如果定义了项目值，为什么不能覆盖SBT子项目中的设置？

Question

I have a subproject that defines root like this:

lazy val root = (project in file(".")).enablePlugins(PlayScala)

and doesn't define any other settings.

In my main project I reference it like this:

lazy val mylib = (project in file("mylib"))
lazy val myapp = (project in file("myapp")).dependsOn(mylib)

The problem is that referenced this way, mylib is built with Scala 2.10 because it doesn't specify a scalaVersion and 2.10 is SBT's default.

If I try to override any settings like this:

lazy val mylib = (project in file("mylib")).settings(Seq(scalaVersion := "2.11.8"))

they get ignored.

However, if I remove the lazy val root = ... from subproject's build.sbt the settings passed from the main build file work as expected. This breaks the subproject's standalone build however since the PlayScala plugin has to be enabled in the main file.

So how can I reference a project like that and override some settings?

I can work around this by changing the settings globally (ie scalaVersion in ThisBuild ), but I would like to be able to override other things like the project id for instance which is fixed as root in this case.

Answer 1

I usually overrides settings like this, and it works fine.

lazy val mylib = (project in file("mylib")).settings(
  scalaVersion := "2.11.8"
  //any other settings, I want to override, separated by comma
  propertyA := "A",
  propertyB := "C"
)

The difference is, I usually have dependencies in my Play application, but everything is listed under one build.sbt