Fix double execution in JSR223 Implementation

compiler/src/dotty/tools/dotc/config/ScalaSettings.scala

@@ -81,6 +81,7 @@ class ScalaSettings extends Settings.SettingGroup {
   val Xprompt: Setting[Boolean] = BooleanSetting("-Xprompt", "Display a prompt after each error (debugging option).")
   val XnoValueClasses: Setting[Boolean] = BooleanSetting("-Xno-value-classes", "Do not use value classes. Helps debugging.")
   val XreplLineWidth: Setting[Int] = IntSetting("-Xrepl-line-width", "Maximal number of columns per line for REPL output", 390)
+  val XreplDisableDisplay: Setting[Boolean] = BooleanSetting("-Xrepl-disable-display", "Do not display definitions in REPL.")
   val XfatalWarnings: Setting[Boolean] = BooleanSetting("-Xfatal-warnings", "Fail the compilation if there are any warnings.")
   val XverifySignatures: Setting[Boolean] = BooleanSetting("-Xverify-signatures", "Verify generic signatures in generated bytecode.")
   val XignoreScala2Macros: Setting[Boolean] = BooleanSetting("-Xignore-scala2-macros", "Ignore errors when compiling code that calls Scala2 macros, these will fail at runtime.")

compiler/src/dotty/tools/repl/ReplDriver.scala

@@ -205,7 +205,9 @@ class ReplDriver(settings: Array[String],
       case _ => // new line, empty tree
         state
     }
-    out.println()
+    implicit val ctx: Context = newState.context
+    if (!ctx.settings.XreplDisableDisplay.value)
+      out.println()
     newState
   }
 
@@ -238,7 +240,11 @@ class ReplDriver(settings: Array[String],
 
             val warnings = newState.context.reporter.removeBufferedMessages(newState.context)
             displayErrors(warnings)(newState) // display warnings
-            displayDefinitions(unit.tpdTree, newestWrapper)(newStateWithImports)
+            implicit val ctx = newState.context
+            if (!ctx.settings.XreplDisableDisplay.value)
+              displayDefinitions(unit.tpdTree, newestWrapper)(newStateWithImports)
+            else
+              newStateWithImports
         }
       )
   }

compiler/src/dotty/tools/repl/ScriptEngine.scala

@@ -21,7 +21,8 @@ class ScriptEngine extends AbstractScriptEngine {
     Array(
       "-classpath", "", // Avoid the default "."
       "-usejavacp",
-      "-color:never"
+      "-color:never",
+      "-Xrepl-disable-display"
     ), Console.out, None)
   private val rendering = new Rendering
   private var state: State = driver.initialState

tests/run-with-compiler/scripting.check

@@ -1,3 +1 @@
-val res0: Int = 42
-
 42

tests/run-with-compiler/scripting.scala

@@ -5,4 +5,3 @@ object Test {
     println(e.eval("42"))
   }
 }
-