From 528777926c4907f323c53d7706d687032a7cfe62 Mon Sep 17 00:00:00 2001
From: Hampus <hampus@fluxer.app>
Date: Thu, 20 Aug 2026 15:50:51 +0200
Subject: [PATCH] fix(api): stop one unreachable community from breaking
 bookmarks (#1779)

---
 .../user/services/UserContentService.test.ts  | 30 +++++++++++++++++++
 .../api/user/services/UserContentService.ts   | 16 ++++++----
 2 files changed, 40 insertions(+), 6 deletions(-)
 create mode 100644 fluxer_api/src/api/user/services/UserContentService.test.ts

diff --git a/fluxer_api/src/api/user/services/UserContentService.test.ts b/fluxer_api/src/api/user/services/UserContentService.test.ts
new file mode 100644
index 000000000..2a69e58c8
--- /dev/null
+++ b/fluxer_api/src/api/user/services/UserContentService.test.ts
@@ -0,0 +1,30 @@
+// SPDX-License-Identifier: AGPL-3.0-or-later
+
+import {UnknownChannelError} from '@fluxer/errors/src/domains/channel/UnknownChannelError';
+import {UnknownMessageError} from '@fluxer/errors/src/domains/channel/UnknownMessageError';
+import {MissingPermissionsError} from '@fluxer/errors/src/domains/core/MissingPermissionsError';
+import {UnknownGuildError} from '@fluxer/errors/src/domains/guild/UnknownGuildError';
+import {describe, expect, it} from 'vitest';
+import {UserContentServiceTestHooks} from './UserContentService';
+
+const {isUnreachableEntityError} = UserContentServiceTestHooks;
+
+describe('isUnreachableEntityError', () => {
+	it('treats a deleted or left community as unreachable rather than fatal', () => {
+		expect(isUnreachableEntityError(new UnknownGuildError())).toBe(true);
+	});
+
+	it('treats a gone channel and a lost permission as unreachable', () => {
+		expect(isUnreachableEntityError(new UnknownChannelError())).toBe(true);
+		expect(isUnreachableEntityError(new MissingPermissionsError())).toBe(true);
+	});
+
+	it('leaves a deleted message to the delete path instead of marking it unavailable', () => {
+		expect(isUnreachableEntityError(new UnknownMessageError())).toBe(false);
+	});
+
+	it('still lets unexpected failures surface', () => {
+		expect(isUnreachableEntityError(new Error('database is on fire'))).toBe(false);
+		expect(isUnreachableEntityError(null)).toBe(false);
+	});
+});
diff --git a/fluxer_api/src/api/user/services/UserContentService.ts b/fluxer_api/src/api/user/services/UserContentService.ts
index afba73b30..1555e705a 100644
--- a/fluxer_api/src/api/user/services/UserContentService.ts
+++ b/fluxer_api/src/api/user/services/UserContentService.ts
@@ -6,6 +6,7 @@ import {UnknownChannelError} from '@fluxer/errors/src/domains/channel/UnknownCha
 import {UnknownMessageError} from '@fluxer/errors/src/domains/channel/UnknownMessageError';
 import {MaxBookmarksError} from '@fluxer/errors/src/domains/core/MaxBookmarksError';
 import {MissingPermissionsError} from '@fluxer/errors/src/domains/core/MissingPermissionsError';
+import {UnknownGuildError} from '@fluxer/errors/src/domains/guild/UnknownGuildError';
 import {HarvestExpiredError} from '@fluxer/errors/src/domains/moderation/HarvestExpiredError';
 import {HarvestFailedError} from '@fluxer/errors/src/domains/moderation/HarvestFailedError';
 import {HarvestNotReadyError} from '@fluxer/errors/src/domains/moderation/HarvestNotReadyError';
@@ -94,6 +95,13 @@ function normalizeProviderEnvironment(
 	return platform === 'ios_apns' ? DEFAULT_APNS_PROVIDER_ENVIRONMENT : null;
 }
 
+const isUnreachableEntityError = (error: unknown): boolean =>
+	error instanceof MissingPermissionsError ||
+	error instanceof UnknownChannelError ||
+	error instanceof UnknownGuildError;
+
+export const UserContentServiceTestHooks = {isUnreachableEntityError};
+
 export class UserContentService {
 	private readonly updatePropagator: BaseUserUpdatePropagator;
 	private readonly userRepository: UserContentRepository;
@@ -138,11 +146,7 @@ export class UserContentService {
 					messageId: mention.messageId,
 				});
 			} catch (error) {
-				if (
-					error instanceof UnknownMessageError ||
-					error instanceof MissingPermissionsError ||
-					error instanceof UnknownChannelError
-				) {
+				if (error instanceof UnknownMessageError || isUnreachableEntityError(error)) {
 					return null;
 				}
 				throw error;
@@ -188,7 +192,7 @@ export class UserContentService {
 					await this.userRepository.deleteSavedMessage(userId, savedMessage.messageId);
 					return null;
 				}
-				if (error instanceof MissingPermissionsError || error instanceof UnknownChannelError) {
+				if (isUnreachableEntityError(error)) {
 					status = 'missing_permissions';
 				} else {
 					throw error;