Can't check requested quantity for products without Source Items support issue on 2.3.1

Question

I have a custom module installed . A module that adds product type to display a product. On the product configuration, it offers other sets of parameters(Min, max price & total price target to set as success transaction ) that doesn't align to quantity parameter. It do not required the default quantity

This is the error when user click into add to cart

I believe 1 of these parameters (which is quantity based on error display)is somehow linked & processed when user place the order is unnecessary

And these are the parameter that module provided to work on the backend

I hope someone who has been through a similar situation would kind to share some insight on fix this issue.

Answer 1

New code from Magento 2.3

<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:module:Magento_Catalog:etc/product_types.xsd">
    <type name="simple" isQty="true" />
    <type name="virtual" isQty="true" />
</config>

Check vendor\vendor\magento\module-catalog-inventory\etc\product_types.xml

So for your custom product type also add isQty="true" in /etc/product_types.xml