Cannot access project-wide dependencies in source-generator files - scala

Question

I have a play framework application with a directory structure like this:
server
- app
- services
- MyService.scala
- project
- Dependencies.scala
- src/main/scala
- MyMetaService.scala
- build.sbt
The /project directory hosts a source code generator task (sbt Task) for which I'd like to be able to use Circe. My build.sbt file does include reference to the circe package and if I issue:
import io.circe._
in MyService.scala the package resolves fine. But if I do the same in MyMetaService.scala the package does not resolve. I know this is because somehow I'm not specifying that the dependency should apply to the /project directory but I don't know how to do that. Here's my build.sbt:
import src.main.scala.generate.ModelGenerator
name := "server"
version := "1.0"
lazy val `server` =
(project in file("."))
.settings(libraryDependencies ++= Dependencies.dependencies)
.enablePlugins(PlayScala)
resolvers ++=
Seq(
"Akka Snapshot Repository" at "http://repo.akka.io/snapshots/",
"scalaz-bintray" at "https://dl.bintray.com/scalaz/releases",
"releases" at "http://oss.sonatype.org/content/repositories/releases",
"snapshots" at "http://oss.sonatype.org/content/repositories/snapshots"
)
scalaVersion := "2.12.2"
sourceGenerators in Compile ++= Seq(
ModelGenerator.generatorTask.taskValue
)
And my Dependencies.scala:
import play.sbt.PlayImport._
import sbt._
object Dependencies {
val dependencies: Seq[ModuleID] =
Seq(
jdbc,
ehcache,
ws,
specs2 % Test,
guice,
"io.circe" %% "circe-core" % "0.11.1",
"io.circe" %% "circe-generic" % "0.11.1",
"io.circe" %% "circe-parser" % "0.11.1"
)
}

Answer 1

Create separate build.sbt for meta-build project in project/build.sbt and import dependencies in the same way as for proper build. For example
// This is project/build.sbt
val circeVersion = "0.10.0"
libraryDependencies ++= Seq(
"io.circe" %% "circe-core",
"io.circe" %% "circe-generic",
"io.circe" %% "circe-parser"
).map(_ % circeVersion)
should now make circe available to project/.../MyMetaService.scala