feat(client): chat timeline renders name_changed + icon_changed system messages

packages/web/src/components/chat/MessageList.tsx

@@ -17,8 +17,8 @@ import { Avatar } from '../ui/Avatar';
 import { hasPermissionBit, PermissionBits } from '../../utils/permissions';
 import { isSelf, parseFederatedUsername } from '../../utils/identity';
 import { useDelayedLoading } from '../../hooks/useDelayedLoading';
-import type { MessageWithUser, SpaceInviteSystemPayload } from '@backspace/shared';
-import { SpaceInviteCard } from './SpaceInviteCard';
+import type { MessageWithUser } from '@backspace/shared';
+import { SystemMessage } from './SystemMessage';
 
 const EMPTY_MESSAGES: MessageWithUser[] = [];
 const EMPTY_PENDING_BUBBLES: PendingBubble[] = [];
@@ -203,6 +203,11 @@ export function MessageList({ channelId, jumpToMessageId, onJumpComplete }: Mess
   const isDm = isDmChannel(channelId);
   const canReadHistory = isDm || hasPermissionBit(channelPerms, PermissionBits.READ_MESSAGE_HISTORY);
 
+  // Channel-specific DM record (if applicable). Passed to SystemMessage so it
+  // can resolve actor display names from the channel roster — needed for
+  // events that don't embed the actor (name_changed, icon_changed, owner_changed).
+  const currentDm = useSpaceStore((s) => isDm ? s.dmChannels.find(d => d.id === channelId) : undefined);
+
   // Pending bubble interleaving — synthetic MessageWithUser-shaped objects
   // representing optimistic sends. `Message.tsx` (Task 19) branches on the
   // `__pending` sentinel to render upload progress instead of confirmed state.
@@ -691,7 +696,7 @@ export function MessageList({ channelId, jumpToMessageId, onJumpComplete }: Mess
                   </div>
                 )}
                 {msg.type === 'system' ? (
-                  <SystemMessage message={msg} />
+                  <SystemMessage message={msg} dm={currentDm ?? null} />
                 ) : (
                   <Message
                     message={msg}
@@ -747,55 +752,6 @@ export function MessageList({ channelId, jumpToMessageId, onJumpComplete }: Mess
   );
 }
 
-function SystemMessage({ message }: { message: MessageWithUser }) {
-  let data: Record<string, unknown> = {};
-  try { data = JSON.parse(message.content ?? '{}'); } catch { /* fall through */ }
-
-  const actorName = message.user?.displayName ?? message.user?.username ?? 'Someone';
-
-  if (data.event === 'space_invite') {
-    return (
-      <div className="px-4 py-1">
-        <SpaceInviteCard payload={data as unknown as SpaceInviteSystemPayload} senderName={actorName} />
-      </div>
-    );
-  }
-
-  // Legacy inline-text events
-  let text = '';
-  let icon = '';
-  switch (data.event) {
-    case 'member_added':
-      icon = '\u2192'; // →
-      text = `${actorName} added ${data.targetDisplayName} to the group`;
-      break;
-    case 'member_removed':
-      if (data.reason === 'leave') {
-        icon = '\u2190'; // ←
-        text = `${data.targetDisplayName} left the group`;
-      } else {
-        icon = '\u2190';
-        text = `${actorName} removed ${data.targetDisplayName} from the group`;
-      }
-      break;
-    case 'owner_changed':
-      icon = '\u265B'; // ♛
-      text = `${data.newOwnerDisplayName} is now the group owner`;
-      break;
-    default:
-      text = message.content ?? '';
-  }
-
-  return (
-    <div className="flex items-center justify-center py-1 px-4 select-none">
-      <span className="text-xs text-txt-tertiary">
-        <span className="mr-1.5">{icon}</span>
-        {text}
-      </span>
-    </div>
-  );
-}
-
 function WelcomeHeader({ channelId }: { channelId: string }) {
   const dmChannels = useSpaceStore((s) => s.dmChannels);
   const authUser = useAuthStore((s) => s.user);

packages/web/src/components/chat/SystemMessage.test.tsx

@@ -0,0 +1,98 @@
+import { describe, it, expect, vi } from 'vitest';
+import { render, screen } from '@testing-library/react';
+import { MemoryRouter } from 'react-router-dom';
+import { SystemMessage } from './SystemMessage';
+import type { DmChannel, MessageWithUser, User } from '@backspace/shared';
+
+// SpaceInviteCard is unrelated to the cases under test but is imported by
+// SystemMessage; stub its store hooks so the import graph resolves cleanly.
+vi.mock('../../stores/spaceStore', () => ({
+  useSpaceStore: (selector: (s: unknown) => unknown) =>
+    selector({ joinByCode: vi.fn() }),
+  getApiForOrigin: vi.fn(),
+}));
+vi.mock('../../api/client', () => ({
+  api: {},
+  createApiClient: vi.fn(),
+}));
+
+const actor: User = {
+  id: 'U1',
+  username: 'jannis',
+  displayName: 'Jannis',
+  avatar: null,
+  banner: null,
+  accentColor: null,
+  avatarColor: 'mint',
+  bio: null,
+  status: 'online',
+  customStatus: null,
+  isAdmin: false,
+  createdAt: 0,
+  homeUserId: null,
+  homeInstance: null,
+  replicatedInstances: [],
+};
+
+function buildMessage(content: object, userId = 'U1'): MessageWithUser {
+  return {
+    id: 'M1',
+    channelId: '',
+    userId,
+    user: actor,
+    content: JSON.stringify(content),
+    type: 'system',
+    createdAt: 1,
+    editedAt: null,
+    replyToId: null,
+    replyTo: null,
+    attachments: [],
+    embeds: [],
+    reactions: [],
+    mentions: [],
+    everyoneMentioned: false,
+    pinnedAt: null,
+  } as unknown as MessageWithUser;
+}
+
+const dm: Pick<DmChannel, 'members'> = { members: [actor] };
+
+function renderSM(message: MessageWithUser, dmArg: Pick<DmChannel, 'members'> | null) {
+  return render(
+    <MemoryRouter>
+      <SystemMessage message={message} dm={dmArg} />
+    </MemoryRouter>,
+  );
+}
+
+describe('SystemMessage — name_changed', () => {
+  it('newName="Cool Group" with resolvable actor → "✎ Jannis renamed the group to \\"Cool Group\\""', () => {
+    const msg = buildMessage({ event: 'name_changed', oldName: null, newName: 'Cool Group' });
+    renderSM(msg, dm);
+    expect(screen.getByText('✎')).toBeDefined();
+    expect(screen.getByText(/Jannis renamed the group to "Cool Group"/)).toBeDefined();
+  });
+
+  it('newName=null (cleared) with resolvable actor → "✎ Jannis cleared the group name"', () => {
+    const msg = buildMessage({ event: 'name_changed', oldName: 'Old', newName: null });
+    renderSM(msg, dm);
+    expect(screen.getByText('✎')).toBeDefined();
+    expect(screen.getByText(/Jannis cleared the group name/)).toBeDefined();
+  });
+
+  it('unresolvable actor (member missing from roster) → "✎ Unknown renamed …"', () => {
+    const msg = buildMessage({ event: 'name_changed', oldName: null, newName: 'X' }, 'GHOST');
+    renderSM(msg, dm); // dm.members has only U1, not GHOST
+    expect(screen.getByText(/Unknown renamed the group to "X"/)).toBeDefined();
+  });
+});
+
+describe('SystemMessage — icon_changed', () => {
+  it('resolvable actor → "🖼 Jannis updated the group icon"', () => {
+    const msg = buildMessage({ event: 'icon_changed' });
+    renderSM(msg, dm);
+    // The 🖼 character is U+1F5BC (FRAME WITH PICTURE), not 🖼️ (with VS-16).
+    expect(screen.getByText('\u{1F5BC}')).toBeDefined();
+    expect(screen.getByText(/Jannis updated the group icon/)).toBeDefined();
+  });
+});

packages/web/src/components/chat/SystemMessage.tsx

@@ -0,0 +1,93 @@
+import type { DmChannel, MessageWithUser, SpaceInviteSystemPayload, User } from '@backspace/shared';
+import { SpaceInviteCard } from './SpaceInviteCard';
+
+interface SystemMessageProps {
+  message: MessageWithUser;
+  /**
+   * The enclosing DM channel, if the message belongs to one. Used to resolve
+   * the actor's display name from the channel roster (`dm.members`) for events
+   * that don't carry it in the payload (e.g. `name_changed`, `icon_changed`,
+   * `owner_changed`). When omitted (e.g. server channels), the renderer falls
+   * back to the embedded `message.user`.
+   */
+  dm?: Pick<DmChannel, 'members'> | null;
+}
+
+function resolveActorName(message: MessageWithUser, dm?: Pick<DmChannel, 'members'> | null): string {
+  if (dm) {
+    const fromRoster = dm.members.find(m => m.id === message.userId) as User | undefined;
+    if (fromRoster) {
+      return fromRoster.displayName ?? fromRoster.username ?? 'Unknown';
+    }
+    return 'Unknown';
+  }
+  return message.user?.displayName ?? message.user?.username ?? 'Someone';
+}
+
+/**
+ * Inline timeline renderer for system DM messages. Mirrors the sidebar's
+ * `formatSystemPreview` semantics but with icons + a slightly fuller phrasing
+ * (e.g. surfacing the new name in `name_changed`).
+ *
+ * Exported so unit tests can render it directly without mounting MessageList.
+ */
+export function SystemMessage({ message, dm }: SystemMessageProps) {
+  let data: Record<string, unknown> = {};
+  try { data = JSON.parse(message.content ?? '{}'); } catch { /* fall through to default branch */ }
+
+  const actorName = resolveActorName(message, dm);
+
+  if (data.event === 'space_invite') {
+    return (
+      <div className="px-4 py-1">
+        <SpaceInviteCard payload={data as unknown as SpaceInviteSystemPayload} senderName={actorName} />
+      </div>
+    );
+  }
+
+  // Inline-text events.
+  let text = '';
+  let icon = '';
+  switch (data.event) {
+    case 'member_added':
+      icon = '→'; // →
+      text = `${actorName} added ${data.targetDisplayName} to the group`;
+      break;
+    case 'member_removed':
+      if (data.reason === 'leave') {
+        icon = '←'; // ←
+        text = `${data.targetDisplayName} left the group`;
+      } else {
+        icon = '←';
+        text = `${actorName} removed ${data.targetDisplayName} from the group`;
+      }
+      break;
+    case 'owner_changed':
+      icon = '♛'; // ♛
+      text = `${data.newOwnerDisplayName} is now the group owner`;
+      break;
+    case 'name_changed':
+      icon = '✎'; // ✎
+      // newName === null is a meaningful "cleared" state — distinct from a
+      // missing field — so we test for a non-empty string explicitly.
+      text = typeof data.newName === 'string' && data.newName.length > 0
+        ? `${actorName} renamed the group to "${data.newName}"`
+        : `${actorName} cleared the group name`;
+      break;
+    case 'icon_changed':
+      icon = '\u{1F5BC}'; // 🖼
+      text = `${actorName} updated the group icon`;
+      break;
+    default:
+      text = message.content ?? '';
+  }
+
+  return (
+    <div className="flex items-center justify-center py-1 px-4 select-none">
+      <span className="text-xs text-txt-tertiary">
+        <span className="mr-1.5">{icon}</span>
+        {text}
+      </span>
+    </div>
+  );
+}

packages/web/src/stores/spaceStore.joinByCode.test.ts

@@ -49,6 +49,7 @@ vi.mock('../utils/crossStoreResolvers', () => ({
   resolveUserIdFromInstances: vi.fn(),
   getCachedUserIdForOrigin: vi.fn(),
   clearMyUserIdCache: vi.fn(),
+  setOwnerInstanceForDmResolver: vi.fn(),
 }));
 
 // Import after mocks so we get the mocked versions