Update data bug on nested property with numeric key

[the-pegu]

Describe the bug

Updating data for nested property with numeric key is working kinda funny 😅
For that kind of schema:

{
  "type": "object",
  "properties": {
    "group-key": {
      "type": "object",
      "properties": {
        "15": {
          "type": "string"
        }
      }
    }
  },
}

updating data for property with "15" key will result in assigning to "group-key" an array of 16 elements where first 15 are null and at index 15 you will have value that you entered.
Something like that:

{
  "group-key": [
    null, null, null, null, null,
    null, null, null, null, null,
    null, null, null, null, null,
    "something"
  ]
}

Expected behavior

Expected data would be:

{
  "group-key": {
    "15": "something"
  }
}

Steps to reproduce the issue

1. Create schema with nested numeric key:

{
  "type": "object",
  "properties": {
    "group-key": {
      "type": "object",
      "properties": {
        "15": {
          "type": "string"
        }
      }
    }
  },
}

2. Create UiSchema:

{
  "type": "VerticalLayout",
  "elements": [
    {
      "type": "Group",
      "label": "Some Group",
      "elements": [
        {
          "type": "Control",
          "label": "Label",
          "scope": "#/properties/group-key/properties/15"
        }
      ]
    }
  ]
}

3. Enter some text in nested input
4. See data of form:

{
  "group": [
    null, null, null, null, null,
    null, null, null, null, null,
    null, null, null, null, null,
    "something"
  ]
}

Screenshots

No response

Which Version of JSON Forms are you using?

v3.2.1

Package

React Material Renderers

Additional context

{
  "type": "object",
  "properties": {
    "group": {
      "type": "object",
      "properties": {
        "15": {
          "type": "string"
        },
        "non-numeric-key": {
          "type": "string"
        }
      }
    }
  },
  "required": []
}

if there are two nested field and firstly you will enter value for "non-numeric-key" then everything will work fine.
It will look like this:

{
  "group-key": {
    "non-numeric-key": "something"
  }
}

then numeric key will be added correctly:

{
  "group-key": {
    "15": "hello there",
    "non-numeric-key": "something"
  }
}

But the other way will result in array with null elements

[lucas-koehler]

Thanks for the report! This is based on discussion: https://jsonforms.discourse.group/t/weird-bug-on-nested-property-with-numeric-key/2464
It can also be reproduced with 3.4.1

From the discussion:

As a guide for a potential fix: I’m pretty sure that is a consequence of lodash set which we are using to update the data, interpreting the “number-string” as an array index.