Infinite loop when subtracting business hours from timezone-aware date with US holidays and workday rules

[garthompson]

A simple test-case to reproduce this issue:

from datetime import datetime, time
from pytz import timezone
from businesstimedelta import BusinessTimeDelta, HolidayRule, Rules, WorkDayRule
from holidays import UnitedStates

la_tz = timezone("America/Los_Angeles")
workday_rule = WorkDayRule(
    start_time=time(8), end_time=time(17), working_days=[0, 1, 2, 3, 4], tz=la_tz,
)
us_holidays_rule = HolidayRule(UnitedStates())
business_hours = Rules([workday_rule, us_holidays_rule])
test_datetime = datetime(2021, 11, 10, 17, 0, 0, 0, la_tz)
output = test_datetime - BusinessTimeDelta(rule=business_hours, hours=4)

Notes:

• November 10th is Columbus Day in the US, although not a federal holiday.

• The holidays library, doesn’t recognise 2021-11-10 as a holiday in the US. 2021-11-11 is recognised as a holiday however - Veteran’s Day. It may be relevant that 1700 in LA is midnight in UTC.

• Results are returned if the timezone is excluded.

• Same issue arises on 2020-11-10

• No issue with times < 1600 on 2021-11-10

• Removing the us_holidays_rule from business hours resolves the issue

• Other holidays also appear to create issues - all times tried on 2021-12-24 and 2021-12-25 errored.

[julifgo]

We experienced a similar issue and turns out that it was an inconsistency of tz. Each set of rules takes a tz info as argument and if not provided will do calculations in UTC. So, in your case you set your workdays in la_tz but not your holidays. Have you tried this?

us_holidays_rule = HolidayRule(UnitedStates(), tz= la_tz)

That solved the issue for us.