Fix talk reminders firing 2h late by using device timezone#1
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GerardPaligot wants to merge 1 commit into
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Fix talk reminders firing 2h late by using device timezone#1GerardPaligot wants to merge 1 commit into
GerardPaligot wants to merge 1 commit into
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Schedule start times come from the backend as event-local wall-clock LocalDateTime strings without an offset (e.g. "2026-06-11T08:30" for a session in Lille). The Android alarm scheduler re-interpreted them as UTC, so for a Europe/Paris event the reminder fired CEST's +2h offset late. Interpret the start time in TimeZone.currentSystemDefault() instead, so the alarm fires at the time displayed in the app. This matches the existing convention in Sessions.kt (tabSelected/closestTimeSlotKey), which already compares schedule times against the device's local now. Extract the conversion into a pure reminderTriggerAtMillis() helper in commonMain so it can be unit-tested deterministically with an explicit timezone. Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
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Problem
Local notifications for favorited talks fire 2 hours late on Android for an event in Lille (
Europe/Paris).The backend returns schedule times as event-local wall-clock
LocalDateTimestrings with no offset, e.g.:AlarmScheduler.android.ktre-attachedTimeZone.UTCto that value, turning "08:30 Lille" into "08:30 UTC" = "10:30 Lille". The error equalsEurope/Paris's summer offset (CEST = UTC+2).Root cause
The backend is correct — it stores UTC instants and renders them into the event timezone for the V4 payload. The bug was solely on the consumer:
Fix
Interpret the start time in
TimeZone.currentSystemDefault()so the alarm fires at the time displayed in the app. This matches the existing convention inSessions.kt(tabSelected()/closestTimeSlotKey()), which already compares schedule times against the device's local "now".The conversion is extracted into a pure
reminderTriggerAtMillis()helper incommonMainso it can be unit-tested deterministically with an explicit timezone.Tests
ReminderTimeTest:"2026-06-11T08:30"inEurope/Paris+ 10-min reminder →06:20 UTC, with a regression guard asserting it is not08:20 UTC(the old behavior).:shared:core:desktopTest,:shared:core:compileAndroidMain,:shared:core:ktlintCheck,:shared:core:detektall pass.Known limitation
Uses the device timezone, which is correct for an attendee whose phone is in the event's zone. Making cross-timezone reminder-setting watertight would require exposing the event timezone (already in
EventsTable.timezone) through the client DTOs/DB — a larger follow-up.🤖 Generated with Claude Code