Feature: #107256 - PSR-14 event to modify options in EmailFinisher 

Description 

A new PSR-14 event \TYPO3\CMS\Form\Event\BeforeEmailFinisherInitializedEvent has been introduced. This event is dispatched before the \EmailFinisher is initialized and allows listeners to modify the finisher options dynamically.

This enables developers to customize email behavior programmatically, such as:

• Setting alternative recipients based on frontend user permissions
• Modifying the email subject or content dynamically
• Replacing recipients with developer email addresses in test environments
• Adding or removing CC or BCC recipients conditionally
• Customizing reply-to addresses

The event provides access to both the finisher context (read-only) and the options array, allowing for flexible manipulation of the email configuration.

To modify the \EmailFinisher options, the following methods are available:

• getFinisherContext(): Returns the FinisherContext containing form runtime and request information
• getOptions(): Returns the current finisher options array
• setOptions(): Allows setting the modified options array

Example 

The corresponding event listener class:

<?php

namespace MyVendor\MyExtension\Form\EventListener;

use TYPO3\CMS\Core\Attribute\AsEventListener;
use TYPO3\CMS\Form\Event\BeforeEmailFinisherInitializedEvent;

final class BeforeEmailFinisherInitializedEventListener
{
    #[AsEventListener('my_extension/form/modify-email-finisher-options')]
    public function __invoke(BeforeEmailFinisherInitializedEvent $event): void
    {
        $options = $event->getOptions();
        $context = $event->getFinisherContext();

        // Overwrite recipients based on FormContext
        if ($context->getFormRuntime()->getFormDefinition()->getIdentifier() === 'my-form-123') {
            $options['recipients'] = ['user@example.org' => 'John Doe'];
        }

        // Modify subject dynamically
        $options['subject'] = 'Custom subject: ' . ($options['subject'] ?? '');

        // Clear CC and BCC recipients
        $options['replyToRecipients'] = [];
        $options['blindCarbonCopyRecipients'] = [];

        $event->setOptions($options);
    }
}

Impact 

It is now possible to dynamically modify \EmailFinisher options before email processing begins, using the new PSR-14 event BeforeEmailFinisherInitializedEvent . This provides developers with full control over email configuration without needing to extend or override the \EmailFinisher class.