Required nested properties valid even though they are empty

We are using the library to generate forms for tasks configured by users as part of scientific workflows. Our schemas usually consist of a taskName property (string), and a parameters property (object with nested properties), for example:

{ "properties": {
      "taskName": {
        "type": "string",
        "title": "Task name",
        "description": "(required)",
        "placeholder": "Enter a name for this task"
      },
      "parameters": {
        "type": "object",
        "description": "Parameters",
        "properties": {
          "paramA": {
            "type": "string",
            "title": "Param A",
            "description": "(required)"
          },
          "paramB": {
            "type": "string",
            "title": "Param B",
            "description": "(not required)"
          }
        },
        "required": ["paramA"]
      }
    },
    "required": ["taskName", "parameters"]
}

In this case, top level property taskName is required, as is nested property paramA. Our issue is that required nested properties have the class has-success, with the input having the class ng-valid even though they are empty. But validation seems to be working, since errors for missing property paramA are displayed. This prevents us from using the has-error/has-success or ng-valid/ng-invalid classes to inform the user about which fields are valid and which are not. On the other hand, top level property taskName has the class 'has-error", with the input having the class ng-invalid as expected when empty.

Stackblitz reproducing the issue

Are we missing something here, or is it a bug?

[develAman]

Thank you @daniele-pecora for your quick answer, will try to customize the validator. Nice working sample btw, I will use them in the future 😃

[daniele-pecora]

Question 1: would be nice to have required working as expected, so how is it possible?

Answer Create a custom schema validator that corrects the error message path, so the error is mapped to the field itself. Working sample: custom-zschema-validator-factory.ts

Question 2: minLength is working as combination of minLength and required now, but what if a field is not required and needs to be set minLength?

Answer Create a custom schema validator that ignores the error if the field is not required. Working sample: fix-optional-empty-fields-z-schema-validator-factory.ts

Usage working sample https://github.com/daniele-pecora/ngx-schema-form-widgets-material