ID 385639 - Hydra Viewer - Crash when viewing subdmesh with fewer geometry.arbitrary.st.index values than that of geometry.poly.vertexList

Problem summary:

When viewing a polymesh location which has a lower ammount of st.index values than verts in the mesh, Hydra viewer and OSG viewer will throw a sensible terminal warning and fail to display the geometry:

Viewer - loading UVs: The number of values in the 'st.index' attribute does not match the required number of values: 12 != 24 (1 for each of 24 'vertex' elements).

If the location is a subdmesh, and has the same issue, then OSG viewer will show the same warning in the terminal, but Hydra will crash immediately

Steps to reproduce:

1. Open attached project: 385639.katana , relink the alembic in node with the file attached 
2. Fully expand the scene, observe a cube in Hydra
3. View the scene from the AttributeSet node

Expected behaviour:

Terminal warning is displayed, the Cube is no longer displayed in Hydra due to it being invalidated

Actual behaviour:

Katana crashes

Workaround:

No known workaround.

Tested versions/platforms:

• 3.0v1 - Affected
• 3.0v7 - Affected
• 3.1dev - Affected

Customer version/platform:

3.0v7