orderEditSetQuantity mutation doesn't allow zero quantities

[keiraarts]

Shopify has a mutation to edit a line item quantity but it only supports increasing quantities of product.

Adjust the line item quantity to add an additional gift wrapping service to the order using the orderEditSetQuantity mutation. In the input, include the order id, lineItemId, and the new quantity value that you want to set. In the response, request the ID and quantity of the line items to verify that it was updated correctly.

https://shopify.dev/api/examples/order-editing#edit-line-item-quantity

By providing a quantity of zero when using this mutation, the calculatedOrder object returns the original order without decreasing the order quantity. The documentation for the API says any negative quantities are not a valid input, but technically inputting zero should still decrease a variant's fulfillable quantity.

The ideal use-case here is to replace one of the purchased products with a different variant.

[keiraarts]

Can I bump this question to a Shopify engineer / staff?

[GrahamS]

Hello @keiraarts ,

I took a look at this, but couldn't replicate what you describe in my own client. Setting the quantity of a calculatedLineItem to 0 removed the product from my order entirely:

I couldn't replicate a situation where my input (aside from negative values) was rejected and set to the previous default value in the returning calculatedOrder. I could take a look at an x-request-id from your headers if you are continuing to encounter this to see what might be happening, though.

[keiraarts]

I'm comparing our queries but I don't think I'm doing anything different. 

Super strange; my request ID is f536770633853481851d0a6ae9c4ff49

I'll give you my queries here too.

fragment PresentmentMoneyFields on MoneyV2 {
  amount
  currencyCode
}

fragment CalculatedOrderFields on CalculatedOrder {
  id
  committed
  totalPriceSet {
    presentmentMoney {
      ...PresentmentMoneyFields
    }
  }
  totalOutstandingSet {
    presentmentMoney {
      ...PresentmentMoneyFields
    }
  }
  lineItems(first: 10) {
    edges {
      node {
        id
        sku
        quantity
      }
    }
  }
  originalOrder {
    id
    lineItems(first: 10) {
      edges {
        node {
          id
          sku
          quantity
          originalUnitPriceSet {
            presentmentMoney {
              amount
              currencyCode
            }
          }
        }
      }
    }
  }
}

mutation decreaseLineItemQuantityDemo($id: ID!, $lineItemId: ID!, $quantity: Int!) {
  orderEditSetQuantity(id: $id, lineItemId: $lineItemId, quantity: $quantity) {
    calculatedOrder {
      ...CalculatedOrderFields
    }
    calculatedLineItem {
      id
      quantity
    }
    userErrors {
      field
      message
    }
  }
}

{
"id": "gid://shopify/CalculatedOrder/13634765006",
"lineItemId": "gid://shopify/CalculatedLineItem/9965111378126",
"quantity": 0
}

 

[GrahamS]

@keiraarts 

The query looks good at a glance, so I would suppose that there's another component of the order here that's preventing the mutation from reducing the quantity of the item. Are you able to run the query against your shop on orders that have different fulfillment statuses for the line item you are trying to modify? My first assumption would be that there's a fulfillment state preventing a quantity reduction, but I'm running the logs at the moment to see what else might be happening.

[keiraarts · Accepted solution]

You are right. When the order is no longer in the original processing state my query won't decrease the line item count, but if the order is fulfilled or pending I can increase it. I didn't think to A/B test the order status Graham! I owe you!

[SrikalyanBurra]

Hi! there is a peculiar case where its failing.

In my usecase i do 2 kinds of syncs with shopify. Orders placed on my system i upsync/create them on shopify(using 2023-07 rest api). for items placed on shopify i downsync and create corresponding orders in my system.

your solution is working for downsync but NOT upsync. 

For downsynced orders when i wish to modify quantities(including qty=0) i am smoothly able to. BUT for orders upsynced from my platform, i am unable to modify quantity to 0. FYI other than qty=0 other quantity modifications are working.

kindly let me know if you have a solution.

[keiraarts]

If you have a minute, I get periodic Shopify internal service errors when changing quantity of items. The changes go through but the request doesn't seem to return any objects. Do you get to see the cause of the internal service response? e5394c96-99de-4e3a-851b-531f8a6075f9