Clameurs/sites/all/modules/contrib/fields/cer/extensions/cer_commerce/cer_commerce.module

<?php

/**
 * Implements hook_cer_insert().
 */
function cer_commerce_cer_insert(CerPreset $preset) {
  // Prevents a race condition when deleting Commerce products which are referred to
  // by Product Reference fields managed by CER.
  if ($preset->wrapper->cer_right->chain->value()->end() instanceof CerCommerceProductReferenceField) {
    $preset->wrapper->cer_bidirectional->set(FALSE);
    $preset->save();

    drupal_set_message(t('In order to prevent a race condition, bidirectionality has been disabled for this preset.'), 'warning');
  }
}