Dedupe contacts/sidebar by key not name

frontend/src/components/Sidebar.tsx

@@ -140,11 +140,12 @@ export function Sidebar({
     [lastMessageTimes]
   );
 
-  // Deduplicate channels by name, keeping the first (lowest index)
+  // Deduplicate channels by key only.
+  // Channel names are not unique; distinct keys must remain visible.
   const uniqueChannels = useMemo(
     () =>
       channels.reduce<Channel[]>((acc, channel) => {
-        if (!acc.some((c) => c.name === channel.name)) {
+        if (!acc.some((c) => c.key === channel.key)) {
           acc.push(channel);
         }
         return acc;

frontend/src/hooks/useConversationMessages.ts

@@ -100,21 +100,24 @@ export function useConversationMessages(
     hasOlderMessagesRef.current = hasOlderMessages;
   }, [hasOlderMessages]);
 
-  const setPendingAck = useCallback((messageId: number, ackCount: number, paths?: MessagePath[]) => {
-    const existing = pendingAcksRef.current.get(messageId);
-    const merged = mergePendingAck(existing, ackCount, paths);
+  const setPendingAck = useCallback(
+    (messageId: number, ackCount: number, paths?: MessagePath[]) => {
+      const existing = pendingAcksRef.current.get(messageId);
+      const merged = mergePendingAck(existing, ackCount, paths);
 
-    // Update insertion order so most recent updates remain in the buffer longest.
-    pendingAcksRef.current.delete(messageId);
-    pendingAcksRef.current.set(messageId, merged);
+      // Update insertion order so most recent updates remain in the buffer longest.
+      pendingAcksRef.current.delete(messageId);
+      pendingAcksRef.current.set(messageId, merged);
 
-    if (pendingAcksRef.current.size > MAX_PENDING_ACKS) {
-      const oldestMessageId = pendingAcksRef.current.keys().next().value as number | undefined;
-      if (oldestMessageId !== undefined) {
-        pendingAcksRef.current.delete(oldestMessageId);
+      if (pendingAcksRef.current.size > MAX_PENDING_ACKS) {
+        const oldestMessageId = pendingAcksRef.current.keys().next().value as number | undefined;
+        if (oldestMessageId !== undefined) {
+          pendingAcksRef.current.delete(oldestMessageId);
+        }
       }
-    }
-  }, []);
+    },
+    []
+  );
 
   const applyPendingAck = useCallback((msg: Message): Message => {
     const pending = pendingAcksRef.current.get(msg.id);
@@ -345,30 +348,33 @@ export function useConversationMessages(
 
   // Add a message if it's new (deduplication)
   // Returns true if the message was added, false if it was a duplicate
-  const addMessageIfNew = useCallback((msg: Message): boolean => {
-    const msgWithPendingAck = applyPendingAck(msg);
-    const contentKey = getMessageContentKey(msgWithPendingAck);
-    if (seenMessageContent.current.has(contentKey)) {
-      console.debug('Duplicate message content ignored:', contentKey.slice(0, 50));
-      return false;
-    }
-    seenMessageContent.current.add(contentKey);
-
-    // Limit set size to prevent memory issues (keep last 500)
-    if (seenMessageContent.current.size > 1000) {
-      const entries = Array.from(seenMessageContent.current);
-      seenMessageContent.current = new Set(entries.slice(-500));
-    }
-
-    setMessages((prev) => {
-      if (prev.some((m) => m.id === msgWithPendingAck.id)) {
-        return prev;
+  const addMessageIfNew = useCallback(
+    (msg: Message): boolean => {
+      const msgWithPendingAck = applyPendingAck(msg);
+      const contentKey = getMessageContentKey(msgWithPendingAck);
+      if (seenMessageContent.current.has(contentKey)) {
+        console.debug('Duplicate message content ignored:', contentKey.slice(0, 50));
+        return false;
       }
-      return [...prev, msgWithPendingAck];
-    });
+      seenMessageContent.current.add(contentKey);
 
-    return true;
-  }, [applyPendingAck]);
+      // Limit set size to prevent memory issues (keep last 500)
+      if (seenMessageContent.current.size > 1000) {
+        const entries = Array.from(seenMessageContent.current);
+        seenMessageContent.current = new Set(entries.slice(-500));
+      }
+
+      setMessages((prev) => {
+        if (prev.some((m) => m.id === msgWithPendingAck.id)) {
+          return prev;
+        }
+        return [...prev, msgWithPendingAck];
+      });
+
+      return true;
+    },
+    [applyPendingAck]
+  );
 
   // Update a message's ack count and paths
   const updateMessageAck = useCallback(
@@ -388,7 +394,9 @@ export function useConversationMessages(
           const current = prev[idx];
           const nextAck = Math.max(current.acked, ackCount);
           const nextPaths =
-            paths !== undefined && paths.length >= (current.paths?.length ?? 0) ? paths : current.paths;
+            paths !== undefined && paths.length >= (current.paths?.length ?? 0)
+              ? paths
+              : current.paths;
 
           const updated = [...prev];
           updated[idx] = {

frontend/src/test/sidebar.test.tsx

@@ -37,6 +37,7 @@ function renderSidebar(overrides?: {
   unreadCounts?: Record<string, number>;
   favorites?: Favorite[];
   lastMessageTimes?: ConversationTimes;
+  channels?: Channel[];
 }) {
   const aliceName = 'Alice';
   const publicChannel = makeChannel('AA'.repeat(16), 'Public');
@@ -53,11 +54,12 @@ function renderSidebar(overrides?: {
   };
 
   const favorites = overrides?.favorites ?? [{ type: 'channel', id: flightChannel.key }];
+  const channels = overrides?.channels ?? [publicChannel, flightChannel, opsChannel];
 
   const view = render(
     <Sidebar
       contacts={[alice, relay]}
-      channels={[publicChannel, flightChannel, opsChannel]}
+      channels={channels}
       activeConversation={null}
       onSelectConversation={vi.fn()}
       onNewMessage={vi.fn()}
@@ -137,4 +139,40 @@ describe('Sidebar section summaries', () => {
     expect(screen.queryByText(opsChannel.name)).not.toBeInTheDocument();
     expect(screen.queryByText(aliceName)).not.toBeInTheDocument();
   });
+
+  it('renders same-name channels when keys differ and allows selecting both', () => {
+    const publicChannel = makeChannel('AA'.repeat(16), 'Public');
+    const channelA = makeChannel('DD'.repeat(16), '#shared');
+    const channelB = makeChannel('EE'.repeat(16), '#shared');
+    const onSelectConversation = vi.fn();
+
+    render(
+      <Sidebar
+        contacts={[]}
+        channels={[publicChannel, channelA, channelB]}
+        activeConversation={null}
+        onSelectConversation={onSelectConversation}
+        onNewMessage={vi.fn()}
+        lastMessageTimes={{}}
+        unreadCounts={{}}
+        mentions={{}}
+        showCracker={false}
+        crackerRunning={false}
+        onToggleCracker={vi.fn()}
+        onMarkAllRead={vi.fn()}
+        favorites={[]}
+        sortOrder="recent"
+        onSortOrderChange={vi.fn()}
+      />
+    );
+
+    const sharedRows = screen.getAllByText('#shared');
+    expect(sharedRows).toHaveLength(2);
+
+    fireEvent.click(sharedRows[0]);
+    fireEvent.click(sharedRows[1]);
+
+    const selectedIds = onSelectConversation.mock.calls.map(([conv]) => conv.id);
+    expect(new Set(selectedIds)).toEqual(new Set([channelA.key, channelB.key]));
+  });
 });

frontend/src/test/useConversationMessages.race.test.ts

@@ -67,7 +67,9 @@ describe('useConversationMessages ACK ordering', () => {
     });
 
     act(() => {
-      const added = result.current.addMessageIfNew(createMessage({ id: 42, acked: 0, paths: null }));
+      const added = result.current.addMessageIfNew(
+        createMessage({ id: 42, acked: 0, paths: null })
+      );
       expect(added).toBe(true);
     });