diff -r 0f9bae334ac6 -r 6b2f3eafdf26 src/Pure/System/isabelle_system.scala
--- a/src/Pure/System/isabelle_system.scala	Sat Nov 01 13:56:39 2025 +0100
+++ b/src/Pure/System/isabelle_system.scala	Sat Nov 01 13:58:07 2025 +0100
@@ -575,12 +575,8 @@
 
   /* default logic */
 
-  def default_logic(args: String*): String = {
-    args.find(_ != "") match {
-      case Some(logic) => logic
-      case None => getenv_strict("ISABELLE_LOGIC")
-    }
-  }
+  def default_logic(args: String*): String =
+    args.find(_.nonEmpty) getOrElse getenv_strict("ISABELLE_LOGIC")
 
 
   /* download file */