[FIX] stock: PO line with unit_price = 0 and cost_method = 'real' or 'average'

Let's consider the stockable product P with an internal category set
with cost_method = 'real' and 'average'. When creating a PO with P
and a unit_price=0, after delivering the product, the cost transfered to
the stock valuation account  was equal to the product cost multplied by
the product quantity instead of the unit_price set on the PO multiplied
by the quantity.

PS: The quant is created with the stock.move in _quant_create_from_move and the unit_price
set on the stock.move is taken with function get_price_unit.

opw:740865

addons/stock/models/stock_move.py

@@ -498,9 +498,12 @@ class StockMove(models.Model):
         self._push_apply()
         return self
 
+    def _set_default_price_moves(self):
+        return self.filtered(lambda move: not move.price_unit)
+
     def set_default_price_unit_from_product(self):
         """ Set price to move, important in inter-company moves or receipts with only one partner """
-        for move in self.filtered(lambda move: not move.price_unit):
+        for move in self._set_default_price_moves():
             move.write({'price_unit': move.product_id.standard_price})
     attribute_price = set_default_price_unit_from_product
 

addons/stock_account/models/stock.py

@@ -173,6 +173,12 @@ class StockQuant(models.Model):
 class StockMove(models.Model):
     _inherit = "stock.move"
 
+    def _set_default_price_moves(self):
+        # When the cost method is in real or average price, the price can be set to 0.0 on the PO
+        # So the price doesn't have to be updated
+        moves = super(StockMove, self)._set_default_price_moves()
+        return moves.filtered(lambda m: not m.product_id.cost_method in ('real', 'average'))
+
     @api.multi
     def action_done(self):
         self.product_price_update_before_done()