[FIX] contract_sale_invoicing

contract_sale_invoicing/__manifest__.py

@@ -16,5 +16,6 @@
     ],
     'data': [
         'views/contract_view.xml',
+        'views/sale_order.xml',
     ],
 }

contract_sale_invoicing/models/sale_order.py

@@ -0,0 +1,10 @@
+# Copyright (C) 2019 Open Source Integrators
+# Copyright (C) 2019 Serpent Consulting Services
+# License AGPL-3.0 or later (https://www.gnu.org/licenses/agpl).
+from odoo import fields, models
+
+
+class SaleOrder(models.Model):
+    _inherit = 'sale.order'
+
+    contract_id = fields.Many2one('contract.contract', string='Contract')

contract_sale_invoicing/views/sale_order.xml

@@ -0,0 +1,14 @@
+<odoo>
+
+    <record id="view_order_form_form_view" model="ir.ui.view">
+        <field name="name">sale.order.form.view</field>
+        <field name="model">sale.order</field>
+        <field name="inherit_id" ref="sale.view_order_form"/>
+        <field name="arch" type="xml">
+            <field name="partner_id" position="after">
+                <field name="contract_id" domain="[('partner_id', '=', partner_id)]"/>
+            </field>
+        </field>
+    </record>
+
+</odoo>