This document discusses updates to Composer 2 support for Magento 2.4.2. Composer 2 is a dependency manager for PHP that was first released in 2012 and had its second major release in 2020. The document outlines backward incompatible changes, performance improvements, and updates to Magento plugins and dependencies to work with Composer 2, including updates to the Magento composer root plugin, installer, and dependencies. Additional resources for the Composer 2 upgrade are also provided.

1. Composer 2 support for
Magento 2.4.2
Max Lesechko | Sr. Software Engineer

2. ©2020 Adobe. All Rights Reserved. Adobe Confidential.
Some facts about Composer
§ Dependency manager for PHP, written in PHP.
§ The first release of Composer 1 was on March 1,
2012.
§ packagist.org is the main and most well-known
composer repository for Open Source.
§ The first release of Composer 2 was on October
24, 2020.

3. ©2020 Adobe. All Rights Reserved. Adobe Confidential.
Composer 2 | Changes
What’s new? Backward incompatible changes
Performance improvements.
Deterministic updates.
Runtime features.
Error reporting.
Partial updates.
Plugins.
Platform-check features.
Repository priority.
PSR-0 / PSR-4 configurations.

4. ©2020 Adobe. All Rights Reserved. Adobe Confidential.
Composer 2 | Changes
What’s new? Backward incompatible changes
Performance improvements.
Deterministic updates.
Runtime features.
Error reporting.
Partial updates.
Plugins.
Platform-check features.
Repository priority.
PSR-0 / PSR-4 configurations.

5. ©2020 Adobe. All Rights Reserved. Adobe Confidential.
Dependencies | Updates
§ magento/magento-composer-installer
(0.2.0).
§ magento/composer-root-update-
plugin (1.1.0)
§ magento/inventory-composer-installer
(1.2.0)
§ laminas/laminas-dependency-plugin
(2.0.0).
§ dealerdirect/phpcodesniffer-composer-
installer (0.7.0).
§ magento/zendframework1 (1.14.5).
Magento plugins 3rd party plugins Libraries & frameworks

6. ©2020 Adobe. All Rights Reserved. Adobe Confidential.
Dependencies | Updates
§ magento/magento-composer-installer
(0.2.0).
§ magento/composer-root-update-
plugin (1.1.0)
§ magento/inventory-composer-installer
(1.2.0)
§ laminas/laminas-dependency-plugin
(2.0.0).
§ dealerdirect/phpcodesniffer-composer-
installer (0.7.0).
§ magento/zendframework1 (1.14.5).
Magento plugins 3rd party plugins Libraries & frameworks

7. ©2020 Adobe. All Rights Reserved. Adobe Confidential.
Fixes | Magento plugins
§ composer/composer (^2.0)
§ composer-plugin-api (^2.0)
§ PluginInterface. § magento/composer-root-update-plugin.
§ magento/magento-composer-installer.
Dependencies Common change Changes in implementation

8. ©2020 Adobe. All Rights Reserved. Adobe Confidential.
Additional resources
§ Blog post on packagist.com.
§ Upgrade guides for Composer 1.x to 2.0 on
getcomposer.org.

9. Q & A