Type 'Null' is not a subtype of type 'String'

[Nidal-Bakir]

New Issue Checklist

• [x] I am not disclosing a vulnerability.
• [x] I am not just asking a question.
• [x] I have searched through existing issues.
• [x] I can reproduce the issue with the latest version of Parse Server and the Parse Flutter SDK.

Issue Description

I'm using parse dio client. When there is no internet connection (disabled wifi and LTE) and trying to do any operation with the parse server like (create or update or any operation from the ParseClient class) The dio throws a DioError and in the SDK we convert the error to ParseNetworkResponse

https://github.com/parse-community/Parse-SDK-Flutter/blob/af76c6b74fcb4d7e60d798a028e207246d4f8b19/packages/dart/lib/src/network/parse_dio_client.dart#L86-L89

And here is the bug the data property in error.response is null. so the next exception will be thrown: Type 'Null' is not a subtype of type 'String'

Steps to reproduce

• init the Parse SDK with dio client

• Disable wifi and LTE (cut off the internet of the device)

• invoke create operation on parse object

Actual Outcome

_TypeError (type 'Null' is not a subtype of type 'String') [log] #0 ParseDioClient.post package:parse_server_sdk/…/network/parse_dio_client.dart:88 #1 ParseObject.create package:parse_server_sdk/…/objects/parse_object.dart:71 #2 ChatRemoteDataSourceImpl.sendNewMessage package:doors/…/data_source/chat_remote_data_source.dart:76 #3 SendTextMessageProcessManager._startSendingProcess package:doors/…/process/send_text_message_process_manager.dart:69 #4 SendTextMessageBloc._onMessageSended package:doors/…/send_text_message_bloc/send_text_message_bloc.dart:45 #5 new SendTextMessageBloc.. package:doors/…/send_text_message_bloc/send_text_message_bloc.dart:24 #6 new SendTextMessageBloc. package:doors/…/send_text_message_bloc/send_text_message_bloc.dart:23 #7 Bloc.on..handleEvent package:bloc/src/bloc.dart:211

Expected Outcome

ParseResponse with error

Environment

Flutter version: 2.10.2 android emulator with android version: 9

Parse Flutter SDK

• SDK version: 3.1.2
• Operating system version: Ubuntu 20.04.4 LTS x86_64

Server

• Parse Server version: 4.5.0

[parse-github-assistant[bot]]

Thanks for opening this issue!

• 🚀 You can help us to fix this issue faster by opening a pull request with a failing test. See our Contribution Guide for how to make a pull request, or read our New Contributor's Guide if this is your first time contributing.