[IMP] mrp: unit_factor as computed field

The next commits will allow changing the initial demand of
confirmed moves as well as adding move once the production
order is confirmed. In order to not duplicate again the unit
factor computation in multiple write and create, make the
field a stored computed.

Unit_factor is stored and only depends on product_uom_qty because
updating only quantity_done (after a partial production for
instance) should leave unit_factor unchanged for the futur
partial production.

Task: 2121714

addons/mrp/models/mrp_production.py

@@ -575,7 +575,6 @@ class MrpProduction(models.Model):
             'product_uom': product_uom,
             'operation_id': operation_id,
             'byproduct_id': byproduct_id,
-            'unit_factor': product_uom_qty / self.product_qty,
             'name': self.name,
             'date': self.date_planned_start,
             'date_expected': self.date_planned_finished,
@@ -671,7 +670,6 @@ class MrpProduction(models.Model):
                 move[0].with_context(do_not_unreserve=True).write({'product_uom_qty': quantity})
                 move[0]._recompute_state()
                 move[0]._action_assign()
-                move[0].unit_factor = remaining_qty and (quantity - move[0].quantity_done) / remaining_qty or 1.0
                 return move[0], old_qty, quantity
             else:
                 if move[0].quantity_done > 0:
@@ -759,7 +757,6 @@ class MrpProduction(models.Model):
             for move_raw in production.move_raw_ids:
                 move_raw.write({
                     'group_id': production.procurement_group_id.id,
-                    'unit_factor': move_raw.product_uom_qty / production.product_qty,
                     'reference': production.name,  # set reference when MO name is different than 'New'
                 })
             production._generate_finished_moves()

addons/mrp/models/stock_move.py

@@ -87,7 +87,7 @@ class StockMove(models.Model):
     byproduct_id = fields.Many2one(
         'mrp.bom.byproduct', 'By-products', check_company=True,
         help="By-product line that generated the move in a manufacturing order")
-    unit_factor = fields.Float('Unit Factor', default=1)
+    unit_factor = fields.Float('Unit Factor', compute='_compute_unit_factor', store=True)
     is_done = fields.Boolean(
         'Done', compute='_compute_is_done',
         store=True,
@@ -135,6 +135,15 @@ class StockMove(models.Model):
         for move in self:
             move.is_done = (move.state in ('done', 'cancel'))
 
+    @api.depends('product_uom_qty')
+    def _compute_unit_factor(self):
+        for move in self:
+            mo = move.raw_material_production_id or move.production_id
+            if mo:
+                move.unit_factor = (move.product_uom_qty - move.quantity_done) / ((mo.product_qty - mo.qty_produced) or 1)
+            else:
+                move.unit_factor = 1.0
+
     @api.model
     def default_get(self, fields_list):
         defaults = super(StockMove, self).default_get(fields_list)