fix(persistence): preserve authoritative state on write failures

Keep SQLite authoritative after completed migration even when legacy JSON is later invalid, reject non-object config documents before any migration state is written, and guard async secret masking by input generation. Persist renderer-facing config and queue mutations before updating memory so SQLite errors reject IPC calls and retain the last durable queue snapshot.

src/main.ts

@@ -52,6 +52,7 @@ import { registerTrustedIpcHandler } from './main/domain/privileged-ipc';
 import { createRendererQueueItem, getMergeGroupCleanupPaths } from './main/domain/renderer-queue-input';
 import { createAppStateStore, type AppStateStore } from './main/domain/app-state-store';
 import { createExportableConfig } from './main/domain/config-export';
+import { persistStateChange } from './main/domain/persistence-commit';
 import { resolveSecretInputUpdate } from './main/domain/secret-input';
 import { createSecretStore, type SecretStore } from './main/domain/secret-store';
 import { createElectronSecureStorage } from './main/infra/secure-storage';
@@ -456,17 +457,15 @@ function normalizeConfigTemplates(input: Config): Config {
 
 function recordDownloadedVodId(vodId: string): void {
     if (!vodId) return;
-    if (!Array.isArray(config.downloaded_vod_ids)) config.downloaded_vod_ids = [];
+    const downloadedVodIds = Array.isArray(config.downloaded_vod_ids) ? config.downloaded_vod_ids : [];
-    if (config.downloaded_vod_ids.includes(vodId)) return;
+    if (downloadedVodIds.includes(vodId)) return;
-    config.downloaded_vod_ids.push(vodId);
-    // Cap to keep config size bounded — drop oldest first.
     const DOWNLOADED_IDS_MAX = 4096;
-    if (config.downloaded_vod_ids.length > DOWNLOADED_IDS_MAX) {
+    const nextDownloadedVodIds = [...downloadedVodIds, vodId].slice(-DOWNLOADED_IDS_MAX);
-        config.downloaded_vod_ids = config.downloaded_vod_ids.slice(
+    config = persistStateChange(config, (current) => ({ ...current, downloaded_vod_ids: nextDownloadedVodIds }), saveConfig);
-            config.downloaded_vod_ids.length - DOWNLOADED_IDS_MAX
-        );
 }
-    saveConfig(config);
+
+function cloneConfig(value: Config): Config {
+    return JSON.parse(JSON.stringify(value)) as Config;
 }
 
 function loadConfig(): Config {
@@ -481,12 +480,14 @@ function loadConfig(): Config {
     return normalizeConfigTemplates(defaultConfig);
 }
 
-function saveConfig(config: Config): void {
+function saveConfig(nextConfig: Config): void {
-    try {
     if (!appStateStore) throw new Error('Application state store is unavailable');
-        appStateStore.saveConfig(config);
+    try {
-    } catch (e) {
+        appStateStore.saveConfig(nextConfig);
-        console.error('Error saving config:', e);
+        lastPersistedConfig = cloneConfig(nextConfig);
+    } catch (error) {
+        if (nextConfig === config) config = cloneConfig(lastPersistedConfig);
+        throw error;
     }
 }
 
@@ -635,12 +636,14 @@ function loadQueue(): QueueItem[] {
 let queueSaveTimer: NodeJS.Timeout | null = null;
 let pendingQueueSnapshot: QueueItem[] | null = null;
 
-function clearQueueFileFromDisk(): void {
+function cloneQueue(queue: QueueItem[]): QueueItem[] {
-    try {
+    return JSON.parse(JSON.stringify(queue)) as QueueItem[];
-        appStateStore?.saveQueue([]);
-    } catch (e) {
-        console.error('Error clearing queue file:', e);
 }
+
+function clearQueueFileFromDisk(): void {
+    if (!appStateStore) throw new Error('Application state store is unavailable');
+    appStateStore.saveQueue([]);
+    lastPersistedQueueSnapshot = [];
 }
 
 function writeQueueToDisk(queue: QueueItem[]): void {
@@ -649,26 +652,14 @@ function writeQueueToDisk(queue: QueueItem[]): void {
         return;
     }
 
-    try {
     if (!appStateStore) throw new Error('Application state store is unavailable');
     appStateStore.saveQueue(queue);
-    } catch (e) {
+    lastPersistedQueueSnapshot = cloneQueue(queue);
-        console.error('Error saving queue:', e);
-    }
 }
 
 function saveQueue(queue: QueueItem[], force = false): void {
-    if (config.persist_queue_on_restart === false) {
+    const snapshot = cloneQueue(queue);
-        pendingQueueSnapshot = null;
+    pendingQueueSnapshot = snapshot;
-        if (queueSaveTimer) {
-            clearTimeout(queueSaveTimer);
-            queueSaveTimer = null;
-        }
-        clearQueueFileFromDisk();
-        return;
-    }
-
-    pendingQueueSnapshot = queue;
 
     if (appShutdownStarted && !force) {
         if (queueSaveTimer) {
@@ -678,28 +669,19 @@ function saveQueue(queue: QueueItem[], force = false): void {
         return;
     }
 
-    if (force) {
     if (queueSaveTimer) {
         clearTimeout(queueSaveTimer);
         queueSaveTimer = null;
     }
 
-        writeQueueToDisk(pendingQueueSnapshot);
+    try {
+        writeQueueToDisk(snapshot);
         pendingQueueSnapshot = null;
-        return;
+    } catch (error) {
-    }
-
-    if (queueSaveTimer) {
-        return;
-    }
-
-    queueSaveTimer = setTimeout(() => {
-        queueSaveTimer = null;
-        if (pendingQueueSnapshot) {
-            writeQueueToDisk(pendingQueueSnapshot);
         pendingQueueSnapshot = null;
+        if (queue === downloadQueue) downloadQueue = cloneQueue(lastPersistedQueueSnapshot);
+        throw error;
     }
-    }, QUEUE_SAVE_DEBOUNCE_MS);
 }
 
 function flushQueueSave(): void {
@@ -731,10 +713,12 @@ function startDevelopmentReload(): void {
 let appStateStore: AppStateStore | null = null;
 let appSecretStore: SecretStore | null = null;
 let config = normalizeConfigTemplates(defaultConfig);
+let lastPersistedConfig = cloneConfig(config);
 let twitchClientSecret = '';
 let discordWebhookUrl = '';
 let accessToken: string | null = null;
 let downloadQueue: QueueItem[] = [];
+let lastPersistedQueueSnapshot: QueueItem[] = [];
 let queueIdCounter = 0;
 let lastQueueBroadcastFingerprint = '';
 let isDownloading = false;
@@ -7289,7 +7273,8 @@ ipcMain.handle('save-config', (event, newConfig: Partial<Config>, fileCapability
             delete acceptedConfig.download_path;
         }
     }
-    config = normalizeConfigTemplates({ ...config, ...acceptedConfig });
+    const nextConfig = normalizeConfigTemplates({ ...config, ...acceptedConfig });
+    config = persistStateChange(config, () => nextConfig, saveConfig);
 
     if (config.client_id !== previousClientId) {
         accessToken = null;
@@ -7304,8 +7289,6 @@ ipcMain.handle('save-config', (event, newConfig: Partial<Config>, fileCapability
         nativeTheme.themeSource = config.theme === 'light' ? 'light' : 'dark';
     }
 
-    saveConfig(config);
-
     if (config.persist_queue_on_restart === false) {
         pendingQueueSnapshot = null;
         if (queueSaveTimer) {
@@ -7408,8 +7391,7 @@ ipcMain.handle('start-live-recording', async (event, streamerName: string) => {
         return { success: false, error: 'ALREADY_RECORDING', streamer: login };
     }
 
-    downloadQueue.push(liveItem);
+    downloadQueue = persistStateChange(downloadQueue, (current) => [...current, liveItem], saveQueue);
-    saveQueue(downloadQueue);
     emitQueueUpdated();
     if (!isDownloading) scheduleQueueProcessing();
     appendDebugLog('live-recording-queued', { streamer: login, title: liveItem.title });
@@ -7434,8 +7416,7 @@ registerTrustedIpcHandler(ipcMain, 'add-to-queue', isTrustedRendererEvent, () =>
         return downloadQueue;
     }
 
-    downloadQueue.push(item);
+    downloadQueue = persistStateChange(downloadQueue, (current) => [...current, item], saveQueue);
-    saveQueue(downloadQueue);
     emitQueueUpdated();
     return downloadQueue;
 });
@@ -7461,16 +7442,14 @@ registerTrustedIpcHandler(ipcMain, 'remove-from-queue', isTrustedRendererEvent,
         try { if (fs.existsSync(cleanupPath)) fs.unlinkSync(cleanupPath); } catch { }
     }
 
-    downloadQueue = downloadQueue.filter(item => item.id !== id);
+    downloadQueue = persistStateChange(downloadQueue, (current) => current.filter((item) => item.id !== id), saveQueue);
-    saveQueue(downloadQueue);
     emitQueueUpdated();
     return downloadQueue;
 });
 
 ipcMain.handle('clear-completed', (event) => {
     if (!isTrustedRendererEvent(event)) return downloadQueue;
-    downloadQueue = downloadQueue.filter(item => item.status !== 'completed');
+    downloadQueue = persistStateChange(downloadQueue, (current) => current.filter((item) => item.status !== 'completed'), saveQueue);
-    saveQueue(downloadQueue);
     emitQueueUpdated();
     return downloadQueue;
 });
@@ -7484,8 +7463,7 @@ ipcMain.handle('reorder-queue', (event, orderIds: string[]) => {
         return ai - bi;
     });
 
-    downloadQueue = withOrder;
+    downloadQueue = persistStateChange(downloadQueue, () => withOrder, saveQueue);
-    saveQueue(downloadQueue);
     emitQueueUpdated();
     return downloadQueue;
 });
@@ -7495,18 +7473,18 @@ ipcMain.handle('retry-failed-downloads', async (event) => {
     const failedIds = downloadQueue.filter((item) => item.status === 'error').map((item) => item.id);
     await Promise.all(failedIds.map((id) => queueProcessRegistry.cancelItem(id)));
     for (const id of failedIds) queueProcessRegistry.resetItem(id);
-    downloadQueue = downloadQueue.map((item) => {
+    const nextQueue: QueueItem[] = downloadQueue.map((item) => {
         if (item.status !== 'error') return item;
 
         return {
             ...item,
-            status: 'pending',
+            status: 'pending' as const,
             progress: 0,
             last_error: ''
         };
     });
 
-    saveQueue(downloadQueue);
+    downloadQueue = persistStateChange(downloadQueue, () => nextQueue, saveQueue);
     emitQueueUpdated();
 
     if (!isDownloading) {
@@ -7527,14 +7505,12 @@ ipcMain.handle('retry-queue-item', async (event, id: string) => {
     await queueProcessRegistry.cancelItem(id);
     queueProcessRegistry.resetItem(id);
 
-    downloadQueue[idx] = {
+    downloadQueue = persistStateChange(downloadQueue, (current) => current.map((candidate) => candidate.id === id ? {
-        ...item,
+        ...candidate,
         status: 'pending',
         progress: 0,
         last_error: ''
-    };
+    } : candidate), saveQueue);
-
-    saveQueue(downloadQueue);
     emitQueueUpdated();
     appendDebugLog('queue-item-retry-single', { id, title: item.title });
 
@@ -7615,10 +7591,9 @@ ipcMain.handle('create-merge-group', (event, itemIds: string[]) => {
     const firstIndex = downloadQueue.findIndex(item => itemIds.includes(item.id));
 
     // Remove selected items and insert merged item at first position
-    downloadQueue = downloadQueue.filter(item => !itemIds.includes(item.id));
+    const nextQueue = downloadQueue.filter((item) => !itemIds.includes(item.id));
-    downloadQueue.splice(firstIndex >= 0 ? Math.min(firstIndex, downloadQueue.length) : downloadQueue.length, 0, mergedItem);
+    nextQueue.splice(firstIndex >= 0 ? Math.min(firstIndex, nextQueue.length) : nextQueue.length, 0, mergedItem);
-
+    downloadQueue = persistStateChange(downloadQueue, () => nextQueue, saveQueue);
-    saveQueue(downloadQueue);
     emitQueueUpdated();
     return downloadQueue;
 });
@@ -7626,26 +7601,24 @@ ipcMain.handle('create-merge-group', (event, itemIds: string[]) => {
 ipcMain.handle('start-download', async (event) => {
     if (!isTrustedRendererEvent(event)) return false;
     if (isDownloading && queuePaused) {
+        const nextQueue = downloadQueue.map((item) => item.status === 'paused' ? { ...item, status: 'downloading' as const } : item);
+        downloadQueue = persistStateChange(downloadQueue, () => nextQueue, saveQueue);
         queuePaused = false;
-        for (const item of downloadQueue) {
-            if (item.status === 'paused') item.status = 'downloading';
-        }
         await Promise.all(queueProcessRegistry.activeItemIds().map((id) => queueProcessRegistry.resumeItem(id)));
-        saveQueue(downloadQueue);
         emitQueueUpdated(true);
         mainWindow?.webContents.send('download-started');
         return true;
     }
 
-    downloadQueue = downloadQueue.map((item) => item.status === 'paused' ? { ...item, status: 'pending' } : item);
+    const nextQueue = downloadQueue.map((item) => item.status === 'paused' ? { ...item, status: 'pending' as const } : item);
 
-    const hasPendingItems = downloadQueue.some(item => item.status === 'pending');
+    const hasPendingItems = nextQueue.some(item => item.status === 'pending');
     if (!hasPendingItems) {
         emitQueueUpdated();
         return false;
     }
 
-    saveQueue(downloadQueue);
+    downloadQueue = persistStateChange(downloadQueue, () => nextQueue, saveQueue);
     emitQueueUpdated();
 
     if (!isDownloading) {
@@ -7658,17 +7631,16 @@ ipcMain.handle('pause-download', async (event) => {
     if (!isTrustedRendererEvent(event)) return false;
     if (!isDownloading || queuePaused) return false;
 
-    queuePaused = true;
     await Promise.all(queueProcessRegistry.activeItemIds().map((id) => queueProcessRegistry.pauseItem(id)));
-    for (const item of downloadQueue) {
+    const nextQueue = downloadQueue.map((item) => item.status === 'downloading' ? {
-        if (item.status === 'downloading') {
+        ...item,
-            item.status = 'paused';
+        status: 'paused' as const,
-            item.speed = '';
+        speed: '',
-            item.eta = '';
+        eta: '',
-            item.progressStatus = tBackend('downloadPaused');
+        progressStatus: tBackend('downloadPaused')
-        }
+    } : item);
-    }
+    downloadQueue = persistStateChange(downloadQueue, () => nextQueue, saveQueue);
-    saveQueue(downloadQueue);
+    queuePaused = true;
     emitQueueUpdated(true);
     mainWindow?.webContents.send('download-paused');
     return true;
@@ -8170,16 +8142,17 @@ ipcMain.handle('export-runtime-metrics', async (event) => {
 ipcMain.handle('mark-vod-downloaded', (event, vodId: string, mark: boolean): { success: boolean } => {
     if (!isTrustedRendererEvent(event)) return { success: false };
     if (typeof vodId !== 'string' || !vodId) return { success: false };
-    if (!Array.isArray(config.downloaded_vod_ids)) config.downloaded_vod_ids = [];
+    const downloadedVodIds = Array.isArray(config.downloaded_vod_ids) ? config.downloaded_vod_ids : [];
-    const has = config.downloaded_vod_ids.includes(vodId);
+    const has = downloadedVodIds.includes(vodId);
+    let nextDownloadedVodIds: string[];
     if (mark && !has) {
-        config.downloaded_vod_ids.push(vodId);
+        nextDownloadedVodIds = [...downloadedVodIds, vodId];
     } else if (!mark && has) {
-        config.downloaded_vod_ids = config.downloaded_vod_ids.filter((id) => id !== vodId);
+        nextDownloadedVodIds = downloadedVodIds.filter((id) => id !== vodId);
     } else {
         return { success: true };
     }
-    saveConfig(config);
+    config = persistStateChange(config, (current) => ({ ...current, downloaded_vod_ids: nextDownloadedVodIds }), saveConfig);
     appendDebugLog('mark-vod-downloaded', { vodId, mark });
     return { success: true };
 });
@@ -8187,8 +8160,7 @@ ipcMain.handle('mark-vod-downloaded', (event, vodId: string, mark: boolean): { s
 ipcMain.handle('reset-downloaded-vod-ids', (event) => {
     if (!isTrustedRendererEvent(event)) return { success: false, removedCount: 0 };
     const count = Array.isArray(config.downloaded_vod_ids) ? config.downloaded_vod_ids.length : 0;
-    config.downloaded_vod_ids = [];
+    config = persistStateChange(config, (current) => ({ ...current, downloaded_vod_ids: [] }), saveConfig);
-    saveConfig(config);
     appendDebugLog('reset-downloaded-vod-ids', { previousCount: count });
     return { success: true, removedCount: count };
 });
@@ -8254,8 +8226,7 @@ ipcMain.handle('import-config', async (event) => {
         delete imported.__exportedAt;
         const merged = normalizeConfigTemplates({ ...config, ...imported } as Config);
 
-        config = merged;
+        config = persistStateChange(config, () => merged, saveConfig);
-        saveConfig(config);
         appendDebugLog('config-import-applied', { source: importPath });
         return { success: true, filePath: importPath };
     } catch (e) {
@@ -8481,8 +8452,10 @@ app.whenReady().then(() => {
         if (result.errors.length > 0) throw new Error(result.errors.map((entry: { source: string; message: string }) => `${entry.source}: ${entry.message}`).join('; '));
         appStateStore = createAppStateStore(database);
         config = loadConfig();
+        lastPersistedConfig = cloneConfig(config);
         downloadQueue = config.persist_queue_on_restart === false ? [] : loadQueue();
         if (config.persist_queue_on_restart === false) appStateStore.saveQueue([]);
+        lastPersistedQueueSnapshot = cloneQueue(downloadQueue);
         twitchClientSecret = appSecretStore.get('twitch_client_secret') ?? '';
         discordWebhookUrl = appSecretStore.get('discord_webhook_url') ?? '';
     } catch (e) {
@@ -8494,7 +8467,9 @@ app.whenReady().then(() => {
         appStateStore = null;
         appSecretStore = null;
         config = normalizeConfigTemplates(defaultConfig);
+        lastPersistedConfig = cloneConfig(config);
         downloadQueue = [];
+        lastPersistedQueueSnapshot = [];
         twitchClientSecret = '';
         discordWebhookUrl = '';
     }

src/main/domain/migrator.test.ts

@@ -181,6 +181,42 @@ describe('migrateJsonToSqlite', () => {
         expect(JSON.parse(language!.value)).toBe('de');
     });
 
+    test('keeps SQLite config queue and secrets authoritative after a corrupted legacy config restart', () => {
+        const configPath = writeJson('config.json', { language: 'de', client_secret: 'persisted-secret' });
+        writeJson('download_queue.json', [{ id: 'q1', status: 'pending', title: 'Persisted queue item' }]);
+        let secrets = createSecretStore(db, new MemorySecureStorage());
+
+        migrateJsonToSqlite({ db, appDataDir, secrets });
+        db.close();
+        db = openDatabase(path.join(tmpDir, 'app.db'));
+        secrets = createSecretStore(db, new MemorySecureStorage());
+        fs.writeFileSync(configPath, '{ no longer valid JSON', 'utf-8');
+
+        const restart = migrateJsonToSqlite({ db, appDataDir, secrets });
+
+        expect(restart).toMatchObject({ alreadyApplied: true, errors: [] });
+        expect(JSON.parse(db.get<{ value: string }>('SELECT value FROM config_kv WHERE key = ?', ['language'])!.value)).toBe('de');
+        expect(db.all<{ id: string }>('SELECT id FROM queue_items ORDER BY queue_position')).toEqual([{ id: 'q1' }]);
+        expect(secrets.get('twitch_client_secret')).toBe('persisted-secret');
+    });
+
+    test.each([
+        ['null', null],
+        ['false', false],
+        ['zero', 0],
+        ['empty string', ''],
+    ])('does not mark or partially migrate a syntactically valid but invalid %s config', (_, invalidConfig) => {
+        writeJson('config.json', invalidConfig);
+        writeJson('download_queue.json', [{ id: 'q1', status: 'pending' }]);
+
+        const result = migrateJsonToSqlite({ db, appDataDir });
+
+        expect(result.errors).toEqual([{ source: 'config.json', message: 'Config JSON must be an object' }]);
+        expect(db.all('SELECT * FROM config_kv')).toEqual([]);
+        expect(db.all('SELECT * FROM queue_items')).toEqual([]);
+        expect(db.get('SELECT name FROM migrations_applied WHERE name = ?', ['authoritative-state-v1'])).toBeUndefined();
+    });
+
     test('does not let the former shadow-migration marker skip authoritative secret import', () => {
         const configPath = writeJson('config.json', { language: 'de', client_secret: 'legacy-secret' });
         db.run('INSERT INTO migrations_applied(name, payload) VALUES (?, ?)', ['v4-to-v5-jsons', '{}']);

src/main/domain/migrator.ts

@@ -82,11 +82,6 @@ export function migrateJsonToSqlite(opts: MigratorOptions): MigrationResult {
     const queuePath = path.join(appDataDir, 'download_queue.json');
     const existing = db.get<{ name: string }>('SELECT name FROM migrations_applied WHERE name = ?', [MIGRATION_NAME]);
     if (existing) {
-        try {
-            scrubExistingConfig(configPath);
-        } catch (error) {
-            return emptyResult(true, [{ source: 'config.json', message: error instanceof Error ? error.message : String(error) }]);
-        }
         return emptyResult(true);
     }
 
@@ -99,7 +94,7 @@ export function migrateJsonToSqlite(opts: MigratorOptions): MigrationResult {
         errors.push({ source: 'download_queue.json', message: 'Queue JSON must be an array' });
     }
     if (errors.length > 0) return emptyResult(false, errors);
-    if (config && (typeof config !== 'object' || Array.isArray(config))) {
+    if (configExists && (!config || typeof config !== 'object' || Array.isArray(config))) {
         return emptyResult(false, [{ source: 'config.json', message: 'Config JSON must be an object' }]);
     }
     if (config && !secrets && [...SECRET_KEYS].some((key) => typeof config[key] === 'string' && config[key])) {

src/main/domain/persistence-commit.test.ts

@@ -0,0 +1,62 @@
+import { afterEach, beforeEach, describe, expect, it } from 'vitest';
+import * as fs from 'node:fs';
+import * as os from 'node:os';
+import * as path from 'node:path';
+import { openDatabase, type DbHandle } from '../infra/db';
+import { createAppStateStore } from './app-state-store';
+import { persistStateChange } from './persistence-commit';
+
+let directory: string;
+let db: DbHandle;
+
+beforeEach(() => {
+    directory = fs.mkdtempSync(path.join(os.tmpdir(), 'persistence-commit-'));
+    db = openDatabase(path.join(directory, 'app.db'));
+});
+
+afterEach(() => {
+    db.close();
+    fs.rmSync(directory, { recursive: true, force: true });
+});
+
+describe('persistStateChange', () => {
+    it('keeps runtime configuration at the persisted value when a SQLite write fails', () => {
+        const previous = { language: 'de' };
+        const next = { language: 'en' };
+        createAppStateStore(db).saveConfig(previous);
+        const failingDb: DbHandle = {
+            ...db,
+            run(sql, params) {
+                if (sql.includes('INSERT INTO config_kv')) throw new Error('SQLITE_IOERR config');
+                db.run(sql, params);
+            },
+        };
+        let runtime = previous;
+
+        expect(() => {
+            runtime = persistStateChange(runtime, () => next, (candidate) => createAppStateStore(failingDb).saveConfig(candidate));
+        }).toThrow('SQLITE_IOERR config');
+        expect(runtime).toEqual(previous);
+        expect(createAppStateStore(db).loadConfig()).toMatchObject(previous);
+    });
+
+    it('keeps runtime queue at the persisted snapshot when a SQLite write fails', () => {
+        const previous = [{ id: 'q1', status: 'pending' }];
+        const next = [{ id: 'q2', status: 'pending' }];
+        createAppStateStore(db).saveQueue(previous);
+        const failingDb: DbHandle = {
+            ...db,
+            run(sql, params) {
+                if (sql.includes('INSERT OR REPLACE INTO queue_items')) throw new Error('SQLITE_IOERR queue');
+                db.run(sql, params);
+            },
+        };
+        let runtime = previous;
+
+        expect(() => {
+            runtime = persistStateChange(runtime, () => next, (candidate) => createAppStateStore(failingDb).saveQueue(candidate));
+        }).toThrow('SQLITE_IOERR queue');
+        expect(runtime).toEqual(previous);
+        expect(createAppStateStore(db).loadQueue()).toEqual(previous);
+    });
+});

src/main/domain/persistence-commit.ts

@@ -0,0 +1,5 @@
+export function persistStateChange<T>(current: T, createNext: (current: T) => T, persist: (next: T) => void): T {
+    const next = createNext(current);
+    persist(next);
+    return next;
+}

src/main/domain/secret-input.test.ts

@@ -1,5 +1,5 @@
 import { describe, expect, it } from 'vitest';
-import { resolveSecretInputUpdate } from './secret-input';
+import { createSecretInputRevision, isSecretInputRevisionCurrent, resolveSecretInputUpdate } from './secret-input';
 
 describe('resolveSecretInputUpdate', () => {
     it('keeps a configured secret when the masked value is unchanged', () => {
@@ -17,4 +17,23 @@ describe('resolveSecretInputUpdate', () => {
     it('ignores an empty field when no secret is configured', () => {
         expect(resolveSecretInputUpdate('', false)).toEqual({ action: 'unchanged' });
     });
+
+    it('does not apply a completed save mask after a newer secret input arrives', async () => {
+        const revision = createSecretInputRevision();
+        const requestRevision = revision.current();
+        let resolveSave: (() => void) | undefined;
+        let visibleValue = 'first-secret';
+        const save = new Promise<void>((resolve) => {
+            resolveSave = resolve;
+        }).then(() => {
+            if (isSecretInputRevisionCurrent(revision, requestRevision)) visibleValue = '••••••••';
+        });
+
+        revision.advance();
+        visibleValue = 'second-secret';
+        resolveSave?.();
+        await save;
+
+        expect(visibleValue).toBe('second-secret');
+    });
 });

src/main/domain/secret-input.ts

@@ -5,6 +5,27 @@ export type SecretInputUpdate =
 
 export const SECRET_INPUT_MASK = '••••••••';
 
+export interface SecretInputRevision {
+    current(): number;
+    advance(): void;
+}
+
+export function createSecretInputRevision(): SecretInputRevision {
+    let value = 0;
+    return {
+        current() {
+            return value;
+        },
+        advance() {
+            value += 1;
+        },
+    };
+}
+
+export function isSecretInputRevisionCurrent(revision: SecretInputRevision, value: number): boolean {
+    return revision.current() === value;
+}
+
 export function resolveSecretInputUpdate(value: string, configured: boolean): SecretInputUpdate {
     if (configured && value === SECRET_INPUT_MASK) return { action: 'unchanged' };
     const normalized = value.trim();

src/renderer-settings.ts

@@ -12,6 +12,11 @@ let secretStatus: SecretStatus = {
     clientSecretConfigured: false,
     discordWebhookConfigured: false
 };
+type SecretInputId = 'clientSecret' | 'discordWebhookUrl';
+const secretInputGenerations: Record<SecretInputId, number> = {
+    clientSecret: 0,
+    discordWebhookUrl: 0
+};
 
 function canRunSettingsAutoRefresh(): boolean {
     if (document.hidden) {
@@ -586,30 +591,44 @@ function collectCredentialsPayload(): Partial<AppConfig> {
     };
 }
 
+function secretConfigured(inputId: SecretInputId): boolean {
+    return inputId === 'clientSecret' ? secretStatus.clientSecretConfigured : secretStatus.discordWebhookConfigured;
+}
+
+function syncSecretField(inputId: SecretInputId): void {
+    byId<HTMLInputElement>(inputId).value = secretConfigured(inputId) ? SECRET_INPUT_MASK : '';
+}
+
 function syncSecretFields(): void {
-    byId<HTMLInputElement>('clientSecret').value = secretStatus.clientSecretConfigured ? SECRET_INPUT_MASK : '';
+    syncSecretField('clientSecret');
-    byId<HTMLInputElement>('discordWebhookUrl').value = secretStatus.discordWebhookConfigured ? SECRET_INPUT_MASK : '';
+    syncSecretField('discordWebhookUrl');
+}
+
+async function persistSecretInput(inputId: SecretInputId): Promise<void> {
+    const requestGeneration = secretInputGenerations[inputId];
+    const value = byId<HTMLInputElement>(inputId).value;
+    if (value === SECRET_INPUT_MASK) return;
+
+    const configured = secretConfigured(inputId);
+    let nextStatus = secretStatus;
+    if (value.trim()) {
+        nextStatus = inputId === 'clientSecret'
+            ? await window.api.setClientSecret(value.trim())
+            : await window.api.setDiscordWebhook(value.trim());
+    } else if (configured) {
+        nextStatus = inputId === 'clientSecret'
+            ? await window.api.clearClientSecret()
+            : await window.api.clearDiscordWebhook();
+    }
+
+    if (secretInputGenerations[inputId] !== requestGeneration) return;
+    secretStatus = nextStatus;
+    syncSecretField(inputId);
 }
 
 async function persistSecretInputs(): Promise<void> {
-    const clientValue = byId<HTMLInputElement>('clientSecret').value;
+    await persistSecretInput('clientSecret');
-    if (clientValue !== SECRET_INPUT_MASK) {
+    await persistSecretInput('discordWebhookUrl');
-        secretStatus = clientValue.trim()
-            ? await window.api.setClientSecret(clientValue.trim())
-            : secretStatus.clientSecretConfigured
-                ? await window.api.clearClientSecret()
-                : secretStatus;
-    }
-
-    const webhookValue = byId<HTMLInputElement>('discordWebhookUrl').value;
-    if (webhookValue !== SECRET_INPUT_MASK) {
-        secretStatus = webhookValue.trim()
-            ? await window.api.setDiscordWebhook(webhookValue.trim())
-            : secretStatus.discordWebhookConfigured
-                ? await window.api.clearDiscordWebhook()
-                : secretStatus;
-    }
-    syncSecretFields();
 }
 
 function syncPartMinutesFieldState(): void {
@@ -725,9 +744,9 @@ function getSettingsFingerprint(payload: Partial<AppConfig>): string {
     ]);
 }
 
-function syncSettingsFormFromConfig(): void {
+function syncSettingsFormFromConfig(syncSecrets = true): void {
     byId<HTMLInputElement>('clientId').value = config.client_id ?? '';
-    syncSecretFields();
+    if (syncSecrets) syncSecretFields();
     byId<HTMLInputElement>('sidebarSplitViewToggle').checked = config.sidebar_split_view !== false;
     applySidebarLayoutPreference(config.sidebar_split_view !== false);
     byId<HTMLSelectElement>('downloadMode').value = (config.download_mode as 'parts' | 'full') ?? 'full';
@@ -790,7 +809,7 @@ async function persistSettings(options: {
 
     await persistSecretInputs();
     config = await window.api.saveConfig(payload);
-    syncSettingsFormFromConfig();
+    syncSettingsFormFromConfig(false);
     pendingCredentialsReconnect = false;
 
     if (options.reconnectAfterSave) {
@@ -830,7 +849,6 @@ async function flushSettingsAutoSave(reconnectAfterSave = false): Promise<void>
     try {
         await persistSecretInputs();
         config = await window.api.saveConfig(payload);
-        syncSecretFields();
         lastPersistedSettingsFingerprint = getSettingsFingerprint({});
         if (reconnectAfterSave && pendingCredentialsReconnect) {
             pendingCredentialsReconnect = false;
@@ -936,6 +954,12 @@ function initSettingsAutoSave(): void {
         });
     }
 
+    for (const id of ['clientSecret', 'discordWebhookUrl'] as const) {
+        byId<HTMLInputElement>(id).addEventListener('input', () => {
+            secretInputGenerations[id] += 1;
+        });
+    }
+
     for (const id of ['clientSecret', 'discordWebhookUrl'] as const) {
         byId<HTMLInputElement>(id).addEventListener('focus', (event) => {
             const input = event.currentTarget as HTMLInputElement;