[FIX] point_of_sale: implement todo

The link between the pos.order.line sequence and the config was lost after
creation.
Using the default with next_by_code is incorrect as every pos.config has a
sequence with the same code.

addons/point_of_sale/models/pos_config.py

@@ -104,6 +104,9 @@ class PosConfig(models.Model):
     sequence_id = fields.Many2one('ir.sequence', string='Order IDs Sequence', readonly=True,
         help="This sequence is automatically created by Odoo but you can change it "
         "to customize the reference numbers of your orders.", copy=False)
+    sequence_line_id = fields.Many2one('ir.sequence', string='Order Line IDs Sequence', readonly=True,
+        help="This sequence is automatically created by Odoo but you can change it "
+        "to customize the reference numbers of your orders lines.", copy=False)
     session_ids = fields.One2many('pos.session', 'config_id', string='Sessions')
     current_session_id = fields.Many2one('pos.session', compute='_compute_current_session', string="Current Session")
     current_session_state = fields.Char(compute='_compute_current_session')
@@ -218,16 +221,15 @@ class PosConfig(models.Model):
         # force sequence_id field to new pos.order sequence
         values['sequence_id'] = IrSequence.create(val).id
 
-        # TODO master: add field sequence_line_id on model
-        # this make sure we always have one available per company
         val.update(name=_('POS order line %s') % values['name'], code='pos.order.line')
-        IrSequence.create(val)
+        values['sequence_line_id'] = IrSequence.create(val).id
         return super(PosConfig, self).create(values)
 
     @api.multi
     def unlink(self):
-        for pos_config in self.filtered(lambda pos_config: pos_config.sequence_id):
+        for pos_config in self.filtered(lambda pos_config: pos_config.sequence_id or pos_config.sequence_line_id):
             pos_config.sequence_id.unlink()
+            pos_config.sequence_line_id.unlink()
         return super(PosConfig, self).unlink()
 
     # Methods to open the POS

addons/point_of_sale/models/pos_order.py

@@ -31,7 +31,7 @@ class PosOrder(models.Model):
 
     @api.model
     def _order_fields(self, ui_order):
-        process_line = partial(self.env['pos.order.line']._order_line_fields)
+        process_line = partial(self.env['pos.order.line']._order_line_fields, session_id=ui_order['pos_session_id'])
         return {
             'name':         ui_order['name'],
             'user_id':      ui_order['user_id'] or False,
@@ -749,14 +749,23 @@ class PosOrderLine(models.Model):
     _description = "Lines of Point of Sale"
     _rec_name = "product_id"
 
-    def _order_line_fields(self, line):
+    def _order_line_fields(self, line, session_id=None):
+        if line and 'name' not in line[2]:
+            if session_id:
+                # set name based on the sequence specified on the config
+                session = self.env['pos.session'].browse(session_id)
+                line[2]['name'] = session.config_id.sequence_line_id._next()
+            else:
+                # fallback on any pos.order.line sequence
+                line[2]['name'] = self.env['ir.sequence'].next_by_code('pos.order.line')
+
         if line and 'tax_ids' not in line[2]:
             product = self.env['product.product'].browse(line[2]['product_id'])
             line[2]['tax_ids'] = [(6, 0, [x.id for x in product.taxes_id])]
         return line
 
     company_id = fields.Many2one('res.company', string='Company', required=True, default=lambda self: self.env.user.company_id)
-    name = fields.Char(string='Line No', required=True, copy=False, default=lambda self: self.env['ir.sequence'].next_by_code('pos.order.line'))
+    name = fields.Char(string='Line No', required=True, copy=False)
     notice = fields.Char(string='Discount Notice')
     product_id = fields.Many2one('product.product', string='Product', domain=[('sale_ok', '=', True)], required=True, change_default=True)
     price_unit = fields.Float(string='Unit Price', digits=0)