rigify stretching bones I've recently had a problem and I want to know how to fix it.
My probleme is when I move the bones in rigify I don't want them to stretch, because when they stretch the leg or arm gets messy and taller than it should be.  

My second question is: How do I deal with elbows controllers so that the arm looks real when rigging?
My third question is: How do I add eyes and face controllers to the rig so that I can control expressions of face without messing with the body rigs
The first two questions are related I will focus on them.
The stretching you face only appears with inverse kinematics (IK) when you move the control bone in a impossible position, this is used for cartonic exaggeration.

You can disable this by setting the Auto Stretch IK slider to 0.



The elbow has an IK-target which can be controlled as knees with a ball shaped control.