Store partner_ref_unique to allow triggering the error updating res.company

Add pre_init_hook to speed up module installation

partner_ref_unique/__init__.py

@@ -1,3 +1,4 @@
 # License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl.html).
 
 from . import models
+from .hooks import pre_init_hook

partner_ref_unique/__manifest__.py

@@ -13,6 +13,7 @@
     "license": "AGPL-3",
     "application": False,
     "installable": True,
+    "pre_init_hook": "pre_init_hook",
     "depends": [
         "base",
     ],

partner_ref_unique/hooks.py

@@ -0,0 +1,27 @@
+# Copyright 2019 Camptocamp SA
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl)
+import logging
+
+_logger = logging.getLogger(__name__)
+
+
+def pre_init_hook(cr):
+    """Create column using SQL to avoid auto-init updating the table row by row
+    :param odoo.sql_db.Cursor cr:
+        Database cursor.
+    """
+    _logger.info(
+        "Creating res.partner.partner_ref_unique column with value from "
+        "res.company"
+    )
+    cr.execute("ALTER TABLE res_partner ADD partner_ref_unique varchar NULL;")
+    cr.execute(
+        "COMMENT ON COLUMN res_partner.partner_ref_unique "
+        "IS 'Unique partner reference for';"
+    )
+    cr.execute(
+        "UPDATE res_partner rp "
+        "SET partner_ref_unique = rc.partner_ref_unique "
+        "FROM res_company rc "
+        "WHERE rc.id = rp.company_id;"
+    )

partner_ref_unique/models/res_partner.py

@@ -11,7 +11,7 @@ class ResPartner(models.Model):
     # This related is needed in order to trigger the check when changing the
     # value on res.company
     partner_ref_unique = fields.Selection(
-        related='company_id.partner_ref_unique',
+        related='company_id.partner_ref_unique', store=True,
     )
 
     @api.multi