Override PHP class from a composer installed package in Magento 2

Question

I want to override a class in a composer installed vendor package on Magento 2.

Firstly I have a child theme of the default theme Luma. Secondly I installed the vendor package via composer.

I have two questions.

1. Can I put my code in app/design/frontend/Myvendor/mytheme/<Vendorname_vendormodule>/ or do I need to put it in app/code/
2. How can I override this specific class only, which is vendor/<vendorname>/module-<vendormodule>/Block/Product/Info.php ?

Answer 1

For your first question : It depends which code you want to override.

• For example you want to change the theme,the layout and front end display (not any functional change) you can do it.app/design/frontend/Myvendor/mytheme/<Vendorname_vendormodule>/

• If you want to update/rewrite the logic you have to do it in app/code/{Vendor}/{Module}.

---

For your second question : To override block you need to add code in app/code/{Vendor}/{Module} directory by following steps

For example you have to override Magento\Catalog\Block\Product\ListProduct block

1.) create file app/code/{Vendor}/{Module}/etc/di.xml

<?xml version="1.0"?>
<config xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:noNamespaceSchemaLocation="urn:magento:framework:ObjectManager/etc/config.xsd">
    <preference for="Magento\Catalog\Block\Product\ListProduct" type="{Vendor}\{Module}\Block\Rewrite\Product\ListProduct" />
</config>

2.) create file app/code/{Vendor}/{Module}/Block/Rewrite/Product/ListProduct.php

<?php
    /**
     * Hello Rewrite Product ListProduct Block
     */
    namespace {Vendor}\{Module}\Block\Rewrite\Product;

    class ListProduct extends \Magento\Catalog\Block\Product\ListProduct
    {
        public function _getProductCollection()
        {
            // Do your stuff here
        }
    }

Ref: Overriding Block, Model, Controller in Magento2