Fix/imposible customize product collection

[dvynograd]

Right now it's impossible to customize product collection on the catalog products list page.

As i can see, Magento supposed to provide this ability in \Magento\Catalog\Block\Product\ListProduct::_beforeToHtml

` $this->_eventManager->dispatch(
'catalog_block_product_list_collection',
['collection' => $this->_getProductCollection()]
);

    $this->_getProductCollection()->load();

`

but due to Magento has the observer CatalogBlockProductCollectionBeforeToHtmlObserver wich listen this event and loads collection. So it prevent to collection modifications in future customizations.

Following PR is fixing that issue.

[maghamed]

why did you change copyright ?

[dvynograd]

I don't know will put in back

[dvynograd]

Fixed

[maghamed]

We can't accept such fix because it will lead to general performance degradation of Product Collection load time.
Theoretically it's correctly to treat reviews as a part of Product Aggregation Root, but this behavior should be consistent with how Catalog APIs work (aka ProductRepositoryInterface::get and ProductRepositoryInterface::getList, whether these API calls fill ProductInterface with Reviews or not).
For now Review module doesn't provide Extension attribute for ProductInterface.
So, to prevent inconsistency between ProductCollection::load and ProductRepository::getList as well as not introduce performance degradation we will not add product reviews for all product collection load calls.

Proposed fix for this issue, taking into account Backward Compatibility requirements.

1. Add Optional dependency (which by default is equal to NULL) to Magento\Catalog\Block\Product\ListProduct class. With name $collectionLoader
2. Class $collectionLoader will have the only public method - load($collection). Which loads collection passed as input parameter.
3. Method load of this class could be pluginized and logic which exists now in CatalogBlockProductCollectionBeforeToHtmlObserver, could be added as a plugin for $collectionLoader::load($productCollection)

[maghamed]

@dvynograd are there any updates?

[maghamed]

@dvynograd are there any updates?

[ishakhsuvarov]

@dvynograd
Would you like to continue with this PR? If so, please see review comments.
Thank you

[ishakhsuvarov]

@dvynograd I am closing this PR for now due to lack of activity.
Please check the code review comments, update with the latest develop and reopen this ticket if you wish to continue.
Thanks!