The difference between composer install and update

When working with PHP and Laravel, Composer is an essential tool for managing dependencies in your project. It is used to install third-party packages and libraries, as well as manage your project's own dependencies. However, there are two primary commands you can use with Composer: composer install and composer update.

Both commands are used to manage dependencies, but they do so in slightly different ways. Understanding when to use each command can help you keep your dependencies up to date and avoid any conflicts or issues in your project.

Composer Install

The composer install command is used to install all the dependencies listed in the composer.lock file. This file is generated when you run composer install or composer update, and it lists all the exact versions of the packages that were installed.

When you run composer install, Composer reads the composer.lock file and installs the exact versions of the packages listed. This ensures that all developers working on the project are using the same versions of the dependencies.

You should use composer install when you first clone a project or when you want to install the exact same versions of the dependencies on a new machine. It is also useful when you want to ensure that everyone on your team is using the same versions of the dependencies.

Composer Update

The composer update command is used to update your dependencies to their latest versions. When you run composer update, Composer looks at the composer.json file, finds the latest versions of the packages, and updates them accordingly. Composer also updates the composer.lock file to reflect the new versions.

You should use composer update when you want to update your dependencies to the latest versions. However, be careful when using this command, as it can potentially cause issues with your code. New versions of packages may introduce breaking changes, which could cause your code to fail.

To mitigate this risk, it is recommended to run composer update on a development or staging environment first to test the changes. It is also a good practice to update your dependencies one at a time, instead of updating everything at once.

Conclusion

In summary, composer install is used to install the exact versions of the dependencies listed in the composer.lock file, while composer update is used to update the dependencies to their latest versions. Use composer install when you want to ensure everyone is using the same versions of the dependencies, and use composer update when you want to update your dependencies to the latest versions. However, be careful when using composer update, as it can introduce breaking changes and potentially cause issues with your code.