Gaffer Cycles Crashes Everytime Parameter Has Changed

[raumafu]

Version: Gaffer 1.2.0.2 - Window (e.g. 0.47.0.0-linux)
Third-party tools: List any third-party tools in use (e.g. Arnold, Tractor)
Third-party modules: List any third-party Gaffer modules in use (e.g. proprietary plugins)

Description

Gaffer Cycles Crashes Everytime Parameter Has Changed and i get these errors. Happens everytime, especially when changing parameters on the principle shader

Steps to reproduce

Start interactive render
Change parameters on principle shader
Crashes

Gaffer_Video.zip
Screenshot and file

Debug log

Click to Expand

WARNING [IECoreCyles::GeometryAlgo::convertPrimitiveVariable] Primitive variable "rman_autoBias" has unsupported type "ShortVectorData".
WARNING [Cycles::SocketAlgo] Unsupported socket type `transform` for socket `ob_tfm` on node `shader:3f106048d3c33c1aadd28cfec0fd37d3:texture_coordinate`.
WARNING [IECoreCyles::GeometryAlgo::convertPrimitiveVariable] Primitive variable "rman_autoBias" has unsupported type "ShortVectorData".

[murraystevenson]

From a quick scan of that script I suspect this is likely the same issue as #4913. Could you please confirm by disabling the MeshType node named "subdivide" in your example script and seeing if the crashes continue?

[raumafu]

I've disabled the meshType, crashed.
I've disconnected from the graph, still crashes.

[johnhaddon]

Are you able to share the Alembic file that goes with this script? That would be a big help in trying to reproduce the crash here so we can fix it.

[raumafu]

https://renderman.pixar.com/stirling-materialx-lama
Download Project as Maya files and the car in the cache/alembic/Stirling_Exterior.abc

[johnhaddon]

I believe this is the same problem as #4913. The cache contains subdivision surfaces, so even with the MeshType node disabled, there are still subdivision surfaces in the scene. If you keep the MeshType node but set the type to Polygon, then the crashes go away.

The question for us is, are we exporting subdivs to Cycles wrong, or are we doing it right and the bug is in Cycles?

[johnhaddon]

Closing as duplicate of #4913.