fix

ortools/sat/synchronization.cc

@@ -345,6 +345,14 @@ void SharedResponseManager::SetStatsFromModelInternal(Model* model) {
 
 bool SharedResponseManager::ProblemIsSolved() const {
   absl::MutexLock mutex_lock(&mutex_);
+
+  // TODO(user): Currently this work because we do not allow enumerate all
+  // solution in multithread.
+  if (!model_proto_.has_objective() &&
+      best_response_.status() == CpSolverStatus::FEASIBLE) {
+    return true;
+  }
+
   return best_response_.status() == CpSolverStatus::OPTIMAL ||
          best_response_.status() == CpSolverStatus::INFEASIBLE;
 }