Not create a package when that already use the product without packages

#038038

locale/ca.po

@@ -18,7 +18,13 @@ msgctxt "field:sale.line,product_template:"
 msgid "Product's template"
 msgstr "Plantilla de producte"
 
-msgctxt "model:ir.message,text:package_quantity"
+msgctxt "model:ir.message,text:msg_product_package_null"
+msgid "You can not create a package because there are sale lines that already "
+"use the product without packages."
+msgstr "No pot crear paquets perque ja hi han línies de venta que ja utilitzen "
+"aquest producte sense paquets."
+
+msgctxt "model:ir.message,text:msg_package_quantity"
 msgid ""
 "The quantity \"%(qty)s\" of product \"%(product)s\" is not a multiple of "
 "it\\'s package \"%(package)s\" quantity \"%(package_qty)s\"."

locale/es.po

@@ -18,7 +18,13 @@ msgctxt "field:sale.line,product_template:"
 msgid "Product's template"
 msgstr "Plantilla de producto"
 
-msgctxt "model:ir.message,text:package_quantity"
+msgctxt "model:ir.message,text:msg_product_package_null"
+msgid "You can not create a package because there are sale lines that already "
+"use the product without packages."
+msgstr "No puede crear paquetes porque hay líneas de venta que ya usan este "
+"producto sin paquetes."
+
+msgctxt "model:ir.message,text:msg_package_quantity"
 msgid ""
 "The quantity \"%(qty)s\" of product \"%(product)s\" is not a multiple of "
 "it\\'s package \"%(package)s\" quantity \"%(package_qty)s\"."

message.xml

@@ -3,8 +3,11 @@
 this repository contains the full copyright notices and license terms. -->
 <tryton>
     <data group="1">
-      <record model="ir.message" id="package_quantity">
+      <record model="ir.message" id="msg_package_quantity">
           <field name="text">The quantity "%(qty)s" of product "%(product)s" is not a multiple of it\'s package "%(package)s" quantity "%(package_qty)s".</field>
       </record>
+      <record model="ir.message" id="msg_product_package_null">
+          <field name="text">You can not create a package because there are sale lines that already use the product without packages.</field>
+      </record>
 </data>
 </tryton>

product.py

@@ -10,6 +10,13 @@ __all__ = ['Package']
 class Package(metaclass=PoolMeta):
     __name__ = 'product.package'
 
+    @classmethod
+    def __setup__(cls):
+        super(Package, cls).__setup__()
+        cls._create_package.append(
+            ('sale.line', 'sale_product_package.msg_product_package_null'),
+            )
+
     @classmethod
     def find_packages(cls, records):
         find_packages = super(Package, cls).find_packages(records)

sale.py

@@ -47,7 +47,8 @@ class SaleLine(metaclass=PoolMeta):
                 and Transaction().context.get('validate_package', True)):
             package_quantity = self.quantity / self.product_package.quantity
             if float(int(package_quantity)) != package_quantity:
-                raise UserError(gettext('sale_product_package.package_quantity',
+                raise UserError(gettext(
+                    'sale_product_package.msg_package_quantity',
                     qty=self.quantity,
                     product=self.product.rec_name,
                     package=self.product_package.rec_name,