fix(detail): clamp a backwards DTEND instead of dropping the event (#34)

toEventDetailCore returned null when a present DTEND preceded DTSTART, the
only remaining false-drop that surfaces as the generic "Something went
wrong." error screen — the same un-openable trap as the pre-1970 DTSTART
bug, and worse because the user can't even open the malformed event to fix
it. Clamp the end to DTSTART (a zero-length event) instead, matching how
SearchMapper already coerces its end. After this the detail mapper drops a
row only when DTSTART is genuinely absent (unrenderable).

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

CHANGELOG.md

@@ -5,9 +5,19 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
-## [Unreleased]
+## [2.13.0] — 2026-07-03
 
 ### Added
+- Calendula now speaks Spanish and Italian. Both arrived as community
+  translations through [Calendula's Weblate](https://weblate.dev.jeanlucmakiola.de/projects/calendula/)
+  — a **huge thank you** to
+  [kikerw](https://weblate.dev.jeanlucmakiola.de/user/kikerw/) for the Spanish
+  translation and to
+  [corrent](https://weblate.dev.jeanlucmakiola.de/user/corrent/) for the Italian
+  one! Pick your language under Settings → Language or in Android's per-app
+  language settings. Strings added in this very release may still show in
+  English until the translations catch up. Want Calendula in your language?
+  Translating happens entirely in the browser — every contribution is welcome.
 - See your contacts' birthdays and anniversaries in your calendar. A new,
   **optional** feature (Settings → Contact special dates) mirrors your contacts'
   birthdays, anniversaries and other dates into local "Birthdays",
@@ -33,6 +43,18 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   date number — now opens that day, and the "today" button snaps the grid back
   to the current month in place. Thanks to @rgz46vic and @ptab for the
   suggestions ([#18], [#20]).
+- Make Calendula's text your own. Settings → Appearance gains **Headings font**
+  and **Body font** pickers: keep the system default, choose a bundled face
+  (Atkinson Hyperlegible, Lora, JetBrains Mono — each previewed in its own
+  face), or load any `.ttf`/`.otf` file from your device, independently per
+  role. Font size and colour stay with Android's accessibility scaling and the
+  app theme, as discussed on the issue. Thanks to @abrossimow for the
+  suggestion ([#19]).
+- Choose what the view-switch button cycles through. Settings → Appearance now
+  lets you pick which views the top-right quick-switch button rotates between
+  and drag them into your preferred order; views you switch off stay reachable
+  from the navigation menu, which can be reordered the same way. Thanks to
+  @abrossimow for the suggestion ([#24]).
 
 ### Fixed
 - Month widget arrows and "today" button work again. On release builds the
@@ -49,6 +71,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   nothing applied. The edited occurrence is now stored correctly, so the change
   lands on just that one event and leaves the rest of the series untouched
   ([#16]).
+- Every calendar can be picked when creating an event. The event editor's
+  calendar picker was a fixed-height dialog, so with many calendars anything
+  past the first nine or so was simply unreachable. It is now a full-screen,
+  scrollable list grouped by account, with each calendar's colour shown.
+  Thanks to @dschuermann for the report ([#29]).
 
 ## [2.12.0] — 2026-06-28
 
@@ -779,4 +806,7 @@ automatically, with zero telemetry and no internet permission.
 [#16]: https://codeberg.org/jlmakiola/calendula/issues/16
 [#17]: https://codeberg.org/jlmakiola/calendula/issues/17
 [#18]: https://codeberg.org/jlmakiola/calendula/issues/18
+[#19]: https://codeberg.org/jlmakiola/calendula/issues/19
 [#20]: https://codeberg.org/jlmakiola/calendula/issues/20
+[#24]: https://codeberg.org/jlmakiola/calendula/issues/24
+[#29]: https://codeberg.org/jlmakiola/calendula/issues/29

app/build.gradle.kts

@@ -28,8 +28,8 @@ android {
         // which builds this version and then creates the matching vX.Y.Z tag +
         // release itself (versionCode is pinned to MAJOR*10000 + MINOR*100 +
         // PATCH from versionName, e.g. 2.7.2 -> 20702). See docs/RELEASING.md.
-        versionCode = 21200
-        versionName = "2.12.0"
+        versionCode = 21300
+        versionName = "2.13.0"
 
         testInstrumentationRunner = "androidx.test.runner.AndroidJUnitRunner"
     }

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/EventDetailMapper.kt

@@ -23,26 +23,29 @@ internal fun ColumnReader.toEventDetailCore(
     attendees: List<Attendee>,
     reminders: List<Reminder>,
 ): EventDetail? {
-    val begin = getLong(EventDetailProjection.IDX_DTSTART)
-
-    if (begin < 0L) {
-        Log.w(TAG, "Dropping event with negative dtstart=$begin")
+    // DTSTART is epoch millis in UTC, so a series anchored before 1970 (common
+    // for yearly birthdays/anniversaries synced over CalDAV) is legitimately
+    // negative — only an *absent* DTSTART marks a malformed row worth dropping.
+    // Dropping negatives made every occurrence of such a series un-openable
+    // (the detail loads the ancient series-master DTSTART), see issue #34.
+    if (isNull(EventDetailProjection.IDX_DTSTART)) {
+        Log.w(TAG, "Dropping event with missing dtstart")
         return null
     }
+    val begin = getLong(EventDetailProjection.IDX_DTSTART)
 
     // Recurring events store DURATION instead of DTEND, so the series row's
     // DTEND is null. Keep the event (end == begin); callers that opened a
     // specific occurrence supply the real per-occurrence times from
-    // CalendarContract.Instances. Only a present-but-backwards DTEND is malformed.
+    // CalendarContract.Instances. A present-but-backwards DTEND is malformed,
+    // but dropping the row would make the event un-openable — the same trap as
+    // the pre-1970 DTSTART bug above (issue #34): it would surface as the
+    // generic error screen with no way to open the event and fix it. Clamp to a
+    // zero-length event instead (matching SearchMapper's coerceAtLeast).
     val end = if (isNull(EventDetailProjection.IDX_DTEND)) {
         begin
     } else {
-        val rawEnd = getLong(EventDetailProjection.IDX_DTEND)
-        if (rawEnd < begin) {
-            Log.w(TAG, "Dropping event with dtend=$rawEnd < dtstart=$begin")
-            return null
-        }
-        rawEnd
+        getLong(EventDetailProjection.IDX_DTEND).coerceAtLeast(begin)
     }
 
     // Kept raw (no untitled fallback): the detail screen substitutes its own

app/src/main/java/de/jeanlucmakiola/calendula/data/calendar/SearchMapper.kt

@@ -10,8 +10,11 @@ import de.jeanlucmakiola.calendula.domain.ics.parseRfc2445DurationMillis
  * of DTEND — reconstruct the end the same way the `.ics` export does.
  */
 internal fun ColumnReader.toSearchResult(): EventInstance? {
+    // A pre-1970 series anchor is a legitimately negative epoch-millis DTSTART
+    // (see EventDetailMapper / issue #34); drop only a genuinely absent one, so
+    // long-running birthdays/anniversaries still surface in search.
+    if (isNull(SearchProjection.IDX_DTSTART)) return null
     val dtStart = getLong(SearchProjection.IDX_DTSTART)
-    if (dtStart < 0L) return null
     val end = when {
         !isNull(SearchProjection.IDX_DTEND) -> getLong(SearchProjection.IDX_DTEND)
         else -> dtStart + parseRfc2445DurationMillis(getString(SearchProjection.IDX_DURATION))

app/src/main/java/de/jeanlucmakiola/calendula/ui/common/TimePickerAlert.kt

@@ -4,14 +4,9 @@ import androidx.compose.material3.AlertDialog
 import androidx.compose.material3.ExperimentalMaterial3Api
 import androidx.compose.material3.Text
 import androidx.compose.material3.TextButton
-import android.content.Context
-import android.content.res.Resources
-import android.provider.Settings
-import android.text.format.DateFormat
 import androidx.compose.material3.TimePicker
 import androidx.compose.material3.rememberTimePickerState
 import androidx.compose.runtime.Composable
-import androidx.compose.ui.platform.LocalContext
 import androidx.compose.ui.res.stringResource
 import de.jeanlucmakiola.calendula.R
 import kotlinx.datetime.LocalTime
@@ -27,10 +22,13 @@ fun TimePickerAlert(
     onConfirm: (LocalTime) -> Unit,
     onDismiss: () -> Unit,
 ) {
+    // Honour the app's own time-format preference (the value every time label
+    // reads), not the system/locale clock — otherwise an explicit 24h setting
+    // still showed an AM/PM dial (issue #27).
     val state = rememberTimePickerState(
         initialHour = initial.hour,
         initialMinute = initial.minute,
-        is24Hour = deviceUses24HourClock(LocalContext.current),
+        is24Hour = LocalUse24HourFormat.current,
     )
     AlertDialog(
         onDismissRequest = onDismiss,
@@ -45,24 +43,3 @@ fun TimePickerAlert(
         text = { TimePicker(state = state) },
     )
 }
-
-/**
- * Whether the clock should read 24-hour, matching the rest of the device.
- *
- * [DateFormat.is24HourFormat] resolves a "locale default" system setting against
- * the *app's* context locale — and this app applies a per-app language
- * (AppCompatDelegate), so an English UI on a German-region phone would wrongly
- * read 12-hour while the system clock shows 24-hour. So we honour an explicit
- * system 12/24 override, and otherwise fall back to the **device** locale
- * (Resources.getSystem), not the app's.
- */
-private fun deviceUses24HourClock(context: Context): Boolean =
-    when (Settings.System.getString(context.contentResolver, Settings.System.TIME_12_24)) {
-        "24" -> true
-        "12" -> false
-        // 'a' is the AM/PM marker; a best-fit pattern without it is 24-hour.
-        else -> {
-            val deviceLocale = Resources.getSystem().configuration.locales[0]
-            !DateFormat.getBestDateTimePattern(deviceLocale, "jm").contains('a')
-        }
-    }

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/EventDetailMapperTest.kt

@@ -22,8 +22,8 @@ class EventDetailMapperTest {
         eventColor: Any? = null,
         eventColorKey: String? = null,
         calendarColor: Int = 0xFFAABBCC.toInt(),
-        dtstart: Long = 1_000_000_000L,
-        dtend: Long = 1_000_003_600L,
+        dtstart: Long? = 1_000_000_000L,
+        dtend: Long? = 1_000_003_600L,
         allDay: Int = 0,
         location: String? = "Berlin",
         calendarId: Long = 7L,
@@ -120,9 +120,31 @@ class EventDetailMapperTest {
     }
 
     @Test
-    fun `dtend before dtstart drops detail`() {
+    fun `dtend before dtstart is clamped to a zero-length event, not dropped`() {
+        // A backwards DTEND is malformed, but dropping it would make the event
+        // un-openable (the "Something went wrong" trap, same as issue #34); keep
+        // it as a zero-length event so the user can still open and fix it.
         val detail = detailReader(dtstart = 2000L, dtend = 1000L).toDetail()
-        assertThat(detail).isNull()
+        assertThat(detail).isNotNull()
+        assertThat(detail!!.instance.start.toEpochMilliseconds()).isEqualTo(2000L)
+        assertThat(detail.instance.end.toEpochMilliseconds()).isEqualTo(2000L)
+    }
+
+    @Test
+    fun `pre-1970 negative dtstart is kept, not dropped (issue #34)`() {
+        // A yearly birthday/anniversary anchored before the epoch has a
+        // legitimately negative UTC epoch-millis DTSTART; recurring rows carry
+        // no DTEND (they use DURATION), so it stays end == begin.
+        val begin = -157_766_400_000L // 1965-01-01T00:00:00Z
+        val detail = detailReader(dtstart = begin, dtend = null).toDetail()
+        assertThat(detail).isNotNull()
+        assertThat(detail!!.instance.start.toEpochMilliseconds()).isEqualTo(begin)
+        assertThat(detail.instance.end.toEpochMilliseconds()).isEqualTo(begin)
+    }
+
+    @Test
+    fun `absent dtstart drops detail`() {
+        assertThat(detailReader(dtstart = null).toDetail()).isNull()
     }
 
     @Test

app/src/test/java/de/jeanlucmakiola/calendula/data/calendar/SearchMapperTest.kt

@@ -0,0 +1,45 @@
+package de.jeanlucmakiola.calendula.data.calendar
+
+import com.google.common.truth.Truth.assertThat
+import org.junit.jupiter.api.Test
+
+class SearchMapperTest {
+
+    private fun searchReader(
+        id: Long = 1L,
+        calendarId: Long = 7L,
+        title: String? = "Birthday",
+        dtstart: Long? = 1_000_000_000L,
+        dtend: Long? = null,
+        duration: String? = "P1D",
+        allDay: Int = 1,
+        eventColor: Any? = null,
+        calendarColor: Int = 0xFFAABBCC.toInt(),
+        location: String? = null,
+    ): MapColumnReader = MapColumnReader(
+        SearchProjection.IDX_ID to id,
+        SearchProjection.IDX_CALENDAR_ID to calendarId,
+        SearchProjection.IDX_TITLE to title,
+        SearchProjection.IDX_DTSTART to dtstart,
+        SearchProjection.IDX_DTEND to dtend,
+        SearchProjection.IDX_DURATION to duration,
+        SearchProjection.IDX_ALL_DAY to allDay,
+        SearchProjection.IDX_EVENT_COLOR to eventColor,
+        SearchProjection.IDX_CALENDAR_COLOR to calendarColor,
+        SearchProjection.IDX_LOCATION to location,
+    )
+
+    @Test
+    fun `pre-1970 negative dtstart still surfaces in search (issue #34)`() {
+        val begin = -157_766_400_000L // 1965-01-01T00:00:00Z
+        val result = searchReader(dtstart = begin, dtend = null, duration = "P1D").toSearchResult()
+        assertThat(result).isNotNull()
+        assertThat(result!!.start.toEpochMilliseconds()).isEqualTo(begin)
+        assertThat(result.title).isEqualTo("Birthday")
+    }
+
+    @Test
+    fun `absent dtstart drops the search hit`() {
+        assertThat(searchReader(dtstart = null).toSearchResult()).isNull()
+    }
+}

fastlane/metadata/android/en-US/changelogs/21300.txt

@@ -0,0 +1,70 @@
+### Added
+- Calendula now speaks Spanish and Italian. Both arrived as community
+  translations through [Calendula's Weblate](https://weblate.dev.jeanlucmakiola.de/projects/calendula/)
+  — a **huge thank you** to
+  [kikerw](https://weblate.dev.jeanlucmakiola.de/user/kikerw/) for the Spanish
+  translation and to
+  [corrent](https://weblate.dev.jeanlucmakiola.de/user/corrent/) for the Italian
+  one! Pick your language under Settings → Language or in Android's per-app
+  language settings. Strings added in this very release may still show in
+  English until the translations catch up. Want Calendula in your language?
+  Translating happens entirely in the browser — every contribution is welcome.
+- See your contacts' birthdays and anniversaries in your calendar. A new,
+  **optional** feature (Settings → Contact special dates) mirrors your contacts'
+  birthdays, anniversaries and other dates into local "Birthdays",
+  "Anniversaries" and "Other dates" calendars that stay in sync as your contacts
+  change. Each is a normal local calendar, so you set its colour, visibility and
+  reminders the usual way — new birthdays even start with a reminder a week before
+  *and* on the day. The title format is yours to customise (`{name}`, `{year}`).
+  This is the first feature to use the contacts permission: it is requested only
+  when you turn the feature on, everything stays on your device (Calendula has no
+  internet access), and your contacts are only ever read, never changed. Thanks
+  to @moonj for the suggestion ([#15]).
+- Set more than one default reminder per calendar. A calendar's default
+  reminders — and the global defaults under Settings → Notifications — can now
+  hold several lead times instead of just one, so new events can start with, say,
+  a reminder a week before *and* one on the day. The reminder pickers are now
+  multi-select; per-calendar overrides can still inherit the global default or
+  turn reminders off entirely. Thanks to @moonj for the suggestion ([#14]).
+- Widget headers now open the app. Tapping the month/year title on the month
+  widget opens the app on the month view, and tapping the "Upcoming" title on
+  the agenda widget opens it on your default view — so there's a one-tap way
+  back into the app that lands where you'd expect, instead of only through a day
+  or event. On the month widget, tapping anywhere on a day — not just the small
+  date number — now opens that day, and the "today" button snaps the grid back
+  to the current month in place. Thanks to @rgz46vic and @ptab for the
+  suggestions ([#18], [#20]).
+- Make Calendula's text your own. Settings → Appearance gains **Headings font**
+  and **Body font** pickers: keep the system default, choose a bundled face
+  (Atkinson Hyperlegible, Lora, JetBrains Mono — each previewed in its own
+  face), or load any `.ttf`/`.otf` file from your device, independently per
+  role. Font size and colour stay with Android's accessibility scaling and the
+  app theme, as discussed on the issue. Thanks to @abrossimow for the
+  suggestion ([#19]).
+- Choose what the view-switch button cycles through. Settings → Appearance now
+  lets you pick which views the top-right quick-switch button rotates between
+  and drag them into your preferred order; views you switch off stay reachable
+  from the navigation menu, which can be reordered the same way. Thanks to
+  @abrossimow for the suggestion ([#24]).
+
+### Fixed
+- Month widget arrows and "today" button work again. On release builds the
+  prev/next-month arrows and the jump-to-today control on the month widget did
+  nothing when tapped — code shrinking had stripped the tap handlers behind
+  them. They respond again. Thanks to @rgz46vic for the report ([#18]).
+- Disabled calendars no longer notify. Reminders for events in a calendar you
+  have disabled (Settings → Calendars) are now suppressed instead of still
+  popping up — matching how a disabled calendar's events already stay hidden
+  everywhere else in the app ([#17]).
+- Editing a single occurrence of a recurring event works again. Choosing **Only
+  this event** and saving a change to one event in a repeating series silently
+  did nothing — the change was rejected and the edit form simply reappeared with
+  nothing applied. The edited occurrence is now stored correctly, so the change
+  lands on just that one event and leaves the rest of the series untouched
+  ([#16]).
+- Every calendar can be picked when creating an event. The event editor's
+  calendar picker was a fixed-height dialog, so with many calendars anything
+  past the first nine or so was simply unreachable. It is now a full-screen,
+  scrollable list grouped by account, with each calendar's colour shown.
+  Thanks to @dschuermann for the report ([#29]).
+