[FIX] sale_stock: do not count discount twice

When a product is a kit and a discount is applied thanks to a pricelist,
the discount is counted twice if the invoice is created from the stock
picking.

This is because the pricelist will modify the price unit, but moreover
the discount will be applied a second time by the method
`_compute_price` of the account move line.

opw-676838

addons/sale_stock/sale_stock.py

@@ -20,7 +20,7 @@
 #
 ##############################################################################
 from datetime import datetime, timedelta
-from openerp.tools import DEFAULT_SERVER_DATE_FORMAT, DEFAULT_SERVER_DATETIME_FORMAT, DATETIME_FORMATS_MAP, float_compare
+from openerp.tools import DEFAULT_SERVER_DATE_FORMAT, DEFAULT_SERVER_DATETIME_FORMAT, DATETIME_FORMATS_MAP, float_compare, float_is_zero
 from openerp.osv import fields, osv
 from openerp.tools.safe_eval import safe_eval as eval
 from openerp.tools.translate import _
@@ -410,10 +410,14 @@ class stock_move(osv.osv):
             res['account_analytic_id'] = sale_line.order_id.project_id and sale_line.order_id.project_id.id or False
             res['discount'] = sale_line.discount
             if move.product_id.id != sale_line.product_id.id:
-                res['price_unit'] = self.pool['product.pricelist'].price_get(
-                    cr, uid, [sale_line.order_id.pricelist_id.id],
-                    move.product_id.id, move.product_uom_qty or 1.0,
-                    sale_line.order_id.partner_id, context=context)[sale_line.order_id.pricelist_id.id]
+                precision = self.pool.get('decimal.precision').precision_get(cr, uid, 'Discount')
+                if float_is_zero(sale_line.discount, precision_digits=precision):
+                    res['price_unit'] = self.pool['product.pricelist'].price_get(
+                        cr, uid, [sale_line.order_id.pricelist_id.id],
+                        move.product_id.id, move.product_uom_qty or 1.0,
+                        sale_line.order_id.partner_id, context=context)[sale_line.order_id.pricelist_id.id]
+                else:
+                    res['price_unit'] = move.product_id.lst_price
             else:
                 res['price_unit'] = sale_line.price_unit
             uos_coeff = move.product_uom_qty and move.product_uos_qty / move.product_uom_qty or 1.0