crash if you try and move a locked prim

[nxkb]

While testing some of the various prim attributes defined in Metadata.h that can customize created maya nodes, I was a little too harshly punished for trying to move a locked prim.

Reproduction steps

• Load a proxy shape with stage that has a prim defined like:

  def Xform "locked" (
      al_usdmaya_lock = "transform"
  )
  {
      def Sphere "ball"
      {
      }
  }

• select it
• try to move it
• crashes with:

  FATAL ERROR: Used null prim
  in Usd_IssueFatalPrimAccessError at line 224 of /mnt/Samsung/luma/rez-build/usd/0.8.2.luma03/src/pxr/usd/lib/usd/primData.cpp

[dbaz]

Hi Nick, I have simple fix locally to stop the crash and need to investigate exactly why the reason. I will have the fix up ASAP.

If you havn't done the fix already on your end, it's a return early in ProxyShape::lockTransformAttribute after the GetPrimAtPath if the returned prim is null.

Also, I'm going to log one more issue publicly about the this lock feature that you may run into shortly.

• Baz

[dbaz]

I have an internal fix in for code review. There is also documentation for the Lock feature coming

[nxkb]

Awesome. Thanks for looking into it!

[dbaz]

Fix is in version AL_USDMaya-0.26