fix(backend): getApTypeでエラーを投げないように (#14361)

* fix(backend): getApTypeでエラーを投げないように

* Update Changelog

* Update Changelog

* Update type.ts

* add comment

2 files changed, 26 insertions, 11 deletions

diff --git a/packages/backend/src/core/activitypub/models/ApNoteService.ts b/packages/backend/src/core/activitypub/models/ApNoteService.ts
index fc7aa1e0b9..5b75da22a0 100644
--- a/packages/backend/src/core/activitypub/models/ApNoteService.ts
+++ b/packages/backend/src/core/activitypub/models/ApNoteService.ts
@@ -78,9 +78,10 @@ export class ApNoteService {
 	@bindThis
 	public validateNote(object: IObject, uri: string): Error | null {
 		const expectHost = this.utilityService.extractDbHost(uri);
+		const apType = getApType(object);
 
-		if (!validPost.includes(getApType(object))) {
-			return new IdentifiableError('d450b8a9-48e4-4dab-ae36-f4db763fda7c', `invalid Note: invalid object type ${getApType(object)}`);
+		if (apType == null || !validPost.includes(apType)) {
+			return new IdentifiableError('d450b8a9-48e4-4dab-ae36-f4db763fda7c', `invalid Note: invalid object type ${apType ?? 'undefined'}`);
 		}
 
 		if (object.id && this.utilityService.extractDbHost(object.id) !== expectHost) {
diff --git a/packages/backend/src/core/activitypub/type.ts b/packages/backend/src/core/activitypub/type.ts
index 131c518c0a..16812b7a4d 100644
--- a/packages/backend/src/core/activitypub/type.ts
+++ b/packages/backend/src/core/activitypub/type.ts
@@ -60,11 +60,14 @@ export function getApId(value: string | IObject): string {
 
 /**
  * Get ActivityStreams Object type
+ *
+ * タイプ判定ができなかった場合に、あえてエラーではなくnullを返すようにしている。
+ * 詳細: https://github.com/misskey-dev/misskey/issues/14239
  */
-export function getApType(value: IObject): string {
+export function getApType(value: IObject): string | null {
 	if (typeof value.type === 'string') return value.type;
 	if (Array.isArray(value.type) && typeof value.type[0] === 'string') return value.type[0];
-	throw new Error('cannot detect type');
+	return null;
 }
 
 export function getOneApHrefNullable(value: ApObject | undefined): string | undefined {
@@ -110,8 +113,10 @@ export interface IOrderedCollection extends IObject {
 
 export const validPost = ['Note', 'Question', 'Article', 'Audio', 'Document', 'Image', 'Page', 'Video', 'Event'];
 
-export const isPost = (object: IObject): object is IPost =>
-	validPost.includes(getApType(object));
+export const isPost = (object: IObject): object is IPost => {
+	const type = getApType(object);
+	return type != null && validPost.includes(type);
+};
 
 export interface IPost extends IObject {
 	type: 'Note' | 'Question' | 'Article' | 'Audio' | 'Document' | 'Image' | 'Page' | 'Video' | 'Event';
@@ -158,8 +163,10 @@ export const isTombstone = (object: IObject): object is ITombstone =>
 
 export const validActor = ['Person', 'Service', 'Group', 'Organization', 'Application'];
 
-export const isActor = (object: IObject): object is IActor =>
-	validActor.includes(getApType(object));
+export const isActor = (object: IObject): object is IActor => {
+	const type = getApType(object);
+	return type != null && validActor.includes(type);
+};
 
 export interface IActor extends IObject {
 	type: 'Person' | 'Service' | 'Organization' | 'Group' | 'Application';
@@ -242,12 +249,16 @@ export interface IKey extends IObject {
 	publicKeyPem: string | Buffer;
 }
 
+export const validDocumentTypes = ['Audio', 'Document', 'Image', 'Page', 'Video'];
+
 export interface IApDocument extends IObject {
 	type: 'Audio' | 'Document' | 'Image' | 'Page' | 'Video';
 }
 
-export const isDocument = (object: IObject): object is IApDocument =>
-	['Audio', 'Document', 'Image', 'Page', 'Video'].includes(getApType(object));
+export const isDocument = (object: IObject): object is IApDocument => {
+	const type = getApType(object);
+	return type != null && validDocumentTypes.includes(type);
+};
 
 export interface IApImage extends IApDocument {
 	type: 'Image';
@@ -325,7 +336,10 @@ export const isAccept = (object: IObject): object is IAccept => getApType(object
 export const isReject = (object: IObject): object is IReject => getApType(object) === 'Reject';
 export const isAdd = (object: IObject): object is IAdd => getApType(object) === 'Add';
 export const isRemove = (object: IObject): object is IRemove => getApType(object) === 'Remove';
-export const isLike = (object: IObject): object is ILike => getApType(object) === 'Like' || getApType(object) === 'EmojiReaction' || getApType(object) === 'EmojiReact';
+export const isLike = (object: IObject): object is ILike => {
+	const type = getApType(object);
+	return type != null && ['Like', 'EmojiReaction', 'EmojiReact'].includes(type);
+};
 export const isAnnounce = (object: IObject): object is IAnnounce => getApType(object) === 'Announce';
 export const isBlock = (object: IObject): object is IBlock => getApType(object) === 'Block';
 export const isFlag = (object: IObject): object is IFlag => getApType(object) === 'Flag';