Fix image focus removing

[afbora]

Changelog

Fixes

• Image focus can't be removed [v5] Image focus can't be removed #7022

Breaking changes

None

Docs

Ready?

• In-code documentation (wherever needed)
• Unit tests for fixed bug/feature
• Tests and CI checks all pass

For review team

• Add lab and/or sandbox examples (wherever helpful)
• Add changes & docs to release notes draft in Notion

[distantnative]

I also saw that this would fix this specific issue.

But I am wondering If this rather points to a general regression, where null/undefined values don't get updated anymore via our new content module. Where in the past they did. @bastianallgeier

[bastianallgeier]

We should test this in the new holy merge branch

[bastianallgeier]

I've added unit tests to the "Holy merge" branch to check if we can still remove fields properly by passing null and that works on the backend. If I remember correctly here, the problem was that null values are not properly sent to the server in the first place. I think we should look into that some more.

[bastianallgeier]

Ok, I know now where this happens. When a field is unset in the changes version by passing null, the Form class merges it with the latest version and the missing field gets overwritten with the value from the latest version:

kirby/src/Panel/Model.php

Lines 49 to 54 in 6c4c378

	return Form::for(
	model: $this->model,
	props: [
	'values' => $changes
	]
	)->values();

[bastianallgeier]

I tracked it down further and it seems like the main issue is the Form::for part in ModelWithContent::update because that's another part where we merge the input with the latest version.