Combining type=variation with attributes for Store API /products endpoint doesn't work

[jelledruut]

Describe the bug

The /products endpoint accepts the parameter type=variation, which returns product variations, instead of products.

An example request:
/wp-json/wc/store/v1/products?type=variation&parent=24958&attributes[0][attribute]=pa_size&attributes[0][slug]=44

However, when combining type=variation with the attributes parameter, the query becomes incorrect. The example I provided should return all variations that have the product attribute term pa_size 44, with parent product ID 24958.

However, instead it returns no variations when using the attributes parameter in combination with type=variation, since the resulting query is incorrect.

https://github.com/woocommerce/woocommerce-blocks/blob/trunk/src/StoreApi/docs/products.md#product-variations
https://github.com/woocommerce/woocommerce-blocks/blob/trunk/src/StoreApi/docs/products.md#list-products

Expected behavior

When using type=variation and the attributes parameter, it should return all variations that have those attribute terms.

For example, this query would work (for the example URL provided) - since attribute terms linked to variations are stored in the wp_postmeta table for variations:

...
'meta_query' => [
    [
        'key' => 'attribute_pa_size',
        'value' => ['44'],
        'compare' => 'IN',
    ],
],

While it currently results in this query (which only works for products, not variations):

...
'tax_query' => [
    [
        'taxonomy' => 'pa_size',
        'field' => 'slug',
        'terms' => ['44'],
        'operator' => 'IN',
    ],
],

Though an issue that arises is that only the slug is stored for variation attribute terms in wp_postmeta as meta_value, and not the term_id, which is supported for the attributes parameter.

My knowledge of the internals of WooCommerce isn't good enough to figure out a better solution. E.g. maybe the wc_product_attributes_lookup table?

Screenshots

Environment

WordPress:

• WordPress version: 6.4.1
• WooCommerce version: 8.2.2
• Site language: EN

[roykho]

Thanks for reporting this. The endpoint documentation mentioned indeed seems to suggest it should be possible. We'll have a look at this.