Merge pull request #6129 from eatkins/bsp-watch-fix

Fix watch when metals sbt bsp is in use

main-command/src/main/scala/sbt/internal/ui/UserThread.scala

@@ -31,31 +31,33 @@ private[sbt] class UserThread(val channel: CommandChannel) extends AutoCloseable
   private[sbt] def reset(state: State): Unit = if (!isClosed.get) {
     uiThread.synchronized {
       val task = channel.makeUIThread(state)
-      def submit(): Thread = {
+      def submit(): Unit = {
         val thread: Thread = new Thread(s"sbt-$name-ui-thread") {
           setDaemon(true)
           override def run(): Unit =
             try task.run()
-            finally uiThread.get match {
+            finally {
-              case (_, t) if t == this => uiThread.set(null)
+              uiThread.getAndSet(null) match {
-              case _                   =>
+                case prev @ (_, th) if th != this => uiThread.set(prev)
+                case _                            =>
+              }
             }
         }
         uiThread.getAndSet((task, thread)) match {
           case null => thread.start()
-          case (task, t) if t.getClass != task.getClass =>
+          case (prevTask, prevThread) if prevTask.getClass != task.getClass =>
-            stopThreadImpl()
+            prevTask.close()
+            prevThread.joinFor(1.second)
             thread.start()
           case t => uiThread.set(t)
         }
-        thread
       }
       uiThread.get match {
-        case null                                  => uiThread.set((task, submit()))
+        case null                                                => submit()
-        case (t, _) if t.getClass == task.getClass =>
+        case (prevTask, _) if prevTask.getClass == task.getClass =>
         case (t, thread) =>
           stopThreadImpl()
-          uiThread.set((task, submit()))
+          submit()
       }
     }
     Option(lastProgressEvent.get).foreach(onProgressEvent)

main/src/main/scala/sbt/Main.scala

@@ -992,12 +992,19 @@ object BuiltinCommands {
       val exchange = StandardMain.exchange
       exchange.channelForName(channel) match {
         case Some(c) if ContinuousCommands.isInWatch(s0, c) =>
-          c.prompt(ConsolePromptEvent(s0))
+          if (c.terminal.prompt != Prompt.Watch) {
+            c.terminal.setPrompt(Prompt.Watch)
+            c.prompt(ConsolePromptEvent(s0))
+          } else if (c.terminal.isSupershellEnabled) {
+            c.terminal.printStream.print(ConsoleAppender.ClearScreenAfterCursor)
+            c.terminal.printStream.flush()
+          }
+
           val s1 = exchange.run(s0)
           val exec: Exec = getExec(s1, Duration.Inf)
           val remaining: List[Exec] =
-            Exec(s"${ContinuousCommands.waitWatch} $channel", None) ::
+            Exec(FailureWall, None) :: Exec(s"${ContinuousCommands.waitWatch} $channel", None) ::
-              Exec(FailureWall, None) :: s1.remainingCommands
+              s1.remainingCommands
           val newState = s1.copy(remainingCommands = exec +: remaining)
           if (exec.commandLine.trim.isEmpty) newState
           else newState.clearGlobalLog

main/src/main/scala/sbt/MainLoop.scala

@@ -226,9 +226,8 @@ object MainLoop {
             // temporarily set the prompt to running during task evaluation
             c.terminal.setPrompt(Prompt.Running)
             (() => {
-              c.terminal.setPrompt(prevPrompt)
+              if (c.terminal.prompt != Prompt.Watch) c.terminal.setPrompt(prevPrompt)
               ITerminal.set(prevTerminal)
-              c.terminal.setPrompt(prevPrompt)
               c.terminal.flush()
             }) -> progressState.put(Keys.terminalKey, Terminal(c.terminal))
           case _ => (() => ()) -> progressState.put(Keys.terminalKey, Terminal(ITerminal.get))

main/src/main/scala/sbt/internal/Continuous.scala

@@ -1344,8 +1344,7 @@ private[sbt] object ContinuousCommands {
   private[sbt] val postWatchCommand = watchCommand(postWatch) { (channel, state) =>
     val cs = watchState(state, channel)
     StandardMain.exchange.channelForName(channel).foreach { c =>
-      c.terminal.setPrompt(Prompt.Watch)
+      c.terminal.setPrompt(Prompt.Pending)
-      c.unprompt(ConsoleUnpromptEvent(Some(CommandSource(channel))))
     }
     val postState = state.get(watchStates) match {
       case None     => state
@@ -1360,7 +1359,10 @@ private[sbt] object ContinuousCommands {
         cs.callbacks.onExit()
         StandardMain.exchange
           .channelForName(channel)
-          .foreach(_.unprompt(ConsoleUnpromptEvent(Some(CommandSource(channel)))))
+          .foreach { c =>
+            c.terminal.setPrompt(Prompt.Pending)
+            c.unprompt(ConsoleUnpromptEvent(Some(CommandSource(channel))))
+          }
         afterWatchState.get(watchStates) match {
           case None    => afterWatchState
           case Some(w) => afterWatchState.put(watchStates, w - channel)