Crash when importing event with invalid VALARM/TRIGGER

WhyNotHugo commented 1 year ago

I tried importing this file, which is generated by NS International.

BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//NS Internationaal B.V.//sales-v2//en
BEGIN:VTIMEZONE
TZID:Europe/Brussels
LAST-MODIFIED:20221105T024525Z
TZURL:http://www.tzurl.org/zoneinfo/Europe/Brussels
X-LIC-LOCATION:Europe/Brussels
X-PROLEPTIC-TZNAME:LMT
BEGIN:STANDARD
TZNAME:BMT
TZOFFSETFROM:+0017
TZOFFSETTO:+0017
DTSTART:18800101T000000
END:STANDARD
BEGIN:STANDARD
TZNAME:WET
TZOFFSETFROM:+0017
TZOFFSETTO:+0000
DTSTART:18920501T001730
END:STANDARD
BEGIN:STANDARD
TZNAME:CET
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
DTSTART:19141108T000000
END:STANDARD
BEGIN:STANDARD
TZNAME:CET
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
DTSTART:19161001T010000
RDATE:19421102T030000
RDATE:19431004T030000
RDATE:19440917T030000
RDATE:19450916T030000
RDATE:19461007T030000
RDATE:19770925T030000
RDATE:19781001T030000
END:STANDARD
BEGIN:STANDARD
TZNAME:CET
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
DTSTART:19170917T030000
RRULE:FREQ=YEARLY;UNTIL=19180916T010000Z;BYDAY=3MO;BYMONTH=9
END:STANDARD
BEGIN:STANDARD
TZNAME:WET
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
DTSTART:19181111T120000
RDATE:19191005T000000
RDATE:19201024T000000
RDATE:19211026T000000
RDATE:19391119T030000
END:STANDARD
BEGIN:STANDARD
TZNAME:WET
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
DTSTART:19221008T000000
RRULE:FREQ=YEARLY;UNTIL=19271001T230000Z;BYDAY=SU;BYMONTHDAY=2,3,4,5,6,7,8;
 BYMONTH=10
END:STANDARD
BEGIN:STANDARD
TZNAME:WET
TZOFFSETFROM:+0100
TZOFFSETTO:+0000
DTSTART:19281007T030000
RRULE:FREQ=YEARLY;UNTIL=19381002T020000Z;BYDAY=SU;BYMONTHDAY=2,3,4,5,6,7,8;
 BYMONTH=10
END:STANDARD
BEGIN:STANDARD
TZNAME:CET
TZOFFSETFROM:+0100
TZOFFSETTO:+0100
DTSTART:19770101T000000
END:STANDARD
BEGIN:STANDARD
TZNAME:CET
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
DTSTART:19790930T030000
RRULE:FREQ=YEARLY;UNTIL=19950924T010000Z;BYDAY=-1SU;BYMONTH=9
END:STANDARD
BEGIN:STANDARD
TZNAME:CET
TZOFFSETFROM:+0200
TZOFFSETTO:+0100
DTSTART:19961027T030000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
END:STANDARD
BEGIN:DAYLIGHT
TZNAME:CEST
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
DTSTART:19160501T000000
RDATE:19400520T030000
RDATE:19430329T020000
RDATE:19440403T020000
RDATE:19450402T020000
RDATE:19460519T020000
END:DAYLIGHT
BEGIN:DAYLIGHT
TZNAME:CEST
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
DTSTART:19170416T020000
RRULE:FREQ=YEARLY;UNTIL=19180415T010000Z;BYDAY=3MO;BYMONTH=4
END:DAYLIGHT
BEGIN:DAYLIGHT
TZNAME:WEST
TZOFFSETFROM:+0000
TZOFFSETTO:+0100
DTSTART:19190301T230000
RDATE:19200214T230000
RDATE:19210314T230000
RDATE:19220325T230000
RDATE:19230421T230000
RDATE:19240329T230000
RDATE:19250404T230000
RDATE:19260417T230000
RDATE:19270409T230000
RDATE:19280414T230000
RDATE:19290421T020000
RDATE:19300413T020000
RDATE:19310419T020000
RDATE:19320403T020000
RDATE:19330326T020000
RDATE:19340408T020000
RDATE:19350331T020000
RDATE:19360419T020000
RDATE:19370404T020000
RDATE:19380327T020000
RDATE:19390416T020000
RDATE:19400225T020000
END:DAYLIGHT
BEGIN:DAYLIGHT
TZNAME:CEST
TZOFFSETFROM:+0200
TZOFFSETTO:+0200
DTSTART:19440903T000000
END:DAYLIGHT
BEGIN:DAYLIGHT
TZNAME:CEST
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
DTSTART:19770403T020000
RRULE:FREQ=YEARLY;UNTIL=19800406T010000Z;BYDAY=1SU;BYMONTH=4
END:DAYLIGHT
BEGIN:DAYLIGHT
TZNAME:CEST
TZOFFSETFROM:+0100
TZOFFSETTO:+0200
DTSTART:19810329T020000
RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
END:DAYLIGHT
END:VTIMEZONE
BEGIN:VEVENT
UID:4e3e3186-28c6-42d4-81cf-eb4f56d587f1
DTSTAMP:20230122T142045Z
SUMMARY:Trip from Utrecht to Bruxelles Central/Brussel Centraal
DESCRIPTION:Trip from Utrecht to Bruxelles Central/Brussel Centraal
LOCATION:Utrecht
URL:https://www.nsinternational.com/en/traintickets-v3/
DTSTART;TZID=Europe/Brussels:20230203T151500
DTEND;TZID=Europe/Brussels:20230203T180600
BEGIN:VALARM
ACTION:DISPLAY
TRIGGER;RELATED=START:PT-2H
END:VALARM
END:VEVENT
BEGIN:VEVENT
UID:28d25a55-84cd-4564-910b-088066fd5244
DTSTAMP:20230122T142045Z
SUMMARY:Trip from Bruxelles Central/Brussel Centraal to Utrecht
DESCRIPTION:Trip from Bruxelles Central/Brussel Centraal to Utrecht
LOCATION:Bruxelles Central/Brussel Centraal
URL:https://www.nsinternational.com/en/traintickets-v3/
DTSTART;TZID=Europe/Brussels:20230206T095000
DTEND;TZID=Europe/Brussels:20230206T125000
BEGIN:VALARM
ACTION:DISPLAY
TRIGGER;RELATED=START:PT-2H
END:VALARM
END:VEVENT
END:VCALENDAR

Khal crashed with the following error:

Traceback (most recent call last):
  File "/usr/bin/khal", line 33, in <module>
    sys.exit(load_entry_point('khal==0.10.5', 'console_scripts', 'khal')())
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/click/core.py", line 1130, in __call__
    return self.main(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/click/core.py", line 1055, in main
    rv = self.invoke(ctx)
         ^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/click/core.py", line 1657, in invoke
    return _process_result(sub_ctx.command.invoke(sub_ctx))
                           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/click/core.py", line 1404, in invoke
    return ctx.invoke(self.callback, **ctx.params)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/click/core.py", line 760, in invoke
    return __callback(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/click/decorators.py", line 26, in new_func
    return f(get_current_context(), *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/khal/cli.py", line 465, in import_ics
    controllers.import_ics(
  File "/usr/lib/python3.11/site-packages/khal/controllers.py", line 595, in import_ics
    vevents = split_ics(ics, random_uid, conf['locale']['default_timezone'])
              ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/khal/icalendar.py", line 50, in split_ics
    cal = cal_from_ics(ics)
          ^^^^^^^^^^^^^^^^^
  File "/usr/lib/python3.11/site-packages/khal/icalendar.py", line 536, in cal_from_ics
    return cal
           ^^^
UnboundLocalError: cannot access local variable 'cal' where it is not associated with a value

The issue seems to be this line in particular: TRIGGER;RELATED=START:PT-2H. I recently wrote a parser for the icalendar duration type, and it also rejects this input. After looking at the spec closely, I found the issue; this should be TRIGGER;RELATED=START:-PT2H. Note that the - goes before the duration itself, and not before each part (otherwise we'd be able to have 2H-3M, which is super quirky.

Anyway, it's clear that this input has a technically invalid alarm, but I think we can do better and khal should be able to:

Ignore any error in an ALARM anyway, khal doesn't deal with them for now, and importing it is better then crashing.
Show a better error message? It took me a while to figure out that my installation wasn't actually broken.

More into details:

The cal_from_ics function tries to return cal even if it's never defined it. Note that the if might be false, at which point cal is never assigned.

I don't think we need to parse alarms; if an alarm is invalid, we should ignore it and import it as-is. Khal doesn't deal with alarms anyway.

geier commented 1 year ago

The issue with trying to return cal will be fixed with #1259

With that applied we get

Invalid iCalendar duration: PT-2H
Traceback (most recent call last):
  File "/Users/cg/workspace/khal/khal/controllers.py", line 612, in import_ics
    vevents = split_ics(ics, random_uid, conf['locale']['default_timezone'])
  File "/Users/cg/workspace/khal/khal/icalendar.py", line 49, in split_ics
    cal = cal_from_ics(ics)
  File "/Users/cg/workspace/khal/khal/icalendar.py", line 539, in cal_from_ics
    cal = icalendar.Calendar.from_ical(ics)
  File "/Users/cg/mambaforge/lib/python3.9/site-packages/icalendar/cal.py", line 380, in from_ical
    vals = factory(factory.from_ical(vals))
  File "/Users/cg/mambaforge/lib/python3.9/site-packages/icalendar/prop.py", line 332, in from_ical
    return vDuration.from_ical(ical)
  File "/Users/cg/mambaforge/lib/python3.9/site-packages/icalendar/prop.py", line 477, in from_ical
    raise ValueError(f'Invalid iCalendar duration: {ical}')
ValueError: Invalid iCalendar duration: PT-2H

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/Users/cg/workspace/khal/khal/cli.py", line 464, in import_ics
    controllers.import_ics(
  File "/Users/cg/workspace/khal/khal/controllers.py", line 614, in import_ics
    raise FatalError(error)
khal.exceptions.FatalError: Invalid iCalendar duration: PT-2H
critical: An error occurred when trying to import the file from ns.ics

geier commented 1 year ago

For the actual issue: I believe we can't do anything about this at khal at the moment, instead we could need to teach icalendar to accept somewhat broken icalendar files.

geier commented 1 year ago

closed as duplicate of #1264

pimutils / khal

Crash when importing event with invalid VALARM/TRIGGER #1217