pub upgrade

Upgrade is one of the commands of the pub tool. Learn more about pub.

$ pub upgrade [dependencies...]

Without any additional arguments, pub upgrade gets the latest versions of all the dependencies listed in the pubspec.yaml file in the current working directory, as well as their transitive dependencies, to the packages directory located next to the pubspec. For example:

$ pub upgrade
Dependencies upgraded!

When pub upgrade upgrades dependency versions, it writes a lockfile to ensure that future pub gets will use the same versions of those dependencies. Application packages should check in the lockfile to source control; this ensures the application will use the exact same versions of all dependencies for all developers and when deployed to production. Library packages should not check in the lockfile, though, since they’re expected to work with a range of dependency versions.

If a lockfile already exists, pub upgrade ignores it and generates a new one from scratch using the latest versions of all dependencies. This is the primary difference between pub upgrade and pub get, which always tries to get the dependency versions specified in the existing lockfile.

Upgrading specific dependencies

It’s possible to tell pub upgrade to upgrade specific dependencies to the latest version while leaving the rest of the dependencies alone as much as possible. For example:

$ pub upgrade test args
Dependencies upgraded!

Upgrading a dependency upgrades its transitive dependencies to their latest versions as well. Usually, no other dependencies are updated; they stay at the versions that are locked in the lockfile. However, if the requested upgrades cause incompatibilities with these locked versions, they are selectively unlocked until a compatible set of versions is found.

Getting a new dependency

If a dependency is added to the pubspec before pub upgrade is run, it gets the new dependency and any of its transitive dependencies and places them in the packages directory. This is the same behavior as pub get.

Removing a dependency

If a dependency is removed from the pubspec before pub upgrade is run, it removes the dependency from the packages directory, thus making it unavailable for importing. Any transitive dependencies of the removed dependency are also removed, as long as no remaining immediate dependencies also depend on them. This is the same behavior as pub get.

Upgrading while offline

If you don’t have network access, you can still run pub upgrade. Since pub downloads packages to a central cache shared by all packages on your system, it can often find previously-downloaded packages there without needing to hit the network.

However, by default, pub always tries to go online when you upgrade if you have any hosted dependencies so that it can see if newer versions of them are available. If you don’t want it to do that, pass the --offline flag when running pub. In this mode, it only looks in your local package cache and tries to find a set of versions that work with your package from what’s already available.

Keep in mind that pub will generate a lockfile after it does this. If the only version of some dependency in your cache happens to be old, this locks your app to that version. The next time you are online, you will likely want to run pub upgrade again to upgrade to a later version.

Options

For options that apply to all pub commands, see Global options.