[FIX] mrp: display correct uom on by products

Before this commit, It was always showing all
Unit of Measures in By Product lines.

With this commit, We are showing UoMs based on Category
of Selected Product's UoM.

closes odoo/odoo#70367

Signed-off-by: Rémy Voet <ryv-odoo@users.noreply.github.com>

addons/mrp/models/mrp_bom.py

@@ -436,7 +436,9 @@ class MrpByProduct(models.Model):
     product_qty = fields.Float(
         'Quantity',
         default=1.0, digits='Product Unit of Measure', required=True)
-    product_uom_id = fields.Many2one('uom.uom', 'Unit of Measure', required=True)
+    product_uom_category_id = fields.Many2one(related='product_id.uom_id.category_id')
+    product_uom_id = fields.Many2one('uom.uom', 'Unit of Measure', required=True,
+                                     domain="[('category_id', '=', product_uom_category_id)]")
     bom_id = fields.Many2one('mrp.bom', 'BoM', ondelete='cascade', index=True)
     allowed_operation_ids = fields.One2many('mrp.routing.workcenter', related='bom_id.operation_ids')
     operation_id = fields.Many2one(
@@ -448,14 +450,3 @@ class MrpByProduct(models.Model):
         """ Changes UoM if product_id changes. """
         if self.product_id:
             self.product_uom_id = self.product_id.uom_id.id
-
-    @api.onchange('product_uom_id')
-    def onchange_uom(self):
-        res = {}
-        if self.product_uom_id and self.product_id and self.product_uom_id.category_id != self.product_id.uom_id.category_id:
-            res['warning'] = {
-                'title': _('Warning'),
-                'message': _('The unit of measure you choose is in a different category than the product unit of measure.')
-            }
-            self.product_uom_id = self.product_id.uom_id.id
-        return res

addons/mrp/views/mrp_bom_views.xml

@@ -17,6 +17,7 @@
                         <field name="allowed_operation_ids" invisible="1"/>
                         <field name="company_id"/>
                         <field name="product_id"/>
+                        <field name="product_uom_category_id" invisible="1"/>
                         <label for="product_qty"/>
                         <div class="o_row">
                             <field name="product_qty"/>
@@ -112,6 +113,7 @@
                             <field name="byproduct_ids"  context="{'form_view_ref' : 'mrp.mrp_bom_byproduct_form_view', 'default_company_id': company_id, 'default_bom_id': id}">
                                 <tree string="By-products"  editable="top">
                                     <field name="company_id" invisible="1"/>
+                                    <field name="product_uom_category_id" invisible="1"/>
                                     <field name="product_id" context="{'default_type': 'product'}"/>
                                     <field name="product_qty"/>
                                     <field name="product_uom_id" groups="uom.group_uom"/>