Add ClearScreenAfterCursor

This communicates intent better than clearScreen(0).

internal/util-logging/src/main/scala/sbt/internal/util/ConsoleAppender.scala

@@ -113,6 +113,7 @@ object ConsoleAppender {
   private[sbt] def clearScreen(n: Int): String = s"\u001B[${n}J"
   private[sbt] def clearLine(n: Int): String = s"\u001B[${n}K"
   private[sbt] final val DeleteLine = "\u001B[2K"
+  private[sbt] final val ClearScreenAfterCursor = clearScreen(0)
   private[sbt] final val CursorLeft1000 = cursorLeft(1000)
   private[sbt] final val CursorDown1 = cursorDown(1)
   private[this] val showProgressHolder: AtomicBoolean = new AtomicBoolean(false)
@@ -558,7 +559,7 @@ private[sbt] object ProgressState {
     case state =>
       if (state.progressLines.get.nonEmpty) {
         val lines = printProgress(0, 0)
-        printStream.print(ConsoleAppender.clearScreen(0) + "\n" + lines)
+        printStream.print(ClearScreenAfterCursor + "\n" + lines)
       } else printStream.write('\n')
   }
 
@@ -603,7 +604,7 @@ private[sbt] object ProgressState {
         val left = cursorLeft(1000) // resets the position to the left
         val offset = width > 0
         val pad = math.max(state.padding.get - height, 0)
-        val start = clearScreen(0) + (if (offset) "\n" else "")
+        val start = ClearScreenAfterCursor + (if (offset) "\n" else "")
         val totalSize = currentLength + state.blankZone + pad
         val blank = left + s"\n$DeleteLine" * (totalSize - currentLength)
         val lines = previousLines.mkString(DeleteLine, s"\n$DeleteLine", s"\n$DeleteLine")
@@ -612,7 +613,7 @@ private[sbt] object ProgressState {
         val resetCursor = resetCursorUp + resetCursorRight
         start + blank + lines + resetCursor
       } else {
-        clearScreen(0)
+        ClearScreenAfterCursor
       }
   }
 

main-command/src/main/scala/sbt/internal/ConsoleChannel.scala

@@ -23,7 +23,7 @@ private[sbt] final class ConsoleChannel(val name: String) extends CommandChannel
     case Some(pf) => pf(s)
     case None =>
       def ansi(s: String): String = if (ConsoleAppender.formatEnabledInEnv) s"$s" else ""
-      s"${ansi(ConsoleAppender.DeleteLine)}> ${ansi(ConsoleAppender.clearScreen(0))}"
+      s"${ansi(ConsoleAppender.DeleteLine)}> ${ansi(ConsoleAppender.ClearScreenAfterCursor)}"
   }
   private[this] class AskUserThread(s: State) extends Thread("ask-user-thread") {
     private val history = s.get(historyPath).getOrElse(Some(new File(s.baseDir, ".history")))
@@ -52,7 +52,7 @@ private[sbt] final class ConsoleChannel(val name: String) extends CommandChannel
     def redraw(): Unit = {
       System.out.print(ConsoleAppender.clearLine(0))
       reader.redraw()
-      System.out.print(ConsoleAppender.clearScreen(0))
+      System.out.print(ConsoleAppender.ClearScreenAfterCursor)
       System.out.flush()
     }
   }

run/src/main/scala/sbt/SelectMainClass.scala

@@ -25,7 +25,7 @@ object SelectMainClass {
           val classes = multiple.zipWithIndex
             .map { case (className, index) => s" [${index + 1}] $className" }
             .mkString("\n")
-          println(ConsoleAppender.clearScreen(0) + header + classes)
+          println(ConsoleAppender.ClearScreenAfterCursor + header + classes)
 
           val line = trim(prompt("\nEnter number: "))
           toInt(line, multiple.length) map multiple.apply