Let's assume a one2many field (editable list) in a form view with
a many2many (e.g. many2many_tags), and an onchange on the one2many
such that, when a row is added to the relation, the server returns
update commands for (a subset of) the records being already in the
relation. For thoses updated records, the many2many field needs to
be read (the onchange only returns the ids in the relation).
Before this rev., the many2many field was read independently for
each record in the one2many. This could cause a performance issue
on large relations. For instance, this was the case on
account.invoice records with a lot of lines.
Issue 2027356
closesodoo/odoo#34785
Signed-off-by: Géry Debongnie (ged) <ged@openerp.com>