More fixes for prompt logger (#4075)

Fixes #4074

We shouldn't sleep for `nonInteractivePromptUpdateIntervalMillis` every
time `readTerminalDims` fails, because that means if there's a transient
failure it doesn't check again for 60s during which there is no prompt
shown

Instead, we always check after `promptUpdateIntervalMillis` seconds, and
but only refresh the prompt if `now - lastUpdate >
nonInteractivePromptUpdateIntervalMillis`

Also we make sure we call `writeTerminalDims` at least once before we
start the Mill background process, rather than relying on the background
thread to reach that code path in time

Either of these fixes alone should solve the issue, but might as well do
both

main/util/src/mill/util/PromptLogger.scala

@@ -63,23 +63,28 @@ private[mill] class PromptLogger(
   if (enableTicker) refreshPrompt()
 
   val promptUpdaterThread = new Thread(
-    () =>
+    () => {
+      var lastUpdate = System.currentTimeMillis()
       while (!runningState.stopped) {
-        val promptUpdateInterval =
-          if (termDimensions._1.isDefined) promptUpdateIntervalMillis
-          else nonInteractivePromptUpdateIntervalMillis
-
-        try Thread.sleep(promptUpdateInterval)
+        try Thread.sleep(promptUpdateIntervalMillis)
         catch {
           case e: InterruptedException => /*do nothing*/
         }
 
         readTerminalDims(terminfoPath).foreach(termDimensions = _)
 
-        synchronized {
-          if (!runningState.paused && !runningState.stopped) refreshPrompt()
+        val now = System.currentTimeMillis()
+        if (
+          termDimensions._1.nonEmpty ||
+          (now - lastUpdate > nonInteractivePromptUpdateIntervalMillis)
+        ) {
+          lastUpdate = now
+          synchronized {
+            if (!runningState.paused && !runningState.stopped) refreshPrompt()
+          }
         }
-      },
+      }
+    },
     "prompt-logger-updater-thread"
   )
 

runner/client/src/mill/runner/client/MillClientMain.java

@@ -5,10 +5,7 @@
 import java.nio.file.Path;
 import java.util.Arrays;
 import java.util.Collections;
-import mill.main.client.OutFiles;
-import mill.main.client.ServerCouldNotBeStarted;
-import mill.main.client.ServerLauncher;
-import mill.main.client.Util;
+import mill.main.client.*;
 import mill.main.client.lock.Locks;
 
 /**

runner/client/src/mill/runner/client/MillProcessLauncher.java

@@ -32,8 +32,8 @@ static int launchMillNoServer(String[] args) throws Exception {
     boolean interrupted = false;
 
     try {
-      Process p = configureRunMillProcess(builder, processDir);
       MillProcessLauncher.runTermInfoThread(processDir);
+      Process p = configureRunMillProcess(builder, processDir);
       return p.waitFor();
 
     } catch (InterruptedException e) {
@@ -230,18 +230,25 @@ static void writeTerminalDims(boolean tputExists, Path serverDir) throws Excepti
     Files.write(serverDir.resolve(ServerFiles.terminfo), str.getBytes());
   }
 
+  public static boolean checkTputExists() {
+    try {
+      getTerminalDim("cols", false);
+      getTerminalDim("lines", false);
+      return true;
+    } catch (Exception e) {
+      return false;
+    }
+  }
+
   public static void runTermInfoThread(Path serverDir) throws Exception {
+    Path sandbox = serverDir.resolve(ServerFiles.sandbox);
+    Files.createDirectories(sandbox);
+    boolean tputExists = checkTputExists();
+
+    writeTerminalDims(tputExists, serverDir);
     Thread termInfoPropagatorThread = new Thread(
         () -> {
           try {
-            boolean tputExists;
-            try {
-              getTerminalDim("cols", false);
-              getTerminalDim("lines", false);
-              tputExists = true;
-            } catch (Exception e) {
-              tputExists = false;
-            }
             while (true) {
               writeTerminalDims(tputExists, serverDir);
               Thread.sleep(100);