planning: speed optimizer skips when no path data is available.

modules/planning/optimizer/dp_st_speed/dp_st_speed_optimizer.cc

@@ -59,6 +59,12 @@ Status DpStSpeedOptimizer::Process(const PathData& path_data,
     return Status(ErrorCode::PLANNING_ERROR, "Not inited.");
   }
 
+  if (path_data.discretized_path().NumOfPoints() == 0) {
+    std::string msg("Empty path data");
+    AERROR << msg;
+    return Status(ErrorCode::PLANNING_ERROR, msg);
+  }
+
   StBoundaryMapper boundary_mapper(st_boundary_config_, reference_line,
                                    path_data,
                                    dp_st_speed_config_.total_path_length(),

modules/planning/optimizer/qp_spline_st_speed/qp_spline_st_speed_optimizer.cc

@@ -59,6 +59,13 @@ Status QpSplineStSpeedOptimizer::Process(const PathData& path_data,
     AERROR << "Please call Init() before Process.";
     return Status(ErrorCode::PLANNING_ERROR, "Not init.");
   }
+
+  if (path_data.discretized_path().NumOfPoints() == 0) {
+    std::string msg("Empty path data");
+    AERROR << msg;
+    return Status(ErrorCode::PLANNING_ERROR, msg);
+  }
+
   StBoundaryMapper boundary_mapper(
       st_boundary_config_, reference_line, path_data,
       qp_spline_st_speed_config_.total_path_length(),