EXDATE parameter parsing was added with #859 / #410.

The parameter parsing, however, does not respect ignoretz=True. This becomes a problem when trying to use any of the utility methods on the rrule, such as .before(dt).

Here's an example:

>>> import dateutil.rrule
>>> import datetime
>>> now = datetime.datetime.now()
>>> rrule = dateutil.rrule.rrulestr("EXDATE;TZID=America/Denver:20220602T110000\nRRULE:FREQ=WEEKLY", dtstart=now, ignoretz=True)
>>> rrule.before(now)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/home/closeio/venv/lib/python3.8/site-packages/dateutil/rrule.py", line 206, in before
    for i in gen:
  File "/home/closeio/venv/lib/python3.8/site-packages/dateutil/rrule.py", line 1401, in _iter
    while exlist and exlist[0] < ritem:
  File "/home/closeio/venv/lib/python3.8/site-packages/dateutil/rrule.py", line 1338, in __lt__
    return self.dt < other.dt
TypeError: can't compare offset-naive and offset-aware datetimes

Prior to 2.8.x, this same snippet worked correctly and did not throw an error.

Version information:

$ python -c "import dateutil; print(dateutil.__version__)"
2.8.2
$ python --version
Python 3.8.10

I realize that 2.8.0 was released in 2019, but this change makes upgrading a bit difficult as the new EXDATE parameter parsing makes the behavior not backwards compatible. The workaround seems to be passing both a tz-aware datetime to dtstart and .before(dt) if there's a TZID included on EXDATE. Though it's sort of hard to tell beforehand if there's going to be a TZID parameter there.

I would expect that passing ignoretz=True torrulestr would make EXDATE parsing ignore any TZID.