Learning how to spot BC breaks before a migration

Ideally, you should go into the PHP 8 migration with an action plan in hand. A critical part of this action plan includes getting an idea of how many potential BC breaks exist in your current code base. In this section, we show you how to develop a BC break sniffer that automates the process of looking through hundreds of code files for potential BC breaks.

First, we'll step back and review what we've learned so far about BC issues that might arise in PHP 8.

Gaining an overview of BC breaks

You already know, having read the previous chapters in this book, that potential code breaks originate from several sources. Let's briefly summarize the general trends that might lead to code failure after a migration. Please note that we do not cover these topics in this chapter as these are the topics that have all been covered in earlier chapters in this book:

• Resource-to-object migration
• Minimum versions for...