[IMP] core, base: avoid multiple xids when importing records w/ inherits

Before this change, we create an xid for every parent of a record
being imported, regardless of whether it already has an xid, or if
it's being created implicitly through the child.

This generates unnecessary extra xids on pre-existing objects
e.g. update 5 product variants -> the product gets 5 new xids despite
already having one.

We should *only* set a xid on parent records which are being
implicitly created by the creation of a child with a specified
xid. That is, we should never set a xid on the parent if it exists
before the child is created.

Update _process_end to try and see if "non-loaded" xids correspond to
an automatically generated "parent" xid: we're still setting a xid on
implicitly created records (if the child is created with a xid) so
they're properly removed if e.g. the module is uninstalled, but
because we're only doing so at creation these xids will not be visited
during update and _process_end will try to delete them.

A special case can be added to check that "unknown" parent xids don't
have children which _inherit them, in which case we want to protect them.

Task 2251039

closes odoo/odoo#53283

Related: odoo/enterprise#12023
Signed-off-by: Xavier Morel (xmo) <xmo@odoo.com>

1 files changed, 12 insertions, 0 deletions

diff --git a/odoo/addons/test_impex/models.py b/odoo/addons/test_impex/models.py
index f5890aec480..ad75f7d43f4 100644
--- a/odoo/addons/test_impex/models.py
+++ b/odoo/addons/test_impex/models.py
@@ -164,3 +164,15 @@ class OnlyOne(models.Model):
         ('value_unique', 'unique (value)', "The value must be unique"),
         ('pair_unique', 'unique (value2, value3)', "The values must be unique"),
     ]
+
+class InheritsParent(models.Model):
+    _name = _description = 'export.inherits.parent'
+
+    value_parent = fields.Integer()
+
+class InheritsChild(models.Model):
+    _name = _description = 'export.inherits.child'
+    _inherits = {'export.inherits.parent': 'parent_id'}
+
+    parent_id = fields.Many2one('export.inherits.parent', required=True, ondelete='cascade')
+    value = fields.Integer()