Using Plugins

Mill plugins are ordinary jars and are loaded as any other external dependency with the import $ivy mechanism.

There exist a large number of Mill plugins, Many of them are available on GitHub and via Maven Central. We also have a list of plugins, which is most likely not complete, but it might be a good start if you are looking for plugins: Third-Party Plugins.

Some plugin contributions are also hosted in Mill’s own git tree as Contrib Plugins.

Mill plugins are typically bound to a specific version range of Mill. This is called the binary platform. To ease the use of the correct versions and avoid runtime issues (caused by binary incompatible plugins, which are hard to debug) you can apply one of the following techniques:

Use the specific Mill Binary Platform notation

// for classic Scala dependencies
import $ivy.`<group>::<plugin>::<version>` (1)
// for dependencies specific to the exact Scala version
import $ivy.`<group>:::<plugin>::<version>` (2)
1 This is equivalent to 
import $ivy.`<group>::<plugin>_mill$MILL_BIN_PLATFORM:<version>`
2 This is equivalent to 
import $ivy.`<group>:::<plugin>_mill$MILL_BIN_PLATFORM:<version>`

Use special placeholders in your import $ivy

$MILL_VERSION

to substitute the currently used Mill version. This is typical required for Mill contrib modules, which are developed in the Mill repository and highly bound to the current Mill version.

Example: Use mill-contrib-bloop plugin matching the current Mill version
import $ivy.`com.lihaoyi:mill-contrib-bloop:$MILL_VERSION`

There is the even more convenient option to leave the version completely empty. Mill will substitute it with its current version. But don’t forget to provide the trailing colon!

Example: Use mill-contrib-bloop plugin matching the current Mill version
import $ivy.`com.lihaoyi:mill-contrib-bloop:`
$MILL_BIN_PLATFORM

to substitute the currently used Mill binary platform.

Example: Using mill-vcs-version plugin matching the current Mill Binary Platfrom
import $ivy.`de.tototec::de.tobiasroeser.mill.vcs.version_mill$MILL_BIN_PLATFORM:0.1.2`
If you want to publish re-usable libraries that other people can use in their builds, simply publish your code as a library to maven central.