Draft: Issue/3174397 invalid argument exception thrown in date time day widget base validate start end
requested to merge issue/3174397-InvalidArgumentException-thrown-in-DateTimeDayWidgetBase-validateStartEnd into 8.x-1.x
InvalidArgumentException() thrown in DateTimeDayWidgetBase::validateStartEnd()
When leaving the date field empty, the validation in DateTimeDayWidgetBase::validateStartEnd() fails due to invalid arguments passed to DrupalDateTime::createFromFormat() (the start or end date will be an empty string).
Steps to reproduce Save a node without entering any start or end date values.