422: Unprocessable Entity when using 100% discounts

  • lsdevign

    (@lsdevign)


    3 months, 3 weeks ago

    Hi Mollie,

    Just so you know, there is a bug in your plugin where your API fails to process line items that have a 100% discount. For example when you apply a coupon set to 100% discount.

    The plugin sets type to ‘discount’ only when $this->get_item_total_amount($cart_item) < 0, but the unitPrice is calculated from line_subtotal (the original price before discounts).

    The problem is:

    unitPrice uses line_subtotal → original positive price
    totalAmount uses line_total → 0 or negative after Smart Coupons discount
    When totalAmount is negative, type becomes ‘discount’, but unitPrice stays positive → Mollie rejects it

    Result: user gets the checkout notice saying something went wrong.

    I added a workaround, just let me know when this is fixed so I can remove it.

Viewing 2 replies - 1 through 2 (of 2 total)
  • Plugin Support Krystian Syde

    (@inpsydekrystian)

    3 months, 3 weeks ago

    Hello @lsdevign

    Thanks for flagging this. I have shared all of the details with devs so they can review this.

    Once I receive feedback or confirmation, I will update you here.

    Kind Regards,
    Krystian

    Plugin Support Krystian Syde

    (@inpsydekrystian)

    3 months, 3 weeks ago

    Hello @lsdevign

    What you described does align with how the plugin currently builds the line item payload, however the only thing I’m missing here is how exactly to reproduce it. You mentioned Smart Coupons – any specific steps or setup I should follow? I want to be sure we’re on the same page before I escalate it properly.

    Kind Regards,
    Krystian

Viewing 2 replies - 1 through 2 (of 2 total)

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