WooCommerce Backend Development

This skill provides guidance for developing WooCommerce backend PHP code according to project standards and conventions.

When to Use This Skill

ALWAYS invoke this skill before:

• Writing new PHP unit tests (*Test.php files)

• Creating new PHP classes

• Modifying existing backend PHP code

• Adding hooks or filters

Instructions

Follow WooCommerce project conventions when adding or modifying backend PHP code:

• Creating new code structures: See file-entities.md for conventions on creating classes and organizing files (but for new unit test files see unit-tests.md).

• Naming conventions: See code-entities.md for naming methods, variables, and parameters

• Coding style: See coding-conventions.md for general coding standards and best practices

• Type annotations: See type-annotations.md for PHPStan-aware PHPDoc annotations

• Working with hooks: See hooks.md for hook callback conventions and documentation

• Dependency injection: See dependency-injection.md for DI container usage

• Data integrity: See data-integrity.md for ensuring data integrity when performing CRUD operations

• Writing tests: See unit-tests.md for unit testing conventions

Key Principles

• Always follow WordPress Coding Standards

• Use class methods instead of standalone functions

• Place new internal classes in src/Internal/ by default

• Use PSR-4 autoloading with Automattic\WooCommerce namespace

• Write comprehensive unit tests for new functionality

• Run linting and tests before committing changes

Version Information

To determine the next WooCommerce version number for @since annotations:

• Read the $version property in includes/class-woocommerce.php on the trunk branch

• Remove the -dev suffix if present

• Example: If trunk shows 10.4.0-dev , use @since 10.4.0

• Note: When reviewing PRs against trunk, the version in trunk is correct even if it seems "future" relative to released versions