fix(downloads): fail closed on invalid stored coordinates

apps/electron-backend/src/app/events/database/download-request-identity.spec.ts

@@ -1,6 +1,9 @@
 import * as schema from '../../database/schema';
 import type { DownloadsDatabase } from './download-task';
-import { resolveExistingDownloadIdentity } from './download-request-identity';
+import {
+    type ExistingDownloadIdentityResolution,
+    resolveExistingDownloadIdentity,
+} from './download-request-identity';
 
 type DownloadRow = typeof schema.downloads.$inferSelect;
 
@@ -66,9 +69,10 @@ describe('resolveExistingDownloadIdentity', () => {
         const row = createDownloadRow();
         const harness = createQueryHarness([row], []);
 
-        await expect(
-            resolveExistingDownloadIdentity(harness.db, episodeRequest)
-        ).resolves.toEqual({
+        const resolution: ExistingDownloadIdentityResolution =
+            await resolveExistingDownloadIdentity(harness.db, episodeRequest);
+
+        expect(resolution).toEqual({
             item: row,
             kind: 'match',
             migrateCanonicalId: false,
@@ -112,6 +116,24 @@ describe('resolveExistingDownloadIdentity', () => {
         ).resolves.toEqual({ kind: 'conflict' });
     });
 
+    it.each([
+        ['series id', { seriesXtreamId: Number.MAX_SAFE_INTEGER + 1 }],
+        ['season number', { seasonNumber: 2.5 }],
+        ['episode number', { episodeNumber: Number.NaN }],
+    ])(
+        'fails closed when the canonical row has a present but unsafe %s',
+        async (_label, override) => {
+            const harness = createQueryHarness(
+                [createDownloadRow(override)],
+                []
+            );
+
+            await expect(
+                resolveExistingDownloadIdentity(harness.db, episodeRequest)
+            ).resolves.toEqual({ kind: 'conflict' });
+        }
+    );
+
     it('fails closed when multiple rows share the legacy coordinates', async () => {
         const harness = createQueryHarness([], [
             createDownloadRow({ id: 42, xtreamId: 77 }),

apps/electron-backend/src/app/events/database/download-request-identity.ts

@@ -11,20 +11,20 @@ export const DOWNLOAD_IDENTITY_KIND = {
 } as const;
 
 interface DownloadIdentityNone {
-    kind: typeof DOWNLOAD_IDENTITY_KIND.NONE;
+    readonly kind: typeof DOWNLOAD_IDENTITY_KIND.NONE;
 }
 
 interface DownloadIdentityConflict {
-    kind: typeof DOWNLOAD_IDENTITY_KIND.CONFLICT;
+    readonly kind: typeof DOWNLOAD_IDENTITY_KIND.CONFLICT;
 }
 
 interface DownloadIdentityMatch {
-    item: DownloadRow;
-    kind: typeof DOWNLOAD_IDENTITY_KIND.MATCH;
-    migrateCanonicalId: boolean;
+    readonly item: DownloadRow;
+    readonly kind: typeof DOWNLOAD_IDENTITY_KIND.MATCH;
+    readonly migrateCanonicalId: boolean;
 }
 
-export type DownloadIdentityResolution =
+export type ExistingDownloadIdentityResolution =
     | DownloadIdentityNone
     | DownloadIdentityConflict
     | DownloadIdentityMatch;
@@ -38,7 +38,7 @@ export interface DownloadIdentityRequest {
     xtreamId: number;
 }
 
-function isSafeInteger(value: number | undefined): value is number {
+function isSafeInteger(value: number | null | undefined): value is number {
     return Number.isSafeInteger(value);
 }
 
@@ -51,25 +51,32 @@ function rowHasConflictingCoordinates(
         >
     >
 ): boolean {
+    const { episodeNumber, seasonNumber, seriesXtreamId } = row;
     if (
-        !isSafeInteger(row.seriesXtreamId ?? undefined) ||
-        !isSafeInteger(row.seasonNumber ?? undefined) ||
-        !isSafeInteger(row.episodeNumber ?? undefined)
+        seriesXtreamId === null ||
+        seriesXtreamId === undefined ||
+        seasonNumber === null ||
+        seasonNumber === undefined ||
+        episodeNumber === null ||
+        episodeNumber === undefined
     ) {
         return false;
     }
 
     return (
-        row.seriesXtreamId !== request.seriesXtreamId ||
-        row.seasonNumber !== request.seasonNumber ||
-        row.episodeNumber !== request.episodeNumber
+        !isSafeInteger(seriesXtreamId) ||
+        !isSafeInteger(seasonNumber) ||
+        !isSafeInteger(episodeNumber) ||
+        seriesXtreamId !== request.seriesXtreamId ||
+        seasonNumber !== request.seasonNumber ||
+        episodeNumber !== request.episodeNumber
     );
 }
 
 export async function resolveExistingDownloadIdentity(
     db: DownloadsDatabase,
     request: DownloadIdentityRequest
-): Promise<DownloadIdentityResolution> {
+): Promise<ExistingDownloadIdentityResolution> {
     const canonicalRows = await db
         .select()
         .from(schema.downloads)