Add stock_conversion module

Closes #14806

.gitlab-ci-modules.yml

@@ -3048,6 +3048,23 @@ test-modules-stock_consignment-postgresql:
     PACKAGE: modules/stock_consignment
     TAG_PATTERN: '/^stock_consignment-.*/'
 
+check-doc-modules-stock_conversion:
+  extends: .check-doc
+  variables:
+    PACKAGE: modules/stock_conversion
+
+test-modules-stock_conversion-sqlite:
+  extends: .test-sqlite
+  variables:
+    PACKAGE: modules/stock_conversion
+    TAG_PATTERN: '/^stock_conversion-.*/'
+
+test-modules-stock_conversion-postgresql:
+  extends: .test-postgresql
+  variables:
+    PACKAGE: modules/stock_conversion
+    TAG_PATTERN: '/^stock_conversion-.*/'
+
 check-doc-modules-stock_ethanol:
   extends: .check-doc
   variables:

doc/stock.rst

@@ -14,6 +14,9 @@ Stock
 :doc:`Consignment <stock_consignment:index>`
    Manage consignment stock from supplier or at customer warehouse.
 
+:doc:`Conversion <stock_conversion:index>`
+   Transform one product into another.
+
 :doc:`Ethanol <stock_ethanol:index>`
    Track ethanol in stock.
 

modules/stock_conversion/CHANGELOG

@@ -0,0 +1 @@
+Initial release

modules/stock_conversion/COPYRIGHT

@@ -0,0 +1,17 @@
+Copyright (C) 2026 B2CK SRL
+Copyright (C) 2026 Cédric Krier <cedric.krier@b2ck.com>
+Copyright (C) 2026 Maxime Richez <maxime.richez@saluc.com>
+Copyright (C) 2026 SALUC SA
+
+This program is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+This program is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with this program.  If not, see <http://www.gnu.org/licenses/>.

modules/stock_conversion/LICENSE

@@ -0,0 +1,674 @@
+                    GNU GENERAL PUBLIC LICENSE
+                       Version 3, 29 June 2007
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+under version 3 of the GNU Affero General Public License into a single
+combined work, and to convey the resulting work.  The terms of this
+License will continue to apply to the part which is the covered work,
+but the special requirements of the GNU Affero General Public License,
+section 13, concerning interaction through a network will apply to the
+combination as such.
+
+  14. Revised Versions of this License.
+
+  The Free Software Foundation may publish revised and/or new versions of
+the GNU General Public License from time to time.  Such new versions will
+be similar in spirit to the present version, but may differ in detail to
+address new problems or concerns.
+
+  Each version is given a distinguishing version number.  If the
+Program specifies that a certain numbered version of the GNU General
+Public License "or any later version" applies to it, you have the
+option of following the terms and conditions either of that numbered
+version or of any later version published by the Free Software
+Foundation.  If the Program does not specify a version number of the
+GNU General Public License, you may choose any version ever published
+by the Free Software Foundation.
+
+  If the Program specifies that a proxy can decide which future
+versions of the GNU General Public License can be used, that proxy's
+public statement of acceptance of a version permanently authorizes you
+to choose that version for the Program.
+
+  Later license versions may give you additional or different
+permissions.  However, no additional obligations are imposed on any
+author or copyright holder as a result of your choosing to follow a
+later version.
+
+  15. Disclaimer of Warranty.
+
+  THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
+APPLICABLE LAW.  EXCEPT WHEN OTHERWISE STATED IN WRITING THE COPYRIGHT
+HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS" WITHOUT WARRANTY
+OF ANY KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING, BUT NOT LIMITED TO,
+THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
+PURPOSE.  THE ENTIRE RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM
+IS WITH YOU.  SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF
+ALL NECESSARY SERVICING, REPAIR OR CORRECTION.
+
+  16. Limitation of Liability.
+
+  IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING
+WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS
+THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY
+GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE
+USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF
+DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
+PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS),
+EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF
+SUCH DAMAGES.
+
+  17. Interpretation of Sections 15 and 16.
+
+  If the disclaimer of warranty and limitation of liability provided
+above cannot be given local legal effect according to their terms,
+reviewing courts shall apply local law that most closely approximates
+an absolute waiver of all civil liability in connection with the
+Program, unless a warranty or assumption of liability accompanies a
+copy of the Program in return for a fee.
+
+                     END OF TERMS AND CONDITIONS
+
+            How to Apply These Terms to Your New Programs
+
+  If you develop a new program, and you want it to be of the greatest
+possible use to the public, the best way to achieve this is to make it
+free software which everyone can redistribute and change under these terms.
+
+  To do so, attach the following notices to the program.  It is safest
+to attach them to the start of each source file to most effectively
+state the exclusion of warranty; and each file should have at least
+the "copyright" line and a pointer to where the full notice is found.
+
+    <one line to give the program's name and a brief idea of what it does.>
+    Copyright (C) <year>  <name of author>
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>.
+
+Also add information on how to contact you by electronic and paper mail.
+
+  If the program does terminal interaction, make it output a short
+notice like this when it starts in an interactive mode:
+
+    <program>  Copyright (C) <year>  <name of author>
+    This program comes with ABSOLUTELY NO WARRANTY; for details type `show w'.
+    This is free software, and you are welcome to redistribute it
+    under certain conditions; type `show c' for details.
+
+The hypothetical commands `show w' and `show c' should show the appropriate
+parts of the General Public License.  Of course, your program's commands
+might be different; for a GUI interface, you would use an "about box".
+
+  You should also get your employer (if you work as a programmer) or school,
+if any, to sign a "copyright disclaimer" for the program, if necessary.
+For more information on this, and how to apply and follow the GNU GPL, see
+<http://www.gnu.org/licenses/>.
+
+  The GNU General Public License does not permit incorporating your program
+into proprietary programs.  If your program is a subroutine library, you
+may consider it more useful to permit linking proprietary applications with
+the library.  If this is what you want to do, use the GNU Lesser General
+Public License instead of this License.  But first, please read
+<http://www.gnu.org/philosophy/why-not-lgpl.html>.

modules/stock_conversion/README.rst

@@ -0,0 +1 @@
+doc/index.rst

modules/stock_conversion/__init__.py

@@ -0,0 +1,2 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.

modules/stock_conversion/doc/conf.py

@@ -0,0 +1,111 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+
+import os
+
+base_url = os.environ.get('DOC_BASE_URL')
+if base_url:
+    modules_url = base_url + '/modules-{module}/'
+    trytond_url = base_url + '/server/'
+else:
+    modules_url = (
+        'https://docs.tryton.org/{series}/modules-{module}/')
+    trytond_url = 'https://docs.tryton.org/{series}/server/'
+
+
+def get_info():
+    import configparser
+    import json
+    import subprocess
+
+    module_dir = os.path.dirname(os.path.dirname(__file__))
+
+    config = configparser.ConfigParser()
+    config.read_file(open(os.path.join(module_dir, 'tryton.cfg')))
+    info = dict(config.items('tryton'))
+
+    metadata_cmd = 'python3 -m build -qq --metadata'
+    if os.environ.get('DOC_NO_ISOLATION'):
+        metadata_cmd += ' --no-isolation'
+    metadata = subprocess.check_output(
+        metadata_cmd, shell=True, encoding='utf-8', cwd=module_dir).strip()
+    metadata = json.loads(metadata)
+    info['name'] = metadata['name']
+    info['description'] = metadata['summary']
+    major_version, minor_version, _ = metadata['version'].split('.', 2)
+    major_version = int(major_version)
+    minor_version = int(minor_version)
+    if minor_version % 2:
+        info['series'] = 'latest'
+        info['branch'] = 'branch/default'
+    else:
+        info['series'] = '.'.join(metadata['version'].split('.', 2)[:2])
+        info['branch'] = 'branch/' + info['series']
+
+    for key in {'depends', 'extras_depend'}:
+        info[key] = info.get(key, '').strip().splitlines()
+    info['modules'] = set(info['depends'] + info['extras_depend'])
+    info['modules'] -= {'ir', 'res'}
+
+    return info
+
+
+info = get_info()
+
+html_theme = 'sphinx_book_theme'
+html_theme_options = {
+    'logo': {
+        'alt_text': "Tryton Documentation",
+        'image_light': 'https://docs.tryton.org/logo-light.svg',
+        'image_dark': 'https://docs.tryton.org/logo-dark.svg',
+        'link': base_url,
+        },
+    'home_page_in_toc': True,
+    'repository_provider': 'gitlab',
+    'repository_url': 'https://code.tryton.org/tryton',
+    'repository_branch': info['branch'],
+    'use_source_button': True,
+    'use_edit_page_button': True,
+    'use_repository_button': True,
+    'use_download_button': False,
+    'path_to_docs': 'modules/stock_conversion/doc',
+    }
+html_title = info['description']
+master_doc = 'index'
+project = info['name']
+release = version = info['series']
+default_role = 'ref'
+highlight_language = 'none'
+exclude_patterns = ['**/*.inc.rst']
+extensions = [
+    'sphinx_copybutton',
+    'sphinx.ext.intersphinx',
+    ]
+intersphinx_mapping = {
+    'trytond': (trytond_url.format(series=version), None),
+    }
+intersphinx_mapping.update({
+        m: (modules_url.format(
+                module=m.replace('_', '-'), series=version), None)
+        for m in info['modules']
+        })
+linkcheck_ignore = [r'/.*', r'https://demo.tryton.org/*']
+linkcheck_request_headers = {
+    'User-Agent': (
+        'TrytonBot/0.0 (https://www.tryton.org/foundation) '
+        'sphinx-linkcheck/0.0'),
+    'Accept-Encoding': 'gzip',
+    }
+linkcheck_workers = 1
+
+try:
+    with open(os.path.join(
+                os.path.dirname(__file__),
+                'linkcheck_ignore.json'), 'r') as f:
+        import json
+        linkcheck_ignore.extend(json.load(f))
+        del json
+except FileNotFoundError:
+    pass
+
+del get_info, info, base_url, modules_url, trytond_url

modules/stock_conversion/doc/design.rst

@@ -0,0 +1,76 @@
+******
+Design
+******
+
+The *Stock Conversion Module* introduces or extends the following concepts.
+
+.. _model-stock.conversion.rule:
+
+Conversion Rule
+===============
+
+A conversion rule specifies the process by which one `Product
+<product:concept-product>` can be converted into another.
+
+
+.. _model-stock.conversion:
+
+Conversion
+==========
+
+A *Conversion* is an order to instantly transform a specific quantity of a
+`Product <product:concept-product>` in place into another product.
+The resulting quantity is calculated using the corresponding `Rule
+<model-stock.conversion.rule>`.
+
+.. seealso::
+
+   The conversions can be found using the main menu item:
+
+      |Inventory & Stock --> Conversions|__
+
+      .. |Inventory & Stock --> Conversions| replace:: :menuselection:`Inventory & Stock --> Conversions`
+      __ https://demo.tryton.org/model/stock.conversion
+
+.. _model-stock.configuration:
+
+Configuration
+=============
+
+When the *Stock Conversion Module* is activated, the configuration gains a
+property to store the sequence used to number the `Conversions
+<model-stock.conversion>`.
+
+.. seealso::
+
+   The `Configuration <stock:model-stock.configuration>` concept is
+   introduced by the :doc:`Stock Module <stock:index>`.
+
+.. _model-stock.location:
+
+Location
+========
+
+When the *Stock Conversion Module* is activated, warehouses gain an extra
+location property for :guilabel:`Conversion` which is used as the default value
+when converting products.
+
+.. seealso::
+
+   The `Location <stock:model-stock.location>` concept is introduced by the
+   :doc:`Stock Module <stock:index>`.
+
+.. _model-product.product:
+
+Product
+=======
+
+When the *Stock Conversion Module* is activated, products gain an additional
+property in the form of a list of `Conversion Rules
+<model-stock.conversion.rule>` which defines the products to which they can be
+converted.
+
+.. seealso::
+
+   The `Product <product:model-product.product>` concept is introduced by the
+   :doc:`Product Module <product:index>`.

modules/stock_conversion/doc/index.rst

@@ -0,0 +1,11 @@
+#######################
+Stock Conversion Module
+#######################
+
+The *Stock Conversion Module* transforms one product into another with ease.
+
+.. toctree::
+   :maxdepth: 2
+
+   design
+   releases

modules/stock_conversion/doc/releases.rst

@@ -0,0 +1,7 @@
+.. _releases-index:
+
+=============
+Release notes
+=============
+
+.. include:: ../CHANGELOG

modules/stock_conversion/doc/requirements-doc.txt

@@ -0,0 +1,3 @@
+build
+sphinx_book_theme
+sphinx_copybutton

modules/stock_conversion/exceptions.py

@@ -0,0 +1,8 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+
+from trytond.exceptions import UserError
+
+
+class ConversionError(UserError):
+    pass

modules/stock_conversion/ir.py

@@ -0,0 +1,16 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+
+from trytond.pool import PoolMeta
+
+
+class Cron(metaclass=PoolMeta):
+    __name__ = 'ir.cron'
+
+    @classmethod
+    def __setup__(cls):
+        super().__setup__()
+        cls.method.selection.extend([
+                ('stock.conversion|set_cost_from_moves',
+                    "Set Cost from Conversion Moves"),
+                ])

modules/stock_conversion/message.xml

@@ -0,0 +1,16 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<tryton>
+    <data grouped="1">
+        <record model="ir.message" id="msg_conversion_rule_input_output_unique">
+            <field name="text">The output of each conversion must be unique for each input.</field>
+        </record>
+        <record model="ir.message" id="msg_stock_conversion_missing_qty">
+            <field name="text">You cannot process conversion "%(conversion)s" because location "%(location)s" is missing %(quantity)s of product "%(product)s"</field>
+        </record>
+        <record model="ir.message" id="msg_conversion_rule_change_product_quantity">
+            <field name="text">You cannot change the products nor the quantities of a conversion rule which is already used in a conversion.</field>
+        </record>
+    </data>
+</tryton>

modules/stock_conversion/product.py

@@ -0,0 +1,19 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+
+from trytond.model import fields
+from trytond.pool import PoolMeta
+from trytond.pyson import Eval
+
+
+class Product(metaclass=PoolMeta):
+    __name__ = 'product.product'
+
+    conversion_rules = fields.One2Many(
+        'stock.conversion.rule', 'input_product', "Conversion Rules",
+        states={
+            'invisible': Eval('type') != 'goods',
+            })
+    reverse_conversion_rules = fields.One2Many(
+        'stock.conversion.rule', 'output_product', "Reverse Conversion Rules",
+        readonly=True)

modules/stock_conversion/product.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<tryton>
+    <data>
+        <record model="ir.ui.view" id="product_view_form">
+            <field name="model">product.product</field>
+            <field name="inherit" ref="product.product_view_form"/>
+            <field name="name">product_form</field>
+        </record>
+    </data>
+</tryton>

modules/stock_conversion/pyproject.toml

@@ -0,0 +1,59 @@
+[build-system]
+requires = ['hatchling >= 1', 'hatch-tryton']
+build-backend = 'hatchling.build'
+
+[project]
+name = 'trytond_stock_conversion'
+dynamic = ['version', 'dependencies', 'optional-dependencies', 'authors', 'readme']
+requires-python = '>=3.10'
+maintainers = [
+    {name = "Tryton", email = "foundation@tryton.org"},
+    ]
+description = "Goods conversion for Tryton"
+license = 'GPL-3.0-or-later'
+license-files = ['LICENSE', 'icons/LICENSE', 'COPYRIGHT']
+keywords = ["tryton", "stock"]
+classifiers = [
+    "Development Status :: 5 - Production/Stable",
+    "Environment :: Plugins",
+    "Framework :: Tryton",
+    "Topic :: Office/Business",
+    "Topic :: Software Development :: Libraries :: Python Modules",
+    ]
+
+[project.entry-points.'trytond.modules']
+stock_conversion = 'trytond.modules.stock_conversion'
+
+[project.urls]
+homepage = "https://www.tryton.org/"
+documentation = "https://docs.tryton.org/modules-stock-conversion/"
+changelog = "https://docs.tryton.org/modules-stock-conversion/releases.html"
+forum = "https://www.tryton.org/forum"
+issues = "https://bugs.tryton.org/tryton"
+repository = "https://code.tryton.org/tryton"
+funding = "https://www.tryton.org/donate"
+
+[tool.hatch.build]
+include = [
+    '**/tryton.cfg',
+    '**/*.py',
+    '**/*.xml',
+    'view/**/*.xml',
+    'locale/**/*.po',
+    '**/*.fodt',
+    'icons/**/*.svg',
+    'tests/**/*.rst',
+    'tests/**/*.json',
+    ]
+exclude = ['doc']
+
+[tool.hatch.build.targets.wheel.sources]
+"" = "trytond/modules/stock_conversion"
+
+[tool.hatch.metadata.hooks.tryton]
+dependencies = []
+copyright = 'COPYRIGHT'
+readme = 'README.rst'
+
+[tool.hatch.metadata.hooks.tryton.tryton-optional-dependencies]
+test = ['proteus']

modules/stock_conversion/stock.py

@@ -0,0 +1,618 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+
+from decimal import Decimal
+from itertools import groupby
+
+from sql import Literal, Null
+from sql.functions import CharLength
+from sql.operators import Equal
+
+from trytond.i18n import gettext
+from trytond.model import (
+    DeactivableMixin, Exclude, ModelSQL, ModelView, Workflow, fields)
+from trytond.model.exceptions import AccessError
+from trytond.modules.company.model import employee_field, set_employee
+from trytond.modules.product import round_price
+from trytond.pool import Pool, PoolMeta
+from trytond.pyson import Eval, Id, If
+from trytond.transaction import Transaction
+
+from .exceptions import ConversionError
+
+
+class Configuration(metaclass=PoolMeta):
+    __name__ = 'stock.configuration'
+
+    conversion_sequence = fields.MultiValue(fields.Many2One(
+            'ir.sequence', "Conversion Sequence", required=True,
+            domain=[
+                ('company', 'in',
+                    [Eval('context', {}).get('company', -1), None]),
+                ('sequence_type', '=',
+                    Id('stock_conversion', 'sequence_type_conversion')),
+                ],
+            help="Used to generate the number given to conversion."))
+
+    @classmethod
+    def multivalue_model(cls, field):
+        pool = Pool()
+        if field == 'conversion_sequence':
+            return pool.get('stock.configuration.sequence')
+        return super().multivalue_model(field)
+
+    @classmethod
+    def default_conversion_sequence(cls, **pattern):
+        return cls.multivalue_model(
+            'conversion_sequence').default_conversion_sequence()
+
+
+class ConfigurationSequence(metaclass=PoolMeta):
+    __name__ = 'stock.configuration.sequence'
+
+    conversion_sequence = fields.Many2One(
+        'ir.sequence', "Conversion Sequence", required=True,
+        domain=[
+            ('company', 'in', [Eval('company', -1), None]),
+            ('sequence_type', '=',
+                Id('stock_conversion', 'sequence_type_conversion')),
+            ])
+
+    @classmethod
+    def default_conversion_sequence(cls):
+        pool = Pool()
+        ModelData = pool.get('ir.model.data')
+        try:
+            return ModelData.get_id('stock_conversion', 'sequence_conversion')
+        except KeyError:
+            return None
+
+
+class Location(metaclass=PoolMeta):
+    __name__ = 'stock.location'
+
+    conversion_location = fields.Many2One(
+        'stock.location', "Conversion",
+        states={
+            'invisible': Eval('type') != 'warehouse',
+            'required': Eval('type') == 'warehouse',
+            },
+        domain=[
+            ('type', '=', 'production'),
+            ],
+        help="Used to convert goods.")
+
+
+class StockConversionRule(DeactivableMixin, ModelSQL, ModelView):
+    __name__ = 'stock.conversion.rule'
+
+    input_product = fields.Many2One(
+        'product.product', "Input Product",
+        required=True, ondelete='CASCADE',
+        domain=[
+            ('type', '=', 'goods'),
+            ('id', '!=', Eval('output_product', -1)),
+            ])
+    input_quantity = fields.Float(
+        "Input Quantity", digits='input_unit', required=True,
+        domain=[
+            ('input_quantity', '>', 0),
+            ])
+    input_unit = fields.Function(
+        fields.Many2One('product.uom', "Input Unit"),
+        'on_change_with_input_unit')
+    output_product = fields.Many2One(
+        'product.product', "Output Product",
+        required=True, ondelete='RESTRICT',
+        domain=[
+            ('type', 'in', ['goods', 'assets']),
+            ('id', '!=', Eval('input_product', -1)),
+            ])
+    output_quantity = fields.Float(
+        "Output Quantity", digits='output_unit', required=True,
+        domain=[
+            ('output_quantity', '>', 0),
+            ])
+    output_unit = fields.Function(
+        fields.Many2One('product.uom', "Output Unit"),
+        'on_change_with_output_unit')
+
+    @classmethod
+    def __setup__(cls):
+        super().__setup__()
+        t = cls.__table__()
+        cls._sql_constraints = [
+            ('input_output_unique',
+                Exclude(t,
+                    (t.input_product, Equal),
+                    (t.output_product, Equal),
+                    where=(t.active == Literal(True))),
+                'stock_conversion.msg_conversion_rule_input_output_unique'),
+            ]
+
+    @classmethod
+    def default_input_quantity(cls):
+        return 1
+
+    @classmethod
+    def default_output_quantity(cls):
+        return 1
+
+    @fields.depends('input_product', '_parent_input_product.default_uom')
+    def on_change_with_input_unit(self, name=None):
+        return self.input_product.default_uom if self.input_product else None
+
+    @fields.depends('output_product', '_parent_output_product.default_uom')
+    def on_change_with_output_unit(self, name=None):
+        return self.output_product.default_uom if self.output_product else None
+
+    def get_rec_name(self, name):
+        return (
+            f"{self.input_product.rec_name} "
+            "\N{black rightwards arrow} "
+            f"{self.output_product.rec_name}")
+
+    @classmethod
+    def search_rec_name(cls, name, clause):
+        _, operator, operand, *extra = clause
+        if operator.startswith('!') or operator.startswith('not '):
+            bool_op = 'AND'
+        else:
+            bool_op = 'OR'
+        return [bool_op,
+            ('input_product', operator, operand, *extra),
+            ('output_product', operator, operand, *extra),
+            ]
+
+    @classmethod
+    def check_modification(cls, mode, rules, values=None, external=False):
+        pool = Pool()
+        StockConversion = pool.get('stock.conversion')
+        super().check_modification(
+            mode, rules, values=values, external=external)
+        if mode == 'write':
+            if values.keys() & {
+                    'input_product', 'input_quantity',
+                    'output_product', 'output_quantity'}:
+                conversions = StockConversion.search([
+                        ('conversion_rule', 'in', [r.id for r in rules]),
+                        ],
+                    limit=1, order=[])
+                if conversions:
+                    raise AccessError(gettext(
+                            'stock_conversion.'
+                            'msg_conversion_rule_change_product_quantity'))
+
+    def convert(self, quantity):
+        return self.output_unit.floor(
+            quantity * self.output_quantity / self.input_quantity)
+
+
+class StockConversion(Workflow, ModelSQL, ModelView):
+    __name__ = 'stock.conversion'
+    _rec_name = 'number'
+
+    number = fields.Char("Number", required=True, readonly=True)
+    date = fields.Date("Date",
+        states={
+            'readonly': Eval('state') != 'draft',
+            'required': Eval('state') == 'done',
+            })
+    company = fields.Many2One('company.company', "Company", required=True,
+        states={
+            'readonly': Eval('state') != 'draft',
+            })
+    warehouse = fields.Many2One(
+        'stock.location', "Warehouse", required=True,
+        domain=[
+            ('type', '=', 'warehouse'),
+            ],
+        states={
+            'readonly': Eval('state') != 'draft',
+            })
+    location = fields.Many2One(
+        'stock.location', "Location", required=True,
+        domain=[
+            ('type', '=', 'storage'),
+            ('parent', 'child_of', [Eval('warehouse', -1)]),
+            ],
+        states={
+            'readonly': Eval('state') != 'draft',
+            })
+
+    input_product = fields.Many2One(
+        'product.product', "Input Product", required=True,
+        ondelete='CASCADE',
+        domain=[
+            If((Eval('state') == 'draft') & Eval('output_product', None),
+                ('conversion_rules.output_product',
+                    '=', Eval('output_product', -1)),
+                ()),
+            ('type', '=', 'goods'),
+            ('id', '!=', Eval('output_product', -1)),
+            ],
+        states={
+            'readonly': Eval('state') != 'draft',
+            },
+        context={
+            'company': Eval('company', -1),
+            },
+        depends={'company'})
+    input_unit = fields.Function(
+        fields.Many2One('product.uom', "Input Unit"),
+        'on_change_with_input_unit')
+    input_quantity = fields.Float(
+        "Input Quantity", digits='input_unit', required=True,
+        domain=[
+            ('input_quantity', '>', 0),
+            ],
+        states={
+            'readonly': Eval('state') != 'draft',
+            })
+    conversion_rule = fields.Many2One(
+        'stock.conversion.rule', "Conversion Rule",
+        required=True, ondelete='RESTRICT',
+        domain=[
+            If(Eval('input_product', None),
+                ('input_product', '=', Eval('input_product', -1)),
+                ()),
+            If(Eval('output_product', None),
+                ('output_product', '=', Eval('output_product', -1)),
+                ()),
+            ],
+        states={
+            'readonly': Eval('state') != 'draft',
+            })
+    output_product = fields.Many2One(
+        'product.product', "Output Product", required=True,
+        domain=[
+            If((Eval('state') == 'draft') & Eval('input_product', None),
+                ('reverse_conversion_rules.input_product',
+                    '=', Eval('input_product', -1)),
+                ()),
+            ('type', 'in', ['goods', 'assets']),
+            ('id', '!=', Eval('input_product', -1)),
+            ],
+        context={
+            'company': Eval('company', -1),
+            },
+        depends={'company'})
+    output_quantity = fields.Function(
+        fields.Float("Output Quantity", digits='output_unit'),
+        'on_change_with_output_quantity')
+    output_unit = fields.Function(
+        fields.Many2One('product.uom', "Output Unit"),
+        'on_change_with_output_unit')
+
+    moves = fields.One2Many(
+        'stock.move', 'origin', "Moves", readonly=True,
+        domain=['OR',
+            [
+                ('product', '=', Eval('input_product', -1)),
+                ('from_location', '=', Eval('location', -1)),
+                ('to_location.type', '=', 'production'),
+                ],
+            [
+                ('product', '=', Eval('output_product', -1)),
+                ('from_location.type', '=', 'production'),
+                ('to_location', '=', Eval('location', -1)),
+                ]
+            ],
+        states={
+            'invisible': ~Eval('moves', None),
+            })
+
+    done_by = employee_field("Done By")
+    state = fields.Selection([
+            ('draft', 'Draft'),
+            ('done', 'Done'),
+            ('cancelled', 'Cancelled'),
+            ], "State", readonly=True, sort=False)
+
+    @classmethod
+    def __setup__(cls):
+        cls.number.search_unaccented = False
+        super().__setup__()
+        cls._order = [
+            ('date', 'DESC NULLS FIRST'),
+            ('id', 'DESC'),
+            ]
+        cls._transitions |= set((
+                ('draft', 'cancelled'),
+                ('draft', 'done'),
+                ('done', 'cancelled'),
+                ))
+        cls._buttons.update({
+                'cancel': {
+                    'invisible': (
+                        (Eval('state') == 'cancelled')
+                        | ((Eval('state') == 'done')
+                            & ~Id('stock',
+                                'group_stock_cancellation').in_(
+                                Eval('context', {}).get('groups', []))
+                            & ~Eval('context', {}).get(
+                                'administrator', False))),
+                    'depends': ['state'],
+                    },
+                'do': {
+                    'invisible': Eval('state') != 'draft',
+                    'depends': ['state'],
+                    },
+                })
+
+    @classmethod
+    def order_number(cls, tables):
+        table, _ = tables[None]
+        return [
+            ~((table.state == 'cancelled') & (table.number == Null)),
+            CharLength(table.number), table.number]
+
+    @classmethod
+    def default_date(cls):
+        return Pool().get('ir.date').today()
+
+    @classmethod
+    def default_company(cls):
+        return Transaction().context.get('company')
+
+    @classmethod
+    def default_warehouse(cls):
+        Location = Pool().get('stock.location')
+        return Location.get_default_warehouse()
+
+    @fields.depends('input_product')
+    def on_change_with_input_unit(self, name=None):
+        if self.input_product:
+            return self.input_product.default_uom
+
+    @fields.depends('conversion_rule', 'input_quantity')
+    def on_change_with_output_quantity(self, name=None):
+        if self.input_quantity is not None and self.conversion_rule:
+            return self.conversion_rule.convert(self.input_quantity)
+
+    @fields.depends('output_product')
+    def on_change_with_output_unit(self, name=None):
+        if self.output_product:
+            return self.output_product.default_uom
+
+    @fields.depends(
+        'input_product', 'output_product', 'conversion_rule',
+        methods=['on_change_with_output_quantity'])
+    def set_conversion_rule(self):
+        pool = Pool()
+        Rule = pool.get('stock.conversion.rule')
+        if self.input_product and self.output_product:
+            rule = self.conversion_rule
+            if (not rule
+                    or rule.input_product != self.input_product
+                    or rule.output_product != self.output_product):
+                try:
+                    self.conversion_rule, = Rule.search([
+                            ('input_product', '=', self.input_product),
+                            ('output_product', '=', self.output_product),
+                            ], limit=1)
+                except ValueError:
+                    pass
+                self.output_quantity = self.on_change_with_output_quantity()
+
+    @fields.depends(methods=['set_conversion_rule'])
+    def on_change_input_product(self):
+        self.set_conversion_rule()
+
+    @fields.depends(methods=['set_conversion_rule'])
+    def on_change_output_product(self):
+        self.set_conversion_rule()
+
+    @fields.depends('conversion_rule')
+    def on_change_conversion_rule(self):
+        if self.conversion_rule:
+            self.input_product = self.conversion_rule.input_product
+            self.output_product = self.conversion_rule.output_product
+
+    @classmethod
+    def default_state(cls):
+        return 'draft'
+
+    @property
+    def input_moves(self):
+        moves = []
+        for move in self.moves:
+            if move.from_location == self.location:
+                moves.append(move)
+        return moves
+
+    @property
+    def output_moves(self):
+        moves = []
+        for move in self.moves:
+            if move.to_location == self.location:
+                moves.append(move)
+        return moves
+
+    def _move(self, type):
+        pool = Pool()
+        Move = pool.get('stock.move')
+        move = Move(**Move.default_get(with_rec_name=False))
+        move.origin = self
+        move.company = self.company
+        move.effective_date = self.date
+        if type == 'input':
+            move.product = self.input_product
+            move.unit = self.input_unit
+            move.quantity = self.input_quantity
+            move.from_location = self.location
+            move.to_location = self.warehouse.conversion_location
+        elif type == 'output':
+            move.product = self.output_product
+            move.unit = self.output_unit
+            move.quantity = self.output_quantity
+            move.from_location = self.warehouse.conversion_location
+            move.to_location = self.location
+            move.currency = self.company.currency
+        else:
+            raise ValueError(f"unsupported type {type}")
+        move.unit_price_required = move.on_change_with_unit_price_required()
+        if move.unit_price_required:
+            if type == 'input':
+                move.unit_price = move.product.cost_price
+            elif type == 'output':
+                cost_price = (
+                    Decimal(str(self.input_quantity))
+                    * self.input_product.cost_price)
+                cost_price /= Decimal(str(self.output_quantity))
+                move.unit_price = round_price(cost_price)
+            if self.company:
+                move.currency = self.company.currency
+        else:
+            move.unit_price = None
+            move.currency = None
+        return move
+
+    @classmethod
+    def preprocess_values(cls, mode, values):
+        pool = Pool()
+        Configuration = pool.get('stock.configuration')
+        config = Configuration(1)
+        values = super().preprocess_values(mode, values)
+        if mode == 'create':
+            if not values.get('number'):
+                values['number'] = config.conversion_sequence.get()
+        return values
+
+    @classmethod
+    def copy(cls, conversions, default=None):
+        default = default.copy() if default is not None else {}
+        default.setdefault('number')
+        default.setdefault('done_by')
+        default.setdefault('moves')
+        return super().copy(conversions, default=default)
+
+    @classmethod
+    @ModelView.button
+    @Workflow.transition('done')
+    @set_employee('done_by')
+    def do(cls, conversions):
+        pool = Pool()
+        Date = pool.get('ir.date')
+        Move = pool.get('stock.move')
+        Lang = pool.get('ir.lang')
+        lang = Lang.get()
+
+        for company, c_conversions in groupby(
+                conversions, key=lambda c: c.company):
+            with Transaction().set_context(company=company.id):
+                today = Date.today()
+            cls.write([c for c in c_conversions if not c.date], {
+                    'date': today,
+                    })
+
+        moves = []
+        for conversion in conversions:
+            moves.append(conversion._move('input'))
+            moves.append(conversion._move('output'))
+        Move.save(moves)
+
+        for conversion in conversions:
+            if not Move.assign_try(conversion.input_moves, with_childs=False):
+                quantity = sum(
+                    m.quantity for m in conversion.input_moves
+                    if m.state not in ['assigned', 'done', 'cancelled'])
+                raise ConversionError(gettext(
+                        'stock_conversion.msg_stock_conversion_missing_qty',
+                        conversion=conversion.rec_name,
+                        location=conversion.location.rec_name,
+                        product=conversion.input_product.rec_name,
+                        quantity=lang.format_number_symbol(
+                            quantity, conversion.input_unit)))
+        Move.do(moves)
+        cls.set_cost(conversions)
+
+    @classmethod
+    @ModelView.button
+    @Workflow.transition('cancelled')
+    def cancel(cls, conversions):
+        pool = Pool()
+        Move = pool.get('stock.move')
+        Move.cancel([m for c in conversions for m in c.moves])
+
+    @property
+    def cost(self):
+        return round_price(sum(
+                m.cost_price * Decimal(str(m.internal_quantity))
+                for m in self.input_moves
+                if m.cost_price and m.state != 'cancelled'))
+
+    @classmethod
+    def set_cost_from_moves(cls):
+        pool = Pool()
+        Move = pool.get('stock.move')
+        conversions = set()
+        moves = Move.search([
+                ('conversion_cost_price_updated', '=', True),
+                ('origin', 'like', 'stock.conversion,%'),
+                ],
+            order=[('effective_date', 'ASC')])
+        for move in moves:
+            if move.origin not in conversions:
+                cls.__queue__.set_cost([move.origin])
+                conversions.add(move.origin)
+        Move.write(moves, {'conversion_cost_price_updated': False})
+
+    @classmethod
+    def set_cost(cls, conversions):
+        pool = Pool()
+        Move = pool.get('stock.move')
+        UoM = pool.get('product.uom')
+
+        moves = []
+        for conversion in conversions:
+            cost = conversion.cost
+            quantity = sum(
+                m.internal_quantity for m in conversion.output_moves
+                if m.state != 'cancelled'
+                and m.product == conversion.output_product)
+            if quantity:
+                unit_price = cost / Decimal(str(quantity))
+            else:
+                unit_price = Decimal(0)
+            for move in conversion.output_moves:
+                if move.product == conversion.output_product:
+                    m_unit_price = round_price(UoM.compute_price(
+                            move.product.default_uom, unit_price, move.unit))
+                else:
+                    m_unit_price = Decimal(0)
+                if (move.unit_price_required
+                        and (move.unit_price != m_unit_price
+                            or move.currency != conversion.company.currency)):
+                    move.unit_price = m_unit_price
+                    move.currency = conversion.company.currency
+                    moves.append(move)
+        Move.save(moves)
+
+
+class Move(metaclass=PoolMeta):
+    __name__ = 'stock.move'
+
+    conversion_cost_price_updated = fields.Boolean(
+        "Conversion Cost Price Updated", readonly=True)
+
+    @classmethod
+    def __setup__(cls):
+        super().__setup__()
+        cls._allow_modify_closed_period.add('conversion_cost_price_updated')
+
+    @classmethod
+    def _get_origin(cls):
+        return [*super()._get_origin(), 'stock.conversion']
+
+    @classmethod
+    def on_modification(cls, mode, moves, field_names=None):
+        pool = Pool()
+        Conversion = pool.get('stock.conversion')
+        super().on_modification(mode, moves, field_names=field_names)
+        if mode == 'write' and 'cost_price' in field_names:
+            cls.write(
+                [m for m in moves
+                    if m.state == 'done'
+                    and isinstance(m.origin, Conversion)],
+                {'conversion_cost_price_updated': True})

modules/stock_conversion/stock.xml

@@ -0,0 +1,164 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<tryton>
+    <data>
+        <record model="ir.ui.view" id="stock_configuration_view_form">
+            <field name="model">stock.configuration</field>
+            <field name="inherit" ref="stock.stock_configuration_view_form"/>
+            <field name="name">stock_configuration_form</field>
+        </record>
+
+        <record model="ir.sequence.type" id="sequence_type_conversion">
+            <field name="name">Stock Conversion</field>
+        </record>
+        <record model="ir.sequence.type-res.group" id="sequence_type_conversion_group_stock_admin">
+            <field name="sequence_type" ref="sequence_type_conversion"/>
+            <field name="group" ref="stock.group_stock_admin"/>
+        </record>
+
+        <record model="ir.ui.view" id="stock_location_view_form">
+            <field name="model">stock.location</field>
+            <field name="inherit" ref="stock.location_view_form"/>
+            <field name="name">stock_location_form</field>
+        </record>
+
+        <record model="ir.ui.view" id="stock_conversion_rule_view_form">
+            <field name="model">stock.conversion.rule</field>
+            <field name="type">form</field>
+            <field name="name">stock_conversion_rule_form</field>
+        </record>
+
+        <record model="ir.ui.view" id="stock_conversion_rule_view_list">
+            <field name="model">stock.conversion.rule</field>
+            <field name="type">tree</field>
+            <field name="name">stock_conversion_rule_list</field>
+        </record>
+
+        <record model="ir.model.access" id="access_stock_conversion_rule">
+            <field name="model">stock.conversion.rule</field>
+            <field name="perm_read" eval="True"/>
+            <field name="perm_write" eval="False"/>
+            <field name="perm_create" eval="False"/>
+            <field name="perm_delete" eval="False"/>
+        </record>
+
+        <record model="ir.model.access" id="access_stock_conversion_rule_admin">
+            <field name="model">stock.conversion.rule</field>
+            <field name="group" ref="stock.group_stock_admin"/>
+            <field name="perm_read" eval="True"/>
+            <field name="perm_write" eval="True"/>
+            <field name="perm_create" eval="True"/>
+            <field name="perm_delete" eval="True"/>
+        </record>
+
+        <record model="ir.ui.view" id="stock_conversion_view_list">
+            <field name="model">stock.conversion</field>
+            <field name="type">tree</field>
+            <field name="name">stock_conversion_list</field>
+        </record>
+
+        <record model="ir.ui.view" id="stock_conversion_view_form">
+            <field name="model">stock.conversion</field>
+            <field name="type">form</field>
+            <field name="name">stock_conversion_form</field>
+        </record>
+
+        <record model="ir.action.act_window" id="act_conversion_list">
+            <field name="name">Conversions</field>
+            <field name="res_model">stock.conversion</field>
+            <field name="search_value"></field>
+        </record>
+        <record model="ir.action.act_window.view" id="act_conversion_list_view1">
+            <field name="sequence" eval="10"/>
+            <field name="view" ref="stock_conversion_view_list"/>
+            <field name="act_window" ref="act_conversion_list"/>
+        </record>
+        <record model="ir.action.act_window.view" id="act_conversion_list_view2">
+            <field name="sequence" eval="20"/>
+            <field name="view" ref="stock_conversion_view_form"/>
+            <field name="act_window" ref="act_conversion_list"/>
+        </record>
+        <record model="ir.action.act_window.domain" id="act_conversion_list_domain_draft">
+            <field name="name">Draft</field>
+            <field name="sequence" eval="10"/>
+            <field name="domain" eval="[('state', '=', 'draft')]" pyson="1"/>
+            <field name="count" eval="True"/>
+            <field name="act_window" ref="act_conversion_list"/>
+        </record>
+        <record model="ir.action.act_window.domain" id="act_conversion_list_domain_all">
+            <field name="name">All</field>
+            <field name="sequence" eval="9999"/>
+            <field name="domain"></field>
+            <field name="act_window" ref="act_conversion_list"/>
+        </record>
+        <menuitem
+            parent="stock.menu_stock"
+            action="act_conversion_list"
+            sequence="20"
+            id="menu_conversion_list"/>
+
+        <record model="ir.rule.group" id="rule_group_stock_conversion_companies">
+            <field name="name">User in companies</field>
+            <field name="model">stock.conversion</field>
+            <field name="global_p" eval="True"/>
+        </record>
+        <record model="ir.rule" id="rule_stock_conversion_companies">
+            <field
+                name="domain"
+                eval="[('company', 'in', Eval('companies', []))]"
+                pyson="1"/>
+            <field name="rule_group" ref="rule_group_stock_conversion_companies"/>
+        </record>
+
+        <record model="ir.model.access" id="access_stock_conversion">
+            <field name="model">stock.conversion</field>
+            <field name="perm_read" eval="True"/>
+            <field name="perm_write" eval="False"/>
+            <field name="perm_create" eval="False"/>
+            <field name="perm_delete" eval="False"/>
+        </record>
+        <record model="ir.model.access" id="access_stock_conversion_group_stock_admin">
+            <field name="model">stock.conversion</field>
+            <field name="group" ref="stock.group_stock_admin"/>
+            <field name="perm_read" eval="True"/>
+            <field name="perm_write" eval="True"/>
+            <field name="perm_create" eval="True"/>
+            <field name="perm_delete" eval="True"/>
+        </record>
+
+        <record model="ir.model.button" id="stock_conversion_cancel_button">
+            <field name="model">stock.conversion</field>
+            <field name="name">cancel</field>
+            <field name="string">Cancel</field>
+            <field name="confirm">Are your sur you want to cancel the conversion?</field>
+        </record>
+
+        <record model="ir.model.button" id="stock_conversion_wait_button">
+            <field name="model">stock.conversion</field>
+            <field name="name">do</field>
+            <field name="string">Do</field>
+        </record>
+    </data>
+    <data noupdate="1">
+        <record model="ir.sequence" id="sequence_conversion">
+            <field name="name">Stock Conversion</field>
+            <field name="sequence_type" ref="sequence_type_conversion"/>
+        </record>
+
+        <record model="stock.location" id="stock_location_conversion">
+            <field name="name">Conversion</field>
+            <field name="code">CONV</field>
+            <field name="type">production</field>
+        </record>
+        <record model="stock.location" id="stock.location_warehouse">
+            <field name="conversion_location" ref="stock_location_conversion"/>
+        </record>
+
+        <record model="ir.cron" id="cron_set_cost_from_moves">
+            <field name="method">stock.conversion|set_cost_from_moves</field>
+            <field name="interval_number" eval="1"/>
+            <field name="interval_type">days</field>
+        </record>
+    </data>
+</tryton>

modules/stock_conversion/tests/__init__.py

@@ -0,0 +1,2 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.

modules/stock_conversion/tests/scenario_stock_conversion.rst

@@ -0,0 +1,133 @@
+=========================
+Stock Conversion Scenario
+=========================
+
+Imports::
+
+    >>> from decimal import Decimal
+
+    >>> from proteus import Model
+    >>> from trytond.modules.company.tests.tools import create_company
+    >>> from trytond.tests.tools import activate_modules, assertEqual, assertIsNotNone
+
+Activate modules::
+
+    >>> config = activate_modules('stock_conversion', create_company)
+
+    >>> Inventory = Model.get('stock.inventory')
+    >>> Location = Model.get('stock.location')
+    >>> Product = Model.get('product.product')
+    >>> ProductTemplate = Model.get('product.template')
+    >>> ProductUom = Model.get('product.uom')
+    >>> StockConversion = Model.get('stock.conversion')
+
+Create products::
+
+    >>> unit, = ProductUom.find([('name', '=', "Unit")])
+
+    >>> template_box = ProductTemplate()
+    >>> template_box.name = "Product Box"
+    >>> template_box.default_uom = unit
+    >>> template_box.type = 'goods'
+    >>> template_box.save()
+    >>> product_box, = template_box.products
+    >>> product_box.cost_price = Decimal('50.0000')
+    >>> product_box.save()
+
+    >>> template = ProductTemplate()
+    >>> template.name = "Product"
+    >>> template.default_uom = unit
+    >>> template.type = 'goods'
+    >>> template.save()
+    >>> product, = template.products
+
+Define a conversion rule::
+
+    >>> conversion_rule = product_box.conversion_rules.new()
+    >>> conversion_rule.input_quantity = 1
+    >>> assertEqual(conversion_rule.input_unit, unit)
+    >>> conversion_rule.output_product = product
+    >>> conversion_rule.output_quantity = 6
+    >>> assertEqual(conversion_rule.output_unit, unit)
+    >>> product_box.save()
+    >>> conversion_rule, = product_box.conversion_rules
+
+Setup an inventory::
+
+    >>> storage, = Location.find([('code', '=', 'STO')], limit=1)
+
+    >>> inventory = Inventory()
+    >>> inventory.location = storage
+    >>> inventory_line = inventory.lines.new(product=product_box)
+    >>> inventory_line.quantity = 100
+    >>> inventory.click('confirm')
+    >>> inventory.state
+    'done'
+
+Try to convert without enough quantity in stock::
+
+    >>> conversion = StockConversion()
+    >>> conversion.location = storage
+    >>> conversion.input_product = product_box
+    >>> conversion.input_quantity = 120
+    >>> conversion.output_product = product
+    >>> assertEqual(conversion.conversion_rule, conversion_rule)
+    >>> conversion.output_quantity
+    720.0
+    >>> conversion.save()
+    >>> assertIsNotNone(conversion.number)
+
+    >>> conversion.click('do')
+    Traceback (most recent call last):
+        ...
+    ConversionError: ...
+
+Change converted quantity for the stock::
+
+    >>> conversion.input_quantity = 10
+    >>> conversion.output_quantity
+    60.0
+    >>> conversion.click('do')
+    >>> conversion.state
+    'done'
+    >>> len(conversion.moves)
+    2
+    >>> input_move, = [m for m in conversion.moves if m.product == product_box]
+    >>> input_move.cost_price
+    Decimal('50.0000')
+    >>> output_move, = [m for m in conversion.moves if m.product == product]
+    >>> output_move.unit_price
+    Decimal('8.3333')
+
+Check stock quantities::
+
+    >>> with config.set_context(location=storage.id):
+    ...     product_box = Product(product_box.id)
+    ...     product = Product(product.id)
+    >>> product_box.quantity
+    90.0
+    >>> product.quantity
+    60.0
+
+Cancel conversion::
+
+    >>> conversion.click('cancel')
+    >>> conversion.state
+    'cancelled'
+
+Check stock quantities::
+
+    >>> product_box.reload()
+    >>> product_box.quantity
+    100.0
+    >>> product.reload()
+    >>> product.quantity
+    0.0
+
+Check conversion rule modification is forbidden once used::
+
+    >>> conversion_rule.input_quantity = 2
+    >>> conversion_rule.save()
+    Traceback (most recent call last):
+        ...
+    AccessError: ...

modules/stock_conversion/tests/test_module.py

@@ -0,0 +1,11 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+from trytond.tests.test_tryton import ModuleTestCase
+
+
+class StockConversionTestCase(ModuleTestCase):
+    "Test Stock Conversion module"
+    module = 'stock_conversion'
+
+
+del ModuleTestCase

modules/stock_conversion/tests/test_scenario.py

@@ -0,0 +1,8 @@
+# This file is part of Tryton.  The COPYRIGHT file at the top level of
+# this repository contains the full copyright notices and license terms.
+
+from trytond.tests.test_tryton import load_doc_tests
+
+
+def load_tests(*args, **kwargs):
+    return load_doc_tests(__name__, __file__, *args, **kwargs)

modules/stock_conversion/tox.ini

@@ -0,0 +1,24 @@
+[tox]
+envlist = {py310,py311,py312,py313,py314}-{sqlite,postgresql}
+
+[testenv]
+changedir = {env_site_packages_dir}
+extras = test
+commands =
+    coverage run --rcfile={toxinidir}/tox.ini --source=trytond.modules.stock_conversion --omit=*/tests/* -m xmlrunner discover -s trytond.modules.stock_conversion {posargs}
+commands_post =
+    coverage report --rcfile={toxinidir}/tox.ini
+    coverage xml --rcfile={toxinidir}/tox.ini -o {package_root}/coverage.xml
+deps =
+    coverage
+    unittest-xml-reporting
+    postgresql: psycopg[pool,binary] >= 3
+passenv = *
+setenv =
+    sqlite: TRYTOND_DATABASE_URI={env:SQLITE_URI:sqlite://}
+    postgresql: TRYTOND_DATABASE_URI={env:POSTGRESQL_URI:postgresql://}
+    sqlite: DB_NAME={env:DB_NAME::memory:}
+    postgresql: DB_NAME={env:DB_NAME:test}
+
+[coverage:run]
+relative_files = true

modules/stock_conversion/tryton.cfg

@@ -0,0 +1,21 @@
+[tryton]
+version=8.1.0
+depends:
+    ir
+    product
+    stock
+xml:
+    product.xml
+    stock.xml
+    message.xml
+
+[register]
+model:
+    ir.Cron
+    product.Product
+    stock.Configuration
+    stock.ConfigurationSequence
+    stock.Location
+    stock.StockConversionRule
+    stock.StockConversion
+    stock.Move

modules/stock_conversion/view/product_form.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<data>
+    <xpath expr="/form/notebook" position="inside">
+        <page string="Conversion Rules" name="conversion_rules">
+            <field name="conversion_rules" colspan="4" view_ids="stock_conversion.stock_conversion_rule_view_list"/>
+        </page>
+    </xpath>
+</data>

modules/stock_conversion/view/stock_configuration_form.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<data>
+    <xpath expr="//form" position="inside">
+        <separator id="conversion" colspan="4" string="Conversion"/>
+        <label name="conversion_sequence"/>
+        <field name="conversion_sequence"/>
+    </xpath>
+</data>

modules/stock_conversion/view/stock_conversion_form.xml

@@ -0,0 +1,49 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<form cursor="location">
+    <label name="date"/>
+    <field name="date"/>
+    <label name="number"/>
+    <field name="number"/>
+
+    <label name="warehouse"/>
+    <field name="warehouse"/>
+    <label name="location"/>
+    <field name="location"/>
+
+    <notebook>
+        <page string="Conversion" id="conversion" col="6">
+            <label name="input_quantity"/>
+            <field name="input_quantity" symbol="input_unit"/>
+            <label name="input_product"/>
+            <field name="input_product"/>
+            <newline/>
+
+            <label name="output_quantity"/>
+            <field name="output_quantity" symbol="output_unit"/>
+            <label name="output_product"/>
+            <field name="output_product"/>
+            <newline/>
+        </page>
+        <page name="moves">
+            <field name="moves" colspan="4"/>
+        </page>
+        <page string="Other Info" id="other">
+            <label name="company"/>
+            <field name="company"/>
+            <label name="conversion_rule"/>
+            <field name="conversion_rule"/>
+
+            <label name="done_by"/>
+            <field name="done_by"/>
+        </page>
+    </notebook>
+
+    <label name="state"/>
+    <field name="state"/>
+    <group col="-1" colspan="2" id="buttons">
+        <button name="cancel" icon="tryton-cancel"/>
+        <button name="do" icon="tryton-forward"/>
+    </group>
+</form>

modules/stock_conversion/view/stock_conversion_list.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<tree>
+    <field name="company" expand="1" optional="1"/>
+    <field name="number" expand="1"/>
+    <field name="date" optional="0"/>
+    <field name="warehouse" optional="1" expand="1"/>
+    <field name="location" expand="1"/>
+    <field name="input_quantity" symbol="input_unit"/>
+    <field name="input_product" expand="2"/>
+    <field name="output_quantity" symbol="output_unit"/>
+    <field name="output_product" expand="2"/>
+    <field name="state"/>
+</tree>

modules/stock_conversion/view/stock_conversion_rule_form.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<form cursor="output_product" col="5">
+    <label name="input_quantity" string="Input:"/>
+    <field name="input_quantity" symbol="input_unit" xexpand="0"/>
+    <field name="input_product"/>
+    <label name="active"/>
+    <field name="active" xexpand="0" width="100"/>
+
+    <label name="output_quantity" string="Output:"/>
+    <field name="output_quantity" symbol="output_unit" xexpand="0"/>
+    <field name="output_product"/>
+</form>

modules/stock_conversion/view/stock_conversion_rule_list.xml

@@ -0,0 +1,9 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<tree>
+    <field name="input_quantity" symbol="input_unit"/>
+    <field name="input_product" expand="1"/>
+    <field name="output_quantity" symbol="output_unit"/>
+    <field name="output_product" expand="1"/>
+</tree>

modules/stock_conversion/view/stock_location_form.xml

@@ -0,0 +1,10 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<data>
+    <xpath expr="/form/field[@name='picking_location']" position="after">
+        <label name="conversion_location"/>
+        <field name="conversion_location"/>
+        <newline/>
+    </xpath>
+</data>

modules/stock_lot/stock.py

@@ -930,3 +930,53 @@ class InventoryCountQuantity(ModelView):
         states={
             'invisible': ~Eval('lot', None),
             })
+
+
+class Conversion(metaclass=PoolMeta):
+    __name__ = 'stock.conversion'
+
+    input_lot = fields.Many2One(
+        'stock.lot', "Input Lot",
+        ondelete='RESTRICT',
+        domain=[
+            ('product', '=', Eval('input_product', -1)),
+            ],
+        states={
+            'readonly': Eval('state') != 'draft',
+            },
+        search_context={
+            'locations': If(Eval('location', None),
+                [Eval('location', -1)], []),
+            'stock_date_end': Eval('date', None),
+            })
+    output_lot = fields.Many2One(
+        'stock.lot', "Output Lot",
+        ondelete='RESTRICT',
+        domain=[
+            ('product', '=', Eval('output_product', -1)),
+            ],
+        states={
+            'readonly': Eval('state') != 'draft',
+            })
+
+    @fields.depends('input_product', 'input_lot')
+    def on_change_input_product(self):
+        super().on_change_input_product()
+        if self.input_product and self.input_lot:
+            if self.input_lot.product != self.input_product:
+                self.input_lot = None
+
+    @fields.depends('output_product', 'output_lot')
+    def on_change_output_product(self):
+        super().on_change_output_product()
+        if self.output_product and self.output_lot:
+            if self.output_lot.product != self.output_product:
+                self.output_lot = None
+
+    def _move(self, type):
+        move = super()._move(type)
+        if type == 'input':
+            move.lot = self.input_lot
+        elif type == 'output':
+            move.lot = self.output_lot
+        return move

modules/stock_lot/stock.xml

@@ -392,4 +392,17 @@ this repository contains the full copyright notices and license terms. -->
         </record>
 
     </data>
+    <data depends="stock_conversion">
+        <record model="ir.ui.view" id="stock_conversion_view_list">
+            <field name="model">stock.conversion</field>
+            <field name="inherit" ref="stock_conversion.stock_conversion_view_list"/>
+            <field name="name">stock_conversion_list</field>
+        </record>
+
+        <record model="ir.ui.view" id="stock_conversion_view_form">
+            <field name="model">stock.conversion</field>
+            <field name="inherit" ref="stock_conversion.stock_conversion_view_form"/>
+            <field name="name">stock_conversion_form</field>
+        </record>
+    </data>
 </tryton>

modules/stock_lot/tests/scenario_stock_lot_conversion.rst

@@ -0,0 +1,99 @@
+==================================
+Stock Conversion with Lot Scenario
+==================================
+
+Imports::
+
+    >>> from proteus import Model
+    >>> from trytond.modules.company.tests.tools import create_company
+    >>> from trytond.tests.tools import activate_modules, assertEqual
+
+Activate modules::
+
+    >>> config = activate_modules(['stock_lot', 'stock_conversion'], create_company)
+
+    >>> Inventory = Model.get('stock.inventory')
+    >>> Location = Model.get('stock.location')
+    >>> Lot = Model.get('stock.lot')
+    >>> Product = Model.get('product.product')
+    >>> ProductTemplate = Model.get('product.template')
+    >>> ProductUom = Model.get('product.uom')
+    >>> StockConversion = Model.get('stock.conversion')
+
+Create products::
+
+    >>> unit, = ProductUom.find([('name', '=', "Unit")])
+
+    >>> template_box = ProductTemplate()
+    >>> template_box.name = "Product Box"
+    >>> template_box.default_uom = unit
+    >>> template_box.type = 'goods'
+    >>> template_box.save()
+    >>> product_box, = template_box.products
+
+    >>> template = ProductTemplate()
+    >>> template.name = "Product"
+    >>> template.default_uom = unit
+    >>> template.type = 'goods'
+    >>> template.save()
+    >>> product, = template.products
+
+Create lots::
+
+    >>> lot_box = Lot(number="1", product=product_box)
+    >>> lot_box.save()
+    >>> lot = Lot(number="2", product=product)
+    >>> lot.save()
+
+Define a conversion rule::
+
+    >>> conversion_rule = product_box.conversion_rules.new()
+    >>> conversion_rule.input_quantity = 1
+    >>> assertEqual(conversion_rule.input_unit, unit)
+    >>> conversion_rule.output_product = product
+    >>> conversion_rule.output_quantity = 6
+    >>> assertEqual(conversion_rule.output_unit, unit)
+    >>> product_box.save()
+    >>> conversion_rule, = product_box.conversion_rules
+
+Setup an inventory::
+
+    >>> storage, = Location.find([('code', '=', 'STO')], limit=1)
+
+    >>> inventory = Inventory()
+    >>> inventory.location = storage
+    >>> inventory_line = inventory.lines.new(product=product_box)
+    >>> inventory_line.quantity = 1
+    >>> inventory_line = inventory.lines.new(product=product_box)
+    >>> inventory_line.quantity = 2
+    >>> inventory_line.lot = lot_box
+    >>> inventory.click('confirm')
+    >>> inventory.state
+    'done'
+
+Try to convert without enough lot quantity in stock::
+
+    >>> conversion = StockConversion()
+    >>> conversion.location = storage
+    >>> conversion.input_product = product_box
+    >>> conversion.input_lot = lot_box
+    >>> conversion.input_quantity = 3
+    >>> conversion.output_product = product
+    >>> conversion.output_lot = lot
+    >>> conversion.save()
+
+    >>> conversion.click('do')
+    Traceback (most recent call last):
+        ...
+    ConversionError: ...
+
+Change converted quantity for the stock::
+
+    >>> conversion.input_quantity = 2
+    >>> conversion.click('do')
+    >>> conversion.state
+    'done'
+
+Check moves::
+
+    >>> assertEqual({m.lot for m in conversion.moves}, {lot_box, lot})

modules/stock_lot/tests/test_module.py

@@ -14,7 +14,7 @@ from trytond.transaction import Transaction
 class StockLotTestCase(CompanyTestMixin, ModuleTestCase):
     'Test Stock Lot module'
     module = 'stock_lot'
-    extras = ['stock_split']
+    extras = ['stock_split', 'stock_conversion']
 
     @with_transaction()
     def test_products_by_location(self):

modules/stock_lot/tryton.cfg

@@ -6,6 +6,7 @@ depends:
     stock
 extras_depend:
     sale_supply_drop_shipment
+    stock_conversion
     stock_split
 xml:
     ir.xml
@@ -44,3 +45,7 @@ wizard:
 [register sale_supply_drop_shipment]
 model:
     stock.ShipmentDrop
+
+[register stock_conversion]
+model:
+    stock.Conversion

modules/stock_lot/view/stock_conversion_form.xml

@@ -0,0 +1,14 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<data>
+    <xpath expr="//field[@name='input_product']" position="after">
+        <label name="input_lot"/>
+        <field name="input_lot"/>
+    </xpath>
+
+    <xpath expr="//field[@name='output_product']" position="after">
+        <label name="output_lot"/>
+        <field name="output_lot"/>
+    </xpath>
+</data>

modules/stock_lot/view/stock_conversion_list.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0"?>
+<!-- This file is part of Tryton.  The COPYRIGHT file at the top level of
+this repository contains the full copyright notices and license terms. -->
+<data>
+    <xpath expr="/tree/field[@name='input_product']" position="after">
+        <field name="input_lot" expand="1"/>
+    </xpath>
+    <xpath expr="/tree/field[@name='output_product']" position="after">
+        <field name="output_lot" expand="1"/>
+    </xpath>
+</data>