[5.x]: Add Catalog pricing rule info to purchasable/line item

[nfourtythree]

What happened?

Description

It is good to be able to know which rule is being used to provide the price to a purchasable and therefore a line item (once it is added to the cart).

At the moment it is a long winded way of finding out that information.

It would be better to populate this info on the purchasable at the same time as the price is populated.

Related issue: #3699

Craft CMS version

5.x

Craft Commerce version

5.x

[linear]

PT-2554 [5.x]: Add Catalog pricing rule info to purchasable/line item

[neilfr]

I’m also looking for a way to identify which specific pricing rule is responsible for the final price a user sees—especially when multiple catalog pricing rules are active. My use case is to display the discount source (e.g., “Member discount” or “Spring Sale”) alongside the adjusted price, on our product detail pages, so users understand why they’re seeing a reduced price.

Currently, I am not able to find a straightforward way to get this information from the purchasable or order.

Thanks in advance for any help or recommendations.