fix: failed to resolve acct URI which points to local Person (#11024)

* fix: resolving alias for local users (#9199)

Signed-off-by: xtex <xtexchooser@duck.com>

* style: return type for RemoteUserResolveService#resolveSelf

Signed-off-by: xtex <xtexchooser@duck.com>

* docs: update CHANGELOG

Signed-off-by: xtex <xtexchooser@duck.com>

* style: fix typecheck

Signed-off-by: xtex <xtexchooser@duck.com>

---------

Signed-off-by: xtex <xtexchooser@duck.com>
Co-authored-by: syuilo <Syuilotan@yahoo.co.jp>

3 files changed, 23 insertions, 4 deletions

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 350afcb30e..9f7df34888 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -79,6 +79,7 @@
 
 ### Server
 - Fix: キャッシュが溜まり続けないように
+- Fix: ローカルの `Person` を指す `acct` URI を解析するときのバグを修正しました
 
 ## 13.13.1
 
diff --git a/packages/backend/src/core/RemoteUserResolveService.ts b/packages/backend/src/core/RemoteUserResolveService.ts
index 952d244823..e19a245e18 100644
--- a/packages/backend/src/core/RemoteUserResolveService.ts
+++ b/packages/backend/src/core/RemoteUserResolveService.ts
@@ -8,8 +8,9 @@ import type { LocalUser, RemoteUser } from '@/models/entities/User.js';
 import type { Config } from '@/config.js';
 import type Logger from '@/logger.js';
 import { UtilityService } from '@/core/UtilityService.js';
-import { WebfingerService } from '@/core/WebfingerService.js';
+import { ILink, WebfingerService } from '@/core/WebfingerService.js';
 import { RemoteLoggerService } from '@/core/RemoteLoggerService.js';
+import { ApDbResolverService } from '@/core/activitypub/ApDbResolverService.js';
 import { ApPersonService } from '@/core/activitypub/models/ApPersonService.js';
 import { bindThis } from '@/decorators.js';
 
@@ -27,6 +28,7 @@ export class RemoteUserResolveService {
 		private utilityService: UtilityService,
 		private webfingerService: WebfingerService,
 		private remoteLoggerService: RemoteLoggerService,
+		private apDbResolverService: ApDbResolverService,
 		private apPersonService: ApPersonService,
 	) {
 		this.logger = this.remoteLoggerService.logger.createSubLogger('resolve-user');
@@ -67,6 +69,22 @@ export class RemoteUserResolveService {
 		if (user == null) {
 			const self = await this.resolveSelf(acctLower);
 
+			if (self.href.startsWith(this.config.url)) {
+				const local = this.apDbResolverService.parseUri(self.href);
+				if (local.local && local.type === 'users') {
+					// the LR points to local
+					return (await this.apDbResolverService
+						.getUserFromApId(self.href)
+						.then((u) => {
+							if (u == null) {
+								throw new Error('local user not found');
+							} else {
+								return u;
+							}
+						})) as LocalUser;
+				}
+			}
+
 			this.logger.succ(`return new remote user: ${chalk.magenta(acctLower)}`);
 			return await this.apPersonService.createPerson(self.href);
 		}
@@ -119,7 +137,7 @@ export class RemoteUserResolveService {
 	}
 
 	@bindThis
-	private async resolveSelf(acctLower: string) {
+	private async resolveSelf(acctLower: string): Promise<ILink> {
 		this.logger.info(`WebFinger for ${chalk.yellow(acctLower)}`);
 		const finger = await this.webfingerService.webfinger(acctLower).catch(err => {
 			this.logger.error(`Failed to WebFinger for ${chalk.yellow(acctLower)}: ${ err.statusCode ?? err.message }`);
diff --git a/packages/backend/src/core/WebfingerService.ts b/packages/backend/src/core/WebfingerService.ts
index f58a6a10fc..6b2428cdf0 100644
--- a/packages/backend/src/core/WebfingerService.ts
+++ b/packages/backend/src/core/WebfingerService.ts
@@ -6,12 +6,12 @@ import { query as urlQuery } from '@/misc/prelude/url.js';
 import { HttpRequestService } from '@/core/HttpRequestService.js';
 import { bindThis } from '@/decorators.js';
 
-type ILink = {
+export type ILink = {
 	href: string;
 	rel?: string;
 };
 
-type IWebFinger = {
+export type IWebFinger = {
 	links: ILink[];
 	subject: string;
 };