This is a common question that asked by newbie PHP devs. and it’s also important as well.
composer update will update your dependencies as they are specified in composer.json
For example, if you require this package as a dependency:
"guzzlehttp/guzzle": "6.3.*",
and you have actually installed the 6.3.1 version of this package, running composer update will cause an upgrade of this package (for example to 6.3.2, if it’s already been released)
in detail composer update will:
- Read
composer.json - Remove installed packages that are no more required in
composer.json - Check the availability of the latest versions of your required packages
- Install the latest versions of your packages
- Update
composer.lockto store the version of the installed package
composer install
composer install will not update anything; it will just install all the dependencies as specified in the composer.lock file
In detail:
- Check if
composer.lockfile exists (if not, runcomposer-updateand create it) - Read
composer.lockfile - Install the packages specified in the
composer.lockfile
When to install and when to update
composer updateis mostly used in the ‘development phase’, to upgrade our project packages according to what we have specified in thecomposer.jsonfile,composer installis primarily used in the ‘deploying phase’ to install our application on a production server or on a testing environment, using the same dependencies stored in the composer.lock file created by the composer update.
So these are the overall differentiation b/w composer update and install.
