Release 1.165.3

[odlbot]

Chris Patti

• Optimize course API pagination query (Optimize course API pagination query #3939) (3ec3dde9)

cp-at-mit

• ENABLE_MULTIPLE_CART_ITEMS=False should disable multi-product baskets even through APIs (ENABLE_MULTIPLE_CART_ITEMS=False should disable multi-product baskets even through APIs  #3909) (7a552055)

[github-actions]

OpenAPI Changes

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[sentry]

Bug: The create_basket_with_products function deletes all basket discounts when ENABLE_MULTIPLE_CART_ITEMS=False but fails to re-apply existing manual discounts, causing them to be silently lost.
_{Severity: HIGH}

Suggested Fix

Mirror the logic in the _create_basket_from_product function. Before deleting discounts, read and store any existing manually-applied discounts from the basket. After clearing the basket and adding the new product, re-apply these stored manual discounts along with any auto-apply discounts. This will ensure discount preservation consistency across different cart update flows.

Prompt for AI Agent

Review the code at the location below. A potential bug has been identified by an AI
agent. Verify if this is a real issue. If it is, propose a fix; if not, explain why it's
not valid.

Location: ecommerce/views/v0/__init__.py#L435

Potential issue: When `ENABLE_MULTIPLE_CART_ITEMS` is `False`, the
`create_basket_with_products` view deletes all existing discounts from a basket but does
not re-apply any manually-added discounts. The code at
`ecommerce/views/v0/__init__.py:435` calls
`BasketDiscount.objects.filter(redeemed_basket=basket).delete()`, clearing all
discounts. Unlike the similar `_create_basket_from_product` function, it lacks logic to
preserve and re-apply these discounts. This causes a user who updates their cart with a
single product to silently lose any previously applied manual discounts, resulting in an
unexpected price increase at checkout.

_{Did we get this right? 👍 / 👎 to inform future reviews.}