trait PrecedingConstraintAwareValidatorTrait

trait PrecedingConstraintAwareValidatorTrait {

  /**
   * Checks whether any preceding constraints have been violated.
   *
   * @param \Symfony\Component\Validator\Constraint $current_constraint
   *   The constraint currently being validated.
   *
   * @return bool
   *   TRUE if any preceding constraints have been violated, FALSE otherwise.
   */
  protected function hasViolationsForPrecedingConstraints(Constraint $current_constraint) : bool {
    assert($this->context instanceof ExecutionContext);
    $earlier_constraints = iterator_to_array($this
      ->getPrecedingConstraints($current_constraint));
    $earlier_violations = array_filter(iterator_to_array($this->context
      ->getViolations()), function (ConstraintViolationInterface $violation) use ($earlier_constraints) {
      return in_array($violation
        ->getConstraint(), $earlier_constraints);
    });
    return !empty($earlier_violations);
  }

  /**
   * Gets the constraints preceding the given constraint in the current context.
   *
   * @param \Symfony\Component\Validator\Constraint $needle
   *   The constraint to find the preceding constraints for.
   *
   * @return iterable
   *   The preceding constraints.
   */
  private function getPrecedingConstraints(Constraint $needle) : iterable {
    assert($this->context instanceof ExecutionContext);
    $constraints = $this->context
      ->getMetadata()
      ->getConstraints();
    if (!in_array($needle, $constraints)) {
      throw new \OutOfBoundsException();
    }
    foreach ($constraints as $constraint) {
      if ($constraint != $needle) {
        (yield $constraint);
      }
    }
  }

}