[FIX] base: allow to archive companies via stat button

Once a branch company has some data associated with it, it can't be
deleted anymore. Since the branches could only be opened in a dialog,
it was also impossible to archive them.

In order to allow (un)archiving a branch, we added a stat button on the
company form to show the branches in a list view, where people can
(un)archive them.

task-3503204

Part-of: odoo/odoo#138942

odoo/addons/base/models/res_company.py

@@ -33,6 +33,7 @@ class Company(models.Model):
     sequence = fields.Integer(help='Used to order Companies in the company switcher', default=10)
     parent_id = fields.Many2one('res.company', string='Parent Company', index=True)
     child_ids = fields.One2many('res.company', 'parent_id', string='Branches')
+    all_child_ids = fields.One2many('res.company', 'parent_id', context={'active_test': False})
     parent_path = fields.Char(index=True, unaccent=False)
     parent_ids = fields.Many2many('res.company', compute='_compute_parent_ids', compute_sudo=True)
     root_id = fields.Many2one('res.company', compute='_compute_parent_ids', compute_sudo=True)
@@ -393,3 +394,17 @@ class Company(models.Model):
             len(self.env.companies.root_id) == 1
             and self.env.companies == self.env['res.company'].sudo().search([('id', 'child_of', self.env.company.root_id.ids)])
         )
+
+    def action_all_company_branches(self):
+        self.ensure_one()
+        return {
+            'type': 'ir.actions.act_window',
+            'name': _('Branches'),
+            'res_model': 'res.company',
+            'domain': [('parent_id', '=', self.id)],
+            'context': {
+                'active_test': False,
+                'default_parent_id': self.id,
+            },
+            'views': [[False, 'tree'], [False, 'kanban'], [False, 'form']],
+        }

odoo/addons/base/views/res_company_views.xml

@@ -6,7 +6,16 @@
             <field name="model">res.company</field>
             <field name="arch" type="xml">
                 <form string="Company" duplicate="0">
+                  <field name="all_child_ids" invisible="1"/>
                   <sheet>
+                    <div class="oe_button_box" name="button_box">
+                        <button class="oe_stat_button"
+                                name="action_all_company_branches"
+                                type="object"
+                                invisible="not all_child_ids"
+                                icon="fa-sitemap"
+                                string="Branches"/>
+                    </div>
                     <field name="logo" widget="image" class="oe_avatar"/>
                     <div class="oe_title">
                         <label for="name"/>
@@ -57,11 +66,12 @@
             <field name="name">res.company.tree</field>
             <field name="model">res.company</field>
             <field name="arch" type="xml">
-                <tree string="Companies">
+                <tree string="Companies" decoration-muted="not active">
                     <field name="sequence" widget="handle"/>
                     <field name="name"/>
                     <field name="partner_id" required="0"/>
                     <field name="child_ids" widget="many2many_tags" options="{'color_field': 'color'}"/>
+                    <field name="active" column_invisible="True"/>
                 </tree>
             </field>
         </record>