[ADD] Module to add a constraint on the internal reference of the pro…

…duct to make it unique across the database.

product_code_unique/README.rst

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+.. image:: https://img.shields.io/badge/licence-AGPL--3-blue.svg
+   :target: http://www.gnu.org/licenses/agpl-3.0-standalone.html
+   :alt: License: AGPL-3
+
+=================================
+Unique Product Internal Reference
+=================================
+
+This module adds a constraint on the internal reference of the product 
+to make it unique across the database.
+
+Usage
+=====
+* Unable to save a product when a new internal reference or default_code value is
+  the same with an existing record.
+* A pre_init_hook process is initiated when there exist records without an internal reference(default_code).
+  A default value is generated to populate empty field as a temporary value.
+
+Bug Tracker
+===========
+
+Bugs are tracked on `GitHub Issues
+<https://github.com/OCA/product-attribute/issues>`_. In case of trouble, please
+check there if your issue has already been reported. If you spotted it first,
+help us smash it by providing detailed and welcomed feedback.
+
+Credits
+=======
+
+Images
+------
+
+* Odoo Community Association: `Icon <https://github.com/OCA/maintainer-tools/blob/master/template/module/static/description/icon.svg>`_.
+
+Contributors
+------------
+
+* Antonio Yamuta <ayamuta@opensourceintegrators.com>
+
+Funders
+-------
+
+The development of this module has been financially supported by:
+
+* Open Source Integrators <http://www.opensourceintegrators.com>
+
+Maintainer
+----------
+
+.. image:: https://odoo-community.org/logo.png
+   :alt: Odoo Community Association
+   :target: https://odoo-community.org
+
+This module is maintained by the OCA.
+
+OCA, or the Odoo Community Association, is a nonprofit organization whose
+mission is to support the collaborative development of Odoo features and
+promote its widespread use.
+
+To contribute to this module, please visit https://odoo-community.org.

product_code_unique/__init__.py

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+# Copyright (C) 2018 - TODAY, Open Source Integrators
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from . import models
+
+
+def pre_init_product_code(cr):
+    cr.execute("""UPDATE product_product
+        SET default_code = 'DEFAULT' || nextval('ir_default_id_seq')
+        WHERE default_code is NULL
+        OR LENGTH(default_code) = 0""")
+    return True

product_code_unique/__manifest__.py

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+# Copyright (C) 2018 - TODAY, Open Source Integrators
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+{
+    "name": "Unique Product Internal Reference",
+    "summary": "Set Product Internal Reference as Unique",
+    "version": "11.0.1.0.0",
+    "license": "AGPL-3",
+    "author": "Open Source Integrators, Odoo Community Association (OCA)",
+    "category": "Product",
+    "website": "https://github.com/OCA/product-attribute",
+    "depends": ["product"],
+    "data": [
+    ],
+    'demo': [
+    ],
+    "pre_init_hook": 'pre_init_product_code',
+    "installable": True,
+}

product_code_unique/models/__init__.py

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+# Copyright (C) 2018 - TODAY, Open Source Integrators
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from . import product

product_code_unique/models/product.py

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+# Copyright (C) 2018 - TODAY, Open Source Integrators
+# License AGPL-3.0 or later (http://www.gnu.org/licenses/agpl).
+
+from odoo import fields, models
+
+
+class ProductProduct(models.Model):
+    _inherit = 'product.product'
+
+    _sql_constraints = [
+        ('default_code_uniq', 'unique(default_code)',
+            'Internal Reference must be unique across the database!'), ]