fix(objc-call): Don't crash when calling an optional protocol method

src/NativeScript/Metadata/Metadata.h

@@ -25,13 +25,15 @@ enum MetaFlags {
     FunctionReturnsUnmanaged = 3,
     FunctionIsVariadic = 5,
     FunctionOwnsReturnedCocoaObject = 4,
+    MemberIsOptional = 0, // Mustn't equal any Method or Property flag since it can be applicable to both
     MethodIsInitializer = 1,
     MethodIsVariadic = 2,
     MethodIsNullTerminatedVariadic = 3,
     MethodOwnsReturnedCocoaObject = 4,
     MethodHasErrorOutParameter = 5,
     PropertyHasGetter = 2,
-    PropertyHasSetter = 3
+    PropertyHasSetter = 3,
+
 };
 
 /// This enum describes the possible ObjectiveC entity types.
@@ -581,6 +583,9 @@ struct VarMeta : Meta {
 };
 
 struct MemberMeta : Meta {
+    bool isOptional() const {
+        return this->flag(MetaFlags::MemberIsOptional);
+    }
 };
 
 struct MethodMeta : MemberMeta {

src/NativeScript/ObjC/ObjCMethodCall.h

@@ -66,6 +66,8 @@ class ObjCMethodCall : public FFICall {
 
     bool _hasErrorOutParameter;
 
+    bool _isOptional;
+
     bool _isInitializer;
 
     SEL _selector;

src/NativeScript/ObjC/ObjCMethodCall.mm

@@ -34,6 +34,7 @@
 
     Base::initializeFFI(vm, { &preInvocation, &postInvocation }, returnTypeCell, parameterTypesCells, 2);
     this->_retainsReturnedCocoaObjects = metadata->ownsReturnedCocoaObject();
+    this->_isOptional = metadata->isOptional();
     this->_isInitializer = metadata->isInitializer();
     this->_hasErrorOutParameter = metadata->hasErrorOutParameter();
 
@@ -130,7 +131,12 @@ static bool isJavaScriptDerived(JSC::JSValue value) {
         bool isInstance = !class_isMetaClass(object_getClass(target));
         NSLog(@"> %@[%@ %@]", isInstance ? @"-" : @"+", NSStringFromClass(object_getClass(target)), NSStringFromSelector(call->_selector));
 #endif
-        invocation.setArgument(0, target);
+        if (call->_isOptional && ![target respondsToSelector:call->_selector]) {
+            // Unimplemented optional method: Silently perform a dummy call to nil object
+            invocation.setArgument(0, nil);
+        } else {
+            invocation.setArgument(0, target);
+        }
         invocation.setArgument(1, call->_selector);
         invocation.function = call->_msgSend;
     }