Cart Line Item Attribute InvalidOutputError

[kakon007]

**I have built a Cart Transform API app that retrieves values from cart line attributes.

In the frontend, I’m passing the cart line attribute like this:-

<input name="properties[_custom_price]" value="22.00" type="hidden" />

It works correctly on my development store, but on the Shopify Plus store, it throws an InvalidOutputError.**

my run.graphql:-

 query RunInput {
  cart {
    lines {
      id
      attribute(key: "_custom_price") {
        value
      }
      cost {
        amountPerQuantity {
          amount
        }
      }
      merchandise {
        ... on ProductVariant {
          id
        }
      }
    }
  }
}

my run.js:-

const NO_CHANGES = {
  operations: [],
};

export function run(input) {
  const hasCustomPrice = input.cart.lines.some(
    (line) => line.attribute?.value && !isNaN(parseFloat(line.attribute.value))
  );
  console.log("hasCustomPrice:", hasCustomPrice);
  if (!hasCustomPrice) return NO_CHANGES;

  const cartOperations = input.cart.lines
    .map((line) => {
      const customPriceStr = line.attribute?.value;
      if (!customPriceStr) return null;

      const customPrice = parseFloat(customPriceStr);
      if (isNaN(customPrice)) return null;

      return {
        update: {
          cartLineId: line.id,
          price: {
            adjustment: {
              fixedPricePerUnit: {
                amount: customPrice.toFixed(2),
              },
            },
          },
        },
      };
    })
    .filter(Boolean);

  return cartOperations.length > 0 ? { operations: cartOperations } : NO_CHANGES;
}