In the recent update to Composer 2.0 the advice is to get rid of the wikimedia/composer-merge-plugin, which was even removed from the dependencies of Drupal core.

There is documentation on how to include custom module's composer.json in the root composer.json, for example Managing dependencies for a custom project, but I cannot find documentation on how to include composer.libraries.json in the root composer.json.

Can anyone explain how to get the Webform module compatible with Composer 2.0?

2 Answers 2


The alternate ways are documented. I think the one you would prefer is:

Execute drush webform:composer:update, to update your Drupal installation's composer.json to include the Webform module's selected libraries as repositories.


here is a specific way how to do it for webform module.

  1. run composer require wikimedia/composer-merge-plugin
  2. in composer add
  "merge-plugin": {
            "include": [
  1. run composer update --lock and verify the files

Reference https://www.drupal.org/docs/8/modules/webform/webform-frequently-asked-questions/how-to-use-composer-to-install-libraries

Reference 2 https://www.drupal.org/docs/8/modules/webform/webform-cookbook/using-the-composer-merge-plugin-to-download-libraries-with

Github issue https://github.com/wikimedia/composer-merge-plugin/issues/184

  • 4
    The question seems to explicitly ask for how to not use the wikimedia/composer-merge-plugin.
    – leymannx
    Jan 3, 2021 at 22:45
  • Hi Ales, thank you for the response. Indeed, as Leymannx says the question is how to not use the wikimedia/composer-merge-plugin... So unfortunately your solution does not work. This is how it is implemented now, but not how it should be implemented according to composer 2.0. Jan 4, 2021 at 9:30
  • 2
    As Ales referenced, there is a GitHub issue for Composer Merge Plugin to be compatible with Composer 2, which has been fixed and it now is, so maybe this is the best answer after all.
    – mlncn
    Apr 7, 2021 at 21:19
  • Is it really fixed? In the last comments of the issue there are still people having errors...
    – 0711master
    Jan 30 at 16:59

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