Intellij analysis not picking up unmanagedSourceDirectories after sbt import - scala

Question

If I define an sbt scala project that depends on two external source folders the analysis does not work correctly. So say I define the following build.sbt:
lazy val root = project.in(file("."))
.settings(
name := "repro",
version := "1.0",
scalaVersion := "2.11.8",
unmanagedSourceDirectories in Compile +=
baseDirectory.value / ".." / "ext1" / "src" / "main" / "scala",
unmanagedSourceDirectories in Compile +=
baseDirectory.value / ".." / "ext2" / "src" / "main" / "scala"
)
such that sources in ext1 depend on sources in ext2. So in this example I've defined a trati T1 in ext1 and a trait T2 in ext2 that depends on T1. And I have a class in my project that depends on T2. This will all compile fine in sbt. But when I import this sbt project in IntelliJ it compiles. However, when I open my trait T2 in the editor it gives me an error when I reference T1, saying "Cannot resolve ext1". Why am I getting this error?
The reproduction of this issue can be found on github with the following links:
https://github.com/hughgearse/repro
https://github.com/hughgearse/ext1
https://github.com/hughgearse/ext2

Answer 1

Create build definition in ext1/build.sbt
lazy val root = project.in(file("."))
.settings(
name := "ext1",
version := "1.0",
scalaVersion := "2.11.8"
)
and then reference ext1 as an external build in ext2/build.sbt via RootProject
val ext1 = RootProject( file("../ext1") )
lazy val root = project.in(file(".")).dependsOn(ext1)
.settings(
name := "ext2",
version := "1.0",
scalaVersion := "2.11.8"
)
and then similarly reference both as external builds in repro/build.sbt
val ext1 = RootProject( file("../ext1") )
val ext2 = RootProject( file("../ext2") )
lazy val root = project.in(file(".")).dependsOn(ext1, ext2)
.settings(
name := "repro",
version := "1.0",
scalaVersion := "2.11.8",
unmanagedSourceDirectories in Compile +=
baseDirectory.value / ".." / "ext1" / "src" / "main" / "scala",
unmanagedSourceDirectories in Compile +=
baseDirectory.value / ".." / "ext2" / "src" / "main" / "scala"
)
Re-import repro project and IntelliJ should be able to analyse all the sources.