Update operation runs without error and does not update the checkout

Retired Boards Appdev Functions
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Topic summary

A developer is attempting to update checkout line items with custom product preview images using a cart transform function. The function uploads images to Shopify’s CDN and stores the URL on cart line items.

Technical Details:

  • The update operation executes without errors but fails to apply changes
  • Function is installed on a Shopify Plus store and activated
  • Code includes proper cart line ID and CDN image URL structure

Resolution:
The issue was identified as a known limitation: cart transform functions do not support draft orders. This was confirmed through a community forum post.

Status: Unresolved for draft orders. The developer hopes this functionality will be supported before an August deadline.

Summarized with AI on November 8. AI used: claude-sonnet-4-5-20250929.
1

We produce custom products so we update the checkout to use a preview image of the custom product. We have built functionality that uploads these preview images to the shopify CDN and store the CDN url on the cart line item. When we run the function to update the image url to the preview image, everything looks correct and there are no errors.

{
  "operations": [
    {
      "update": {
        "cartLineId": "gid://shopify/CartLine/49d3c7c5-c946-4065-b488-de1a49e46c22",
        "image": {
          "url": "https://cdn.shopify.com/s/files/1/0136/7713/3883/files/SVpfATaaFRgxwnMSdMZ3MOrMTkMBpMMdACsHHhPPmAW12AH16x5625FN7c329f6e4a8986e6a076574fe27ca89cbdc29f4a.png?v=1720468195"
        }
      }
    }
  ]
}

The cart transform function is installed on a shopify plus store and has been activated. Any ideas on what could be causing the update to fail silently?

2

Found out that this is not supported for draft orders from this post. Hopefully this will be working before the August deadline.