[IMP] hr_holidays: add a leave request without validation mechanism

Purpose
=======

Allow to create a leave type for which leaves are not required to be approved
by a manager.

When a leave is created, it is automatically approved if the
validation type is set to "No validation".

It is useful if a manager does not need to manually approve some leave types.

Specification
=============

Add a validation type option for 'hr.leave.request': 'no_validation'

Automatically approve the leave when created and add the approver as follower
so that he can be notified about the leave creation/validation.

closes odoo/odoo#28268

addons/hr_holidays/models/hr_leave.py

@@ -471,6 +471,11 @@ class HolidaysRequest(models.Model):
     def create(self, values):
         """ Override to avoid automatic logging of creation """
         employee_id = values.get('employee_id', False)
+        leave_type_id = values.get('holiday_status_id')
+        leave_type = self.env['hr.leave.type'].browse(leave_type_id)
+        if leave_type.validation_type == 'no_validation':
+            values.update({'state': 'confirm'})
+
         if not values.get('department_id'):
             values.update({'department_id': self.env['hr.employee'].browse(employee_id).department_id.id})
         holiday = super(HolidaysRequest, self.with_context(mail_create_nolog=True, mail_create_nosubscribe=True)).create(values)
@@ -479,6 +484,10 @@ class HolidaysRequest(models.Model):
             holiday._onchange_employee_id()
         if 'number_of_days' not in values and ('date_from' in values or 'date_to' in values):
             holiday._onchange_leave_dates()
+        if leave_type.validation_type == 'no_validation':
+            holiday.sudo().action_validate()
+            holiday.message_subscribe(partner_ids=[holiday._get_responsible_for_approval().partner_id.id])
+            holiday.sudo().message_post(body=_("The leave has been automatically approved"), subtype="mt_comment") # Message from OdooBot (sudo)
         holiday.activity_update()
         return holiday
 

addons/hr_holidays/models/hr_leave_type.py

@@ -63,9 +63,10 @@ class HolidaysType(models.Model):
         compute='_compute_group_days_leave', string='Group Leaves')
     company_id = fields.Many2one('res.company', string='Company', default=lambda self: self.env.user.company_id)
     validation_type = fields.Selection([
-        ('hr', 'Human Resource officer'),
-        ('manager', 'Employee Manager'),
-        ('both', 'Double Validation')], default='hr', string='Validation By')
+        ('no_validation', 'No Validation'),
+        ('hr', 'Payroll Officer'),
+        ('manager', 'Team Leader'),
+        ('both', 'Team Leader and Payroll Officer')], default='hr', string='Validation By')
     allocation_type = fields.Selection([
         ('fixed', 'Fixed by HR'),
         ('fixed_allocation', 'Fixed by HR + allocation request'),