This traceback arises when the user tries to remove the start date Steps to produce 1. Install 'resource' 2. Open 'Settings/Technical/resource/Resource Time Off' 3. Create a new record and remove start date AttributeError 'bool' object has no attribute 'tzinfo' when the user tries to remove the start date, an error will be produced because _compute_date_to seems to be computing the date_to based on the date_from field. when removing the date_from from calculations on empty or none which leads to traceback from here https://github.com/odoo/odoo/blob/322e7ea19b7c069fdb92d3b86e5615c55489ca21/addons/resource/models/resource_calendar_leaves.py#L54-L59 This commit solves the above issue by computing `date_to` for records that have `date_from`. Apart from that, this commit also removes `# -*- coding: utf-8 -*-` from the first line of the modified file. sentry-4983497879 closes odoo/odoo#163311 X-original-commit: 5032a8ffed10bfbd619c85a266092f129716ceca Signed-off-by: Bertrand Dossogne (bedo) <bedo@odoo.com>