ensure to always detect if a new event was inserted

Author: cmnrd

lib/scheduler.cc

@@ -291,6 +291,7 @@ void Scheduler::next() { // NOLINT
       } else {
         // find the next tag
         auto t_next = event_queue_.begin()->first;
+        log_.debug() << "try to advance logical time to tag " << t_next;
 
         // synchronize with physical time if not in fast forward mode
         if (!environment_->fast_fwd_execution()) {
@@ -305,9 +306,12 @@ void Scheduler::next() { // NOLINT
         // Wait until all input actions mark the tag as safe to process.
         bool result{true};
         for (auto* action : environment_->input_actions_) {
-          result = action->acquire_tag(t_next, lock, cv_schedule_,
+          bool inner_result = action->acquire_tag(t_next, lock, cv_schedule_,
                                        [&t_next, this]() { return t_next != event_queue_.begin()->first; });
-          if (!result) {
+          // If the wait was aborted or if the next tag changed in the meantime,
+          // we need to break from the loop and continue with the main loop.
+          if (!inner_result || t_next != event_queue_.begin()->first) {
+            result = false;
             break;
           }
         }