Thanks for looking into this. I think it probably set the mesh to null as a way to guarantee that only edit mode data was used when the user is in edit mode. The selection attributes on Mesh (object->data) might not match the selection in the edit BMesh.

I did miss this though, and it's weird. Just using a smaller scope for the variable would be much better than setting it to null in some cases.

In this case it probably makes sense to lower the scope of the attribute lookup, or skip it when the mesh is null.

In D16406#446559, @Hans Goudey (HooglyBoogly) wrote:

Thanks for looking into this. I think it probably set the mesh to null as a way to guarantee that only edit mode data was used when the user is in edit mode. The selection attributes on Mesh (object->data) might not match the selection in the edit BMesh.

I did miss this though, and it's weird. Just using a smaller scope for the variable would be much better than setting it to null in some cases.

In this case it probably makes sense to lower the scope of the attribute lookup, or skip it when the mesh is null.

IS_ME_VERT_WRITE uses the attribute (indirectly) though, so you mean we`d rely on the BM_ELEM_SELECT in editmode instead?

Only IS_BM_VERT_READ should be used in the BMesh edit mode case, which doesn't use the attribute.

In D16406#447000, @Hans Goudey (HooglyBoogly) wrote:

Only IS_BM_VERT_READ should be used in the BMesh edit mode case, which doesn't use the attribute.

OK, got it, will update shortly