Breaking: #102968 - FormEngine itemFormElID removed

See forge#102968

Description

When dealing with custom FormEngine elements in the backend record editing interface, the infrastructure prepares a huge data array and hands it over to single element classes for rendering.

The specific data key $this->data['parameterArray']['itemFormElID'] has been removed. The intention of that key was to prepare some unique id to be used as id attribute. This never made a lot of sense, single element classes can easily take care of this on their own if needed.

Since the Core can't actively deprecate and log access to members of the main data array as such, there is no point in declaring a deprecation for it, and the array entry has been removed directly.

Impact

Extensions with custom backend FormEngine elements may raise an "undefined array key" PHP warning, or may create empty id attributes in their HTML output if accessing itemFormElID.

Affected installations

Instances with extensions that deliver custom FormEngine elements may be affected.

Migration

A typical use case for a unique id attribute on a form element is to connect it with a label element. Accessing itemFormElID can usually be easily avoided by creating a unique string using StringUtility::getUniqueId(), with a custom prefix:

// Before
$attributeId = htmlspecialchars($this->data['parameterArray']['itemFormElID']);
$html[] = '<input id="' . $attributeId . '">';

// After
$attributeId = htmlspecialchars(StringUtility::getUniqueId('formengine-my-custom-element-'));
$html[] = '<input id="' . $attributeId . '">';