src/Pure/PIDE/command.ML

--- a/src/Pure/PIDE/command.ML	Sat Sep 01 14:25:03 2018 +0200
+++ b/src/Pure/PIDE/command.ML	Sat Sep 01 16:08:54 2018 +0200
@@ -443,7 +443,7 @@
 fun run_process execution_id exec_id process =
   let val group = Future.worker_subgroup () in
     if Execution.running execution_id exec_id [group] then
-      ignore (task_context group Lazy.force_result process)
+      ignore (task_context group Lazy.force_result {strict = true} process)
     else ()
   end;