fix(backend): handle array or string in alsoKnownAs (#17275)

* fix: handle array or string in alsoKnownAs, closes #17274

* style: use more idiomatic toArray() for UserEntityService handling of alsoKnownAs

* fix: handle array-valued or unwrapped alsoKnownAs in ApPersonService

* doc: note about bugfix for alsoKnownAs

packages/backend/src/core/activitypub/models/ApPersonService.ts

@@ -376,7 +376,7 @@ export class ApPersonService implements OnModuleInit {
 					isLocked: person.manuallyApprovesFollowers,
 					movedToUri: person.movedTo,
 					movedAt: person.movedTo ? new Date() : null,
-					alsoKnownAs: person.alsoKnownAs,
+					alsoKnownAs: toArray(person.alsoKnownAs),
 					isExplorable: person.discoverable,
 					username: person.preferredUsername,
 					usernameLower: person.preferredUsername?.toLowerCase(),
@@ -568,7 +568,7 @@ export class ApPersonService implements OnModuleInit {
 			isCat: (person as any).isCat === true,
 			isLocked: person.manuallyApprovesFollowers,
 			movedToUri: person.movedTo ?? null,
-			alsoKnownAs: person.alsoKnownAs ?? null,
+			alsoKnownAs: person.alsoKnownAs ? toArray(person.alsoKnownAs) : null,
 			isExplorable: person.discoverable,
 			...(await this.resolveAvatarAndBanner(exist, person.icon, person.image).catch(() => ({}))),
 		} as Partial<MiRemoteUser> & Pick<MiRemoteUser, 'isBot' | 'isCat' | 'isLocked' | 'movedToUri' | 'alsoKnownAs' | 'isExplorable'>;

packages/backend/src/core/entities/UserEntityService.ts

@@ -51,6 +51,7 @@ import { ChatService } from '@/core/ChatService.js';
 import type { OnModuleInit } from '@nestjs/common';
 import type { NoteEntityService } from './NoteEntityService.js';
 import type { PageEntityService } from './PageEntityService.js';
+import { toArray } from '@/misc/prelude/array.js';
 
 const Ajv = _Ajv.default;
 const ajv = new Ajv();
@@ -527,10 +528,10 @@ export class UserEntityService implements OnModuleInit {
 				url: profile!.url,
 				uri: user.uri,
 				movedTo: user.movedToUri ? this.apPersonService.resolvePerson(user.movedToUri).then(user => user.id).catch(() => null) : null,
-				alsoKnownAs: user.alsoKnownAs
-					? Promise.all(user.alsoKnownAs.map(uri => this.apPersonService.fetchPerson(uri).then(user => user?.id).catch(() => null)))
-						.then(xs => xs.length === 0 ? null : xs.filter(x => x != null))
-					: null,
+				alsoKnownAs: user.alsoKnownAs ?
+					Promise.all(toArray(user.alsoKnownAs).map(uri => this.apPersonService.fetchPerson(uri).then(user => user?.id).catch(() => null)))
+				.then(xs => xs.length === 0 ? null : xs.filter(x => x != null))
+				: null,
 				createdAt: this.idService.parse(user.id).date.toISOString(),
 				updatedAt: user.updatedAt ? user.updatedAt.toISOString() : null,
 				lastFetchedAt: user.lastFetchedAt ? user.lastFetchedAt.toISOString() : null,

packages/backend/test/unit/activitypub.ts

@@ -224,6 +224,51 @@ describe('ActivityPub', () => {
 		});
 	});
 
+	describe('alsoKnownAs field', () => {
+		test('Handle alsoKnownAs as an array', async () => {
+			const actor = {
+				...createRandomActor(),
+				alsoKnownAs: ['https://example.com/users/alice', 'https://example.com/users/alice2'],
+			};
+
+			resolver.register(actor.id, actor);
+
+			const user = await personService.createPerson(actor.id, resolver);
+
+			assert.deepStrictEqual(user.alsoKnownAs, actor.alsoKnownAs);
+		});
+
+		test('Handle alsoKnownAs as a string', async () => {
+			const actor = {
+				...createRandomActor(),
+				alsoKnownAs: 'https://example.com/users/alice',
+			};
+
+			resolver.register(actor.id, actor);
+
+			const user = await personService.createPerson(actor.id, resolver);
+
+			assert.deepStrictEqual(user.alsoKnownAs, [actor.alsoKnownAs]);
+		});
+
+		test('Update person with alsoKnownAs as a string', async () => {
+			const actor = createRandomActor();
+			resolver.register(actor.id, actor);
+			const user = await personService.createPerson(actor.id, resolver);
+
+			const updatedActor = {
+				...actor,
+				alsoKnownAs: 'https://example.com/users/alice',
+			};
+			resolver.register(actor.id, updatedActor);
+
+			await personService.updatePerson(actor.id, resolver, updatedActor);
+
+			const updatedUser = await personService.fetchPerson(actor.id);
+			assert.deepStrictEqual(updatedUser?.alsoKnownAs, [updatedActor.alsoKnownAs]);
+		});
+	});
+
 	describe('Collection visibility', () => {
 		test('Public following/followers', async () => {
 			const actor = createRandomActor();

packages/backend/test/unit/entities/UserEntityService.ts

@@ -248,6 +248,16 @@ describe('UserEntityService', () => {
 			expect(actual.achievements).toEqual(achievements);
 		});
 
+		test('alsoKnownAs as string does not throw', async () => {
+			const me = await createUser();
+			const who = await createUser();
+
+			const whoWithStringAlsoKnownAs: MiUser = { ...who, alsoKnownAs: 'https://remote.example.com/users/alice' as any };
+
+			const actual = await service.pack(whoWithStringAlsoKnownAs, me, { schema: 'UserDetailedNotMe' }) as any;
+			expect(Array.isArray(actual.alsoKnownAs)).toBe(true);
+		});
+
 		describe('packManyによるpreloadがある時、preloadが無い時とpackの結果が同じになるか見たい', () => {
 			test('no-preload', async() => {
 				const me = await createUser();