Bug related to permissions for displaying reledit form
======================================================

Summary
-------

There was a bug in the computation of permissions for relations in the context of displaying reledit form. It has been fixed in version 3.32 of CubicWeb.

Long description of the problem
-------------------------------

The method :file:`_should_edit_relation` who chooses if the reledit form must or not be displayed. This is computed through the method :file:`cubicweb.schema.CubicWebRelationSchema.has_perm`, which will (among others things) try to satisfy all RQL expressions for permissions.

In the case of a project, we have this:

.. code:: python

    my_relation = SubjectRelation(
        'MyEntity', cardinality='1*',
        composite='object', inlined=True,
        __permissions__=rperms('O'))

where

.. code:: python

    def rperms(var, read=('managers', 'users')):
        return {
            'read': read,
            'add': (
                'managers',
                RRQLExpression('U has_update_permission {}'.format(var))),
            'delete': (
                'managers',
                RRQLExpression('U has_delete_permission {}'.format(var))),
        }

This expression will generate a RQL request like :file:`Any O,U WHERE U has_update_permission O, O eid %(o)s, U eid %(u)s` which will not be satisfied, because the eid of the object won't be given by reledit.

In consequence, we have to find an other way to check permissions for reledit.

Links on the development forge
------------------------------

- issue: <https://forge.extranet.logilab.fr/cubicweb/cubicweb/-/issues/324>
- fix: <https://forge.extranet.logilab.fr/cubicweb/cubicweb/-/merge_requests/313>