT_EQ(jobject{global_object}, AsGlobal(Fake<jobject>()));
 }
 
 TEST_F(JniTest, GlobalObject_DoesNotDeleteAnyLocalsForAdoptedGlobalJobject) {

implementation/local_object_test.cc

@@ -44,6 +44,14 @@ using ::testing::StrEq;
 static constexpr Class kClass{"kClass"};
 static constexpr Class kClass2{"kClass2"};
 
+TEST_F(JniTest, LocalObject_AllowsNullPtrT) {
+  EXPECT_CALL(*env_, NewLocalRef).Times(0);
+  EXPECT_CALL(*env_, DeleteLocalRef).Times(0);
+
+  LocalObject<kClass> obj{nullptr};
+  EXPECT_EQ(jobject{obj}, nullptr);
+}
+
 TEST_F(JniTest, LocalObject_DoesntTryToDeleteNull) {
   EXPECT_CALL(*env_, NewLocalRef).Times(0);
   EXPECT_CALL(*env_, DeleteLocalRef).Times(0);

implementation/local_string.h

@@ -46,7 +46,6 @@ class LocalString : public LocalStringImpl {
   using Base = LocalStringImpl;
   using Base::Base;
 
-  LocalString(std::nullptr_t) : Base(jstring{nullptr}) {}
   LocalString(LocalObject<kJavaLangString>&& obj)
       : Base(AdoptLocal{}, static_cast<jstring>(obj.Release())) {}
 

implementation/object_ref.h

@@ -82,6 +82,8 @@ class ObjectRef
   }
 
  public:
+  ObjectRef(std::nullptr_t) : RefBase(nullptr) {}
+
   explicit ObjectRef(RefBaseTag<typename JniT::StorageType>&& rhs)
       : RefBase(std::move(rhs)) {}