fix issue #338

Author: Mihail Slavchev

src/jni/FieldAccessor.cpp

@@ -60,6 +60,13 @@ Local<Value> FieldAccessor::GetJavaField(const Local<Object>& target, FieldCallb
 	if (!isStatic)
 	{
 		targetJavaObject = objectManager->GetJavaObjectByJsObject(target);
+
+		if (targetJavaObject == nullptr)
+		{
+			stringstream ss;
+			ss << "Cannot access property '" << fieldData->name << "' because there is no corresponding Java object";
+			throw NativeScriptException(ss.str());
+		}
 	}
 
 	auto fieldId = fieldData->fid;
@@ -283,6 +290,13 @@ void FieldAccessor::SetJavaField(const Local<Object>& target, const Local<Value>
 	if (!isStatic)
 	{
 		targetJavaObject = objectManager->GetJavaObjectByJsObject(target);
+
+		if (targetJavaObject == nullptr)
+		{
+			stringstream ss;
+			ss << "Cannot access property '" << fieldData->name << "' because there is no corresponding Java object";
+			throw NativeScriptException(ss.str());
+		}
 	}
 
 	auto fieldId = fieldData->fid;

src/jni/MetadataNode.cpp

@@ -284,6 +284,13 @@ void MetadataNode::FieldAccessorGetterCallback(Local<String> property, const Pro
 	{
 		auto thiz = info.This();
 		auto fieldCallbackData = reinterpret_cast<FieldCallbackData*>(info.Data().As<External>()->Value());
+
+		if (!fieldCallbackData->isStatic && thiz->StrictEquals(info.Holder()))
+		{
+			info.GetReturnValue().SetUndefined();
+			return;
+		}
+
 		auto value = NativeScriptRuntime::GetJavaField(thiz, fieldCallbackData);
 		info.GetReturnValue().Set(value);
 	}
@@ -306,11 +313,15 @@ void MetadataNode::FieldAccessorSetterCallback(Local<String> property, Local<Val
 {
 	try
 	{
-		DEBUG_WRITE("FieldAccessorSetterCallback");
-
 		auto thiz = info.This();
 		auto fieldCallbackData = reinterpret_cast<FieldCallbackData*>(info.Data().As<External>()->Value());
 
+		if (!fieldCallbackData->isStatic && thiz->StrictEquals(info.Holder()))
+		{
+			info.GetReturnValue().SetUndefined();
+			return;
+		}
+
 		if (fieldCallbackData->isFinal)
 		{
 			stringstream ss;

test-app/assets/app/mainpage.js

@@ -40,6 +40,7 @@ require("./tests/testJniReferenceLeak");
 require("./tests/testNativeModules");
 require("./tests/requireExceptionTests");
 require("./tests/java-array-test");
+require("./tests/field-access-test");
 
 var MainActivity = {
     onCreate: function (bundle) {

test-app/assets/app/tests/field-access-test.js

@@ -0,0 +1,24 @@
+describe("Tests Java object field access", function () {
+	it("should not crash when Java object protytype is enumerated", function () {
+		var count = 0;
+		var obj = android.view.ViewGroup.LayoutParams.prototype;
+		for(var propertyName in obj) {
+			__log(">>obj." + propertyName + "=" + obj[propertyName]);
+			++count;
+		}
+		expect(count > 0).toBe(true);
+	});
+	
+	it("should not crash when Java property is acceess through plain JavaScritp object", function () {
+		function createLayoutParams() {}
+		createLayoutParams.prototype = new android.view.ViewGroup.LayoutParams(1, 2);
+		var exceptionCaught = false;
+		try {
+			var p = createLayoutParams();
+			p.width = 1;
+		} catch(e) {
+			exceptionCaught = true;
+		}
+		expect(exceptionCaught).toBe(true);
+	});
+});