It doesn't work on image field

Do you have any more information as to why this is happening?

I just encountered this issue with an image field using Drupal 9.5.11. field_config_cardinality settings on the image field are ignored by the site.

Added next widget that replaces original one.

<?php
/**
 * Add field_config_cardinality support to image widget.
 */
class CardinalityImageWidget extends ImageWidget {

  /**
   * Gets the cardinality of the field.
   *
   * @return int
   *   The cardinality of the field.
   */
  public function getCardinality(): int {
    if (
      $this->fieldDefinition instanceof ThirdPartySettingsInterface
    ) {
      return (int) $this->fieldDefinition->getThirdPartySetting('field_config_cardinality', 'cardinality_config');
    }

    return $this->fieldDefinition->getFieldStorageDefinition()
      ->getCardinality();
  }

  /**
   * {@inheritdoc}
   */
  protected function formMultipleElements(FieldItemListInterface $items, array &$form, FormStateInterface $form_state) {
    $elements = parent::formMultipleElements($items, $form, $form_state);
    $cardinality = $this->getCardinality();
    $elements["#file_upload_description"]["#cardinality"] = $cardinality;
    if (count(Element::children($elements)) > $cardinality) {
      $elements[$elements["#file_upload_delta"]]['#access'] = FALSE;
    }
    $elements[$elements["#file_upload_delta"]]["#cardinality"] = $cardinality;
    if ($cardinality === 1) {
      $elements[$elements["#file_upload_delta"]]["#multiple"] = FALSE;
    }
    return $elements;
  }

}
?>

and alter original:

<?php

/**
 * Implements hook_field_widget_info_alter().
 */
function custom_module_field_widget_info_alter(array &$info) {
  if (isset($info['image_image'])) {
    $info['image_image']['class'] = CardinalityImageWidget::class;
  }
}

?>

The tricky thing is that ImageWidget and FileWidget has complex form that depends on cardinality, so there are now easy way to change it.

Can you confirm is still experiencing this?

I confirm that this issue is still there even in 4.0.0 version.

@zviryatko, I am using your provided code. But it right now throws a lot of warnings because your code works even for single image fields too. We need it to work only for multiple image fields.

@er.garg.karan , you opened a MR for 4.0.x but the branch is still 3.0.x. Can you please update that? I'm not able to do it for you...