fix(settings): re-check lock removals at their durable commit points

A lock removal that passed the unlocked check before its write is asked
again right after the store write and, for Xtream, after the index
stamps. A relock in between writes the previous store back or rolls the
stamps back before anything is published. The stale-index bookkeeping,
index stamping and store merge move into helpers to keep the lock store
within the file size limit.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

docs/architecture/parental-lock.md

@@ -416,7 +416,11 @@ by the index alone:
   unlocked, checked inside the write queue at commit time
   (`ParentalLockLockStore.setRemovalGate`, set by `ParentalLockService`).
   An editor opened while unlocked may still be saving, or queued behind
-  another write, when the app relocks. Adding locks is always allowed.
+  another write, when the app relocks. The answer is asked again at the
+  durable commit points: right after the store write (a refusal writes the
+  previous store back) and, for Xtream, after the index stamps (a refusal
+  rolls back like a failed stamp), before the revision is published.
+  Adding locks is always allowed.
   Playlist deletion and "Remove all playlists" are not edits and are not
   gated.
 - Every launch re-derives the index from the store for each playlist that

libs/services/src/lib/parental-lock/parental-lock-lock-store.service.spec.ts

@@ -465,6 +465,59 @@ describe('ParentalLockLockStore', () => {
         await expect(store.setM3uLocks('pl-1', [])).resolves.toBe(true);
         expect(store.lockedGroupTitles('pl-1')).toEqual([]);
     });
+    it('rolls back a removal when the app relocks while its store write is in flight', async () => {
+        storage.readLocks.mockResolvedValue({
+            'pl-1': { xtream: [], stalker: [], m3u: ['Adults'] },
+        });
+        await store.load();
+        await store.ensureReadable();
+        let unlocked = true;
+        store.setRemovalGate(() => unlocked);
+        jest.spyOn(console, 'warn').mockImplementation(() => undefined);
+        let finishWrite: (ok: boolean) => void = () => undefined;
+        storage.writeLocks.mockImplementationOnce(
+            () => new Promise<boolean>((resolve) => (finishWrite = resolve))
+        );
+        const revision = store.revision();
+
+        const removing = store.setM3uLocks('pl-1', []);
+        await waitFor(() => storage.writeLocks.mock.calls.length > 0);
+        unlocked = false;
+        finishWrite(true);
+
+        await expect(removing).resolves.toBe(false);
+        expect(store.lockedGroupTitles('pl-1')).toEqual(['Adults']);
+        expect(store.revision()).toBe(revision);
+        // The durable store is put back.
+        expect(storage.writeLocks).toHaveBeenLastCalledWith({
+            'pl-1': { xtream: [], stalker: [], m3u: ['Adults'] },
+        });
+    });
+
+    it('rolls back an Xtream removal when the app relocks during the index stamps', async () => {
+        await store.load();
+        await store.ensureReadable();
+        let unlocked = true;
+        store.setRemovalGate(() => unlocked);
+        jest.spyOn(console, 'warn').mockImplementation(() => undefined);
+        await store.setXtreamLocks('pl-1', 'live', [7, 9]);
+        setCategoryLocks.mockImplementationOnce(async () => {
+            unlocked = false;
+            return true;
+        });
+
+        await expect(store.setXtreamLocks('pl-1', 'live', [7])).resolves.toBe(
+            false
+        );
+
+        expect(store.lockedXtreamIds('pl-1', 'live')).toEqual([7, 9]);
+        expect(setCategoryLocks).toHaveBeenLastCalledWith(
+            'pl-1',
+            'live',
+            [7, 9]
+        );
+        expect(store.readable()).toBe(true);
+    });
 });
 
 async function waitFor(condition: () => boolean): Promise<void> {

libs/services/src/lib/parental-lock/parental-lock-lock-store.service.ts

@@ -12,10 +12,13 @@ import {
 } from '@iptvnator/shared/interfaces';
 import { DatabaseService } from '../database-electron.service';
 import { RuntimeCapabilitiesService } from '../runtime-capabilities.service';
+import { ParentalLockStaleIndex } from './parental-lock-stale-index';
 import { ParentalLockStorageService } from './parental-lock-storage';
 import {
-    isLockRemovalAllowed,
+    lockRemovalGate,
+    stampXtreamIndex,
     withM3uLocks,
+    withPlaylistLocksInStore,
     withStalkerLocks,
     withXtreamLocks,
 } from './parental-lock-store.util';
@@ -74,13 +77,7 @@ export class ParentalLockLockStore {
     private writeQueue: Promise<unknown> = Promise.resolve();
     /** "Remove all playlists" could not clear the persisted store yet. */
     private pendingClearAll = false;
-    /**
-     * Playlists whose SQLite index could not be brought in line with the
-     * store (a failed re-stamp whose rollback failed too); re-stamped on
-     * the next store access.
-     */
-    private readonly staleIndexPlaylists = new Set<string>();
-    private readonly staleIndexCount = signal(0);
+    private readonly staleIndex = new ParentalLockStaleIndex();
 
     /** The persisted store could not be read; see `ensureReadable()`. */
     readonly unreadable = signal(false);
@@ -96,7 +93,7 @@ export class ParentalLockLockStore {
         () =>
             this.loadedState() &&
             !this.unreadable() &&
-            this.staleIndexCount() === 0
+            this.staleIndex.isEmpty()
     );
     /** Bumps whenever the lock set changes; consumers re-query. */
     readonly revision = this.revisionState.asReadonly();
@@ -119,7 +116,7 @@ export class ParentalLockLockStore {
                 } else {
                     this.locks.set(locks);
                     for (const playlistId of Object.keys(locks)) {
-                        this.markIndexStale(playlistId);
+                        this.staleIndex.mark(playlistId);
                     }
                     // Awaited: catalog reads issued before the index agrees
                     // with the store would serve rows stamped unlocked, and
@@ -156,7 +153,7 @@ export class ParentalLockLockStore {
             // the read did; re-derive it from the recovered store as load()
             // does.
             for (const playlistId of Object.keys(locks)) {
-                this.markIndexStale(playlistId);
+                this.staleIndex.mark(playlistId);
             }
             this.revisionState.update((value) => value + 1);
         }
@@ -164,27 +161,17 @@ export class ParentalLockLockStore {
         return this.readable();
     }
 
-    private markIndexStale(playlistId: string): void {
-        this.staleIndexPlaylists.add(playlistId);
-        this.staleIndexCount.set(this.staleIndexPlaylists.size);
-    }
-
-    private unmarkIndexStale(playlistId: string): void {
-        this.staleIndexPlaylists.delete(playlistId);
-        this.staleIndexCount.set(this.staleIndexPlaylists.size);
-    }
-
     /** Re-stamps every playlist whose index may lag behind the store. */
     private async reconcileXtreamIndex(): Promise<void> {
         if (!this.runtime.supportsXtreamSqliteDataSource) {
-            this.staleIndexPlaylists.clear();
-            this.staleIndexCount.set(0);
+            this.staleIndex.clear();
             return;
         }
-        for (const playlistId of [...this.staleIndexPlaylists]) {
+        const restamped: string[] = [];
+        for (const playlistId of this.staleIndex.ids()) {
             try {
                 if (await this.stampXtreamLocks(playlistId)) {
-                    this.staleIndexPlaylists.delete(playlistId);
+                    restamped.push(playlistId);
                 }
             } catch (error) {
                 console.error(
@@ -193,8 +180,8 @@ export class ParentalLockLockStore {
                 );
             }
         }
-        if (this.staleIndexCount() !== this.staleIndexPlaylists.size) {
-            this.staleIndexCount.set(this.staleIndexPlaylists.size);
+        if (restamped.length > 0) {
+            this.staleIndex.unmark(...restamped);
             this.revisionState.update((value) => value + 1);
         }
     }
@@ -251,9 +238,6 @@ export class ParentalLockLockStore {
                     this.lockedXtreamIds(playlistId, categoryType)
                 )
             );
-            if (!isLockRemovalAllowed(previous, next, this.mayRemoveLocks)) {
-                return false;
-            }
             return this.commitLocks(playlistId, previous, next, [categoryType]);
         });
     }
@@ -276,10 +260,7 @@ export class ParentalLockLockStore {
                     this.lockedStalkerIds(playlistId, categoryType)
                 )
             );
-            return (
-                isLockRemovalAllowed(previous, next, this.mayRemoveLocks) &&
-                this.persistPlaylistLocks(playlistId, next)
-            );
+            return this.persistEdit(playlistId, previous, next);
         });
     }
 
@@ -299,10 +280,7 @@ export class ParentalLockLockStore {
                     this.lockedGroupTitles(playlistId)
                 )
             );
-            return (
-                isLockRemovalAllowed(previous, next, this.mayRemoveLocks) &&
-                this.persistPlaylistLocks(playlistId, next)
-            );
+            return this.persistEdit(playlistId, previous, next);
         });
     }
 
@@ -315,13 +293,9 @@ export class ParentalLockLockStore {
             if (!(await this.ensureReadable())) {
                 return false;
             }
-            const previous = this.locksFor(playlistId);
-            if (!isLockRemovalAllowed(previous, locks, this.mayRemoveLocks)) {
-                return false;
-            }
             return this.commitLocks(
                 playlistId,
-                previous,
+                this.locksFor(playlistId),
                 locks,
                 XTREAM_CATEGORY_TYPES
             );
@@ -357,14 +331,26 @@ export class ParentalLockLockStore {
             // rewrites the whole store from this empty copy.
             this.locks.set({});
             this.unreadable.set(false);
-            this.staleIndexPlaylists.clear();
-            this.staleIndexCount.set(0);
+            this.staleIndex.clear();
             this.revisionState.update((value) => value + 1);
             this.pendingClearAll = !(await this.storage.writeLocks({}));
             return !this.pendingClearAll;
         });
     }
 
+    /** Stalker and M3U edits: no index, only the store write. */
+    private async persistEdit(
+        playlistId: string,
+        previous: ParentalLockPlaylistLocks,
+        next: ParentalLockPlaylistLocks
+    ): Promise<boolean> {
+        const authorize = lockRemovalGate(previous, next, this.mayRemoveLocks);
+        return (
+            authorize() &&
+            this.persistPlaylistLocks(playlistId, next, { authorize })
+        );
+    }
+
     private enqueue<T>(task: () => Promise<T>): Promise<T> {
         const run = this.writeQueue.then(task, task);
         this.writeQueue = run.catch(() => undefined);
@@ -387,6 +373,10 @@ export class ParentalLockLockStore {
         next: ParentalLockPlaylistLocks,
         categoryTypes: readonly ParentalLockXtreamCategoryType[]
     ): Promise<boolean> {
+        const authorize = lockRemovalGate(previous, next, this.mayRemoveLocks);
+        if (!authorize()) {
+            return false;
+        }
         const normalizedNext = normalizeParentalLockPlaylistLocks(next);
         if (isParentalLockPlaylistLocksEmpty(normalizedNext)) {
             if (!(await this.ensureReadable())) {
@@ -405,9 +395,10 @@ export class ParentalLockLockStore {
                 )) &&
                 (await this.persistPlaylistLocks(playlistId, normalizedNext, {
                     publish: false,
+                    authorize,
                 }))
             ) {
-                this.unmarkIndexStale(playlistId);
+                this.staleIndex.unmark(playlistId);
                 this.revisionState.update((value) => value + 1);
                 return true;
             }
@@ -425,13 +416,19 @@ export class ParentalLockLockStore {
         if (
             !(await this.persistPlaylistLocks(playlistId, next, {
                 publish: false,
+                authorize,
             }))
         ) {
             return false;
         }
         this.markStaleWhileStamping(playlistId);
-        if (await this.stampXtreamLocks(playlistId, categoryTypes)) {
-            this.unmarkIndexStale(playlistId);
+        // Asked again once the stamps landed: a relock during them must not
+        // see the removal published.
+        if (
+            (await this.stampXtreamLocks(playlistId, categoryTypes)) &&
+            authorize()
+        ) {
+            this.staleIndex.unmark(playlistId);
             this.revisionState.update((value) => value + 1);
             return true;
         }
@@ -464,9 +461,9 @@ export class ParentalLockLockStore {
             (await this.stampXtreamLocks(playlistId, categoryTypes));
         if (!restored || !restamped) {
             console.error('Failed to roll back the parental lock index.');
-            this.markIndexStale(playlistId);
+            this.staleIndex.mark(playlistId);
         } else {
-            this.unmarkIndexStale(playlistId);
+            this.staleIndex.unmark(playlistId);
         }
         this.revisionState.update((value) => value + 1);
     }
@@ -479,7 +476,7 @@ export class ParentalLockLockStore {
      */
     private markStaleWhileStamping(playlistId: string): void {
         if (this.runtime.supportsXtreamSqliteDataSource) {
-            this.markIndexStale(playlistId);
+            this.staleIndex.mark(playlistId);
         }
     }
 
@@ -491,9 +488,9 @@ export class ParentalLockLockStore {
     ): Promise<void> {
         if (!(await this.stampXtreamLocks(playlistId, categoryTypes, locks))) {
             console.error('Failed to restore the parental lock index.');
-            this.markIndexStale(playlistId);
+            this.staleIndex.mark(playlistId);
         } else {
-            this.unmarkIndexStale(playlistId);
+            this.staleIndex.unmark(playlistId);
         }
         this.revisionState.update((value) => value + 1);
     }
@@ -507,25 +504,22 @@ export class ParentalLockLockStore {
         categoryTypes: readonly ParentalLockXtreamCategoryType[] = XTREAM_CATEGORY_TYPES,
         locks: ParentalLockPlaylistLocks = this.locksFor(playlistId)
     ): Promise<boolean> {
-        if (!this.runtime.supportsXtreamSqliteDataSource) {
-            return true;
-        }
-        let success = true;
-        for (const categoryType of categoryTypes) {
-            success =
-                (await this.databaseService.setCategoryLocks(
-                    playlistId,
-                    categoryType,
-                    lockedXtreamCategoryIds(locks, categoryType)
-                )) && success;
-        }
-        return success;
+        return (
+            !this.runtime.supportsXtreamSqliteDataSource ||
+            stampXtreamIndex(
+                (id, type, ids) =>
+                    this.databaseService.setCategoryLocks(id, type, ids),
+                playlistId,
+                categoryTypes,
+                locks
+            )
+        );
     }
 
     private async persistPlaylistLocks(
         playlistId: string,
         locks: ParentalLockPlaylistLocks,
-        options: { publish?: boolean } = {}
+        options: { publish?: boolean; authorize?: () => boolean } = {}
     ): Promise<boolean> {
         // Every public mutation runs `ensureReadable()` before it builds its
         // edit. Here only the STORE must be known: the index of the
@@ -534,16 +528,18 @@ export class ParentalLockLockStore {
         if (this.unreadable()) {
             return false;
         }
-        const normalized = normalizeParentalLockPlaylistLocks(locks);
-        const next: ParentalLockStore = { ...this.locks() };
-        if (isParentalLockPlaylistLocksEmpty(normalized)) {
-            delete next[playlistId];
-        } else {
-            next[playlistId] = normalized;
-        }
+        const next = withPlaylistLocksInStore(this.locks(), playlistId, locks);
         if (!(await this.storage.writeLocks(next))) {
             return false;
         }
+        if (options.authorize && !options.authorize()) {
+            // Relocked while the write was in flight: the durable store goes
+            // back to the in-memory one, which still holds the lock.
+            if (!(await this.storage.writeLocks(this.locks()))) {
+                console.error('Failed to revert a refused parental lock edit.');
+            }
+            return false;
+        }
         this.locks.set(next);
         if (options.publish !== false) {
             this.revisionState.update((value) => value + 1);

libs/services/src/lib/parental-lock/parental-lock-stale-index.ts

@@ -0,0 +1,34 @@
+import { computed, signal } from '@angular/core';
+
+/**
+ * Playlists whose SQLite `categories.locked` index may lag behind the lock
+ * store: a re-stamp in progress, or one that failed (with its rollback) and
+ * is retried on the next store access. The lock store is not `readable`
+ * while any playlist is listed.
+ */
+export class ParentalLockStaleIndex {
+    private readonly playlists = new Set<string>();
+    private readonly count = signal(0);
+
+    readonly isEmpty = computed(() => this.count() === 0);
+
+    ids(): string[] {
+        return [...this.playlists];
+    }
+
+    mark(playlistId: string): void {
+        this.playlists.add(playlistId);
+        this.count.set(this.playlists.size);
+    }
+
+    unmark(...playlistIds: string[]): void {
+        for (const playlistId of playlistIds) {
+            this.playlists.delete(playlistId);
+        }
+        this.count.set(this.playlists.size);
+    }
+
+    clear(): void {
+        this.unmark(...this.playlists);
+    }
+}

libs/services/src/lib/parental-lock/parental-lock-store.util.ts

@@ -1,6 +1,10 @@
 import {
+    isParentalLockPlaylistLocksEmpty,
+    lockedXtreamCategoryIds,
+    normalizeParentalLockPlaylistLocks,
     ParentalLockPlaylistLocks,
     ParentalLockStalkerCategoryType,
+    ParentalLockStore,
     ParentalLockXtreamCategoryType,
 } from '@iptvnator/shared/interfaces';
 
@@ -79,17 +83,65 @@ export function removesParentalLocks(
 }
 
 /**
- * Whether an edit from `previous` to `next` may commit: adding locks always
- * may, removing one only while `mayRemove()` says so (logged when refused).
+ * Whether an edit from `previous` to `next` may commit, asked each time the
+ * returned function is called: adding locks always may, removing one only
+ * while `mayRemove()` says so (logged when refused). Asked before a write
+ * and again at its durable commit points, since a relock can land while
+ * the write is in flight.
  */
-export function isLockRemovalAllowed(
+export function lockRemovalGate(
     previous: ParentalLockPlaylistLocks,
     next: ParentalLockPlaylistLocks,
     mayRemove: () => boolean
-): boolean {
-    if (!removesParentalLocks(previous, next) || mayRemove()) {
-        return true;
-    }
-    console.warn('A parental lock edit was refused: the app is locked.');
-    return false;
+): () => boolean {
+    const removes = removesParentalLocks(previous, next);
+    return () => {
+        if (!removes || mayRemove()) {
+            return true;
+        }
+        console.warn('A parental lock edit was refused: the app is locked.');
+        return false;
+    };
+}
+
+/** `store` with one playlist's locks replaced; an empty set drops its key. */
+export function withPlaylistLocksInStore(
+    store: ParentalLockStore,
+    playlistId: string,
+    locks: ParentalLockPlaylistLocks
+): ParentalLockStore {
+    const normalized = normalizeParentalLockPlaylistLocks(locks);
+    const next: ParentalLockStore = { ...store };
+    if (isParentalLockPlaylistLocksEmpty(normalized)) {
+        delete next[playlistId];
+    } else {
+        next[playlistId] = normalized;
+    }
+    return next;
+}
+
+/**
+ * Stamps the SQLite `categories.locked` index of one playlist from `locks`,
+ * type by type. Every type is attempted; false when any of them failed.
+ */
+export async function stampXtreamIndex(
+    setCategoryLocks: (
+        playlistId: string,
+        categoryType: ParentalLockXtreamCategoryType,
+        lockedXtreamIds: number[]
+    ) => Promise<boolean>,
+    playlistId: string,
+    categoryTypes: readonly ParentalLockXtreamCategoryType[],
+    locks: ParentalLockPlaylistLocks
+): Promise<boolean> {
+    let success = true;
+    for (const categoryType of categoryTypes) {
+        success =
+            (await setCategoryLocks(
+                playlistId,
+                categoryType,
+                lockedXtreamCategoryIds(locks, categoryType)
+            )) && success;
+    }
+    return success;
 }