pub downgrade

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

$ pub downgrade [dependencies...]

Without any additional arguments, pub downgrade gets the lowest 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 downgrade
Resolving dependencies... (1.2s)
+ barback 0.13.0
+ collection 0.9.1
+ path 1.2.0
+ source_maps 0.9.0
+ source_span 1.0.0
+ stack_trace 0.9.1
Changed 6 dependencies!

The pub downgrade command creates a lockfile. If one already exists, it ignores it and generates a new one from scratch using the lowest versions of all dependencies.

Downgrading specific dependencies

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

$ pub downgrade unittest
Resolving dependencies... 
  barback 0.15.2+2
  bot 0.27.0+2
  browser 0.10.0+2
  chrome 0.6.5
  collection 1.1.0
  path 1.3.0
  pool 1.0.1
  source_span 1.0.2
< stack_trace 0.9.2 (was 1.1.1)
  stagexl 0.10.2
< unittest 0.10.0 (was 0.11.4)
These packages are no longer being depended on:
- matcher 0.11.3
Changed 3 dependencies!

If you are downgrading a specific dependency, pub tries to find the highest versions of any transitive dependencies that fit the new dependency constraints. Any transitive dependencies are usually also downgraded as a result.

Getting a new dependency

If a dependency is added to the pubspec before pub downgrade 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 downgrade 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.

Downgrading while offline

If you don’t have network access, you can still run pub downgrade. 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 downgrade 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.

Options

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