Bad conversion to UTC

[sam-s]

Based on my question:

import datetime
from zoneinfo import ZoneInfo
import pandas_market_calendars as mcal

nyse = mcal.get_calendar("NYSE")

def local2utc(date, time):
    return datetime.datetime.combine(date,time).astimezone(datetime.timezone.utc)

for mon in [1,6]:
    date = datetime.datetime(2024,mon,1)
    time0 = nyse.open_time_on(date)
    print(f"date={date}; time={time0}; tz={time0.tzinfo!r}")
    print(f"bad UTC ={local2utc(date,time0)}")
    time1 = time0.replace(tzinfo=ZoneInfo(time0.tzname()))
    print(f"good UTC={local2utc(date,time1)}")

prints

date=2024-01-01 00:00:00; time=09:30:00; tz=<DstTzInfo 'America/New_York' LMT-1 day, 19:04:00 STD>
bad UTC =2024-01-01 14:26:00+00:00
good UTC=2024-01-01 14:30:00+00:00
date=2024-06-01 00:00:00; time=09:30:00; tz=<DstTzInfo 'America/New_York' LMT-1 day, 19:04:00 STD>
bad UTC =2024-06-01 14:26:00+00:00
good UTC=2024-06-01 13:30:00+00:00

You can see that local2utc works for stock zoneinfo.ZoneInfo but not for your DstTzInfo on two counts:

1. it converts to non-round "solar" time
2. it ignores DST status