Cannot instantiate interface Company\Module\Api\Quote\Data\AddressInterface

Question

Iam using Magento 2.3.5-p2. I add custom field in the cart and checkout page which is successfully showing there.

In app\code\Company\Module\etc\di.xml

<preference for="Magento\Quote\Api\Data\AddressInterface" type="Company\Module\Api\Quote\Data\AddressInterface"/>

In app\code\Company\Module\Api\Quote\Data\AddressInterface.php

<?php
namespace Company\Module\Api\Quote\Data;

use Magento\Quote\Api\Data\AddressInterface as MagentoDataAddressInterface;

interface AddressInterface extends MagentoDataAddressInterface
{
    const KEY_SUBDISTRICT = 'subdistrict_id';

    public function getSubdistrictId();

    public function setSubdistrictId($subdistrictId);
}

But while getting shipping estimate, it was error

Uncaught Error: Cannot instantiate interface Company\Module\Api\Quote\Data\AddressInterface in C:\wamp64\www\magento2-2\vendor\magento\framework\ObjectManager\Factory\Dynamic\Developer.php:50

I already

• Delete /generated/code
• Delete /static/frontend
• php bin\magento cache:clean

Answer 1

You cannot override any interface in such way.

If you have to use extension attribute for this case.

extension_attributes.xml code look like:

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:Api/etc/extension_attributes.xsd">
    <extension_attributes for="Magento\Quote\Api\Data\AddressInterface">
        <attribute code="subdistrict_id" type="int" />
    </extension_attributes>
</config>

Using extension attribute you can update and get data for your custom field.See https://store.fooman.co.nz/blog/an-introduction-to-extension-attributes.html