This post was written collaboratively by tedbow and hestenet.
Drupal 9.0.0-beta2 has been released, and Drupal 9.0.0 is scheduled to be released on June 3, 2020. The upgrade from Drupal 8 to Drupal 9 should be the easiest major version update in the last decade of Drupal’s history. One of the reasons for this is because over 1,700 contributed modules already have a Drupal 9 compatible release. Making a module that’s already compatible with Drupal 8 compatible with Drupal 9 just requires removing deprecations. When looking at just one module, these changes are usually trivial, but when we consider managing over 8,800 Drupal 8 modules on drupal.org the upgrade process could easily take hundreds or thousands of hours from the Drupal community.
Fortunately we can accelerate this process dramatically by using Drupal Rector, a tool developed by Palantir.net and Pronovix. Drupal Rector can be used by developers to automatically fix many of the deprecations needed to make a module Drupal 9 compatible. In fact Drupal Rector can currently fix deprecations in more than 2000 existing projects on Drupal.org. Although using Drupal Rector is not difficult, running it manually on all Drupal 8 modules would have taken hundreds of developer hours to complete.
To accelerate upgrading of modules to Drupal 9 the Drupal Association has partnered with Acquia and Palantir to automatically provide patches generated by Drupal Rector for all contributed modules possible. For many modules these patches will be able to make the modules fully compatible with Drupal 9. For some modules it will still be necessary for a developer to manually replace other deprecations. Patches will also be provided for contributed themes but preparing a theme for Drupal 9 will require other changes such as updates for Twig 2.
These patches will be posted to issues created by the new Project Update Bot. An example issue can be seen here: https://www.drupal.org/project/entity_block_visibility/issues/3134823
The Project Update Bot is not associated with any individual or company and therefore will not affect issue credits for any individual or company. If maintainers find the patches provided by the bot useful they are welcome to credit the bot account as a way to provide feedback on this initiative.
It will be up to the project maintainers to decide if they want to use these patches but in many cases the patches can help speed up the process of updating a module for Drupal 9 dramatically.
For project maintainers there are a few options for dealing with these issues
Leave the issue open and apply the provided patch to remove some or all Drupal 9 deprecations. The Project Update Bot will check weekly if Drupal Rector is able to remove new deprecations and post a new patch if possible.
Remove the “ProjectUpdateBotD9” tag from the issue to stop new patches from being posted. If you would like to use the issue and the patch as a starting point simply remove this tag and the bot will not post any new patches. Add the tag back and the bot will post new patches if possible.
Close the issue to stop the bot from posting new patches. If you are already handling deprecations in another issue or otherwise don’t find the patches helpful simply close the issue and the bot will not post any new patches
If there are problems with one of the patches posted by the Project Update Bot, such as it does not correctly replace a deprecation, you can file an issue in the Rector issue queue. For other issues with the bot, for instance if the issue summary created by the bot is unclear, use the Infrastructure project issue queue using the component “Bot: Drupal Rector”.
How can you help?
While Drupal Rector can currently fix some or all of the deprecations in over 2000 contributed modules to Drupal 9 it currently only covers 50% of total Drupal 9 deprecations. New Rector rules are being added with every new release of Drupal Rector. You can help by making new Drupal Rector rules which will make it possible for Drupal Rector to upgrade even more modules.