Fix for dtstart persisted with an invalid timezone

ical/todo.py

@@ -25,7 +25,7 @@
 from .component import ComponentModel, validate_until_dtstart, validate_recurrence_dates
 from .exceptions import CalendarParseError
 from .iter import RulesetIterable
-from .parsing.property import ParsedProperty
+from .parsing.property import ParsedProperty, ParsedPropertyParameter
 from .timespan import Timespan
 from .types import (
     CalAddress,
@@ -37,6 +37,7 @@
     RequestStatus,
     Uri,
     RelatedTo,
+    date_time,
 )
 from .util import dtstamp_factory, normalize_datetime, uid_factory, local_timezone
 
@@ -364,7 +365,46 @@ def _validate_due_later(cls, values: dict[str, Any]) -> dict[str, Any]:
             values["dtstart"] = due - datetime.timedelta(days=1)
         return values
 
+    @classmethod
+    def _parse_single_property(cls, field_type: type, prop: ParsedProperty) -> Any:
+        """Parse an individual field as a single type."""
+        try:
+            return super()._parse_single_property(field_type, prop)
+        except ValueError as err:
+            if (
+                prop.name == "dtstart"
+                and field_type == datetime.datetime
+                and prop.params is not None
+            ):
+                new_prop = ParsedProperty(
+                    prop.name, prop.value, _repair_tzid_param(prop.params)
+                )
+                _LOGGER.debug(
+                    "Applying todo dtstart repair for invalid timezone: %s", new_prop
+                )
+                try:
+                    return date_time.parse_property_value(new_prop)
+                except ValueError as repair_err:
+                    _LOGGER.debug(
+                        "To-do dtstart repair failed %s, raising original error",
+                        repair_err,
+                    )
+            raise err
+
     _validate_until_dtstart = root_validator(allow_reuse=True)(validate_until_dtstart)
     _validate_recurrence_dates = root_validator(allow_reuse=True)(
         validate_recurrence_dates
     )
+
+
+def _repair_tzid_param(
+    params: list[ParsedPropertyParameter],
+) -> list[ParsedPropertyParameter]:
+    """Repair the TZID parameter."""
+    result_params = []
+    for param in params:
+        if param.name == "TZID":
+            result_params.append(ParsedPropertyParameter(param.name, ["UTC"]))
+            continue
+        result_params.append(param)
+    return result_params

ical/types/date_time.py

@@ -20,6 +20,46 @@
 ATTR_VALUE = "VALUE"
 
 
+def parse_property_value(
+    prop: ParsedProperty, allow_invalid_timezone: bool = False
+) -> datetime.datetime:
+    """Parse a rfc5545 into a datetime.datetime."""
+    if not (match := DATETIME_REGEX.fullmatch(prop.value)):
+        raise ValueError(f"Expected value to match DATE-TIME pattern: {prop.value}")
+
+    # Example: TZID=America/New_York:19980119T020000
+    timezone: datetime.tzinfo | None = None
+    if param := prop.get_parameter(TZID):
+        if param.values and (value := param.values[0]):
+            if isinstance(value, datetime.tzinfo):
+                timezone = value
+            else:
+                try:
+                    timezone = zoneinfo.ZoneInfo(value)
+                except zoneinfo.ZoneInfoNotFoundError:
+                    if allow_invalid_timezone:
+                        timezone = None
+                    raise ValueError(
+                        f"Expected DATE-TIME TZID value '{value}' to be valid timezone"
+                    )
+    elif match.group(3):  # Example: 19980119T070000Z
+        timezone = datetime.timezone.utc
+
+    # Example: 19980118T230000
+    date_value = match.group(1)
+    year = int(date_value[0:4])
+    month = int(date_value[4:6])
+    day = int(date_value[6:])
+    time_value = match.group(2)
+    hour = int(time_value[0:2])
+    minute = int(time_value[2:4])
+    second = int(time_value[4:6])
+
+    result = datetime.datetime(year, month, day, hour, minute, second, tzinfo=timezone)
+    _LOGGER.debug("DateTimeEncoder returned %s", result)
+    return result
+
+
 @DATA_TYPE.register("DATE-TIME", parse_order=2)
 class DateTimeEncoder:
     """Class to handle encoding for a datetime.datetime."""
@@ -31,40 +71,7 @@ def __property_type__(cls) -> type:
     @classmethod
     def __parse_property_value__(cls, prop: ParsedProperty) -> datetime.datetime:
         """Parse a rfc5545 into a datetime.datetime."""
-        if not (match := DATETIME_REGEX.fullmatch(prop.value)):
-            raise ValueError(f"Expected value to match DATE-TIME pattern: {prop.value}")
-
-        # Example: TZID=America/New_York:19980119T020000
-        timezone: datetime.tzinfo | None = None
-        if param := prop.get_parameter(TZID):
-            if param.values and (value := param.values[0]):
-                if isinstance(value, datetime.tzinfo):
-                    timezone = value
-                else:
-                    try:
-                        timezone = zoneinfo.ZoneInfo(value)
-                    except zoneinfo.ZoneInfoNotFoundError:
-                        raise ValueError(
-                            f"Expected DATE-TIME TZID value '{value}' to be valid timezone"
-                        )
-        elif match.group(3):  # Example: 19980119T070000Z
-            timezone = datetime.timezone.utc
-
-        # Example: 19980118T230000
-        date_value = match.group(1)
-        year = int(date_value[0:4])
-        month = int(date_value[4:6])
-        day = int(date_value[6:])
-        time_value = match.group(2)
-        hour = int(time_value[0:2])
-        minute = int(time_value[2:4])
-        second = int(time_value[4:6])
-
-        result = datetime.datetime(
-            year, month, day, hour, minute, second, tzinfo=timezone
-        )
-        _LOGGER.debug("DateTimeEncoder returned %s", result)
-        return result
+        return parse_property_value(prop, allow_invalid_timezone=False)
 
     @classmethod
     def __encode_property_json__(cls, value: datetime.datetime) -> str | dict[str, str]:

tests/__snapshots__/test_calendar_stream.ambr

@@ -1088,6 +1088,41 @@
     ]),
   })
 # ---
+# name: test_parse[todo-invalid-dtstart-tzid]
+  dict({
+    'calendars': list([
+      dict({
+        'prodid': '-//hacksw/handcal//NONSGML v1.0//EN',
+        'todos': list([
+          dict({
+            'categories': list([
+              'FAMILY',
+              'FINANCE',
+            ]),
+            'classification': 'CONFIDENTIAL',
+            'dtstamp': '2007-03-13T12:34:32+00:00',
+            'dtstart': '2007-05-01T11:00:00+00:00',
+            'due': '2007-05-01T11:00:00-07:00',
+            'status': 'NEEDS-ACTION',
+            'summary': 'Submit Quebec Income Tax Return for 2006',
+            'uid': '20070313T123432Z-456553@example.com',
+          }),
+          dict({
+            'completed': '2007-07-07T10:00:00+00:00',
+            'dtstamp': '2007-05-14T10:32:11+00:00',
+            'dtstart': '2007-05-14T11:00:00+00:00',
+            'due': '2007-07-09T13:00:00+00:00',
+            'priority': 1,
+            'status': 'NEEDS-ACTION',
+            'summary': 'Submit Revised Internet-Draft',
+            'uid': '20070514T103211Z-123404@example.com',
+          }),
+        ]),
+        'version': '2.0',
+      }),
+    ]),
+  })
+# ---
 # name: test_parse[todo]
   dict({
     'calendars': list([
@@ -1799,6 +1834,35 @@
   END:VCALENDAR
   '''
 # ---
+# name: test_serialize[todo-invalid-dtstart-tzid]
+  '''
+  BEGIN:VCALENDAR
+  PRODID:-//hacksw/handcal//NONSGML v1.0//EN
+  VERSION:2.0
+  BEGIN:VTODO
+  DTSTAMP:20070313T123432Z
+  UID:20070313T123432Z-456553@example.com
+  CATEGORIES:FAMILY
+  CATEGORIES:FINANCE
+  CLASS:CONFIDENTIAL
+  DTSTART:20070501T110000Z
+  DUE;TZID=America/Los_Angeles:20070501T110000
+  STATUS:NEEDS-ACTION
+  SUMMARY:Submit Quebec Income Tax Return for 2006
+  END:VTODO
+  BEGIN:VTODO
+  DTSTAMP:20070514T103211Z
+  UID:20070514T103211Z-123404@example.com
+  COMPLETED:20070707T100000Z
+  DTSTART:20070514T110000Z
+  DUE:20070709T130000Z
+  PRIORITY:1
+  STATUS:NEEDS-ACTION
+  SUMMARY:Submit Revised Internet-Draft
+  END:VTODO
+  END:VCALENDAR
+  '''
+# ---
 # name: test_serialize[todo]
   '''
   BEGIN:VCALENDAR

tests/testdata/todo-invalid-dtstart-tzid.ics

@@ -0,0 +1,24 @@
+BEGIN:VCALENDAR
+PRODID:-//hacksw/handcal//NONSGML v1.0//EN
+VERSION:2.0
+BEGIN:VTODO
+UID:20070313T123432Z-456553@example.com
+DTSTAMP:20070313T123432Z
+SUMMARY:Submit Quebec Income Tax Return for 2006
+DTSTART;TZID=CST:20070501T110000
+DUE;TZID=America/Los_Angeles:20070501T110000
+CLASS:CONFIDENTIAL
+CATEGORIES:FAMILY,FINANCE
+STATUS:NEEDS-ACTION
+END:VTODO
+BEGIN:VTODO
+UID:20070514T103211Z-123404@example.com
+DTSTAMP:20070514T103211Z
+SUMMARY:Submit Revised Internet-Draft
+DTSTART;TZID=CST:20070514T110000
+DUE:20070709T130000Z
+COMPLETED:20070707T100000Z
+PRIORITY:1
+STATUS:NEEDS-ACTION
+END:VTODO
+END:VCALENDAR