Changelog

All notable changes to this project will be documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

0.1.4 - 2026-05-21

Fixed iCalendar DTSTART/DTEND parsing to handle TZID parameters (e.g., DTSTART;TZID=America/Los_Angeles:20260120T160000)
Events with timezone-aware datetime properties now correctly parse and convert to UTC
Added proper handling for DST transitions:
- Fall-back (ambiguous times): chooses first occurrence
- Spring-forward (gap times): chooses time after the gap
Events from Apple Calendar and other iCalendar clients with TZID parameters now parse correctly
CRITICAL: Fixed timezone database dependency - library now works without consumer config
- All datetime operations use explicit Tz.TimeZoneDatabase parameter
- Applies to TZID parsing, UTC conversion, and CalDAV time-range formatting
- Previously required consumers to configure :elixir, :time_zone_database in their app
- Library now works out-of-the-box when added as a dependency
Fixed RFC5545 compliance: TZID parameter now correctly parsed regardless of position or case
- Handles multiple parameters in any order (e.g., DTSTART;VALUE=DATE-TIME;TZID=...)
- Case-insensitive property name matching per RFC5545 specification
- Supports quoted TZID parameter values (e.g., TZID="America/New_York")

Improved test coverage with comprehensive test cases for TZID parsing, including:
- Timezone conversion for various timezones
- DST transition handling (fall-back ambiguous and spring-forward gap times)
- Error handling for invalid timezones and malformed datetimes
- Backward compatibility with UTC and DATE formats
- RFC5545 compliance (multiple parameters, quoted values, case-insensitivity)
Performance optimization: precompiled TZID extraction regexes at module compile-time
- Eliminates repeated regex compilation overhead when processing multiple events
- Zero runtime cost for regex compilation
Stricter datetime validation: regex now enforces exact iCalendar DATE-TIME format (YYYYMMDDTHHmmss)
- Rejects malformed datetime values early (e.g., extra digits, missing separators)
- Prevents partial matches on invalid input
RFC5545 line unfolding: properly handles continuation lines in iCalendar data
- Unfolds lines that begin with space or tab per RFC5545 section 3.1
- Ensures TZID extraction works with folded properties and XML-indented content
Improved error handling: replaced bang functions with explicit error handling
- Uses DateTime.shift_zone/3 instead of shift_zone!/2 with blanket rescue
- Explicit handling of {:ok, dt} and {:error, reason} for better debugging
- Separated timezone resolution logic for clarity