## Summary
Ensure that address deletion during order deletion is handled correctly with respect to cascading deletes. Currently, when deleting an order that does not have a shipping or billing address, we incorrectly attempt to delete all order addresses. This happens because `undefined` address IDs are not handled properly during deletion.
More specifically, when deleting an order without addresses, the following method is called with these arguments:
```ts
await deleteOrderAddresses([undefined, undefined])
```
This triggers deletion of all order addresses.
To make matters worse, because we have a cascade delete defined from order addresses to orders, the same call also deletes all associated orders.
The root cause is the following filtering logic:
```ts
const orderAddressIds = orders
.map((order) => [order.shipping_address_id, order.billing_address_id])
.flat(1)
```
For orders without addresses, this produces `[undefined, undefined]` as input filter, which our delete methods interpret as:
```ts
await delete({ '$or': [ { id: undefined }, { id: undefined } ] })
```
This effectively translates to “delete all addresses.”
In this PR, we make two changes to prevent this going forward:
1. Filter out undefined address IDs before attempting deletion
2. Remove the cascade delete from address to order, as this is an aggressive constraint
The latter change is open for discussion, but cascading deletes from a child entity to a parent is slightly off IMO. Let me know your thoughts.
## Checklist
Please ensure the following before requesting a review:
- [x] I have added a **changeset** for this PR
- Every non-breaking change should be marked as a **patch**
- To add a changeset, run `yarn changeset` and follow the prompts
- [x] The changes are covered by relevant **tests**
- [x] I have verified the code works as intended locally
- [ ] I have linked the related issue(s) if applicable
---
## Additional Context
Add any additional context, related issues, or references that might help the reviewer understand this PR.
---
> [!NOTE]
> Strengthens order deletion to avoid unintended cascades and validates behavior with tests.
>
> - Update FK constraints in migration to `ON DELETE SET NULL` for `order.shipping_address_id` and `order.billing_address_id` (was `CASCADE`)
> - In `order-module-service.ts` `deleteOrders`, filter falsy address IDs and conditionally batch-delete `order_address`/`order_change` via `promiseAll`
> - Add integration tests `integration-tests/__tests__/delete-order.spec.ts` covering deletion of orders and associated entities, deleting orders without addresses (no cross-order impact), and address deletion setting `NULL` on the order
> - Add changeset marking `@medusajs/order` patch
>
> <sup>Written by [Cursor Bugbot](https://cursor.com/dashboard?tab=bugbot) for commit 8e4ab59af407ec865f73fbf286ec93e710915c8e. This will update automatically on new commits. Configure [here](https://cursor.com/dashboard?tab=bugbot).</sup>
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