How to validate a paragraph field?

Question

I have a paragraph type with 2 fields: year and quarter

I have a content type with a paragraph field (field_year_and_quarter) targeting ONLY this paragraph type

I am trying to create a constraint to disallow the encoding of a duplicate (same year/quarter)

I have tried:

1-A constraint at the node level which is looping into field_year_and_quarter with $node->get('field_year_and_quarter')->referencedEntities() to check if any duplicate

=>This is not working as it is not taking into account what is encoded in the widget, only the last saved version is checked

2-A constraint at the paragraph level which is getting its Parent to be able to loop into field_year_and_quarter with $node_parent->get('field_year_and_quarter')->referencedEntities() to check if any duplicate [I replace one item by the paragraph provided in the parameter ]

Here is the code:

  public function validate($certificate_p, Constraint $constraint) {
    /* @var \Drupal\paragraphs\Entity\Paragraph $certificate_p */
    if ($certificate_p->bundle() == 'qoc') {
      $prod_company = $certificate_p->getParentEntity();
      $certificates = $prod_company->get('field_year_and_quarter')
        ->referencedEntities();
      $all_certificates = [];
      foreach ($certificates as $certificate) {
        // use the paragraph provided in the function parameter
        $certif_to_check = ($certificate_p->id() == $certificate->id()) ? $certificate_p : $certificate;
        $year = $certif_to_check->get('field_qoc_year')->value;
        $quarter = $certif_to_check->get('field_qoc_quarter')->value;
        // Year/Quarter are already encoded
        if (isset($all_certificates[$year][$quarter])) {
          $this->context->addViolation($constraint->duplicate_certif, [
            '%quarter' => surround_by_nbsp($quarter),
            '%year' => surround_by_nbsp($year),
          ]);
          break;
        }
        $all_certificates[$year][$quarter] = TRUE;
      }
    }

=>This is not working for the same reason

3- A constraint at the field level... here is the code:

  public function validate($items, Constraint $constraint) {
    $certificates = $items->referencedEntities();
    $all_certificates = [];
    foreach ($certificates as $certificate) {
      $year = $certificate->get('field_qoc_year')->value;
      $quarter = $certificate->get('field_qoc_quarter')->value;
      // Year/Quarter are already encoded
      if (isset($all_certificates[$year][$quarter])) {
        $this->context->addViolation($constraint->duplicate_certif, [
          '%quarter' => surround_by_nbsp($quarter),
          '%year' => surround_by_nbsp($year),
        ]);
        break;
      }
      $all_certificates[$year][$quarter] = TRUE;
    }
  }

=>Not working for the same reason

What should I do? (I have also tried to validate in the form without luck)

Answer 1

OK, looking at the ERR implementations of $items->referencedEntities() and $item->entity it seems like the first function is able to handle new entities, but only the second is able to handle unsaved entities.

So loop over $items and then get the paragraph from the single field item:

foreach ($items as $item) {
  $paragaph = $item->entity;
  $value = $paragraph->field_foo->value;
  // ...
}