More refined, and manual, activation of scripted

Allows to do a `sbt ++2.11.11 test:compile`, without the sbt plugin
modules or scripted being an issue.

build.sbt

@@ -240,7 +240,7 @@ lazy val `sbt-shared` = project
 
 lazy val `sbt-coursier` = project
   .dependsOn(coreJvm, cache, extra, `sbt-shared`)
-  .enablePlugins(ScriptedPlugin)
+  .disablePlugins(ScriptedPlugin)
   .settings(
     plugin,
     utest
@@ -248,7 +248,7 @@ lazy val `sbt-coursier` = project
 
 lazy val `sbt-pgp-coursier` = project
   .dependsOn(`sbt-coursier`)
-  .enablePlugins(ScriptedPlugin)
+  .disablePlugins(ScriptedPlugin)
   .settings(
     plugin,
     libs ++= {
@@ -261,7 +261,8 @@ lazy val `sbt-pgp-coursier` = project
   )
 
 lazy val `sbt-shading` = project
-  .enablePlugins(ScriptedPlugin, ShadingPlugin)
+  .enablePlugins(ShadingPlugin)
+  .disablePlugins(ScriptedPlugin)
   .dependsOn(`sbt-coursier`)
   .settings(
     plugin,

project/Aliases.scala

@@ -2,11 +2,40 @@
 import sbt._
 import sbt.Defaults.itSettings
 import sbt.Keys._
+import sbt.ScriptedPlugin.autoImport.{ScriptedConf, ScriptedLaunchConf, scriptedSbt}
+import sbt.ScriptedPlugin.{projectSettings => scriptedSettings}
+import sbt.librarymanagement.CrossVersion.partialVersion
 
 object Aliases {
 
   def libs = libraryDependencies
 
+  def withScriptedTests =
+    // see https://github.com/sbt/sbt/issues/3325#issuecomment-315670424
+    scriptedSettings.filterNot(_.key.key.label == libraryDependencies.key.label) ++ Seq(
+      libraryDependencies ++= {
+        scalaBinaryVersion.value match {
+          case "2.10" | "2.12" =>
+            partialVersion(scriptedSbt.value) match {
+              case Some((0, 13)) =>
+                Seq(
+                  "org.scala-sbt" % "scripted-sbt" % scriptedSbt.value % ScriptedConf,
+                  "org.scala-sbt" % "sbt-launch" % scriptedSbt.value % ScriptedLaunchConf
+                )
+              case Some((1, _)) =>
+                Seq(
+                  "org.scala-sbt" %% "scripted-sbt" % scriptedSbt.value % ScriptedConf,
+                  "org.scala-sbt" % "sbt-launch" % scriptedSbt.value % ScriptedLaunchConf
+                )
+              case other =>
+                sys.error(s"Unrecognized sbt partial version: $other")
+            }
+          case _ =>
+            Seq()
+        }
+      }
+  )
+
   def hasITs = itSettings
 
   def ShadingPlugin = coursier.ShadingPlugin

project/Settings.scala

@@ -191,6 +191,7 @@ object Settings {
   lazy val plugin =
     javaScalaPluginShared ++
     divertThingsPlugin ++
+    withScriptedTests ++
     Seq(
       scriptedLaunchOpts ++= Seq(
         "-Xmx1024M",