**Impacted versions:**
11.0 
**Steps to reproduce:**
  - Create payslip
  - Add a contract with any structure
  - Add a structure in payslip, different from the one defined in step 2
  - Confirm or compute sheet

**Current behavior:**
Payslip is computed using the contract structure

**Expected behavior:**
Payslip should be computed using the payslip structure

**FYI:**  This is an issue because, sometimes, it's necessary to pay the employee using a structure different from their contract, e.g. in case of Christmas bonuses

**Video/Screenshot link (optional):**
[Video](https://www.youtube.com/watch?v=32H01n503uU&feature=youtu.be)


addons/hr_payroll/models/hr_payslip.py
if (not self.employee_id) or (not self.date_from) or (not self.date_to):
            return
        employee = self.employee_id
        date_from = self.date_from
        date_to = self.date_to
        contract_ids = []
        ttyme = datetime.fromtimestamp(time.mktime(time.strptime(date_from, "%Y-%m-%d")))
        locale = self.env.context.get('lang') or 'en_US'
        self.name = _('Salary Slip of %s for %s') % (employee.name, tools.ustr(babel.dates.format_date(date=ttyme, format='MMMM-y', locale=locale)))
        self.company_id = employee.company_id
        if not self.env.context.get('contract') or not self.contract_id:
            contract_ids = self.get_contract(employee, date_from, date_to)
            if not contract_ids:
                return
            self.contract_id = self.env['hr.contract'].browse(contract_ids[0])