[form] how to check if form changed after prefill

[LarsDenBakker]

Describe the bug

When prefilling a form, there isn't any way to know whether the form has changed after prefilling. The form dirty value is true, while the prefilled value is false.

To Reproduce

See this reproduction: https://webcomponents.dev/edit/HgFCAaNA1jyOhkpWYiei

In firstUpdated I'm logging dirty and prefilled

Additional context

Is there another value that can be used for this?

[daKmoR]

that prefilled value looks definitely wrong 🙈

something strange is going on there... in the firstUpdated the value even of the input is wrong (e.g. it's prefilled false)
whereas if I select <lion-input name="firstName"> in the developer tools and do $0.prefilled it correctly says true
🙈

the idea is that if any of the form elements are prefilled that then the form/fieldset becomes prefilled... but it seems the fieldset is not prefilled...

definitely something wrong here... will need to investigate 😅

[tlouisse]

@LarsDenBakker There is an initInteractionState() that runs on connectedCallback.
This runs too early, since it only has the right values on registrationReady.

I have a fix in this in a branch: #583