Properly propagate exit codes from server output to client

3 files changed, 14 insertions, 2 deletions

diff --git a/clientserver/src/mill/clientserver/Client.scala b/clientserver/src/mill/clientserver/Client.scala
index 1a4b1539..5e1af0aa 100644
--- a/clientserver/src/mill/clientserver/Client.scala
+++ b/clientserver/src/mill/clientserver/Client.scala
@@ -33,7 +33,7 @@ class Client(lockBase: String,
              stdin: InputStream,
              stdout: OutputStream,
              stderr: OutputStream) extends ClientServer(lockBase){
-  def run(args: Array[String]) = {
+  def run(args: Array[String]): Int = {
     val f = new FileOutputStream(runFile)
     ClientServer.writeArgs(System.console() != null, args, f)
     f.close()
@@ -55,5 +55,12 @@ class Client(lockBase: String,
 
     locks.serverLock.await()
 
+    try{
+      new BufferedReader(
+        new InputStreamReader(
+          new FileInputStream(exitCodePath)
+        )
+      ).readLine().toInt
+    } catch{case e: Throwable => 1}
   }
 }
diff --git a/clientserver/src/mill/clientserver/ClientServer.scala b/clientserver/src/mill/clientserver/ClientServer.scala
index f775f8d6..a7de2ba3 100644
--- a/clientserver/src/mill/clientserver/ClientServer.scala
+++ b/clientserver/src/mill/clientserver/ClientServer.scala
@@ -7,6 +7,7 @@ import scala.annotation.tailrec
 
 class ClientServer(lockBase: String){
   val ioPath = lockBase + "/io"
+  val exitCodePath = lockBase + "/exitCode"
   val logFile = new java.io.File(lockBase + "/log")
   val runFile = new java.io.File(lockBase + "/run")
 }
diff --git a/clientserver/src/mill/clientserver/Server.scala b/clientserver/src/mill/clientserver/Server.scala
index 52549f69..de8097fb 100644
--- a/clientserver/src/mill/clientserver/Server.scala
+++ b/clientserver/src/mill/clientserver/Server.scala
@@ -69,7 +69,7 @@ class Server[T](lockBase: String,
       try {
         val stdout = new PrintStream(new ProxyOutputStream(currentOutErr, 0), true)
         val stderr = new PrintStream(new ProxyOutputStream(currentOutErr, 1), true)
-        val (_, newStateCache) = sm.main0(
+        val (result, newStateCache) = sm.main0(
           args,
           sm.stateCache,
           interactive,
@@ -79,6 +79,10 @@ class Server[T](lockBase: String,
         )
 
         sm.stateCache = newStateCache
+        java.nio.file.Files.write(
+          java.nio.file.Paths.get(exitCodePath),
+          (if (result) 0 else 1).toString.getBytes
+        )
       } catch{case WatchInterrupted(sc: Option[T]) =>
         sm.stateCache = sc
       } finally{