diff -r 60fa7a0b9372 -r 5c91541284cd src/Pure/Tools/build_process.scala
--- a/src/Pure/Tools/build_process.scala	Wed Jun 28 12:13:46 2023 +0200
+++ b/src/Pure/Tools/build_process.scala	Wed Jun 28 12:16:02 2023 +0200
@@ -148,7 +148,9 @@
     options: String,
     start: Date,
     stop: Option[Date]
-  )
+  ) {
+    def active: Boolean = stop.isEmpty
+  }
 
   case class Worker(
     worker_uuid: String,  // Database_Progress.agent_uuid