How to override the dependency of an sbt plugin?
I've written an sbt plugin called sbt-jumi which implements sbt integration for Jumi. Right now the sbt-jumi plugin depends on the current Jumi release.
Here is the relevant line from the plugin's build.sbt:
libraryDependencies += "fi.jumi" % "jumi-launcher" % "0.5.376"
And a user of the plugin would add this to his project/plugins.sbt file:
addSbtPlugin("fi.jumi.sbt" % "sbt-jumi" % "0.1.0")
Now let's say that Jumi 0.6.400 is released and it's backward compatible. How can a user of the sbt-jumi plugin configure it to use Jumi 0.6.400, without me having to release a new version of the plugin?
Here is how to do it in Maven. But how to do it in sbt?
Answer
Overriding the dependencies of plugins happens the same way as overriding normal dependencies, except that the configuration must be entered into project/plugins.sbt. Overriding dependencies is explained in Library Management. Here is a summary:
If the version you wish to use is greater than the dependency that you would get transitively, sbt will use the larger version by default. You may change the conflict manager to change the default behavior - for example this will create an error on conflict:
conflictManager := ConflictManager.strict
In other words, this in project/plugins.sbt would work:
libraryDependencies += "fi.jumi" % "jumi-launcher" % "0.6.400"
You may check your plugin dependencies using reload plugins and then show update. It should now show the older version as "(EVICTED)".
If the version you wish to use is lower than the default dependency, then you will need to override differently. One way is to force the dependency:
libraryDependencies += "fi.jumi" % "jumi-launcher" % "0.4.350" force()
Another way is to use the dependencyOverrides setting:
dependencyOverrides += "fi.jumi" % "jumi-launcher" % "0.4.350"
The difference between the two methods is that overriding doesn't introduce a direct dependency. I don't think the difference matters for plugins, but for published artifacts it has some differences.