Cause by trying to deference a null batch.
In normal case, these calls never create a command
and are discarded early. 4.4 introduced the
polyline_draw_workaround to remove the use of geometry
shaders. These were not guarded against zero vertices
calls.
Adding an early out clause fixes the issue.
Pull Request: https://projects.blender.org/blender/blender/pulls/136840