would still like to hear @Sergey Sharybin (sergey) 's opinion, still sounds like bpy.data.meshes.new_from_object() is not meant for temporary usage.
Still the case presented in D5112 [other addons calling this as well -- that might also have called ob_eval.to_mesh()] sounds like it would apply to many addons?
Should all relevant addons use meshes.new_from_object()+ meshes.remove() as opposed to ob.to_mesh() + ob.to_mesh_clear() then?

meshes.new_from_object() is indeed not meant for temporary usage, but historically it was used as such.

I am not sure what you mean by would apply to many addons.

In D5114#116173, @Sergey Sharybin (sergey) wrote:

meshes.new_from_object() is indeed not meant for temporary usage, but historically it was used as such.

I am not sure what you mean by would apply to many addons.

What I mean is we have a couple of addon-operators calling ob.to_mesh_clear().
If these are called from other addons that also use ob.to_mesh(), this would make the other calling code's meshes invalid, right?
(see @Jacques Lucke (JacquesLucke) 's inline comment in D5112)

To me this does not justify pollution of main database with a temporary objects. It's the same as operator storing point to ID/data and calling an operator which modifies that ID/operator.