Pullrequest thunderbird zero duration workaround

test_files/thunderbird_duration_pt0s_workaround.ics

@@ -0,0 +1,69 @@
+BEGIN:VCALENDAR
+PRODID:-//Mozilla.org/NONSGML Mozilla Calendar V1.1//EN
+VERSION:2.0
+
+BEGIN:VTIMEZONE
+TZID:Europe/Berlin
+BEGIN:DAYLIGHT
+TZOFFSETFROM:+0100
+TZOFFSETTO:+0200
+TZNAME:CEST
+DTSTART:19700329T020000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=3
+END:DAYLIGHT
+BEGIN:STANDARD
+TZOFFSETFROM:+0200
+TZOFFSETTO:+0100
+TZNAME:CET
+DTSTART:19701025T030000
+RRULE:FREQ=YEARLY;BYDAY=-1SU;BYMONTH=10
+END:STANDARD
+END:VTIMEZONE
+
+BEGIN:VEVENT
+CREATED:20190812T160437Z
+LAST-MODIFIED:20190813T140315Z
+DTSTAMP:20190813T140315Z
+UID:a13cca03-860a-4094-b162-e06f161a7681
+SUMMARY:flummy
+EXDATE:20190826T170000Z
+RRULE:FREQ=WEEKLY;UNTIL=20190923T170000Z;INTERVAL=2
+X-MOZ-LASTACK:20190812T164503Z
+DTSTART;TZID=Europe/Berlin:20190812T190000
+DTEND;TZID=Europe/Berlin:20190812T200000
+DESCRIPTION:descr
+LOCATION:location
+SEQUENCE:2
+TRANSP:OPAQUE
+X-MOZ-GENERATION:5
+BEGIN:VALARM
+ACTION:DISPLAY
+TRIGGER;VALUE=DURATION:-PT15M
+DESCRIPTION:Default Mozilla Description
+END:VALARM
+END:VEVENT
+
+BEGIN:VEVENT
+CREATED:20190813T140257Z
+LAST-MODIFIED:20190813T140315Z
+DTSTAMP:20190813T140315Z
+UID:a13cca03-860a-4094-b162-e06f161a7681
+SUMMARY:flummy
+RECURRENCE-ID;TZID=Europe/Berlin:20190909T190000
+DTSTART;TZID=Europe/Berlin:20190909T130000
+DTEND;TZID=Europe/Berlin:20190909T140000
+DESCRIPTION:descr
+LOCATION:location
+SEQUENCE:3
+TRANSP:OPAQUE
+X-MOZ-GENERATION:5
+DURATION:PT0S
+CLASS:
+BEGIN:VALARM
+ACTION:DISPLAY
+TRIGGER;VALUE=DURATION:-PT15M
+DESCRIPTION:Default Mozilla Description
+END:VALARM
+END:VEVENT
+
+END:VCALENDAR

tests.py

@@ -444,6 +444,14 @@ def test_parseParams(self):
              ['NEXT', 'Nope'], ['BAR']]
         )
 
+    def test_thunderbird_duration_pt0s_workaround(self):
+        """
+        Test parsing thundebird generated ics streams having both a duration of
+        0 seconds and a dtend attribute.
+        """
+        cal = get_test_file("thunderbird_duration_pt0s_workaround.ics")
+        c = base.readOne(cal, validate=True)
+
 
 class TestVcards(unittest.TestCase):
     """

vobject/icalendar.py

@@ -1161,13 +1161,23 @@ class VEvent(RecurringBehavior):
     @classmethod
     def validate(cls, obj, raiseException, *args):
         if 'dtend' in obj.contents and 'duration' in obj.contents:
-            if raiseException:
-                m = "VEVENT components cannot contain both DTEND and DURATION\
-                     components"
-                raise ValidateError(m)
-            return False
-        else:
-            return super(VEvent, cls).validate(obj, raiseException, *args)
+            # Hack: Thunderbird's lightning calendar sometimes generates
+            # VEvents with dtend and a zero duration. Clean up these errors.
+            ignore = True
+            for duration in obj.contents.get('duration', ()):
+                duration.transformToNative()
+                if duration.value != datetime.timedelta(0):
+                    ignore = False
+            if ignore:
+                # Delete redundant zero duration
+                del obj.contents['duration']
+            else:
+                if raiseException:
+                    m = "VEVENT components cannot contain both DTEND and DURATION\
+                         components"
+                    raise ValidateError(m)
+                return False
+        return super(VEvent, cls).validate(obj, raiseException, *args)
 
 registerBehavior(VEvent)