feat(server): PATCH /api/dm/:id — group name + icon update

packages/server/src/routes/dm.metadataUpdate.test.ts

@@ -0,0 +1,576 @@
+import { describe, it, expect, beforeEach, vi } from 'vitest';
+import Fastify, { type FastifyInstance } from 'fastify';
+import Database from 'better-sqlite3';
+import { drizzle } from 'drizzle-orm/better-sqlite3';
+import { eq } from 'drizzle-orm';
+import fs from 'node:fs';
+import path from 'node:path';
+import { fileURLToPath } from 'node:url';
+import * as schema from '../db/schema.js';
+import { setWorkerId } from '../utils/snowflake.js';
+
+setWorkerId(1);
+
+const __dirname = path.dirname(fileURLToPath(import.meta.url));
+
+type TestDb = ReturnType<typeof drizzle<typeof schema>>;
+let sqlite: Database.Database;
+let testDb: TestDb;
+let currentUserId = 'owner-A';
+
+vi.mock('../db/index.js', () => ({
+  getDb: () => testDb,
+  getRawDb: () => sqlite,
+  schema,
+}));
+
+vi.mock('../utils/auth.js', () => ({
+  authenticate: async (req: { userId?: string }) => {
+    req.userId = currentUserId;
+  },
+}));
+
+vi.mock('../ws/handler.js', () => ({
+  connectionManager: {
+    sendToUser: vi.fn(),
+    sendToDmMembers: vi.fn(),
+    sendToAdmins: vi.fn(),
+    getAllOnlineUserIds: () => [],
+    getRoom: () => undefined,
+    getUserRoom: () => undefined,
+  },
+}));
+
+// Federation: keep the real queueGroupMetadataRelay AND its underlying outbox
+// writes (queueOutboxEvent / appendMutationLog) so we can assert the wire
+// payload by reading the federation_outbox table directly. Same-module callers
+// inside the helper bypass vi.mock, so spy-on-the-helper is the wrong axis —
+// inspect the persisted outbox row instead. The unrelated queue helpers
+// (queueDmRelay, queueDmCloseRelay, sendTypingRelay) are still stubbed because
+// they are not under test here.
+vi.mock('../utils/federationOutbox.js', async () => {
+  const actual = await vi.importActual<typeof import('../utils/federationOutbox.js')>('../utils/federationOutbox.js');
+  return {
+    ...actual,
+    isFederationRelayEnabled: () => true,
+    queueDmCloseRelay: vi.fn(),
+    sendTypingRelay: vi.fn(),
+    queueDmRelay: vi.fn(),
+  };
+});
+
+vi.mock('../utils/federationAuth.js', async (importActual) => {
+  const actual = await importActual<typeof import('../utils/federationAuth.js')>();
+  return { ...actual, getOurOrigin: () => 'https://local.test' };
+});
+
+// Mock fileCleanup so we can observe icon-deletion calls without touching disk.
+vi.mock('../utils/fileCleanup.js', async () => {
+  const actual = await vi.importActual<typeof import('../utils/fileCleanup.js')>('../utils/fileCleanup.js');
+  return {
+    ...actual,
+    deleteUploadFile: vi.fn(),
+    deleteAttachmentByFilename: vi.fn(),
+    deleteAttachmentFiles: vi.fn(),
+  };
+});
+import { deleteUploadFile, deleteAttachmentByFilename } from '../utils/fileCleanup.js';
+
+// Connection manager mock retrieval for spy assertions
+import { connectionManager } from '../ws/handler.js';
+
+function applyMigrations(db: Database.Database): void {
+  const migrationsDir = path.resolve(__dirname, '../../drizzle');
+  const files = fs.readdirSync(migrationsDir).filter((f) => f.endsWith('.sql')).sort();
+  for (const f of files) {
+    const sqlText = fs.readFileSync(path.join(migrationsDir, f), 'utf8');
+    const statements = sqlText.split(/-->\s*statement-breakpoint/);
+    for (const stmt of statements) {
+      const clean = stmt.trim();
+      if (clean) db.exec(clean);
+    }
+  }
+}
+
+function seedUsers(): void {
+  testDb.insert(schema.users).values({
+    id: 'owner-A',
+    username: 'alice',
+    displayName: 'Alice',
+    passwordHash: 'x',
+    homeUserId: 'owner-A',
+    homeInstance: 'https://local.test',
+    createdAt: Date.now(),
+  }).run();
+
+  testDb.insert(schema.users).values({
+    id: 'member-B',
+    username: 'bob',
+    displayName: 'Bob',
+    passwordHash: 'x',
+    homeUserId: 'member-B',
+    homeInstance: 'https://local.test',
+    createdAt: Date.now(),
+  }).run();
+
+  testDb.insert(schema.users).values({
+    id: 'remote-C',
+    username: 'carol@remote.test',
+    displayName: 'Carol',
+    passwordHash: 'x',
+    homeUserId: 'remote-carol',
+    homeInstance: 'https://remote.test',
+    createdAt: Date.now(),
+  }).run();
+
+  testDb.insert(schema.users).values({
+    id: 'stranger-D',
+    username: 'dan',
+    displayName: 'Dan',
+    passwordHash: 'x',
+    homeUserId: 'stranger-D',
+    homeInstance: 'https://local.test',
+    createdAt: Date.now(),
+  }).run();
+}
+
+function seedInstanceSettings(): void {
+  testDb.insert(schema.instanceSettings).values({
+    id: 1,
+    federationRelayEnabled: 1,
+    updatedAt: Date.now(),
+  }).run();
+}
+
+function seedFederationPeer(origin: string): void {
+  testDb.insert(schema.federationPeers).values({
+    id: `peer-${origin}`,
+    origin,
+    status: 'active',
+    hmacSecret: 'x',
+    createdAt: Date.now(),
+  }).run();
+}
+
+interface GroupSeed {
+  id: string;
+  ownerId: string;
+  members: string[];
+  federatedId?: string | null;
+  name?: string | null;
+  icon?: string | null;
+  metadataUpdatedAt?: number;
+}
+
+function seedGroupDm(opts: GroupSeed): void {
+  testDb.insert(schema.dmChannels).values({
+    id: opts.id,
+    ownerId: opts.ownerId,
+    federatedId: opts.federatedId ?? null,
+    name: opts.name ?? null,
+    icon: opts.icon ?? null,
+    metadataUpdatedAt: opts.metadataUpdatedAt ?? 0,
+    createdAt: Date.now(),
+  }).run();
+  for (const userId of opts.members) {
+    testDb.insert(schema.dmMembers).values({
+      dmChannelId: opts.id,
+      userId,
+    }).run();
+  }
+}
+
+function seed1on1Dm(id: string, a: string, b: string): void {
+  testDb.insert(schema.dmChannels).values({
+    id,
+    ownerId: null,
+    createdAt: Date.now(),
+  }).run();
+  testDb.insert(schema.dmMembers).values({ dmChannelId: id, userId: a }).run();
+  testDb.insert(schema.dmMembers).values({ dmChannelId: id, userId: b }).run();
+}
+
+function seedAttachment(opts: {
+  id: string;
+  filename: string;
+  uploaderId: string;
+  mimetype: string;
+  size: number;
+}): void {
+  testDb.insert(schema.attachments).values({
+    id: opts.id,
+    uploaderId: opts.uploaderId,
+    filename: opts.filename,
+    originalName: opts.filename,
+    mimetype: opts.mimetype,
+    size: opts.size,
+    createdAt: Date.now(),
+  }).run();
+}
+
+async function buildApp(): Promise<FastifyInstance> {
+  const app = Fastify({ logger: false });
+  const { dmRoutes } = await import('./dm.js');
+  await app.register(dmRoutes);
+  await app.ready();
+  return app;
+}
+
+describe('PATCH /api/dm/:id — group metadata update', () => {
+  let app: FastifyInstance;
+
+  beforeEach(async () => {
+    sqlite = new Database(':memory:');
+    testDb = drizzle(sqlite, { schema });
+    applyMigrations(sqlite);
+    seedInstanceSettings();
+    seedUsers();
+    seedFederationPeer('https://remote.test');
+    currentUserId = 'owner-A';
+    vi.clearAllMocks();
+    app = await buildApp();
+  });
+
+  it('owner rename succeeds → 200, channel updated, broadcast, system msg, outbox payload', async () => {
+    seedGroupDm({
+      id: 'dm-1',
+      ownerId: 'owner-A',
+      members: ['owner-A', 'member-B', 'remote-C'],
+      federatedId: 'fed-abc-1',
+    });
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/dm/dm-1',
+      payload: { name: 'My Group' },
+    });
+    expect(res.statusCode).toBe(200);
+
+    // Channel row updated
+    const updated = testDb.select().from(schema.dmChannels).where(eq(schema.dmChannels.id, 'dm-1')).get();
+    expect(updated?.name).toBe('My Group');
+    expect(updated?.icon).toBeNull();
+    expect(updated?.metadataUpdatedAt).toBeGreaterThan(0);
+
+    // dm_channel_updated broadcast
+    const sendCalls = (connectionManager.sendToDmMembers as ReturnType<typeof vi.fn>).mock.calls;
+    const updatedBroadcast = sendCalls.find((c) => c[1]?.type === 'dm_channel_updated');
+    expect(updatedBroadcast).toBeDefined();
+    expect(updatedBroadcast?.[1]).toMatchObject({ type: 'dm_channel_updated', dmChannelId: 'dm-1', name: 'My Group', icon: null });
+
+    // Single system message for name change
+    const sysRows = testDb.select().from(schema.dmMessages).where(eq(schema.dmMessages.dmChannelId, 'dm-1')).all();
+    expect(sysRows.length).toBe(1);
+    expect(sysRows[0]!.type).toBe('system');
+    const parsed = JSON.parse(sysRows[0]!.content!);
+    expect(parsed).toEqual({ event: 'name_changed', oldName: null, newName: 'My Group' });
+    expect(sysRows[0]!.sourceMessageId).toMatch(/:name$/);
+
+    // Federation outbox row queued — full payload
+    const outboxRows = testDb.select().from(schema.federationOutbox).all();
+    const metaRows = outboxRows.filter((r) => r.eventType === 'group_metadata_update');
+    expect(metaRows.length).toBe(1);
+    const wire = JSON.parse(metaRows[0]!.payload);
+    expect(wire.federatedId).toBe('fed-abc-1');
+    expect(wire.metadata.name).toBe('My Group');
+    expect(wire.metadata.icon).toBeNull();
+    expect(wire.metadata.metadataUpdatedAt).toBeGreaterThan(0);
+    expect(wire.metadata.actor.homeUserId).toBe('owner-A');
+    expect(wire.metadata.actor.homeInstance).toBe('https://local.test');
+  });
+
+  it('owner sets icon (filename) → outbox icon is absolute URL ${ourOrigin}/api/uploads/<filename>', async () => {
+    seedGroupDm({
+      id: 'dm-2',
+      ownerId: 'owner-A',
+      members: ['owner-A', 'member-B', 'remote-C'],
+      federatedId: 'fed-abc-2',
+    });
+    seedAttachment({
+      id: 'att-1',
+      filename: 'icon123.png',
+      uploaderId: 'owner-A',
+      mimetype: 'image/png',
+      size: 1024,
+    });
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/dm/dm-2',
+      payload: { icon: 'icon123.png' },
+    });
+    expect(res.statusCode).toBe(200);
+
+    const outboxRows = testDb.select().from(schema.federationOutbox).all();
+    const metaRows = outboxRows.filter((r) => r.eventType === 'group_metadata_update');
+    expect(metaRows.length).toBe(1);
+    const wire = JSON.parse(metaRows[0]!.payload);
+    expect(wire.metadata.icon).toBe('https://local.test/api/uploads/icon123.png');
+
+    // Bare filename stored in DB (not absolute URL)
+    const updated = testDb.select().from(schema.dmChannels).where(eq(schema.dmChannels.id, 'dm-2')).get();
+    expect(updated?.icon).toBe('icon123.png');
+  });
+
+  it('non-owner → 403', async () => {
+    seedGroupDm({
+      id: 'dm-3',
+      ownerId: 'owner-A',
+      members: ['owner-A', 'member-B'],
+    });
+    currentUserId = 'member-B';
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/dm/dm-3',
+      payload: { name: 'Nope' },
+    });
+    expect(res.statusCode).toBe(403);
+    const body = res.json();
+    expect(body.error).toMatch(/owner/i);
+  });
+
+  it('1-on-1 DM → 400', async () => {
+    seed1on1Dm('dm-1on1', 'owner-A', 'member-B');
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/dm/dm-1on1',
+      payload: { name: 'Cant' },
+    });
+    expect(res.statusCode).toBe(400);
+    expect(res.json().error).toMatch(/1-on-1/i);
+  });
+
+  it('name length 0 (after trim) → cleared (stored null), system message reflects oldName/newName', async () => {
+    seedGroupDm({
+      id: 'dm-4',
+      ownerId: 'owner-A',
+      members: ['owner-A', 'member-B'],
+      name: 'Old Name',
+    });
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/dm/dm-4',
+      payload: { name: '   ' },
+    });
+    expect(res.statusCode).toBe(200);
+
+    const updated = testDb.select().from(schema.dmChannels).where(eq(schema.dmChannels.id, 'dm-4')).get();
+    expect(updated?.name).toBeNull();
+
+    const sys = testDb.select().from(schema.dmMessages).where(eq(schema.dmMessages.dmChannelId, 'dm-4')).all();
+    expect(sys.length).toBe(1);
+    expect(JSON.parse(sys[0]!.content!)).toEqual({ event: 'name_changed', oldName: 'Old Name', newName: null });
+  });
+
+  it('name length 51 → 400', async () => {
+    seedGroupDm({
+      id: 'dm-5',
+      ownerId: 'owner-A',
+      members: ['owner-A', 'member-B'],
+    });
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/dm/dm-5',
+      payload: { name: 'x'.repeat(51) },
+    });
+    expect(res.statusCode).toBe(400);
+    expect(res.json().error).toMatch(/between 1 and 50/i);
+  });
+
+  it('icon clear (icon: null) → row updated, icon_changed system message, old local file deletion called', async () => {
+    seedGroupDm({
+      id: 'dm-6',
+      ownerId: 'owner-A',
+      members: ['owner-A', 'member-B'],
+      icon: 'oldicon.png',
+    });
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/dm/dm-6',
+      payload: { icon: null },
+    });
+    expect(res.statusCode).toBe(200);
+
+    const updated = testDb.select().from(schema.dmChannels).where(eq(schema.dmChannels.id, 'dm-6')).get();
+    expect(updated?.icon).toBeNull();
+
+    const sys = testDb.select().from(schema.dmMessages).where(eq(schema.dmMessages.dmChannelId, 'dm-6')).all();
+    expect(sys.length).toBe(1);
+    expect(JSON.parse(sys[0]!.content!)).toEqual({ event: 'icon_changed' });
+    expect(sys[0]!.sourceMessageId).toMatch(/:icon$/);
+
+    expect(deleteUploadFile).toHaveBeenCalledWith('oldicon.png');
+    expect(deleteAttachmentByFilename).toHaveBeenCalledWith('oldicon.png');
+  });
+
+  it('icon filename uploaded by another user → 403', async () => {
+    seedGroupDm({
+      id: 'dm-7',
+      ownerId: 'owner-A',
+      members: ['owner-A', 'member-B'],
+    });
+    seedAttachment({
+      id: 'att-2',
+      filename: 'someoneelse.png',
+      uploaderId: 'stranger-D',
+      mimetype: 'image/png',
+      size: 1024,
+    });
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/dm/dm-7',
+      payload: { icon: 'someoneelse.png' },
+    });
+    expect(res.statusCode).toBe(403);
+    expect(res.json().error).toMatch(/own/i);
+  });
+
+  it('icon filename with non-image mimetype → 400', async () => {
+    seedGroupDm({
+      id: 'dm-8',
+      ownerId: 'owner-A',
+      members: ['owner-A', 'member-B'],
+    });
+    seedAttachment({
+      id: 'att-3',
+      filename: 'notanimage.txt',
+      uploaderId: 'owner-A',
+      mimetype: 'text/plain',
+      size: 100,
+    });
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/dm/dm-8',
+      payload: { icon: 'notanimage.txt' },
+    });
+    expect(res.statusCode).toBe(400);
+    expect(res.json().error).toMatch(/image/i);
+  });
+
+  it('icon filename oversize → 400', async () => {
+    seedGroupDm({
+      id: 'dm-9',
+      ownerId: 'owner-A',
+      members: ['owner-A', 'member-B'],
+    });
+    seedAttachment({
+      id: 'att-4',
+      filename: 'huge.png',
+      uploaderId: 'owner-A',
+      mimetype: 'image/png',
+      size: 9 * 1024 * 1024, // > 8 MB cap
+    });
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/dm/dm-9',
+      payload: { icon: 'huge.png' },
+    });
+    expect(res.statusCode).toBe(400);
+    expect(res.json().error).toMatch(/MB/i);
+  });
+
+  it('icon absolute URL accepted (no attachment lookup attempted)', async () => {
+    seedGroupDm({
+      id: 'dm-10',
+      ownerId: 'owner-A',
+      members: ['owner-A', 'member-B'],
+      federatedId: 'fed-abc-10',
+    });
+    // Note: NO attachment seeded — proves no lookup happens for absolute URLs.
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/dm/dm-10',
+      payload: { icon: 'https://remote.test/api/uploads/icon999.png' },
+    });
+    expect(res.statusCode).toBe(200);
+
+    const updated = testDb.select().from(schema.dmChannels).where(eq(schema.dmChannels.id, 'dm-10')).get();
+    expect(updated?.icon).toBe('https://remote.test/api/uploads/icon999.png');
+  });
+
+  it('no-op (same name + same icon) → 200, no system messages, no broadcast, no outbox row', async () => {
+    seedGroupDm({
+      id: 'dm-11',
+      ownerId: 'owner-A',
+      members: ['owner-A', 'member-B', 'remote-C'],
+      federatedId: 'fed-abc-11',
+      name: 'Stable',
+      icon: 'stable.png',
+    });
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/dm/dm-11',
+      payload: { name: 'Stable', icon: 'stable.png' },
+    });
+    expect(res.statusCode).toBe(200);
+
+    // No system messages
+    const sys = testDb.select().from(schema.dmMessages).where(eq(schema.dmMessages.dmChannelId, 'dm-11')).all();
+    expect(sys.length).toBe(0);
+
+    // No broadcast
+    const sendCalls = (connectionManager.sendToDmMembers as ReturnType<typeof vi.fn>).mock.calls;
+    expect(sendCalls.length).toBe(0);
+
+    // No outbox row
+    const outboxRows = testDb.select().from(schema.federationOutbox).all();
+    expect(outboxRows.length).toBe(0);
+
+    // No icon deletion
+    expect(deleteUploadFile).not.toHaveBeenCalled();
+  });
+
+  it('concurrent change of both fields → two system messages with deterministic dedup-suffixed sourceMessageId', async () => {
+    seedGroupDm({
+      id: 'dm-12',
+      ownerId: 'owner-A',
+      members: ['owner-A', 'member-B', 'remote-C'],
+      federatedId: 'fed-abc-12',
+      name: 'Old',
+      icon: 'old.png',
+    });
+    seedAttachment({
+      id: 'att-12',
+      filename: 'newicon.png',
+      uploaderId: 'owner-A',
+      mimetype: 'image/png',
+      size: 2048,
+    });
+
+    const res = await app.inject({
+      method: 'PATCH',
+      url: '/api/dm/dm-12',
+      payload: { name: 'New Name', icon: 'newicon.png' },
+    });
+    expect(res.statusCode).toBe(200);
+
+    const sys = testDb.select().from(schema.dmMessages).where(eq(schema.dmMessages.dmChannelId, 'dm-12')).all();
+    expect(sys.length).toBe(2);
+
+    const nameRow = sys.find((r) => JSON.parse(r.content!).event === 'name_changed');
+    const iconRow = sys.find((r) => JSON.parse(r.content!).event === 'icon_changed');
+    expect(nameRow).toBeDefined();
+    expect(iconRow).toBeDefined();
+
+    // Both rows share the same eventMessageId root, suffixed by :name / :icon.
+    expect(nameRow!.sourceMessageId).toMatch(/:name$/);
+    expect(iconRow!.sourceMessageId).toMatch(/:icon$/);
+    const nameRoot = nameRow!.sourceMessageId!.replace(/:name$/, '');
+    const iconRoot = iconRow!.sourceMessageId!.replace(/:icon$/, '');
+    expect(nameRoot).toBe(iconRoot);
+
+    // Old icon was a local filename — cleanup should fire
+    expect(deleteUploadFile).toHaveBeenCalledWith('old.png');
+    expect(deleteAttachmentByFilename).toHaveBeenCalledWith('old.png');
+  });
+});

packages/server/src/routes/dm.ts

@@ -24,13 +24,21 @@ import {
 } from '@backspace/shared';
 import { fetchSpaceInviteSnapshot, getLocalInviteSnapshot } from '../utils/spaceInviteSnapshot.js';
 import { sanitizeUser } from '../utils/sanitize.js';
-import { deleteAttachmentFiles } from '../utils/fileCleanup.js';
+import { deleteAttachmentFiles, deleteUploadFile, deleteAttachmentByFilename } from '../utils/fileCleanup.js';
+import { isValidAssetUrl } from './users.js';
+import {
+  GROUP_DM_NAME_MIN_LENGTH,
+  GROUP_DM_NAME_MAX_LENGTH,
+  GROUP_DM_ICON_MAX_BYTES,
+  GROUP_DM_ICON_MIME_PREFIX,
+} from '@backspace/shared/src/constants.js';
 import { fetchDmEmbedsForMessages, resolveEmbeds, reResolveEmbeds, embedRowToEmbed } from '../utils/embedResolver.js';
 import {
   appendMutationLog,
   queueOutboxEvent,
   queueDmRelay,
   queueDmCloseRelay,
+  queueGroupMetadataRelay,
   getDmParticipants,
   getGroupDmTargetOrigins,
   isFederationRelayEnabled,
@@ -973,6 +981,258 @@ export async function dmRoutes(app: FastifyInstance): Promise<void> {
     return reply.code(201).send(result);
   });
 
+  // PATCH /api/dm/:id — Update group DM metadata (name + icon). Owner-only.
+  // Body: { name?: string | null, icon?: string | null }
+  // - name: trimmed; empty → cleared (null); otherwise length must be in
+  //   [GROUP_DM_NAME_MIN_LENGTH, GROUP_DM_NAME_MAX_LENGTH].
+  // - icon: null/empty → cleared; bare filename → must be an attachment
+  //   uploaded by the caller, image/* mimetype, ≤ GROUP_DM_ICON_MAX_BYTES;
+  //   absolute http(s) URL → accepted as-is (federated rebroadcast path).
+  app.patch<{ Params: { id: string }; Body: { name?: string | null; icon?: string | null } }>('/api/dm/:id', async (request, reply) => {
+    const { id } = request.params;
+    const body = request.body ?? {};
+    const db = getDb();
+
+    // Fetch channel
+    const dmChannel = db.select()
+      .from(schema.dmChannels)
+      .where(and(eq(schema.dmChannels.id, id), isNull(schema.dmChannels.deletedAt)))
+      .get();
+    if (!dmChannel) {
+      return reply.code(404).send({ error: 'DM channel not found', statusCode: 404 });
+    }
+
+    // 1-on-1 DMs (ownerId=NULL) cannot have metadata
+    if (!dmChannel.ownerId) {
+      return reply.code(400).send({ error: 'Cannot update metadata on a 1-on-1 DM', statusCode: 400 });
+    }
+
+    // Caller must be a member
+    if (!isDmMember(id, request.userId)) {
+      return reply.code(403).send({ error: 'You are not a member of this DM channel', statusCode: 403 });
+    }
+
+    // Caller must be the owner
+    if (dmChannel.ownerId !== request.userId) {
+      return reply.code(403).send({ error: 'Only the group owner can update metadata', statusCode: 403 });
+    }
+
+    const nameProvided = Object.prototype.hasOwnProperty.call(body, 'name');
+    const iconProvided = Object.prototype.hasOwnProperty.call(body, 'icon');
+
+    if (!nameProvided && !iconProvided) {
+      // No fields to update — return the channel unchanged.
+      return reply.code(200).send({ id: dmChannel.id, name: dmChannel.name, icon: dmChannel.icon, metadataUpdatedAt: dmChannel.metadataUpdatedAt });
+    }
+
+    const oldName = dmChannel.name ?? null;
+    const oldIcon = dmChannel.icon ?? null;
+
+    // ---- Resolve next name (with no-op short-circuit) ----
+    let nextName: string | null = oldName;
+    let nameChanged = false;
+    if (nameProvided) {
+      const raw = body.name;
+      let candidate: string | null;
+      if (raw === null || raw === undefined) {
+        candidate = null;
+      } else if (typeof raw !== 'string') {
+        return reply.code(400).send({ error: 'name must be a string or null', statusCode: 400 });
+      } else {
+        const trimmed = raw.trim();
+        candidate = trimmed.length === 0 ? null : trimmed;
+      }
+      // Validate length only if the value is actually changing — a no-op repeat
+      // of the stored value (even one that wouldn't pass current validation,
+      // e.g. legacy data) must not 400.
+      if (candidate !== oldName) {
+        if (candidate !== null) {
+          if (candidate.length < GROUP_DM_NAME_MIN_LENGTH || candidate.length > GROUP_DM_NAME_MAX_LENGTH) {
+            return reply.code(400).send({
+              error: `Group DM name must be between ${GROUP_DM_NAME_MIN_LENGTH} and ${GROUP_DM_NAME_MAX_LENGTH} characters`,
+              statusCode: 400,
+            });
+          }
+        }
+        nextName = candidate;
+        nameChanged = true;
+      }
+    }
+
+    // ---- Resolve next icon (with no-op short-circuit) ----
+    let nextIcon: string | null = oldIcon;
+    let iconChanged = false;
+    if (iconProvided) {
+      const raw = body.icon;
+      let candidate: string | null;
+      if (raw === null || raw === undefined) {
+        candidate = null;
+      } else if (typeof raw !== 'string') {
+        return reply.code(400).send({ error: 'icon must be a string or null', statusCode: 400 });
+      } else {
+        const trimmed = raw.trim();
+        if (trimmed.length === 0) {
+          candidate = null;
+        } else if (!isValidAssetUrl(trimmed)) {
+          return reply.code(400).send({ error: 'Invalid icon URL', statusCode: 400 });
+        } else if (trimmed.startsWith('http://') || trimmed.startsWith('https://')) {
+          candidate = trimmed;
+        } else {
+          // Bare filename or `/api/uploads/<filename>` — normalize to bare filename.
+          candidate = trimmed.startsWith('/api/uploads/') ? trimmed.slice('/api/uploads/'.length) : trimmed;
+        }
+      }
+      // Only validate attachment ownership/mimetype/size when the icon is
+      // actually changing AND the new value is a local filename (not an
+      // absolute URL or null clear).
+      if (candidate !== oldIcon) {
+        if (candidate !== null
+            && !candidate.startsWith('http://')
+            && !candidate.startsWith('https://')) {
+          const attachment = db.select()
+            .from(schema.attachments)
+            .where(eq(schema.attachments.filename, candidate))
+            .get();
+
+          if (!attachment) {
+            return reply.code(400).send({ error: 'Icon attachment not found', statusCode: 400 });
+          }
+          if (attachment.uploaderId !== request.userId) {
+            return reply.code(403).send({ error: 'You do not own this icon attachment', statusCode: 403 });
+          }
+          if (!attachment.mimetype.startsWith(GROUP_DM_ICON_MIME_PREFIX)) {
+            return reply.code(400).send({ error: 'Icon must be an image', statusCode: 400 });
+          }
+          if (attachment.size > GROUP_DM_ICON_MAX_BYTES) {
+            return reply.code(400).send({
+              error: `Icon must be smaller than ${Math.floor(GROUP_DM_ICON_MAX_BYTES / (1024 * 1024))} MB`,
+              statusCode: 400,
+            });
+          }
+        }
+        nextIcon = candidate;
+        iconChanged = true;
+      }
+    }
+
+    // ---- No-op short-circuit ----
+    if (!nameChanged && !iconChanged) {
+      return reply.code(200).send({
+        id: dmChannel.id,
+        name: dmChannel.name,
+        icon: dmChannel.icon,
+        metadataUpdatedAt: dmChannel.metadataUpdatedAt,
+      });
+    }
+
+    // Caller user row — needed for federation actor identity
+    const callerUser = db.select().from(schema.users).where(eq(schema.users.id, request.userId)).get();
+
+    // Single eventMessageId so name/icon system messages share a federation correlation root.
+    const eventMessageId = generateSnowflake();
+    const sysMessageRows: Array<{
+      id: string;
+      sourceMessageId: string;
+      content: string;
+    }> = [];
+
+    // ---- Transaction: persist channel update + system message rows ----
+    let metadataUpdatedAt = 0;
+    db.transaction((tx) => {
+      metadataUpdatedAt = Date.now();
+      tx.update(schema.dmChannels)
+        .set({ name: nextName, icon: nextIcon, metadataUpdatedAt })
+        .where(eq(schema.dmChannels.id, id))
+        .run();
+
+      if (nameChanged) {
+        const sysId = generateSnowflake();
+        const content = JSON.stringify({ event: 'name_changed', oldName, newName: nextName });
+        tx.insert(schema.dmMessages).values({
+          id: sysId,
+          dmChannelId: id,
+          userId: request.userId,
+          content,
+          type: 'system',
+          sourceMessageId: `${eventMessageId}:name`,
+          createdAt: metadataUpdatedAt,
+        }).run();
+        sysMessageRows.push({ id: sysId, sourceMessageId: `${eventMessageId}:name`, content });
+      }
+
+      if (iconChanged) {
+        const sysId = generateSnowflake();
+        const content = JSON.stringify({ event: 'icon_changed' });
+        tx.insert(schema.dmMessages).values({
+          id: sysId,
+          dmChannelId: id,
+          userId: request.userId,
+          content,
+          type: 'system',
+          sourceMessageId: `${eventMessageId}:icon`,
+          createdAt: metadataUpdatedAt,
+        }).run();
+        sysMessageRows.push({ id: sysId, sourceMessageId: `${eventMessageId}:icon`, content });
+      }
+    });
+
+    // ---- Broadcast channel update to local members ----
+    connectionManager.sendToDmMembers(id, {
+      type: 'dm_channel_updated',
+      dmChannelId: id,
+      name: nextName,
+      icon: nextIcon,
+    });
+
+    // ---- Broadcast each new system message ----
+    const sanitizedActor = callerUser ? sanitizeUser(callerUser) : undefined;
+    for (const sys of sysMessageRows) {
+      connectionManager.sendToDmMembers(id, {
+        type: 'dm_message_created',
+        message: {
+          id: sys.id,
+          dmChannelId: id,
+          userId: request.userId,
+          content: sys.content,
+          type: 'system',
+          createdAt: metadataUpdatedAt,
+          user: sanitizedActor,
+          attachments: [],
+          embeds: [],
+          reactions: [],
+        } as DmMessageWithUser,
+      });
+    }
+
+    // ---- Federation relay ----
+    if (isFederationRelayEnabled()) {
+      const domainOrigin = getOurOrigin();
+      queueGroupMetadataRelay(id, {
+        name: nextName,
+        icon: nextIcon,
+        metadataUpdatedAt,
+        actor: {
+          userId: request.userId,
+          homeUserId: callerUser?.homeUserId ?? request.userId,
+          homeInstance: callerUser?.homeInstance ?? domainOrigin,
+        },
+      });
+    }
+
+    // ---- Old icon cleanup (mirror users.ts:463-466 precedent) ----
+    if (iconChanged && oldIcon && !oldIcon.startsWith('http')) {
+      deleteUploadFile(oldIcon);
+      deleteAttachmentByFilename(oldIcon);
+    }
+
+    return reply.code(200).send({
+      id,
+      name: nextName,
+      icon: nextIcon,
+      metadataUpdatedAt,
+    });
+  });
+
   // DELETE /api/dm/:id - Close (hide) a DM channel for the requesting user
   app.delete<{ Params: { id: string } }>('/api/dm/:id', async (request, reply) => {
     const { id } = request.params;

packages/server/src/routes/users.ts

@@ -17,7 +17,7 @@ import { extractDomain } from './federation.js';
 import path from 'path';
 
 /** Validates that a URL is a safe asset URL (relative upload path, bare filename, or http/https) */
-function isValidAssetUrl(url: string | null | undefined): boolean {
+export function isValidAssetUrl(url: string | null | undefined): boolean {
   if (!url || url.trim().length === 0) return true; // empty/null = clearing
   const trimmed = url.trim();
   if (trimmed.startsWith('/api/uploads/')) return true;