Keep object position in parent folder when migrating with migrate_base_class_to_new_class

[laulaz]

When an object is migrated with migrate_base_class_to_new_class, its position in parent folder changes : the object always ends up last. Position should be kept.

plone.app.contenttypes/plone/app/contenttypes/migration/dxmigration.py

Line 162 in 3a7ea8c

parent._setOb(obj_id, obj)

The fix in our custom migration code looks like this :

from Acquisition import aq_inner
from Acquisition import aq_parent
from OFS.interfaces import IOrderedContainer
from plone.app.contenttypes.migration import dxmigration

[...]
obj_id = obj.getId()
parent = aq_parent(aq_inner(obj))
position_in_parent = None
ordered = IOrderedContainer(parent, None)
if ordered is not None:
    position_in_parent = ordered.getObjectPosition(obj_id)
if dxmigration.migrate_base_class_to_new_class(obj) and position_in_parent is not None:
    ordered.moveObject(obj_id, position_in_parent)
[...]

We should add this in the base migration script.
Any feedback on this ?

[vincentfretin]

This looks like a bug to me. Can you create a PR to fix the issue?