From 1937acd6e0f5b0d946c2c100a52dad4227e4d8c8 Mon Sep 17 00:00:00 2001
From: Li Haoyi <haoyi.sg@gmail.com>
Date: Sun, 24 Nov 2024 18:25:27 +0800
Subject: [PATCH 01/13] wip

---
 main/client/src/mill/main/client/ServerLauncher.java | 4 +++-
 main/server/src/mill/main/server/Server.scala        | 5 +++--
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/main/client/src/mill/main/client/ServerLauncher.java b/main/client/src/mill/main/client/ServerLauncher.java
index 64cb9b75404..1b6e50f386c 100644
--- a/main/client/src/mill/main/client/ServerLauncher.java
+++ b/main/client/src/mill/main/client/ServerLauncher.java
@@ -116,6 +116,8 @@ public Result acquireLocksAndRun(String outDir) throws Exception {
   }
 
   int run(Path serverDir, boolean setJnaNoSys, Locks locks) throws Exception {
+    Files.deleteIfExists(serverDir.resolve(ServerFiles.exitCode));
+    Files.deleteIfExists(serverDir.resolve(ServerFiles.socketPort));
     String serverPath = serverDir + "/" + ServerFiles.runArgs;
     try (OutputStream f = Files.newOutputStream(Paths.get(serverPath))) {
       f.write(System.console() != null ? 1 : 0);
@@ -166,7 +168,7 @@ int run(Path serverDir, boolean setJnaNoSys, Locks locks) throws Exception {
 
     try {
       return Integer.parseInt(
-          Files.readAllLines(Paths.get(serverDir + "/" + ServerFiles.exitCode)).get(0));
+          Files.readAllLines(serverDir.resolve(ServerFiles.exitCode)).get(0));
     } catch (Throwable e) {
       return Util.ExitClientCodeCannotReadFromExitCodeFile();
     } finally {
diff --git a/main/server/src/mill/main/server/Server.scala b/main/server/src/mill/main/server/Server.scala
index 08700759c5d..a3101e7e279 100644
--- a/main/server/src/mill/main/server/Server.scala
+++ b/main/server/src/mill/main/server/Server.scala
@@ -196,8 +196,9 @@ abstract class Server[T](
             )
 
             stateCache = newStateCache
-            serverLog("exitCode " + ServerFiles.exitCode)
-            os.write.over(serverDir / ServerFiles.exitCode, if (result) "0" else "1")
+            val exitCode = if (result) "0" else "1"
+            serverLog("exitCode " + exitCode)
+            os.write.over(serverDir / ServerFiles.exitCode, exitCode)
           } finally {
             done = true
             idle = true

From a681dd0b518797e277a59bb58158ed3c35ee7a99 Mon Sep 17 00:00:00 2001
From: Li Haoyi <haoyi.sg@gmail.com>
Date: Sun, 24 Nov 2024 18:26:47 +0800
Subject: [PATCH 02/13] wip

---
 main/client/src/mill/main/client/ServerLauncher.java | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/main/client/src/mill/main/client/ServerLauncher.java b/main/client/src/mill/main/client/ServerLauncher.java
index 1b6e50f386c..8ffd8c5662a 100644
--- a/main/client/src/mill/main/client/ServerLauncher.java
+++ b/main/client/src/mill/main/client/ServerLauncher.java
@@ -118,8 +118,7 @@ public Result acquireLocksAndRun(String outDir) throws Exception {
   int run(Path serverDir, boolean setJnaNoSys, Locks locks) throws Exception {
     Files.deleteIfExists(serverDir.resolve(ServerFiles.exitCode));
     Files.deleteIfExists(serverDir.resolve(ServerFiles.socketPort));
-    String serverPath = serverDir + "/" + ServerFiles.runArgs;
-    try (OutputStream f = Files.newOutputStream(Paths.get(serverPath))) {
+    try (OutputStream f = Files.newOutputStream(serverDir.resolve(ServerFiles.runArgs))) {
       f.write(System.console() != null ? 1 : 0);
       Util.writeString(f, BuildInfo.millVersion);
       Util.writeArgs(args, f);

From 3f279990a3acddc8ddc39e7289ad8b9150f6e959 Mon Sep 17 00:00:00 2001
From: Li Haoyi <haoyi.sg@gmail.com>
Date: Sun, 24 Nov 2024 19:00:50 +0800
Subject: [PATCH 03/13] wip

---
 main/client/src/mill/main/client/ServerLauncher.java | 12 ++++++++----
 main/server/src/mill/main/server/Server.scala        |  5 ++---
 .../src/mill/runner/client/MillClientMain.java       |  4 ++++
 3 files changed, 14 insertions(+), 7 deletions(-)

diff --git a/main/client/src/mill/main/client/ServerLauncher.java b/main/client/src/mill/main/client/ServerLauncher.java
index 8ffd8c5662a..c506fc81862 100644
--- a/main/client/src/mill/main/client/ServerLauncher.java
+++ b/main/client/src/mill/main/client/ServerLauncher.java
@@ -116,8 +116,14 @@ public Result acquireLocksAndRun(String outDir) throws Exception {
   }
 
   int run(Path serverDir, boolean setJnaNoSys, Locks locks) throws Exception {
+    // Clear out run-related files from the server folder to make sure we
+    // never hit issues where we are reading the files from a previous run
     Files.deleteIfExists(serverDir.resolve(ServerFiles.exitCode));
-    Files.deleteIfExists(serverDir.resolve(ServerFiles.socketPort));
+    Files.deleteIfExists(serverDir.resolve(ServerFiles.stdout));
+    Files.deleteIfExists(serverDir.resolve(ServerFiles.stderr));
+    Files.deleteIfExists(serverDir.resolve(ServerFiles.terminfo));
+    Files.deleteIfExists(serverDir.resolve(ServerFiles.runArgs));
+
     try (OutputStream f = Files.newOutputStream(serverDir.resolve(ServerFiles.runArgs))) {
       f.write(System.console() != null ? 1 : 0);
       Util.writeString(f, BuildInfo.millVersion);
@@ -140,7 +146,7 @@ int run(Path serverDir, boolean setJnaNoSys, Locks locks) throws Exception {
         ioSocket = new java.net.Socket("127.0.0.1", port);
       } catch (Throwable e) {
         socketThrowable = e;
-        Thread.sleep(10);
+        Thread.sleep(1);
       }
     }
 
@@ -168,8 +174,6 @@ int run(Path serverDir, boolean setJnaNoSys, Locks locks) throws Exception {
     try {
       return Integer.parseInt(
           Files.readAllLines(serverDir.resolve(ServerFiles.exitCode)).get(0));
-    } catch (Throwable e) {
-      return Util.ExitClientCodeCannotReadFromExitCodeFile();
     } finally {
       ioSocket.close();
     }
diff --git a/main/server/src/mill/main/server/Server.scala b/main/server/src/mill/main/server/Server.scala
index a3101e7e279..76c83edeb39 100644
--- a/main/server/src/mill/main/server/Server.scala
+++ b/main/server/src/mill/main/server/Server.scala
@@ -43,11 +43,10 @@ abstract class Server[T](
 
     try Server.tryLockBlock(locks.processLock) {
         watchServerIdFile()
-
+        val serverSocket = new java.net.ServerSocket(0, 0, InetAddress.getByName(null))
+        os.write.over(serverDir / ServerFiles.socketPort, serverSocket.getLocalPort.toString)
         while (
           running && {
-            val serverSocket = new java.net.ServerSocket(0, 0, InetAddress.getByName(null))
-            os.write.over(serverDir / ServerFiles.socketPort, serverSocket.getLocalPort.toString)
             try
               interruptWithTimeout(() => serverSocket.close(), () => serverSocket.accept()) match {
                 case None => false
diff --git a/runner/client/src/mill/runner/client/MillClientMain.java b/runner/client/src/mill/runner/client/MillClientMain.java
index 471b74713f2..aecee51404e 100644
--- a/runner/client/src/mill/runner/client/MillClientMain.java
+++ b/runner/client/src/mill/runner/client/MillClientMain.java
@@ -79,6 +79,10 @@ public void preRun(Path serverDir) throws Exception {
               "Loading Mill in-process isn't possible.\n" + "Please check your Mill installation!");
           throw e;
         }
+      } catch (Exception e) {
+        System.err.println("Mill client failed with unknown exception");
+        e.printStackTrace();
+        System.exit(1);
       }
   }
 }

From 1d0962c80d7aeb9a418a1c50168390b254010d36 Mon Sep 17 00:00:00 2001
From: Li Haoyi <haoyi.sg@gmail.com>
Date: Sun, 24 Nov 2024 19:21:56 +0800
Subject: [PATCH 04/13] .

---
 main/client/src/mill/main/client/Util.java | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/main/client/src/mill/main/client/Util.java b/main/client/src/mill/main/client/Util.java
index d6e88c6ad8e..fd6ececad09 100644
--- a/main/client/src/mill/main/client/Util.java
+++ b/main/client/src/mill/main/client/Util.java
@@ -10,7 +10,6 @@
 import java.nio.charset.StandardCharsets;
 import java.security.MessageDigest;
 import java.security.NoSuchAlgorithmException;
-import java.util.Base64;
 import java.util.HashMap;
 import java.util.LinkedList;
 import java.util.List;
@@ -131,7 +130,7 @@ static String sha1Hash(String path) throws NoSuchAlgorithmException {
     byte[] pathBytes = path.getBytes(StandardCharsets.UTF_8);
     md.update(pathBytes);
     byte[] digest = md.digest();
-    return Base64.getEncoder().encodeToString(digest);
+    return hexArray(digest);
   }
 
   /**

From 5df256f764e4d498e36a4bb9da3cab4db0ea90b9 Mon Sep 17 00:00:00 2001
From: Li Haoyi <haoyi.sg@gmail.com>
Date: Sun, 24 Nov 2024 19:29:13 +0800
Subject: [PATCH 05/13] .

---
 .../src/mill/main/client/ServerLauncher.java  |  2 --
 main/server/src/mill/main/server/Server.scala | 24 +++++++++----------
 2 files changed, 11 insertions(+), 15 deletions(-)

diff --git a/main/client/src/mill/main/client/ServerLauncher.java b/main/client/src/mill/main/client/ServerLauncher.java
index c506fc81862..4fddca0ec72 100644
--- a/main/client/src/mill/main/client/ServerLauncher.java
+++ b/main/client/src/mill/main/client/ServerLauncher.java
@@ -119,8 +119,6 @@ int run(Path serverDir, boolean setJnaNoSys, Locks locks) throws Exception {
     // Clear out run-related files from the server folder to make sure we
     // never hit issues where we are reading the files from a previous run
     Files.deleteIfExists(serverDir.resolve(ServerFiles.exitCode));
-    Files.deleteIfExists(serverDir.resolve(ServerFiles.stdout));
-    Files.deleteIfExists(serverDir.resolve(ServerFiles.stderr));
     Files.deleteIfExists(serverDir.resolve(ServerFiles.terminfo));
     Files.deleteIfExists(serverDir.resolve(ServerFiles.runArgs));
 
diff --git a/main/server/src/mill/main/server/Server.scala b/main/server/src/mill/main/server/Server.scala
index 76c83edeb39..61697dabfdb 100644
--- a/main/server/src/mill/main/server/Server.scala
+++ b/main/server/src/mill/main/server/Server.scala
@@ -47,19 +47,17 @@ abstract class Server[T](
         os.write.over(serverDir / ServerFiles.socketPort, serverSocket.getLocalPort.toString)
         while (
           running && {
-            try
-              interruptWithTimeout(() => serverSocket.close(), () => serverSocket.accept()) match {
-                case None => false
-                case Some(sock) =>
-                  serverLog("handling run")
-                  try handleRun(sock, initialSystemProperties)
-                  catch {
-                    case e: Throwable =>
-                      serverLog(e.toString + "\n" + e.getStackTrace.mkString("\n"))
-                  } finally sock.close();
-                  true
-              }
-            finally serverSocket.close()
+            interruptWithTimeout(() => serverSocket.close(), () => serverSocket.accept()) match {
+              case None => false
+              case Some(sock) =>
+                serverLog("handling run")
+                try handleRun(sock, initialSystemProperties)
+                catch {
+                  case e: Throwable =>
+                    serverLog(e.toString + "\n" + e.getStackTrace.mkString("\n"))
+                } finally sock.close();
+                true
+            }
           }
         ) ()
 

From ea2e688af5d96cfbac745c2be452b61379652e68 Mon Sep 17 00:00:00 2001
From: Li Haoyi <haoyi.sg@gmail.com>
Date: Sun, 24 Nov 2024 20:02:47 +0800
Subject: [PATCH 06/13] wip

---
 main/server/src/mill/main/server/Server.scala   | 17 ++++++++++-------
 .../mill/main/server/ClientServerTests.scala    | 16 +++++++---------
 2 files changed, 17 insertions(+), 16 deletions(-)

diff --git a/main/server/src/mill/main/server/Server.scala b/main/server/src/mill/main/server/Server.scala
index 61697dabfdb..f57733fc797 100644
--- a/main/server/src/mill/main/server/Server.scala
+++ b/main/server/src/mill/main/server/Server.scala
@@ -20,7 +20,6 @@ abstract class Server[T](
     serverDir: os.Path,
     acceptTimeoutMillis: Int,
     locks: Locks,
-    testLogEvenWhenServerIdWrong: Boolean = false
 ) {
 
   @volatile var running = true
@@ -30,9 +29,7 @@ abstract class Server[T](
 
   val serverId: String = java.lang.Long.toHexString(scala.util.Random.nextLong())
   def serverLog0(s: String): Unit = {
-    if (running && (testLogEvenWhenServerIdWrong || checkServerIdFile().isEmpty)) {
-      os.write.append(serverDir / ServerFiles.serverLog, s"$s\n", createFolders = true)
-    }
+    os.write.append(serverDir / ServerFiles.serverLog, s"$s\n", createFolders = true)
   }
 
   def serverLog(s: String): Unit = serverLog0(s"$serverId $s")
@@ -41,10 +38,13 @@ abstract class Server[T](
     serverLog("running server in " + serverDir)
     val initialSystemProperties = sys.props.toMap
 
-    try Server.tryLockBlock(locks.processLock) {
+    try {
+      Server.tryLockBlock(locks.processLock) {
+        serverLog("server file locked")
         watchServerIdFile()
         val serverSocket = new java.net.ServerSocket(0, 0, InetAddress.getByName(null))
         os.write.over(serverDir / ServerFiles.socketPort, serverSocket.getLocalPort.toString)
+        serverLog("listening on port " + serverSocket.getLocalPort)
         while (
           running && {
             interruptWithTimeout(() => serverSocket.close(), () => serverSocket.accept()) match {
@@ -60,9 +60,12 @@ abstract class Server[T](
             }
           }
         ) ()
-
+        serverLog("server loop ended")
       }.getOrElse(throw new Exception("Mill server process already present"))
-    finally exitServer()
+    } finally {
+      serverLog("exitServer")
+      exitServer()
+    }
   }
 
   def proxyInputStreamThroughPumper(in: InputStream): PipedInputStream = {
diff --git a/main/server/test/src/mill/main/server/ClientServerTests.scala b/main/server/test/src/mill/main/server/ClientServerTests.scala
index e240e90ef78..62e6805a074 100644
--- a/main/server/test/src/mill/main/server/ClientServerTests.scala
+++ b/main/server/test/src/mill/main/server/ClientServerTests.scala
@@ -22,8 +22,7 @@ object ClientServerTests extends TestSuite {
       override val serverId: String,
       serverDir: os.Path,
       locks: Locks,
-      testLogEvenWhenServerIdWrong: Boolean
-  ) extends Server[Option[Int]](serverDir, 1000, locks, testLogEvenWhenServerIdWrong)
+  ) extends Server[Option[Int]](serverDir, 1000, locks)
       with Runnable {
     override def exitServer() = {
       serverLog("exiting server")
@@ -69,7 +68,7 @@ object ClientServerTests extends TestSuite {
     }
   }
 
-  class Tester(testLogEvenWhenServerIdWrong: Boolean) {
+  class Tester() {
 
     var nextServerId: Int = 0
     val terminatedServers = collection.mutable.Set.empty[String]
@@ -104,7 +103,6 @@ object ClientServerTests extends TestSuite {
             serverId,
             os.Path(serverDir, os.pwd),
             locks,
-            testLogEvenWhenServerIdWrong
           )).start()
         }
       }.acquireLocksAndRun(outDir.relativeTo(os.pwd).toString)
@@ -139,7 +137,7 @@ object ClientServerTests extends TestSuite {
     test("hello") - retry(3) {
       // Continue logging when out folder is deleted so we can see the logs
       // and ensure the correct code path is taken as the server exits
-      val tester = new Tester(testLogEvenWhenServerIdWrong = true)
+      val tester = new Tester()
       val res1 = tester(args = Array("world"))
 
       assert(
@@ -179,7 +177,7 @@ object ClientServerTests extends TestSuite {
       }
     }
     test("dontLogWhenOutFolderDeleted") - retry(3) {
-      val tester = new Tester(testLogEvenWhenServerIdWrong = false)
+      val tester = new Tester()
       val res1 = tester(args = Array("world"))
 
       assert(
@@ -199,7 +197,7 @@ object ClientServerTests extends TestSuite {
     }
 
     test("concurrency") {
-      val tester = new Tester(testLogEvenWhenServerIdWrong = false)
+      val tester = new Tester()
       // Make sure concurrently running client commands results in multiple processes
       // being spawned, running in different folders
       import concurrent._
@@ -224,7 +222,7 @@ object ClientServerTests extends TestSuite {
     }
 
     test("clientLockReleasedOnFailure") {
-      val tester = new Tester(testLogEvenWhenServerIdWrong = false)
+      val tester = new Tester()
       // When the client gets interrupted via Ctrl-C, we exit the server immediately. This
       // is because Mill ends up executing arbitrary JVM code, and there is no generic way
       // to interrupt such an execution. The two options are to leave the server running
@@ -250,7 +248,7 @@ object ClientServerTests extends TestSuite {
     }
 
     test("envVars") - retry(3) {
-      val tester = new Tester(testLogEvenWhenServerIdWrong = false)
+      val tester = new Tester()
       // Make sure the simple "have the client start a server and
       // exchange one message" workflow works from end to end.
 

From f0f4a191d4a18f467d18be927a080cbaeccde9e6 Mon Sep 17 00:00:00 2001
From: Li Haoyi <haoyi.sg@gmail.com>
Date: Sun, 24 Nov 2024 20:12:31 +0800
Subject: [PATCH 07/13] wip

---
 main/client/src/mill/main/client/ServerLauncher.java |  6 +++---
 main/server/src/mill/main/server/Server.scala        | 11 ++++++++---
 2 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/main/client/src/mill/main/client/ServerLauncher.java b/main/client/src/mill/main/client/ServerLauncher.java
index 4fddca0ec72..2e68a95089c 100644
--- a/main/client/src/mill/main/client/ServerLauncher.java
+++ b/main/client/src/mill/main/client/ServerLauncher.java
@@ -129,9 +129,9 @@ int run(Path serverDir, boolean setJnaNoSys, Locks locks) throws Exception {
       Util.writeMap(env, f);
     }
 
-    if (locks.processLock.probe()) {
-      initServer(serverDir, setJnaNoSys, locks);
-    }
+    boolean lockProbe = locks.processLock.probe();
+    System.out.println("lockProbe: " + lockProbe);
+    if (lockProbe) initServer(serverDir, setJnaNoSys, locks);
 
     while (locks.processLock.probe()) Thread.sleep(3);
 
diff --git a/main/server/src/mill/main/server/Server.scala b/main/server/src/mill/main/server/Server.scala
index f57733fc797..9ede39cba11 100644
--- a/main/server/src/mill/main/server/Server.scala
+++ b/main/server/src/mill/main/server/Server.scala
@@ -29,7 +29,9 @@ abstract class Server[T](
 
   val serverId: String = java.lang.Long.toHexString(scala.util.Random.nextLong())
   def serverLog0(s: String): Unit = {
-    os.write.append(serverDir / ServerFiles.serverLog, s"$s\n", createFolders = true)
+    if (os.exists(serverDir / ServerFiles.serverLog)){
+      os.write.append(serverDir / ServerFiles.serverLog, s"$s\n", createFolders = true)
+    }
   }
 
   def serverLog(s: String): Unit = serverLog0(s"$serverId $s")
@@ -260,8 +262,11 @@ object Server {
     lock.tryLock() match {
       case null => None
       case l =>
-        try Some(t)
-        finally l.release()
+        if (l.isLocked) {
+          try Some(t) finally l.release()
+        } else {
+          None
+        }
     }
   }
 }

From a7b73aaa871a11d32f65f40c8afcd082f9f68178 Mon Sep 17 00:00:00 2001
From: Li Haoyi <haoyi.sg@gmail.com>
Date: Sun, 24 Nov 2024 20:50:34 +0800
Subject: [PATCH 08/13] wip

---
 main/client/src/mill/main/client/InputPumper.java    | 2 +-
 main/client/src/mill/main/client/ServerLauncher.java | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/main/client/src/mill/main/client/InputPumper.java b/main/client/src/mill/main/client/InputPumper.java
index 3cf432a65b3..ef3d8e7f6d7 100644
--- a/main/client/src/mill/main/client/InputPumper.java
+++ b/main/client/src/mill/main/client/InputPumper.java
@@ -38,7 +38,7 @@ public void run() {
       while (running) {
         if (!runningCheck.getAsBoolean()) {
           running = false;
-        } else if (checkAvailable && src.available() == 0) Thread.sleep(2);
+        } else if (checkAvailable && src.available() == 0) Thread.sleep(1);
         else {
           int n;
           try {
diff --git a/main/client/src/mill/main/client/ServerLauncher.java b/main/client/src/mill/main/client/ServerLauncher.java
index 2e68a95089c..2f2b03dc374 100644
--- a/main/client/src/mill/main/client/ServerLauncher.java
+++ b/main/client/src/mill/main/client/ServerLauncher.java
@@ -133,7 +133,7 @@ int run(Path serverDir, boolean setJnaNoSys, Locks locks) throws Exception {
     System.out.println("lockProbe: " + lockProbe);
     if (lockProbe) initServer(serverDir, setJnaNoSys, locks);
 
-    while (locks.processLock.probe()) Thread.sleep(3);
+    while (locks.processLock.probe()) Thread.sleep(1);
 
     long retryStart = System.currentTimeMillis();
     Socket ioSocket = null;

From 5cfd96657458bd170f53748e6e73ead9fbe6e112 Mon Sep 17 00:00:00 2001
From: Li Haoyi <haoyi.sg@gmail.com>
Date: Sun, 24 Nov 2024 21:05:07 +0800
Subject: [PATCH 09/13] wip

---
 kotlinlib/src/mill/kotlinlib/detekt/DetektModule.scala | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kotlinlib/src/mill/kotlinlib/detekt/DetektModule.scala b/kotlinlib/src/mill/kotlinlib/detekt/DetektModule.scala
index b21812cbfc3..f7280d7ab69 100644
--- a/kotlinlib/src/mill/kotlinlib/detekt/DetektModule.scala
+++ b/kotlinlib/src/mill/kotlinlib/detekt/DetektModule.scala
@@ -21,7 +21,7 @@ trait DetektModule extends KotlinModule {
 
   private def detekt0() = T.task {
 
-    val args = detektOptions() ++ Seq("-i", PathRef(T.workspace).path.toString()) ++
+    val args = detektOptions() ++ Seq("-i", T.workspace.toString()) ++
       Seq("-c", detektConfig().path.toString())
 
     T.log.info("running detekt ...")

From 73c8b07fd40698c6cb8cdaa5281fc52af07f81ec Mon Sep 17 00:00:00 2001
From: Li Haoyi <haoyi.sg@gmail.com>
Date: Sun, 24 Nov 2024 21:06:48 +0800
Subject: [PATCH 10/13] wip

---
 main/client/src/mill/main/client/ServerLauncher.java | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/main/client/src/mill/main/client/ServerLauncher.java b/main/client/src/mill/main/client/ServerLauncher.java
index 2f2b03dc374..a4fc61fcd4f 100644
--- a/main/client/src/mill/main/client/ServerLauncher.java
+++ b/main/client/src/mill/main/client/ServerLauncher.java
@@ -129,9 +129,7 @@ int run(Path serverDir, boolean setJnaNoSys, Locks locks) throws Exception {
       Util.writeMap(env, f);
     }
 
-    boolean lockProbe = locks.processLock.probe();
-    System.out.println("lockProbe: " + lockProbe);
-    if (lockProbe) initServer(serverDir, setJnaNoSys, locks);
+    if (locks.processLock.probe()) initServer(serverDir, setJnaNoSys, locks);
 
     while (locks.processLock.probe()) Thread.sleep(1);
 

From e1002d28ce1a1b54c7a6270d1a8edde721164119 Mon Sep 17 00:00:00 2001
From: Li Haoyi <haoyi.sg@gmail.com>
Date: Mon, 25 Nov 2024 08:03:23 +0800
Subject: [PATCH 11/13] wip

---
 main/server/src/mill/main/server/Server.scala | 11 +++++---
 .../mill/main/server/ClientServerTests.scala  | 25 +++++++++++--------
 2 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/main/server/src/mill/main/server/Server.scala b/main/server/src/mill/main/server/Server.scala
index 9ede39cba11..bd1a59f1d6d 100644
--- a/main/server/src/mill/main/server/Server.scala
+++ b/main/server/src/mill/main/server/Server.scala
@@ -20,6 +20,7 @@ abstract class Server[T](
     serverDir: os.Path,
     acceptTimeoutMillis: Int,
     locks: Locks,
+    testLogEvenWhenServerIdWrong: Boolean = false
 ) {
 
   @volatile var running = true
@@ -29,7 +30,7 @@ abstract class Server[T](
 
   val serverId: String = java.lang.Long.toHexString(scala.util.Random.nextLong())
   def serverLog0(s: String): Unit = {
-    if (os.exists(serverDir / ServerFiles.serverLog)){
+    if (os.exists(serverDir) || testLogEvenWhenServerIdWrong) {
       os.write.append(serverDir / ServerFiles.serverLog, s"$s\n", createFolders = true)
     }
   }
@@ -65,7 +66,7 @@ abstract class Server[T](
         serverLog("server loop ended")
       }.getOrElse(throw new Exception("Mill server process already present"))
     } finally {
-      serverLog("exitServer")
+      serverLog("finally exitServer")
       exitServer()
     }
   }
@@ -208,10 +209,11 @@ abstract class Server[T](
         "MillServerActionRunner"
       )
       t.start()
+
       // We cannot simply use Lock#await here, because the filesystem doesn't
       // realize the clientLock/serverLock are held by different threads in the
       // two processes and gives a spurious deadlock error
-      while (!done && !locks.clientLock.probe()) Thread.sleep(3)
+      while (!done && !locks.clientLock.probe()) Thread.sleep(1)
 
       if (!idle) {
         serverLog("client interrupted while server was executing command")
@@ -263,7 +265,8 @@ object Server {
       case null => None
       case l =>
         if (l.isLocked) {
-          try Some(t) finally l.release()
+          try Some(t)
+          finally l.release()
         } else {
           None
         }
diff --git a/main/server/test/src/mill/main/server/ClientServerTests.scala b/main/server/test/src/mill/main/server/ClientServerTests.scala
index 62e6805a074..7f4aea70c27 100644
--- a/main/server/test/src/mill/main/server/ClientServerTests.scala
+++ b/main/server/test/src/mill/main/server/ClientServerTests.scala
@@ -22,7 +22,8 @@ object ClientServerTests extends TestSuite {
       override val serverId: String,
       serverDir: os.Path,
       locks: Locks,
-  ) extends Server[Option[Int]](serverDir, 1000, locks)
+      testLogEvenWhenServerIdWrong: Boolean = false
+  ) extends Server[Option[Int]](serverDir, 1000, locks, testLogEvenWhenServerIdWrong)
       with Runnable {
     override def exitServer() = {
       serverLog("exiting server")
@@ -68,7 +69,7 @@ object ClientServerTests extends TestSuite {
     }
   }
 
-  class Tester() {
+  class Tester(testLogEvenWhenServerIdWrong: Boolean) {
 
     var nextServerId: Int = 0
     val terminatedServers = collection.mutable.Set.empty[String]
@@ -103,6 +104,7 @@ object ClientServerTests extends TestSuite {
             serverId,
             os.Path(serverDir, os.pwd),
             locks,
+            testLogEvenWhenServerIdWrong
           )).start()
         }
       }.acquireLocksAndRun(outDir.relativeTo(os.pwd).toString)
@@ -137,7 +139,7 @@ object ClientServerTests extends TestSuite {
     test("hello") - retry(3) {
       // Continue logging when out folder is deleted so we can see the logs
       // and ensure the correct code path is taken as the server exits
-      val tester = new Tester()
+      val tester = new Tester(testLogEvenWhenServerIdWrong = true)
       val res1 = tester(args = Array("world"))
 
       assert(
@@ -173,11 +175,11 @@ object ClientServerTests extends TestSuite {
         Thread.sleep(500)
 
         assert(res3.logsFor("serverId file missing") == Seq("server-1"))
-        assert(res3.logsFor("exiting server") == Seq("server-1"))
+        assert(res3.logsFor("exiting server") == Seq("server-1", "server-1"))
       }
     }
     test("dontLogWhenOutFolderDeleted") - retry(3) {
-      val tester = new Tester()
+      val tester = new Tester(testLogEvenWhenServerIdWrong = false)
       val res1 = tester(args = Array("world"))
 
       assert(
@@ -197,7 +199,7 @@ object ClientServerTests extends TestSuite {
     }
 
     test("concurrency") {
-      val tester = new Tester()
+      val tester = new Tester(testLogEvenWhenServerIdWrong = false)
       // Make sure concurrently running client commands results in multiple processes
       // being spawned, running in different folders
       import concurrent._
@@ -222,7 +224,7 @@ object ClientServerTests extends TestSuite {
     }
 
     test("clientLockReleasedOnFailure") {
-      val tester = new Tester()
+      val tester = new Tester(testLogEvenWhenServerIdWrong = false)
       // When the client gets interrupted via Ctrl-C, we exit the server immediately. This
       // is because Mill ends up executing arbitrary JVM code, and there is no generic way
       // to interrupt such an execution. The two options are to leave the server running
@@ -235,20 +237,23 @@ object ClientServerTests extends TestSuite {
       }
 
       val s"Force failure for testing: $pathStr" = res1.getMessage
-      Thread.sleep(100) // give a moment for logs to all turn up on disk
+      Thread.sleep(1000) // give a moment for logs to all turn up on disk
       val logLines = os.read.lines(os.Path(pathStr, os.pwd) / "server.log")
 
       assert(
-        logLines.takeRight(2) ==
+        logLines.takeRight(5) ==
           Seq(
             "server-0 client interrupted while server was executing command",
+            "server-0 exiting server",
+            "server-0 server loop ended",
+            "server-0 finally exitServer",
             "server-0 exiting server"
           )
       )
     }
 
     test("envVars") - retry(3) {
-      val tester = new Tester()
+      val tester = new Tester(testLogEvenWhenServerIdWrong = false)
       // Make sure the simple "have the client start a server and
       // exchange one message" workflow works from end to end.
 

From faa3b0e1bf4c274071d4919f843100f9bfd80fa9 Mon Sep 17 00:00:00 2001
From: Li Haoyi <haoyi.sg@gmail.com>
Date: Mon, 25 Nov 2024 08:15:28 +0800
Subject: [PATCH 12/13] wip

---
 .../watch-source-input/src/WatchSourceInputTests.scala   | 1 +
 main/client/src/mill/main/client/ServerLauncher.java     | 9 +++++++--
 2 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/integration/invalidation/watch-source-input/src/WatchSourceInputTests.scala b/integration/invalidation/watch-source-input/src/WatchSourceInputTests.scala
index 8cea62874ac..732d8b4efad 100644
--- a/integration/invalidation/watch-source-input/src/WatchSourceInputTests.scala
+++ b/integration/invalidation/watch-source-input/src/WatchSourceInputTests.scala
@@ -51,6 +51,7 @@ object WatchSourceInputTests extends UtestIntegrationTestSuite {
         .filter(!_.contains("Watching for changes"))
         .filter(!_.contains("[info] compiling"))
         .filter(!_.contains("[info] done compiling"))
+        .filter(!_.contains("mill-server/ exitCode file not found"))
 
       assert(out == expectedOut)
 
diff --git a/main/client/src/mill/main/client/ServerLauncher.java b/main/client/src/mill/main/client/ServerLauncher.java
index a4fc61fcd4f..f619ba7b9f3 100644
--- a/main/client/src/mill/main/client/ServerLauncher.java
+++ b/main/client/src/mill/main/client/ServerLauncher.java
@@ -168,8 +168,13 @@ int run(Path serverDir, boolean setJnaNoSys, Locks locks) throws Exception {
     outPumperThread.join();
 
     try {
-      return Integer.parseInt(
-          Files.readAllLines(serverDir.resolve(ServerFiles.exitCode)).get(0));
+      Path exitCodeFile = serverDir.resolve(ServerFiles.exitCode);
+      if (Files.exists(exitCodeFile)) {
+        return Integer.parseInt(Files.readAllLines(exitCodeFile).get(0));
+      } else {
+        System.err.println("mill-server/ exitCode file not found");
+        return 1;
+      }
     } finally {
       ioSocket.close();
     }

From 0f261ce72325a5463e08ccb0defda78bb7202b6c Mon Sep 17 00:00:00 2001
From: Li Haoyi <haoyi.sg@gmail.com>
Date: Mon, 25 Nov 2024 08:17:50 +0800
Subject: [PATCH 13/13] wip

---
 main/server/test/src/mill/main/server/ClientServerTests.scala | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/main/server/test/src/mill/main/server/ClientServerTests.scala b/main/server/test/src/mill/main/server/ClientServerTests.scala
index 7f4aea70c27..44ae7490bd3 100644
--- a/main/server/test/src/mill/main/server/ClientServerTests.scala
+++ b/main/server/test/src/mill/main/server/ClientServerTests.scala
@@ -22,7 +22,7 @@ object ClientServerTests extends TestSuite {
       override val serverId: String,
       serverDir: os.Path,
       locks: Locks,
-      testLogEvenWhenServerIdWrong: Boolean = false
+      testLogEvenWhenServerIdWrong: Boolean
   ) extends Server[Option[Int]](serverDir, 1000, locks, testLogEvenWhenServerIdWrong)
       with Runnable {
     override def exitServer() = {
@@ -237,7 +237,7 @@ object ClientServerTests extends TestSuite {
       }
 
       val s"Force failure for testing: $pathStr" = res1.getMessage
-      Thread.sleep(1000) // give a moment for logs to all turn up on disk
+      Thread.sleep(100) // give a moment for logs to all turn up on disk
       val logLines = os.read.lines(os.Path(pathStr, os.pwd) / "server.log")
 
       assert(