build of the build is also based on pure Scala files

Author: Roman Janusz

project/build.sbt

@@ -1,5 +1 @@
-lazy val macros = project.settings(
-  libraryDependencies += "org.scala-lang" % "scala-reflect" % scalaVersion.value
-)
-
-lazy val root = project.in(file(".")).dependsOn(macros)
+lazy val root = BuildBuild.root

project/plugins.sbt

@@ -0,0 +1,31 @@
+import sbt.Keys._
+import sbt._
+
+object BuildBuild extends AutoPlugin {
+  val scalaJSVersion: String =
+    Option(System.getenv("SCALAJS_VERSION")).getOrElse("1.7.1")
+
+  override def extraProjects: Seq[Project] = Seq(macros)
+
+  lazy val root = project.in(file("."))
+    .enablePlugins(this)
+    .dependsOn(macros)
+    .settings(
+      logLevel := Level.Warn,
+
+      addSbtPlugin("org.scala-js" % "sbt-scalajs" % scalaJSVersion),
+      addSbtPlugin("org.jetbrains.scala" % "sbt-ide-settings" % "1.1.1"),
+      addSbtPlugin("pl.project13.scala" % "sbt-jmh" % "0.4.0"),
+      addSbtPlugin("com.geirsson" % "sbt-ci-release" % "1.5.7"),
+      addSbtPlugin("com.eed3si9n" % "sbt-unidoc" % "0.4.3"),
+      addSbtPlugin("com.typesafe" % "sbt-mima-plugin" % "0.9.2"),
+      addSbtPlugin("com.timushev.sbt" % "sbt-updates" % "0.6.0"),
+      addSbtPlugin("ch.epfl.scala" % "sbt-bloop" % "1.4.8"),
+      addSbtPlugin("com.codecommit" % "sbt-github-actions" % "0.9.5"),
+    )
+
+  lazy val macros = project
+    .settings(
+      libraryDependencies += "org.scala-lang" % "scala-reflect" % scalaVersion.value
+    )
+}