[FIX] product: template creation packaging_ids

Create a new product, but don't save it just yet
give it a name,
Add some packagings
Save

Before this commit:
- the form to create the packaging had a mandatory product_id field
which is useless in a x2m context (fixed in v11.5 with a6557a2306)
- the packages disappeared after save
This was because at template creation, all "real" fields that are on
its variants must be manually set after the creation, including packaging_ids

OPW 1970589

closes odoo/odoo#32925

Signed-off-by: Lucas Perais (lpe) <lpe@odoo.com>

addons/product/models/product_template.py

@@ -312,6 +312,9 @@ class ProductTemplate(models.Model):
             related_vals['volume'] = vals['volume']
         if vals.get('weight'):
             related_vals['weight'] = vals['weight']
+        # Please do forward port
+        if vals.get('packaging_ids'):
+            related_vals['packaging_ids'] = vals['packaging_ids']
         if related_vals:
             template.write(related_vals)
         return template

addons/product/views/product_views.xml

@@ -87,7 +87,7 @@
                                 colspan="4"
                                 attrs="{'invisible':['|', ('type', 'not in', ['product', 'consu']), ('product_variant_count', '>', 1)]}"
                                 groups="product.group_stock_packaging">
-                                <field name="packaging_ids" nolabel="1" context="{'default_product_id': product_variant_id,'tree_view_ref':'product.product_packaging_tree_view', 'form_view_ref':'product.product_packaging_form_view'}"/>
+                                <field name="packaging_ids" nolabel="1" context="{'default_product_id': product_variant_id,'tree_view_ref':'product.product_packaging_tree_view', 'form_view_ref':'product.product_packaging_form_view2'}"/>
                             </group>
                         </page>
                         <page string="Notes" name="notes">
@@ -505,6 +505,18 @@
             </field>
         </record>
 
+        <!-- Don't forward port in V >= saas-11.5 -->
+        <record id="product_packaging_form_view2" model="ir.ui.view">
+            <field name="name">product.packaging.form.view2</field>
+            <field name="model">product.packaging</field>
+            <field name="mode">primary</field>
+            <field name="inherit_id" ref="product.product_packaging_form_view"/>
+            <field name="arch" type="xml">
+                <xpath expr="//field[@name='product_id']" position="replace"/>
+                <xpath expr="//field[@name='id']" position="replace"/>
+            </field>
+        </record>
+
         <record model="ir.actions.act_window" id="action_packaging_view">
             <field name="name">Product Packages</field>
             <field name="res_model">product.packaging</field>