How to resolve a “Can only install one of:” conflict?

by

The “Can only install one [x, y]” message appears when two different packages point to the same dependency, but different major, mutually exclusive versions where only one can be installed.

Troubleshooting

For example, one version can be “locked at” due to the information present in your composer.lock file which may conflict with what you’re trying to install. In this case, when the confusion error comes with “locked at x.y.z” message, you may use the following commands to understand the existing dependencies of installed packages:

composer show -t

Note: -t shows as a nested tree view, drop it to see the flat list.

To see where the problematic package is referenced from in your project, run:

composer why org/package -t

Note: -t shows as a nested tree view, drop it to see the flat list.

To see the details of the package which you’re trying to install, you may run:

composer show -a org/package # Package to inspect.

Note: To inspect the specific version, add x.y.z, e.g.: composer show -a guzzlehttp/guzzle 6.2.0

To further troubleshoot the problem, depending on your situation, you can try to:

  • Update the existing packages with dependencies via:

    composer update --with-dependencies

  • Upgrade or remove conflicting dependencies from your composer.json (keep it simple).

  • When the confusion message shows “locked at x.y.z“, use composer why org/package to see where the package is referenced (or check the content of composer.lock manually by looking for x.y.z). If won’t help, consider removing composer.lock and re-try again;
  • When asked to use composer.json from the different folder, select n.
  • Re-try your plain composer.json, simplified configuration on the empty folder.
  • Run composer diagnose to check for any common error.
  • Use -v/-vv/-vvv to increase the verbosity of your commands.
  • See also: How to explain Composer’s error log?

More Related Contents:

  1. How to get list of all installed packages along with version in composer?
  2. Composer Content-Length Mismatch
  3. What is the difference between require and require-dev sections in composer.json?
  4. Composer/PSR – How to autoload functions?
  5. Composer [UnexpectedValueException] error will trying to use composer to install a github project
  6. Composer: The requested PHP extension ext-intl * is missing from your system
  7. How to use a specific tag/version with composer and a private git repository?
  8. Remove composer
  9. How do I use a Git submodule with a Composer loaded library?
  10. What are these exactly?: Composer, Git and Pyrus [closed]
  11. How to explain Composer’s error log?
  12. How to require a fork with composer?
  13. Override PHP base dependency in composer
  14. PHP7 : install ext-dom issue
  15. Why use a PSR-0 or PSR-4 autoload in composer if classmap is actually faster?
  16. Composer error: “PHP extension fileinfo is missing from your system”
  17. How to update a single library with Composer?
  18. Composer Warning: openssl extension is missing. How to enable in WAMP
  19. Should composer.lock be committed to version control?
  20. Autoloading classes in PHPUnit using Composer and autoload.php
  21. How to specify Composer install path?
  22. Laravel 5 Class ‘form’ not found
  23. PHP Composer behind http proxy
  24. What are the differences between composer update and composer install?
  25. Running Composer returns: “Could not open input file: composer.phar”
  26. 3rd party dependency conflict in developing WordPress Plugin
  27. How to downgrade or install a specific version of Composer?
  28. Could not open input file: composer.phar
  29. PHP adding custom namespace using autoloader from composer
  30. Difference between require and install vs create-project in composer

Leave a Comment