github composer/composer 2.0.0-alpha1

Try it out now and get ready for the upcoming stable release

  • Use composer self-update --preview to try the latest alpha/prerelease version (2.x).
  • Use composer self-update --snapshot to try the latest dev build (2.x).
  • Use composer self-update --stable to go back to stable releases (1.x for now).
  • Use composer self-update --1 in CI/scripts if you want to pin Composer to 1.x until you are ready to migrate, this will ensure you stay on 1.x releases even once a 2.0 stable comes out.


  • Breaking: This is a major release and while we tried to keep things compatible for most users, you might want to have a look at the UPGRADE guides
  • Many CPU and memory performance improvements
  • The update command is now much more deterministic as it does not take the already installed packages into account
  • Package installation now performs all network operations first before doing any changes on disk, to reduce the chances of ending up with a partially updated vendor dir
  • Partial updates and require/remove are now much faster as they only load the metadata required for the updated packages
  • Added a platform-check step when vendor/autoload.php gets initialized which checks the current PHP version/extensions match what is expected and fails hard otherwise. Can be disabled with the platform-check config option
  • Added a Composer\InstalledVersions class which is autoloaded in every project and lets you check which packages/versions are present at runtime
  • Added a composer-runtime-api virtual package which you can require (as e.g. ^2.0) to ensure things like the InstalledVersions class above are present. It will effectively force people to use Composer 2.x to install your project
  • Added support for parallel downloads of package metadata and zip files, this requires that the curl extension is present and we thus strongly recommend enabling curl
  • Added much clearer dependency resolution error reporting for common error cases
  • Added support for updating to a specific version with partial updates, as well as a --with flag to pass in temporary constraint overrides
  • Added support for TTY mode on Linux/OSX/WSL so that script handlers now run in interactive mode
  • Added only, exclude and canonical options to all repositories, see repository priorities for details
  • Added support for lib-zip platform package
  • Added pre-operations-exec event to be fired before the packages get installed/upgraded/removed
  • Added pre-pool-create event to be fired before the package pool for the dependency solver is created, which lets you modify the list of packages going in
  • Added post-file-download event to be fired after package dist files are downloaded, which lets you do additional checks on the files
  • Added --locked flag to show command to see the packages from the composer.lock file
  • Added --unused flag to remove command to make sure any packages which are not needed anymore get removed
  • Added --dry-run flag to require and remove commands
  • Added --no-install flag to update, require and remove commands to disable the install step and only do the update step (composer.lock file update)
  • Added --with-dependencies and --with-all-dependencies flag aliases to require and remove commands for consistency with update
  • Added more info to vendor/composer/installed.json, a dev key stores whether dev requirements were installed, and every package now has an install-path key with its install location
  • Added COMPOSER_DISABLE_NETWORK which if set makes Composer do its best to run offline. This can be useful when you have poor connectivity or to do benchmarking without network jitter
  • Added --json and --merge flags to config command to allow editing complex extra.* values by using json as input
  • Added confirmation prompt when running Composer as superuser in interactive mode
  • Added --no-check-version to validate command to remove the warning in case the version is defined
  • Added --ignore-platform-req (without s) to all commands supporting --ignore-platform-reqs, which accepts a package name so you can ignore only specific platform requirements
  • Added support for wildcards (*) in classmap autoloader paths
  • Added support for configuring GitLab deploy tokens in addition to private tokens, see gitlab-token
  • Added support for package version guessing for require and init command to take all platform packages into account, not just php version
  • Fixed package ordering when autoloading and especially when loading plugins, to make sure dependencies are loaded before their dependents
  • Fixed suggest output being very spammy, it now is only one line long and shows more rarely
  • Fixed conflict rules like e.g. >=5 from matching dev-master, as it is not normalized to 9999999-dev internally anymore
latest releases: 2.0.0-RC2, 1.10.15, 1.10.14...
4 months ago