Problem
When using Form.Schema.date() fields in Neos.Fusion.Form, the following error occurs only when form validation fails (i.e., not all required fields are filled):
Object of class DateTime could not be converted to string Exception Type: Error
The form works fine when all required fields are properly filled. The error only appears when the form is re-rendered with validation errors.
We are using version 3.0.3.
Root Cause
When form validation fails and the form is re-rendered, the form data containing DateTime objects is passed back to the form fields via Neos.Fusion.Form:Input with type="date".
The AbstractFormObject::stringifyValue() method tries to convert these DateTime objects to strings for rendering in HTML input fields, but it doesn’t have a specific handler for DateTimeInterface objects, causing the fatal error.
The function currently looks like this:
protected function stringifyValue($value): string
{
if (is_object($value)) {
$identifier = $this->persistenceManager->getIdentifierByObject($value);
if ($identifier !== null) {
return $identifier;
}
}
if (is_array($value)) {
$value = json_encode($value);
}
return (string)$value;
}Solution
Modify Neos.Fusion.Form Package
Edit AbstractFormObject.php:
<?php
protected function stringifyValue($value): string
{
// Convert DateTime objects to a safe HTML value string (e.g. for <input type="date">)
if ($value instanceof \DateTimeInterface) {
return $value->format('Y-m-d');
}
if (is_object($value)) {
$identifier = $this->persistenceManager->getIdentifierByObject($value);
if ($identifier !== null) {
return $identifier;
}
}
if (is_array($value)) {
$value = json_encode($value);
}
return (string)$value;
}This ensures DateTime objects are properly formatted before being rendered as HTML form values. I believe this is a bug in Neos.Fusion.Form that should be fixed in the core package, as it's a common use case to pre-fill date fields with DateTime values.
Problem
When using Form.Schema.date() fields in Neos.Fusion.Form, the following error occurs only when form validation fails (i.e., not all required fields are filled):
Object of class DateTime could not be converted to string Exception Type: ErrorThe form works fine when all required fields are properly filled. The error only appears when the form is re-rendered with validation errors.
We are using version 3.0.3.
Root Cause
When form validation fails and the form is re-rendered, the form data containing DateTime objects is passed back to the form fields via Neos.Fusion.Form:Input with type="date".
The AbstractFormObject::stringifyValue() method tries to convert these DateTime objects to strings for rendering in HTML input fields, but it doesn’t have a specific handler for DateTimeInterface objects, causing the fatal error.
The function currently looks like this:
Solution
Modify Neos.Fusion.Form Package
Edit AbstractFormObject.php:
This ensures DateTime objects are properly formatted before being rendered as HTML form values. I believe this is a bug in Neos.Fusion.Form that should be fixed in the core package, as it's a common use case to pre-fill date fields with DateTime values.