Radio/checkbox: prefined default option stays checked when user submits a different value

[kitzberger]

Component: Classes/ViewHelpers/Misc/PrefillMultiFieldViewHelper.php

Setup: a checkbox field with this setting:

one|1
two|2|*
three|3

So three options with option 2 being preselected.

How to reproduce:

• select option 1
• submit form
• then
  • either trigger a validation error (so the form re-renders)
  • or come back from confirmation view (so the form re-renders)

Expected: only option 1 is checked.

Actual: options 1 and 2 are both checked.

Root cause: buildSelectedValue() chains prefill sources per-option with if (!$selected) guards. For option 2, all comparison methods (isFromMail, isFromMarker, …) return false (submitted 1 != 2), so the chain falls through to isFromPrefillValue(), which just returns the static * flag:

protected function isFromPrefillValue(): bool
{
    return (bool)$this->options[$this->index]['selected'];
}

It ignores whether the user already submitted a value for the field. Same flaw affects isFromTypoScriptContentObject/Raw and isFromSession. The sibling PrefillFieldViewHelper avoids this by resolving one field-level value with empty($value) guards.

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TYPO3 13.
EXT:powermail 13.2