Add support for product reference field

Unfortunately, the Drupal Commerce does not support products referenced from nodes. The same with the Commerce Bulk, as it totally relies on a bare product, not a reference field.

if (get_class($product) == 'Drupal\node\Entity\Node') {
   $product = $product->get('field_product')->entity;
}

This assumes that the field is always called product resulting in 'field_product' but it may be called whatever. In my test case I've called it 'field_my_product', french may call it 'field_produit' and so on. Also, assuming that product will be always referenced from the node entity is a bit specific one. If we'd fix it, tomorrow someone will open a new issue: "Add support for xyz entity!!!".

Below are the DC issues related with node as a housing for products. The whole issue is quite complex and potentially might be fixed here, therefore I don't close it yet in a hope that some day I'll have a free time for the work. Contributed patches are welcomed but, ... you should think carefully whether the play worth candles. Is it not simpler to use products for placing the required content? (стоит ли овчинка выделки ваще)

#2821338: (Commerce:) Error when creating both product and variations via nested inline entity forms
#2651026: Fatal error with AddToCartForm.php
#2927505: Using existing Node as Product Entity
#2892201: How to reference and connect products to nodes and nodes to products
#2861197: Allow to use non commerce_product entity (example - node)

I mean, the fatal error when adding / editing node could be fixed right now:

function commerce_bulk_field_widget_form_alter(&$element, FormStateInterface $form_state, $context) {
  $product = $form_state->getFormObject()->getEntity();
  if (!($product instanceof Drupal\commerce_product\Entity\ProductInterface)) {
    return;
  }
  /** @var \Drupal\Core\Field\FieldDefinitionInterface $field_definition */
  $field_definition = $context['items']->getFieldDefinition();
  $field_name = $field_definition->getName();
  $entity_type = $field_definition->getTargetEntityTypeId();
// ....
}

But the Commerce Bulk will not work on this form. No variations could be bulk created. You can create variations manually, one by one, but they will not work properly. See issues on the #1 comment.

Conclusion: if all that you need to prevent fatal error then I'll fix it right now (has no sense at all). If you need Commerce Bulk working with node referenced products then please, wait a bit. Or, would be glad to review a patch if that will be contributed.

I really like the patch and want to commit it but...

What I've found:

The fatal error is gone: good!

The bulk creation of variations works inside nested IEF product form: good!

The created reference product could be deleted outside the housing node: not good but might be ignored as a site admin's trouble.

The created reference product is not deleted when the housing node is deleted: actually good.

The node could be saved without referenced product is saved on the IEF form (variations are bulk created but the Create product button is not pressed): not good but could considered as admin's trouble.

After everything is saved as needed and attempted to press the Add to cart button there is a fatal error:

The website encountered an unexpected error. Please try again later.</br></br><em class="placeholder">Exception</em>: The given entity is not assigned to any store. in <em class="placeholder">Drupal\commerce_cart\Form\AddToCartForm-&gt;selectStore()</em> (line <em class="placeholder">255</em> of <em class="placeholder">modules/commerce_core_modules/commerce/modules/cart/src/Form/AddToCartForm.php</em>)

Opened the node for editing again and checked: the store checkbox is checked as it was before saving product & node.

And only after pressing the Update product button and resaving the node everything works as expected.

Obviously that you and me can easily remember the trick and apply each time when creating referenced products but that's inappropriate for most of the users.

Would be great if we'd found the reason for not saved store issue because many people are used to D7 product displays and that way they can more easily migrate to D8 products. Which are actually better than displays.

#2721349: Nested inline entities must be saved in "inside-out" order

Might be related, I am not sure yet, needs digging in.

Thank you. Waiting impatiently because this will be cool. Even the Drupal Commerce does not provide this but we will!

I found same issues:

TypeError: Argument 1 passed to Drupal\commerce_bulk\BulkVariationsCreator::getProductVariation() must be an instance of Drupal\commerce_product\Entity\Product, instance of Drupal\commerce_bulk\Entity\BulkProductVariation given, called in .\modules\commerce_bulk\commerce_bulk.module on line 171 in Drupal\commerce_bulk\BulkVariationsCreator->getProductVariation() (line 105 of ..\modules\commerce_bulk\src\BulkVariationsCreator.php)

line 171: commerce_bulk.module

$variation = $creator->getProductVariation($product);

line 105 BulkVariationsCreator.php

public function getProductVariation(Product $product) {
    $variations = $product->getVariations();
    $variation = end($variations);
    $timestamp = time();
    if (!$variation instanceof ProductVariation) {
      $variation = \Drupal::entityTypeManager()->getStorage('commerce_product_variation')->create([
        'type' => $product->getFieldDefinition('variations')->getSettings()['handler_settings']['target_bundles'][0],
        'created' => $timestamp,
        'changed' => $timestamp,
      ]);
    }

    return $variation;
  }

@ncxn

Please, refer to this issue:

#3009439: Crash when editing variation on the Variations tab