[FIX] account_fleet: Improve performances

Performances issues have been noticed in account_fleet when computing
the move_ids of vehicles.
This change has been made in order to fix this issue.

Task id #2700407

closes odoo/odoo#80683

Signed-off-by: William André (wan) <wan@odoo.com>

addons/account_fleet/models/account_move.py

@@ -39,7 +39,7 @@ class AccountMove(models.Model):
 class AccountMoveLine(models.Model):
     _inherit = 'account.move.line'
 
-    vehicle_id = fields.Many2one('fleet.vehicle', string='Vehicle')
+    vehicle_id = fields.Many2one('fleet.vehicle', string='Vehicle', index=True)
     need_vehicle = fields.Boolean(compute='_compute_need_vehicle',
         help="Technical field to decide whether the vehicle_id field is editable")
 

addons/account_fleet/models/fleet_vehicle.py

 # -*- coding: utf-8 -*-
 # Part of Odoo. See LICENSE file for full copyright and licensing details.
 
-from odoo import models, fields
+from odoo import Command, models, fields
 
 
 class FleetVehicle(models.Model):
@@ -16,8 +16,14 @@ class FleetVehicle(models.Model):
             self.bill_count = 0
             return
 
+        moves = self.env['account.move.line'].read_group(
+            domain=[('vehicle_id', 'in', self.ids), ('move_id.state', '!=', 'cancel')],
+            fields=['vehicle_id', 'move_id:array_agg'],
+            groupby=['vehicle_id'],
+        )
+        vehicle_move_mapping = {move['vehicle_id'][0]: set(move['move_id']) for move in moves}
         for vehicle in self:
-            vehicle.account_move_ids = self.env['account.move.line'].search([('vehicle_id', '=', vehicle.id), ('move_id.state', '!=', 'cancel')]).move_id
+            vehicle.account_move_ids = [Command.set(vehicle_move_mapping.get(vehicle.id, []))]
             vehicle.bill_count = len(vehicle.account_move_ids)
 
     def action_view_bills(self):