Problem: the update of custom models/fields is not fully transactional, and may
potentially lead to an inconsistent database. An other problem is creating two
custom fields by writing on a model: if the second one fails, the first one has
been committed without notice. Retrying the request will give an unexpected
error (duplicate field name).
Solution: never commit in the middle of a request. If the changes have an
impact on the registry, then mark it as invalid (with a new flag), and signal
registry invalidation after everything has been committed. If the request
fails, reset the registry. Both registry and cache invalidation are handled
the same way.
The dictionary `_group_by_full` is replaced by a field parameter `group_expand`
that is assigned to the method name. The API of the method has been simplified
as well:
@api.multi
def _read_group_stage_ids(self, domain, read_group_order=None, access_rights_uid=None):
# the stages are given by self.ids (wrong model);
# read_group_order is the order given to read_group() on self;
# return stages.name_get(), {stage.id: stage.fold)
_group_by_full = {'stage_id': _read_group_stage_ids}
is now written:
stage_id = fields.Many2one(..., group_expand='_read_group_stage_ids')
@api.model
def _read_group_stage_ids(self, stages, domain, order):
# stages is a recordset;
# order is the order to use on stages' model;
# return a recordset which is a superset of stages
Christophe Simonis