check PluginCross.scala consisntency

build.sbt

@@ -561,6 +561,12 @@ lazy val mainProj = (project in file("main"))
   .settings(
     testedBaseSettings,
     name := "Main",
+    checkPluginCross := {
+      val sv = scalaVersion.value
+      val xs = IO.readLines(baseDirectory.value / "src" / "main" / "scala" / "sbt" / "PluginCross.scala")
+      if (xs exists { s => s.contains(s""""$sv"""") }) ()
+      else sys.error("PluginCross.scala does not match up with the scalaVersion " + sv)
+    },
     libraryDependencies ++= scalaXml.value ++ Seq(launcherInterface) ++ log4jDependencies ++ Seq(scalaCacheCaffeine),
     Compile / scalacOptions -= "-Xfatal-warnings",
     managedSourceDirectories in Compile +=

main/src/main/scala/sbt/PluginCross.scala

@@ -96,7 +96,7 @@ private[sbt] object PluginCross {
     VersionNumber(sv) match {
       case VersionNumber(Seq(0, 12, _*), _, _) => "2.9.2"
       case VersionNumber(Seq(0, 13, _*), _, _) => "2.10.7"
-      case VersionNumber(Seq(1, 0, _*), _, _)  => "2.12.6"
+      case VersionNumber(Seq(1, 0, _*), _, _)  => "2.12.7"
       case _                                   => sys.error(s"Unsupported sbt binary version: $sv")
     }
 }

project/Dependencies.scala

@@ -5,6 +5,7 @@ import sbt.contraband.ContrabandPlugin.autoImport._
 object Dependencies {
   // WARNING: Please Scala update versions in PluginCross.scala too
   val scala212 = "2.12.7"
+  lazy val checkPluginCross = settingKey[Unit]("Make sure scalaVersion match up")
   val baseScalaVersion = scala212
 
   // sbt modules