Lenient with it, Drupal 11 with it.

The Drupal community introduced a lenient Composer facade that modified the drupal/core constraint for packages. This was done to remove a barrier with getting extensions installed via Composer to work on making modules Drupal 9 ready.

We hit the same problem, again. At DrupalCon Portland we sat down and decided a Composer plugin is the best approach.

See Add a composer plugin that supports 'composer require-lenient' to support major version transitions.

Drupal documentation page: Using Drupal's Lenient Composer Endpoint.

This subscribes to PluginEvents::PRE_POOL_CREATE and filters packages. This is inspired by symfony/flex, but it does not filter out packages. It rewrites the drupal/core constraint on any package with a type of drupal-*, excluding drupal-core. The constraint is set to '^8 || ^9 || ^10 || ^11 || ^12' for drupal/core.

Set up a fresh Drupal 11 site with this plugin (remember to press y for the new allow-plugins prompt.)

composer create-project drupal/recommended-project d11 cd d11 composer require mglaman/composer-drupal-lenient

The plugin only works against specified packages. To allow a package to have a lenient Drupal core version constraint, you must add it to extra.drupal-lenient.allowed-list. The following is an example to add Simplenews via the command line with composer config

composer config --merge --json extra.drupal-lenient.allowed-list '["drupal/simplenews"]'

Now, add a module that does not have a Drupal 11 compatible release!

composer require drupal/simplenews

🥳 Now you can use cweagans/composer-patches to patch the module for Drupal 11 compatibility!

For a quick start, allow installing the module by installing Backward Compatibility:

Backward Compatibility allows you to install old Drupal modules in current Drupal.

Alternatively, manually add the latest version in the module *.info.yml file:

core_version_requirement: ^9.3 || ^10 || ^11

If you want to allow all packages to have a lenient Drupal core version constraint, you can set extra.drupal-lenient.allow-all to true.

composer config --json extra.drupal-lenient.allow-all true

Using allow-all allows you to install any package without needing to add it to the allowed-list.

This plugin must be installed globally if your project's composer.lock file is removed.

composer global config --no-plugins allow-plugins.mglaman/composer-drupal-lenient true composer global require mglaman/composer-drupal-lenient

Warning: this means the plugin will run on all Composer commands. This is not recommended, but it is the only way the plugin can work when composer.lock is removed.