Somehow, each of the line items in one order have 3 tax_lines with identical data.

[dwene]

Bug report

We use a 3rd party plugin to calculate taxes, using the Medusa tax plugin system.

I noticed one of my recent orders had 3x the tax I was expecting. Looking at the order it appears that each line_item has 3 tax lines, each with the same percentage added. Seems like somehow the tax lines were added 3 times. I would expect that if any part of the order failed, it would be rolled back in a transaction, but that didn't appear to happen.

Describe the bug

https://www.loom.com/share/2f6ce6cc7ba34a08b8296ad505804052

Tax is 3x higher than it should be

System information

Medusa version (including plugins): .1.3.4 Node.js version: 14 Database: PG Operating system: Linux Browser (if relevant):

Steps to reproduce the behavior

See above.

Expected behavior

Screenshots

Code snippets

Additional context

Add any other context about the problem here

[olivermrbl]

Thanks for reporting it in @dwene! We'll attend to it immediately and release a fix asap. Will keep you posted :)

[adrien2p]

Also, @dwene @olivermrbl that pr https://github.com/medusajs/medusa/pull/1894 will probably fix some issues as well around transaction and wrong object usage. Might not fix everything but it could help

[olivermrbl]

@dwene Latest release includes a bunch of fixes around transactions in the core. Let us know if the issue persists, when you get a chance to update to latest

[akramaskar]

I've identified a potential issue in the order creation process, where the tax rate triples after transforming a cart into an order. Below is the relevant code and logs that highlight the problem:

Path: OrderService - createFromCart

 console.log("[DEBUGGING] ::: Start of createFromCart");
      console.log(
        "[DEBUGGING] ::: order :: create from cart : items",
        cart?.items.map((item) => item.tax_lines.map((tl) => tl.rate)),
      );

      const itemsReturn = await Promise.all(
        [
          cart.items.map(async (lineItem): Promise<unknown[]> => {
            console.log("[DEBUGGING] ::: Processing line item:", lineItem.id);

            const toReturn: unknown[] = [
              lineItemServiceTx.update(lineItem.id, { order_id: order.id }),
            ];

            console.log(
              "[DEBUGGING] ::: After updating line item:",
              lineItem.id,
              "tax_lines:",
              lineItem.tax_lines.map((tl) => tl.rate),
            );

            if (lineItem.is_giftcard) {
              toReturn.push(
                this.createGiftCardsFromLineItem_(order, lineItem, manager),
              );
            }

            return toReturn;
          }),
          cart.shipping_methods.map(async (method) => {
            console.log(
              "[DEBUGGING] ::: Processing shipping method:",
              method.id,
            );

            (method.tax_lines as any) = undefined;
            return shippingOptionServiceTx.updateShippingMethod(method.id, {
              order_id: order.id,
            });
          }),
        ].flat(Infinity),
      );

      console.log("[DEBUGGING] ::: After all Promise.all operations");

      orderTemp = await this.retrieve(order.id, {
        relations: ["items", "items.tax_lines"],
      });

      console.log(
        "[DEBUGGING] ::: order :: create from cart : after itemsReturn",
        orderTemp?.items.map((item) => item.tax_lines.map((tl) => tl.rate)),
      );

Logs

[DEBUGGING] ::: Start of createFromCart
[DEBUGGING] ::: order :: create from cart : items [ [ 19 ] ]
[DEBUGGING] ::: Processing line item: item_01HDY2B3BVH8VDMYADA22TD0G8
[DEBUGGING] ::: Start of lineItemService.update
[DEBUGGING] ::: line item update ::: idOrSelector:  item_01HDY2B3BVH8VDMYADA22TD0G8
[DEBUGGING] ::: line item update ::: data:  { order_id: 'order_01HDY2D5G5SKV1SR5NHJNDSDN3' }
[DEBUGGING] ::: Inside atomicPhase_
[DEBUGGING] ::: After updating line item: item_01HDY2B3BVH8VDMYADA22TD0G8 tax_lines: [ 19 ]
[DEBUGGING] ::: Processing shipping method: sm_01HDY2CQA5ZZ6Y5E9PGV58N8PK
[DEBUGGING] ::: Before modifying line items: [ { id: 'item_01HDY2B3BVH8VDMYADA22TD0G8', tax_lines: undefined } ]
[DEBUGGING] ::: After modifying line items: [ { id: 'item_01HDY2B3BVH8VDMYADA22TD0G8', tax_lines: undefined } ]
[DEBUGGING] ::: After all Promise.all operations
[DEBUGGING] ::: order :: create from cart : after itemsReturn [ [ 19, 19, 19 ] ]
[DEBUGGING] ::: End of createFromCart

Observation:

• Tax rate is recorded as [19] initially.
• Post order creation, it becomes [19, 19, 19].

It's worth noting that the "line item update" log is from the line-item service, which I suspect isn't the root of the problem.

Would appreciate insights on potential fixes or workarounds.

[akramaskar]

Found the in our case

We are using a custom cart-completion strategy based on the one provided in the strategies folder in the medusa repository.

In here, in the handlePaymentAuthorized as well as handleTaxLinesCreated, the following code is called again to recreate the tax lines. After removing it in both cases above, the tax calculation works as it is supposed to.

const res = await this.handleCreateTaxLines(id, { manager })
    if (res.response_code) {
      return res
    }

[nickmonad]

We are hitting this issue as well. Pretty big blocker for us to use a custom tax provider. I mentioned it on discord, and only just now saw this issue

[nickmonad]

We don't have a custom cart completion strategy, but rather a custom tax provider

[nickmonad]

Ok, figured it out. Because of the fix in https://github.com/medusajs/medusa/pull/1262, code cannot be null. There is a unique constraint that apparently depends on code not being null. After setting code in the line items returned from our customer tax provider, we are left with only one line applied to both the item and the shipping method