Franka Gripper Sim: Gripper Command Action Goal results has always zero effort

[torydebra]

Hi all, I was using the simulated gripper and the gripper action command goal, but I see that in the result of the action, the effort is always set to zero:

franka_ros/franka_gazebo/src/franka_gripper_sim.cpp

Lines 471 to 472 in c11f000

	result.effort = 0;
	result.stalled = static_cast<decltype(result.stalled)>(false);

Is there any reason for this? Why not giving back the actual effort like done for the joint state?

franka_ros/franka_gazebo/src/franka_gripper_sim.cpp

Line 108 in c11f000

pub_.msg_.effort = {this->finger1_.getEffort(), this->finger2_.getEffort()};

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In general, I would like to command the gripper (only) in effort, since I do not know how much should be the actual width. I saw that this issue has been discussed a lot, like here #172, with a possible hotfix this one:

Users can work around this limitation by setting the /franka_gripper/gripper_action/width_tolerance parameter to a value more significant than the max gripper width (see frankaemika.github.io/docs/franka_ros.html#frankagrippersim). When this is done, the gripper_action correctly grasps objects.

Still, playing with the max gripper width results in the action result giving always reached_goal: True.
Since neither the effort is reliable because always zero nor the stalled field which is always set to False, who is calling for the action can not really know if the action succeeded...