Will get null message when locale is not default even if there is default messages.properties

[dongxuwang]

For instance, if the locale is en_US and only messages.properties is offered, null will be rendered like this:

#classpath:messages.properties
some_code: Something

Error result:

{
  "errors": [
    {
      "code": "some_code",
      "message": "null"
    }
  ]
}

The result should grab the default message when its locale is not found.

[alimate]

Hello @dongxuwang. Hope you're doing well.
Unfortunately, I couldn't manage to reproduce the problem you described. I would be grateful if you state the exact steps to reproduce the bug or even provide a sample project.

Thanks for your time and contribution 🙏

[dongxuwang]

The issue is wired. It was back to normal after I added a message_en_US.properties and then deleted it.
I'll try to reproduce it and continue to focus on this issue.