Do not rely on generatePlan() to set error code

Do not rely on generatePlan() to set the error code in all cases and
ensure that the error code is set to FAILURE if `generatePlan()` returns
false.

Signed-off-by: Gaël Écorchard <gael@km-robotics.cz>

Author: Gaël Écorchard

moveit_ros/planning/planning_pipeline_interfaces/src/planning_pipeline_interfaces.cpp

@@ -38,7 +38,6 @@
 #include <moveit/utils/logger.hpp>
 
 #include <thread>
-#include <tuple>  // std::ignore.
 
 namespace moveit
 {
@@ -64,7 +63,16 @@ planWithSinglePipeline(const ::planning_interface::MotionPlanRequest& motion_pla
     return motion_plan_response;
   }
   const planning_pipeline::PlanningPipelinePtr pipeline = it->second;
-  std::ignore = pipeline->generatePlan(planning_scene, motion_plan_request, motion_plan_response);
+  if (!pipeline->generatePlan(planning_scene, motion_plan_request, motion_plan_response))
+  {
+    if ((motion_plan_response.error_code.val == moveit::core::MoveItErrorCode::SUCCESS) ||
+        (motion_plan_response.error_code.val == moveit::core::MoveItErrorCode::UNDEFINED))
+    {
+      RCLCPP_ERROR(getLogger(), "Planning pipeline '%s' failed to plan, but did not set an error code",
+                   motion_plan_request.pipeline_id.c_str());
+      motion_plan_response.error_code = moveit::core::MoveItErrorCode::FAILURE;
+    }
+  }
   return motion_plan_response;
 }