Merge pull request #4405 from eed3si9n/bport/plugincross

[1.2.x]  check PluginCross.scala consisntency

build.sbt

@@ -107,6 +107,20 @@ lazy val sbtRoot: Project = (project in file("."))
   .settings(
     buildLevelSettings,
     minimalSettings,
+    onLoadMessage := {
+      """           __    __ 
+        |     _____/ /_  / /_
+        |    / ___/ __ \/ __/
+        |   (__  ) /_/ / /_  
+        |  /____/_.___/\__/ 
+        |Welcome to the build for sbt.
+        |""".stripMargin +
+          (if (sys.props("java.specification.version") != "1.8")
+            s"""!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
+               |  Java versions is ${sys.props("java.specification.version")}. We recommend 1.8.
+               |!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!""".stripMargin
+          else "")
+    },
     Util.baseScalacOptions,
     Docs.settings,
     Sxr.settings,
@@ -545,6 +559,12 @@ lazy val mainProj = (project in file("main"))
   .settings(
     testedBaseSettings,
     name := "Main",
+    checkPluginCross := {
+      val sv = scalaVersion.value
+      val xs = IO.readLines(baseDirectory.value / "src" / "main" / "scala" / "sbt" / "PluginCross.scala")
+      if (xs exists { s => s.contains(s""""$sv"""") }) ()
+      else sys.error("PluginCross.scala does not match up with the scalaVersion " + sv)
+    },
     libraryDependencies ++= scalaXml.value ++ Seq(launcherInterface) ++ log4jDependencies ++ Seq(scalaCacheCaffeine),
     managedSourceDirectories in Compile +=
       baseDirectory.value / "src" / "main" / "contraband-scala",

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