Blender Git Loki

Patch #21267 by Sergey Sharybin

His log:
There is a small typo in copy_curve(): there will be serious troubles
if this functions is called for OB_FONT in edit mode (for my cases
it is segmentation fault).
I think we should set editfont to NULL for cloned curves (as it is made
for edit nurb).

This bug was found by trying to edit text with applied Cast modifier
and while I was searching what's wrong, I've found that in
castModifier_deformVerts() DerivedMesh is creating for all objects,
but in castModifier_*_do() derived mesh is used only for OB_MESH
objects. Maybe this place could be optimized a bit by skipping DM
creation for non-meshes?