fix: stop a series edit or delete after an account switch instead of finishing it in the next account

src/components/calendar/EventModal.tsx

@@ -45,6 +45,7 @@ import {
 import { displayNow } from '../../lib/calendar-timezone';
 import { editorTimesChanged, editorTimesFromEvent, eventTimeFieldsToSave } from '../../lib/event-editor-times';
 import { useSettingsStore } from '../../stores/settings-store';
+import { CalendarAccountChangedError } from '../../stores/calendar-store';
 import { canCreateEventsIn } from '../../lib/calendar-editability';
 import { useCalendarLocale } from '../../lib/calendar-locale';
 import { formatCalendarDate } from '../../lib/date-format';
@@ -417,6 +418,12 @@ export function EventModal({
       });
       onClose();
     } catch (err) {
+      // The account changed under the save: the event is the previous
+      // account's, and the calendar shows another one now.
+      if (err instanceof CalendarAccountChangedError) {
+        onClose();
+        return;
+      }
       // The editor stays open with everything typed, and says why.
       NativeAlert.alert(
         t('calendar.notifications.event_error', 'Failed to save event'),

src/lib/__tests__/recurrence-scope-edit.test.ts

@@ -125,6 +125,25 @@ function actions(master: CalendarEvent | null) {
   } satisfies OccurrenceEditActions & { deleteEvent: (id: string) => Promise<void> };
 }
 
+/**
+ * `deps` with the account the operation starts in, as the store's
+ * calendarOperationScope gives it: after `switchAccount` its check throws.
+ */
+function scoped<D extends object>(deps: D) {
+  let changed = false;
+  return {
+    deps: {
+      ...deps,
+      operationScope: () => ({
+        assert: () => {
+          if (changed) throw new Error('The account changed');
+        },
+      }),
+    },
+    switchAccount: () => { changed = true; },
+  };
+}
+
 beforeEach(() => useSettingsStore.setState({ calendarTimeZone: 'Europe/Berlin' }));
 afterEach(() => useSettingsStore.setState({ calendarTimeZone: 'auto' }));
 
@@ -864,6 +883,39 @@ describe.each(occurrences)('saving this and the following occurrences on Stalwar
     expect(statusOf(created.participants, ORGANIZER)).toBe('accepted');
     expect(statusOf(created.participants, ATTENDEE)).toBe('needs-action');
   });
+
+  // The store writes to the account the client serves when a write begins:
+  // the rest of the series went to the next account's calendar of the same
+  // id, and invited its attendees.
+  it('makes no rest of the series once the account changed after ending it', async () => {
+    const occurrence = make();
+    const { deps, switchAccount } = scoped(actions(series(version)));
+    deps.updateEvent.mockImplementationOnce(async () => { switchAccount(); return undefined; });
+
+    await expect(saveOccurrenceEdit('this_and_future', {
+      event: occurrence, updates: editorUpdates(occurrence), editor: editorOn(occurrence),
+      calendarId: 'cal', sendScheduling: true, userEmails: [ORGANIZER],
+    }, deps)).rejects.toThrow('account changed');
+
+    expect(deps.updateEvent).toHaveBeenCalledTimes(1);
+    expect(deps.createEvent).not.toHaveBeenCalled();
+  });
+
+  it('puts nothing back in the next account when the account changed while making the rest', async () => {
+    const occurrence = make();
+    const { deps, switchAccount } = scoped(actions(series(version)));
+    deps.createEvent.mockImplementationOnce(async () => {
+      switchAccount();
+      throw new Error('The account changed while the calendar was saving.');
+    });
+
+    await expect(saveOccurrenceEdit('this_and_future', {
+      event: occurrence, updates: editorUpdates(occurrence), editor: editorOn(occurrence), sendScheduling: true, userEmails: [ORGANIZER],
+    }, deps)).rejects.toThrow('account changed');
+
+    // The truncation alone, no rollback.
+    expect(deps.updateEvent).toHaveBeenCalledTimes(1);
+  });
 });
 
 describe('the new series from this and the following occurrences', () => {
@@ -1156,6 +1208,31 @@ describe.each<[string, Version]>([['1.0', '1.0'], ['0.16', '0.16']])('the series
     expect(statusOf(change['recurrenceOverrides/2026-10-05T10:00:00'].participants as CalendarEvent['participants'], ATTENDEE)).toBe('accepted');
   });
 
+  it('sends no second step once the account changed after the first', async () => {
+    const master = base();
+    const { deps, switchAccount } = scoped(actions(master));
+    deps.updateEvent.mockImplementationOnce(async () => { switchAccount(); return undefined; });
+
+    await expect(saveOccurrenceEdit('this', {
+      event: master, updates: kickOff(master), sendScheduling: true, userEmails: [ORGANIZER],
+    }, deps)).rejects.toThrow('account changed');
+
+    expect(deps.updateEvent).toHaveBeenCalledTimes(1);
+    expect(deps.updateEvent.mock.calls[0][2]).toEqual({ sendSchedulingMessages: false });
+  });
+
+  it('excludes nothing once the account changed while the series was read', async () => {
+    const master = base();
+    const { deps, switchAccount } = scoped(actions(master));
+    deps.getMasterEvent.mockImplementationOnce(async () => { switchAccount(); return master; });
+
+    await expect(deleteOccurrence('this', { event: master, userEmails: [ORGANIZER] }, deps)).rejects.toThrow('account changed');
+    await expect(deleteOccurrence('this_and_future', { event: master, userEmails: [ORGANIZER] }, deps)).rejects.toThrow('account changed');
+
+    expect(deps.updateEvent).not.toHaveBeenCalled();
+    expect(deps.deleteEvent).not.toHaveBeenCalled();
+  });
+
   it('changes it in one write when nobody has answered, or nothing is sent', async () => {
     const unanswered = base({
       participants: { org: participant(version, ORGANIZER, true, 'accepted'), b: participant(version, ATTENDEE, false, 'needs-action') },

src/lib/recurrence-scope-edit.ts

@@ -581,6 +581,39 @@ export interface OccurrenceEditActions {
   ) => Promise<CalendarEvent | null | undefined>;
   /** The base event of a series, from one of its occurrences. */
   getMasterEvent: (occurrence: CalendarEvent) => Promise<CalendarEvent | null>;
+  /**
+   * The account the edit is made in, taken once when it starts (the store's
+   * calendarOperationScope); `assert` throws once the client serves another.
+   * Each step is a write of its own: after an account switch the next one
+   * went to the next account with this one's ids - the rest of a split
+   * series made in its calendar of the same id, mailed to its attendees.
+   */
+  operationScope?: () => { assert: () => void };
+}
+
+/**
+ * `actions` with the account checked before every step, against one scope
+ * for the whole operation: the store writes to the account the client serves
+ * when a write begins, and a rollback after the switch would undo nothing of
+ * this account. Steps handed on (a this-and-future edit from the first
+ * occurrence saves as 'all') keep that scope.
+ */
+function inOneScope<A extends Partial<OccurrenceEditActions & OccurrenceDeleteActions>>(actions: A): A {
+  const scope = actions.operationScope?.();
+  if (!scope) return actions;
+  const checked = <F extends (...args: never[]) => Promise<unknown>>(step: F | undefined) =>
+    step && (((...args: Parameters<F>) => {
+      scope.assert();
+      return step(...args);
+    }) as unknown as F);
+  return {
+    ...actions,
+    operationScope: () => scope,
+    updateEvent: checked(actions.updateEvent),
+    createEvent: checked(actions.createEvent),
+    deleteEvent: checked(actions.deleteEvent),
+    getMasterEvent: checked(actions.getMasterEvent),
+  };
 }
 
 export interface OccurrenceEdit {
@@ -923,8 +956,9 @@ export function followingSeriesData(
 export async function saveOccurrenceEdit(
   scope: RecurrenceEditScope,
   edit: OccurrenceEdit,
-  actions: OccurrenceEditActions,
+  unscoped: OccurrenceEditActions,
 ): Promise<boolean> {
+  const actions = inOneScope(unscoped);
   const { updateEvent, createEvent } = actions;
   const { event, updates, sendScheduling } = edit;
   const scheduling = { sendSchedulingMessages: sendScheduling };
@@ -1009,7 +1043,7 @@ export async function saveOccurrenceEdit(
 }
 
 /** What deleting part of a series works with: the calendar store's actions. */
-export interface OccurrenceDeleteActions extends Pick<OccurrenceEditActions, 'updateEvent' | 'getMasterEvent'> {
+export interface OccurrenceDeleteActions extends Pick<OccurrenceEditActions, 'updateEvent' | 'getMasterEvent' | 'operationScope'> {
   deleteEvent: (id: string) => Promise<void>;
 }
 
@@ -1022,8 +1056,9 @@ export interface OccurrenceDeleteActions extends Pick<OccurrenceEditActions, 'up
 export async function deleteOccurrence(
   scope: RecurrenceEditScope,
   deletion: { event: CalendarEvent; userEmails: string[] },
-  actions: OccurrenceDeleteActions,
+  unscoped: OccurrenceDeleteActions,
 ): Promise<boolean> {
+  const actions = inOneScope(unscoped);
   const { event } = deletion;
   if (scope === 'this') {
     if (isServerRecurrenceInstance(event) || isBrowserExpandedOccurrence(event)) {

src/screens/CalendarScreen.tsx

@@ -40,7 +40,7 @@ import { useCalendarLocale } from '../lib/calendar-locale';
 import { displayNow } from '../lib/calendar-timezone';
 import { spacing, radius, typography, type ThemePalette } from '../theme/tokens';
 import { useColors } from '../theme/colors';
-import { useCalendarStore } from '../stores/calendar-store';
+import { CalendarAccountChangedError, calendarOperationScope, useCalendarStore } from '../stores/calendar-store';
 import { useSettingsStore } from '../stores/settings-store';
 import { MonthView } from '../components/calendar/MonthView';
 import { MonthScrollView } from '../components/calendar/MonthScrollView';
@@ -635,6 +635,9 @@ export default function CalendarScreen() {
 
   const reportError = React.useCallback(
     (err: unknown) => {
+      // The account changed under the write: nothing failed in the account
+      // shown now, and the previous one shows what got in when it is back.
+      if (err instanceof CalendarAccountChangedError) return;
       Alert.alert(
         t('calendar.notifications.event_error', 'Something went wrong'),
         err instanceof Error ? err.message : undefined,
@@ -724,12 +727,14 @@ export default function CalendarScreen() {
             sendScheduling: action.sendScheduling,
             userEmails: currentUserEmails,
             resolveName: resolveContactName,
-          }, { updateEvent, createEvent, getMasterEvent })
+          }, { updateEvent, createEvent, getMasterEvent, operationScope: calendarOperationScope })
           : await deleteOccurrence(scope, { event, userEmails: currentUserEmails }, {
-            updateEvent, deleteEvent, getMasterEvent,
+            updateEvent, deleteEvent, getMasterEvent, operationScope: calendarOperationScope,
           });
         if (!done) throw new Error('Master event not found');
       } catch (err) {
+        // The account changed under the edit: it stopped there (see reportError).
+        if (err instanceof CalendarAccountChangedError) return;
         Alert.alert(
           t('calendar.notifications.event_error', 'Something went wrong'),
           participantLimitMessage(err, t) ?? (err instanceof Error ? err.message : undefined),

src/screens/__tests__/calendar-account-change-silent.test.ts

@@ -0,0 +1,41 @@
+// A calendar write the account switch overtook throws
+// CalendarAccountChangedError: the write stopped so that nothing reaches the
+// next account. Nothing failed in the account shown now, and the alert
+// "Something went wrong" came up over it. The places that show a calendar
+// write's error pass it over in silence.
+import { describe, it, expect } from 'vitest';
+import { readFileSync } from 'node:fs';
+import { join } from 'node:path';
+
+const SRC = join(__dirname, '../..');
+
+/** The text of `file` from `marker` to the first `Alert.alert(` after it. */
+function beforeAlert(file: string, marker: string): string {
+  const src = readFileSync(join(SRC, file), 'utf8');
+  const start = src.indexOf(marker);
+  expect(start).toBeGreaterThanOrEqual(0);
+  const alert = src.indexOf('Alert.alert(', start);
+  expect(alert).toBeGreaterThan(start);
+  return src.slice(start, alert);
+}
+
+const SILENT = /if \(err instanceof CalendarAccountChangedError\)/;
+
+describe('a calendar write the account switch stopped shows no error', () => {
+  it('CalendarScreen reportError', () => {
+    expect(beforeAlert('screens/CalendarScreen.tsx', 'const reportError = React.useCallback(')).toMatch(SILENT);
+  });
+
+  it('CalendarScreen saving or deleting part of a series', () => {
+    expect(beforeAlert('screens/CalendarScreen.tsx', "if (!done) throw new Error('Master event not found');")).toMatch(SILENT);
+  });
+
+  it('EventModal save', () => {
+    expect(beforeAlert('components/calendar/EventModal.tsx', 'await onSave(data, calendarId, {')).toMatch(SILENT);
+  });
+
+  it('CalendarScreen gives the scope edits one account for the whole operation', () => {
+    const src = readFileSync(join(SRC, 'screens/CalendarScreen.tsx'), 'utf8');
+    expect(src.match(/operationScope: calendarOperationScope/g)).toHaveLength(2);
+  });
+});

src/stores/__tests__/calendar-store-account-switch.test.ts

@@ -99,7 +99,10 @@ describe('a write the account switch overtook', () => {
   it('names the account it started in and leaves the next account\'s event alone (updateEvent)', async () => {
     mockUpdate.mockImplementationOnce(async () => switchAccount());
 
-    await useCalendarStore.getState().updateEvent('c', { title: 'Renamed' });
+    // Fails, so that a caller with more steps (lib/recurrence-scope-edit)
+    // sends no next one to the next account.
+    await expect(useCalendarStore.getState().updateEvent('c', { title: 'Renamed' }))
+      .rejects.toBeInstanceOf(CalendarAccountChangedError);
 
     expect(mockUpdate).toHaveBeenCalledWith('c', { title: 'Renamed' }, undefined, 'acc-1');
     expect(useCalendarStore.getState().events).toEqual([THEIRS]);
@@ -108,7 +111,7 @@ describe('a write the account switch overtook', () => {
   it('leaves the next account\'s event of the same id in the store (deleteEvent)', async () => {
     mockDelete.mockImplementationOnce(async () => switchAccount());
 
-    await useCalendarStore.getState().deleteEvent('c');
+    await expect(useCalendarStore.getState().deleteEvent('c')).rejects.toBeInstanceOf(CalendarAccountChangedError);
 
     expect(mockDelete).toHaveBeenCalledWith(['c'], undefined, 'acc-1');
     expect(useCalendarStore.getState().events).toEqual([THEIRS]);
@@ -120,7 +123,7 @@ describe('a write the account switch overtook', () => {
       return event('n', 'New');
     });
 
-    await useCalendarStore.getState().createEvent({ title: 'New' }, 'b');
+    await expect(useCalendarStore.getState().createEvent({ title: 'New' }, 'b')).rejects.toBeInstanceOf(CalendarAccountChangedError);
 
     expect(mockCreate).toHaveBeenCalledWith({ title: 'New' }, 'b', undefined, 'acc-1');
     expect(mockGetEvents).not.toHaveBeenCalled();

src/stores/__tests__/calendar-store-series-edits.test.ts

@@ -36,7 +36,8 @@ vi.mock('../../api/jmap-client', () => ({
 
 import * as calendarApi from '../../api/calendar';
 import type { CalendarEvent } from '../../api/types';
-import { useCalendarStore } from '../calendar-store';
+import { jmapClient } from '../../api/jmap-client';
+import { CalendarAccountChangedError, calendarOperationScope, useCalendarStore } from '../calendar-store';
 import { saveOccurrenceEdit } from '../../lib/recurrence-scope-edit';
 import { editorTimesFromEvent } from '../../lib/event-editor-times';
 
@@ -98,6 +99,39 @@ describe('this and the following occurrences on the calendar store (Stalwart 1.0
     expect([calendarId, schedule]).toEqual(['cal-1', true]);
     expect(created).toMatchObject({ start: '2026-10-19T10:00:00', recurrenceRules: [{ '@type': 'RecurrenceRule', frequency: 'weekly', count: 3 }] });
   });
+
+  // The account changes while the store reloads after ending the series:
+  // that write is done, and the next one took the account the client served
+  // by then - the rest of the series went to acc-2's calendar of the same id.
+  it('makes no rest of the series in the account the client serves after a switch', async () => {
+    const store = useCalendarStore.getState();
+    const refresh = store.refresh;
+    useCalendarStore.setState({
+      refresh: async () => {
+        useCalendarStore.getState().reset();
+        (jmapClient as { accountId: string }).accountId = 'acc-2';
+      },
+    });
+    try {
+      await expect(saveOccurrenceEdit('this_and_future', {
+        event: occurrence,
+        updates: { title: 'Planning, room 2', start: occurrence.start, duration: 'PT1H', timeZone: 'Europe/Berlin', participants },
+        editor: { attendees: [{ name: '', email: 'userb@example.org' }], when: editorTimesFromEvent(occurrence) },
+        calendarId: 'cal-1', sendScheduling: true, userEmails: [ORGANIZER],
+      }, {
+        updateEvent: store.updateEvent, createEvent: store.createEvent, getMasterEvent: store.getMasterEvent,
+        operationScope: calendarOperationScope,
+      })).rejects.toBeInstanceOf(CalendarAccountChangedError);
+    } finally {
+      (jmapClient as { accountId: string }).accountId = 'acc-1';
+      useCalendarStore.setState({ refresh });
+    }
+
+    // The truncation in acc-1, and nothing after it: no new series, no rollback.
+    expect(mockUpdate).toHaveBeenCalledTimes(1);
+    expect(mockUpdate.mock.calls[0][3]).toBe('acc-1');
+    expect(mockCreate).not.toHaveBeenCalled();
+  });
 });
 
 // The series itself, opened from a reminder or a link: not in the grid, and

src/stores/calendar-store.ts

@@ -361,6 +361,19 @@ function assertInScope(scope: WriteScope): void {
   if (!inScope(scope)) throw new CalendarAccountChangedError();
 }
 
+/**
+ * The account an operation of several store writes runs in (the scope edits
+ * in lib/recurrence-scope-edit), taken once when it starts. Each write takes
+ * the account the client serves when it begins, so a step after an account
+ * switch went to the next account with the ids of this one. `assert` throws
+ * CalendarAccountChangedError once the store was reset or the client serves
+ * another account.
+ */
+export function calendarOperationScope(): { assert: () => void } {
+  const scope = writeScope();
+  return { assert: () => assertInScope(scope) };
+}
+
 /**
  * The JMAP account a write goes to, named on every request: a shared
  * calendar's owner, else the primary account the write started in.
@@ -1072,8 +1085,9 @@ export const useCalendarStore = create<CalendarState>()(
       schedule,
       writeAccount(scope, accountId),
     );
-    // Made; the store shows another account by now.
-    if (!inScope(scope)) return created;
+    // Made; the store shows another account by now. Throws so that a caller
+    // with more to do stops here, and opens nothing of the previous account.
+    assertInScope(scope);
     // The /set echo lacks server-computed properties (utcStart/utcEnd, the
     // normalised recurrence rule); re-read the event so it renders at the
     // right instant, then expand a recurring series across the loaded range
@@ -1085,7 +1099,7 @@ export const useCalendarStore = create<CalendarState>()(
     } catch {
       // Keep the echo; the next refresh reconciles.
     }
-    if (!inScope(scope)) return full;
+    assertInScope(scope);
     // Map the same way fetchEvents does so the optimistic insert doesn't
     // collide with the user's own events and stays visible under the right
     // calendar filter.
@@ -1179,8 +1193,9 @@ export const useCalendarStore = create<CalendarState>()(
     } else {
       await updateBaseEvent(realId, patch, schedule, account, scope);
     }
-    // Saved; the store shows another account by now, whose events can carry the same ids.
-    if (!inScope(scope)) return;
+    // Saved; the store shows another account by now, whose events can carry
+    // the same ids. Throws so that a caller with more steps sends no next one.
+    assertInScope(scope);
     set({
       events: get().events.map((e) => (e.id === id ? { ...e, ...(changes as Partial<CalendarEvent>) } : e)),
     });
@@ -1206,16 +1221,17 @@ export const useCalendarStore = create<CalendarState>()(
     const schedule = hasSchedulingParticipants(storeEvent) ? true : undefined;
     if (target.isOccurrence && storeEvent) {
       await destroyOccurrence(storeEvent, realId, schedule, writeAccount(scope, accountId), scope);
-      if (!inScope(scope)) return;
+      assertInScope(scope);
       set({ events: get().events.filter((e) => e.id !== id) });
     } else if (target.isBrowserOccurrence) {
       await destroyBrowserOccurrence(target, schedule, scope);
-      if (!inScope(scope)) return;
+      assertInScope(scope);
       set({ events: get().events.filter((e) => e.id !== id) });
     } else {
       await apiDeleteEvents([realId], schedule, writeAccount(scope, accountId));
-      // Deleted; the store shows another account by now, whose events can carry the same ids.
-      if (!inScope(scope)) return;
+      // Deleted; the store shows another account by now, whose events can
+      // carry the same ids. Throws as updateEvent does.
+      assertInScope(scope);
       knownMasters.delete(id);
       // Destroying a master removes every expanded occurrence of it, not
       // just the tapped one.