Operating system: Windows-7-6.1.7601-SP1 64 Bits
Graphics card: GeForce GTX 770/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 430.64
Broken: version: 2.81 (sub 3), branch: master, commit date: 2019-08-25 19:05, hash: rBaf8e8be7b1c8
Description of error
Rigify keeps crashing when I click Generate.
I was debugging IT to find what's wrong and consistently found the crash at two particular instances where it tries to set a data.bone's bbone_ease_in property.
Rigify's code has it always do this when in object mode, despite this being a edit bone type thing. (it's not literally an editbone but it functionally is).
The code in Rigify should be changed to run this stuff in Edit mode but I assume your priority is to fix the crash.
Exact steps for others to reproduce the error
While in Object or Pose mode, change a pose.bone's bone.bbone_easein property, or change a data.bone's easein property.
bpy.context.object.data.bones.bbone_easein = 1
bpy.context.object.pose.bones.bone.bbone_easein = 1