We have found an error with any private line item attribute or cart attribute on the latest version of the Debut theme.
We have prepared a demo store to show the issue, brand new store with no apps or any special configuration. You can check it at https://cart-attribute-issue.myshopify.com/ (password 12345), where we have simply set a private attribute by adding the following HTML to the product form, as documented at https://shopify.dev/docs/themes/liquid/reference/objects/line_item/#line_item-properties
<input type="hidden" name="properties[_private_attribute]" value="test" />
If you add a product to the cart and go to the cart page, you will see the attribute there (by the way, it is displayed against the convention explained at https://shopify.dev/docs/themes/ajax-api/reference/cart#private-properties-and-attributes
The problem happens when you try to modify the product quantity or remove the product from the cart. In either case, the following error is displayed:
You can also see the following video recording of the issue:
Code Black Belt
Solved! Go to the solution
@Jose_Samper Not sure what version of Debut you're using, but if you can find the relevant sections of theme.js in your theme using the screenshot of the diff I posted above, it should fix the issue.
I just grabbed these changes from the newest version of Debut, in which the theme devs have corrected the cart error.
Yes, you are totally right. I've just tested it with a fresh development store (which comes with Debut 17.6.1) and it works smoothly.
Thanks for the update!