diff --git a/components/mail/__tests__/mail-app-mv-composer-move.test.tsx b/components/mail/__tests__/mail-app-mv-composer-move.test.tsx
new file mode 100644
index 000000000..d7e4acb55
--- /dev/null
+++ b/components/mail/__tests__/mail-app-mv-composer-move.test.tsx
@@ -0,0 +1,121 @@
+import React from 'react';
+import { fireEvent, render, screen, waitFor } from '@testing-library/react';
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+import type { Email, Mailbox } from '@/lib/jmap/types';
+import { useAuthStore } from '@/stores/auth-store';
+import { useEmailStore } from '@/stores/email-store';
+import { useSettingsStore } from '@/stores/settings-store';
+import { usePluginStore } from '@/stores/plugin-store';
+import { useThemeStore } from '@/stores/theme-store';
+import { DEFAULT_SEARCH_FILTERS } from '@/lib/jmap/search-utils';
+
+// Mountain View draws the composer in a window, a card or the reading pane
+// depending on the width, and React mounts it anew in each. What was typed has
+// to come along, or a narrowed window silently empties the message.
+
+const device = vi.hoisted(() => ({ current: { isMobile: false, isTablet: false, isDesktop: true } }));
+
+vi.mock('@/components/layout/mv-top-bar', () => ({ MvTopBar: () => null }));
+vi.mock('@/components/layout/sidebar', () => ({
+ Sidebar: ({ onCompose }: { onCompose: () => void }) => ,
+}));
+// The real composer's contract: its state starts from initialData, and it hands
+// its edits to onSaveState as it unmounts.
+vi.mock('@/components/email/email-composer', async () => {
+ const { useEffect, useRef, useState } = await import('react');
+ return {
+ EmailComposer: ({ initialData, onSaveState }: {
+ initialData?: { subject?: string } | null;
+ onSaveState: (data: { subject: string }) => void;
+ }) => {
+ const [subject, setSubject] = useState(initialData?.subject ?? '');
+ const latest = useRef(subject);
+ latest.current = subject;
+ useEffect(() => () => {
+ if (latest.current) onSaveState({ subject: latest.current });
+ // eslint-disable-next-line react-hooks/exhaustive-deps
+ }, []);
+ return setSubject(e.target.value)} />;
+ },
+ };
+});
+vi.mock('@/components/search/mv-search-form', () => ({
+ MvSearchForm: ({ onSearch }: { onSearch: () => void }) => ,
+}));
+vi.mock('@/components/email/email-viewer', () => ({ EmailViewer: () =>
message viewer
}));
+vi.mock('@/components/layout/navigation-rail', () => ({ NavigationRail: () => null }));
+vi.mock('@/components/layout/calendar-event-notification-toaster', () => ({ CalendarEventNotificationToaster: () => null }));
+vi.mock('@/components/layout/share-notification-toaster', () => ({ ShareNotificationToaster: () => null }));
+vi.mock('@/components/layout/mobile-header', () => ({ MobileHeader: () => null }));
+vi.mock('@/components/layout/mv-side-panel', () => ({ MvSidePanel: () => null }));
+vi.mock('@/components/email/message-list-tabs', () => ({ useMessageListPanelProps: (id: string) => ({ id }), MessageListTabs: () => null }));
+vi.mock('@/components/search/search-box', () => ({ SearchBox: () => null }));
+vi.mock('@/components/tour/tour-provider', () => ({ useTour: () => ({ activeTour: null, registerStep: vi.fn() }) }));
+vi.mock('@/components/plugins/plugin-slot', () => ({ PluginSlot: () => null }));
+vi.mock('@/hooks/use-plugin-slot-offers', () => ({ usePluginSlotOffers: () => [] }));
+vi.mock('@/hooks/use-config', () => ({ useConfig: () => ({ appName: 'Mail' }) }));
+vi.mock('@/hooks/use-identity-sync', () => ({ useIdentitySync: () => {} }));
+vi.mock('@/hooks/use-pro-multi-account-identities', () => ({ useProMultiAccountIdentities: () => [] }));
+vi.mock('@/hooks/use-pro-multi-account-mailboxes', () => ({ useProMultiAccountMailboxes: () => {} }));
+vi.mock('@/hooks/use-wopi-status', () => ({ useWopiStatus: () => null, canWopiOpen: () => false }));
+vi.mock('@/hooks/use-browser-navigation', () => ({ useBrowserNavigation: () => {} }));
+vi.mock('@/hooks/use-media-query', () => ({
+ useDeviceDetection: () => device.current,
+ useMediaQuery: () => false,
+ useIsDesktop: () => true,
+}));
+vi.mock('@/lib/push-bindings', () => ({ reconcilePushBindings: () => {}, releasePushBindings: () => {} }));
+vi.mock('@/components/email/email-list', () => ({ EmailList: () => message list
}));
+
+
+const { MailApp } = await import('../mail-app');
+
+const inbox = { id: 'inbox', name: 'Inbox', role: 'inbox', totalEmails: 0, unreadEmails: 0 } as Mailbox;
+
+beforeEach(() => {
+ device.current = { isMobile: false, isTablet: false, isDesktop: true };
+ vi.stubGlobal('fetch', vi.fn().mockRejectedValue(new Error('Unexpected network request')));
+ vi.stubGlobal('ResizeObserver', class { observe() {} unobserve() {} disconnect() {} });
+ usePluginStore.setState({ initializePlugins: vi.fn().mockResolvedValue(undefined) });
+ useThemeStore.setState({ syncServerThemes: vi.fn().mockResolvedValue(undefined) });
+ const client = {
+ getAccountId: () => 'acc', getUsername: () => 'a@example.org',
+ getSieveAccountId: () => null, hasDelayedSend: () => false, getSession: () => null,
+ };
+ useAuthStore.setState({
+ isAuthenticated: true, isLoading: false, client: client as never, activeAccountId: 'login-a', identities: [],
+ getClientForAccount: () => client as never,
+ getAllConnectedClients: () => new Map([['login-a', client]]) as never,
+ });
+ useSettingsStore.setState({ enableUnifiedMailbox: false, interfaceLayout: 'mountain-view', mailLayout: 'focus' } as never);
+ useEmailStore.setState({
+ emails: [], selectedEmail: null, selectedMailbox: 'inbox', selectedKeyword: null, mailboxes: [inbox],
+ viewingAccountId: null, accountMailboxes: {}, isUnifiedView: false, unifiedRole: null,
+ isScheduledView: false, isLoadingEmail: false, isLoading: false, searchQuery: '',
+ searchFilters: { ...DEFAULT_SEARCH_FILTERS }, searchMailboxId: '', isAdvancedSearchOpen: false,
+ selectedEmailKeys: new Set(), unreadSection: null,
+ fetchMailboxes: vi.fn().mockResolvedValue(undefined), fetchEmails: vi.fn().mockResolvedValue(undefined),
+ fetchQuota: vi.fn().mockResolvedValue(undefined), fetchTagCounts: vi.fn().mockResolvedValue(undefined),
+ refreshScheduledMetadata: vi.fn().mockResolvedValue(undefined),
+ } as never);
+});
+afterEach(() => {
+ vi.restoreAllMocks();
+ vi.unstubAllGlobals();
+});
+
+describe('moving the Mountain View composer between layouts', () => {
+ it('keeps what was typed when the window narrows past the desktop width and back', async () => {
+ const { rerender } = render();
+ fireEvent.click(screen.getByText('stub compose'));
+ fireEvent.change(await screen.findByLabelText('stub subject'), { target: { value: 'Still here' } });
+
+ device.current = { isMobile: false, isTablet: true, isDesktop: false };
+ rerender();
+ await waitFor(() => expect(screen.getByLabelText('stub subject').value).toBe('Still here'));
+
+ device.current = { isMobile: false, isTablet: false, isDesktop: true };
+ rerender();
+ await waitFor(() => expect(screen.getByLabelText('stub subject').value).toBe('Still here'));
+ });
+});
diff --git a/components/mail/mail-app.tsx b/components/mail/mail-app.tsx
index d68c18c98..592c33edd 100644
--- a/components/mail/mail-app.tsx
+++ b/components/mail/mail-app.tsx
@@ -259,6 +259,18 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
const [composerDraftText, setComposerDraftText] = useState("");
const [pendingDraft, setPendingDraft] = useState(null);
const [composerSessionId, setComposerSessionId] = useState(0);
+ // Mountain View draws the composer in a window, a card or the reading pane
+ // depending on the width, and React mounts it anew in each. The composer hands
+ // its edits over as it unmounts, too late for the one already mounting there,
+ // so that one is mounted once more with them.
+ const [composerRemount, setComposerRemount] = useState(0);
+ const composerSessionRef = useRef(composerSessionId);
+ composerSessionRef.current = composerSessionId;
+ const composerHostRef = useRef('pane');
+ const composerRemountHostRef = useRef('pane');
+ const composerRemountSessionRef = useRef(composerSessionId);
+ const showComposerRef = useRef(showComposer);
+ showComposerRef.current = showComposer;
// Fields a plugin filled in through onBeforeCompose for the composer about
// to open. Dropped once the composer hands its own state back, so a
// remount restores what the user wrote instead.
@@ -4525,6 +4537,12 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
const mvInlineReply = mvShell && showComposer && !isEmbedded && !mvReplyPoppedOut
&& (pendingDraft?.mode ?? composerMode) !== 'compose' && Boolean(selectedEmail);
const floatingComposer = mvShell && showComposer && !isEmbedded && !mvInlineReply;
+ const composerHost = floatingComposer ? 'window' : mvInlineReply ? 'inline' : 'pane';
+ composerHostRef.current = composerHost;
+ if (!showComposer || composerRemountSessionRef.current !== composerSessionId) {
+ composerRemountSessionRef.current = composerSessionId;
+ composerRemountHostRef.current = composerHost;
+ }
const hasViewerContent = (showComposer && !floatingComposer) || Boolean(conversationThread)
|| Boolean(selectedEmail && !(mvShell && cursorOnly)) || deepLinkPane !== null;
// A linked message on a phone opens over the list, as one picked there does.
@@ -4835,7 +4853,7 @@ export function MailApp({ linkSegments: routeSegments }: MailAppProps = {}) {
}}
>
n + 1);
+ }
setPendingDraft(data);
}}
onSend={async (data) => {