Grouped products have position: 0 for all linked products

[didkan]

Problem
position attribute for Grouped Products is always 0 for all linked products. I.e. the order/position of the products that make up the grouped product are not mirrored in Elasticsearch.

Root cause
In magento2-vsbridge-indexer/src/module-vsbridge-indexer-catalog/Model/ResourceModel/Product/Links.php the function fetchPositionAttributeData() returns a single row from db (first row in result set). The problem is that the where clause used here actually returns multiple rows, ie the position attribute for all link types.

We would need to add the link_type_id to the where clause to get the correct product_link_attribute_id to use in the join.

Solution
Add link_type = [current link type] to the where clause here
https://github.com/DivanteLtd/magento2-vsbridge-indexer/blob/3565158727d421013419cc45904a0e00f756a124/src/module-vsbridge-indexer-catalog/Model/ResourceModel/Product/Links.php#L222

I'm not sure exactly how to handle this one myself or if maybe there is a better/simpler solution than the one I proposed. the problem I see is that we actually don't have the link_type yet since we are still building the query when fetchPositionAttributeData() is called if I interpret the code correctly.

[afirlejczyk]

We could load linked product by type.. and load correct position attribute in fetchPositionAttributeData, but I decided to change logic a little:

#245

[didkan]

@afirlejczyk Nice! I'll test it for my use cases early next week and report back in the PR.

[afirlejczyk]

Should be OKAY now, previously select return null values, now we got positions in ES:

    "product_links": [
      {
        "sku": "24-WG085_Group",
        "link_type": "associated",
        "linked_product_sku": "24-WG085",
        "linked_product_type": "simple",
        "position": 0
      },
      {
        "sku": "24-WG085_Group",
        "link_type": "associated",
        "linked_product_sku": "24-WG086",
        "linked_product_type": "simple",
        "position": 1
      },
      {
        "sku": "24-WG085_Group",
        "link_type": "associated",
        "linked_product_sku": "24-WG087",
        "linked_product_type": "simple",
        "position": 2
      }
    ],