Fix observer not seeing messages sent while they were away from the page

app/features/chat/chat-client.test.ts

@@ -590,6 +590,32 @@ describe("createChatClient", () => {
 		expect(client.getSnapshot().messagesByRoomId.has(50)).toBe(true);
 	});
 
+	test("reopening an observed room refetches its history", async () => {
+		const observed = room({ id: 50 });
+		const harness = createHarness({
+			observedRoom: observed,
+			messages: [message({ id: 1, roomId: 50 })],
+		});
+		const client = await startedClient(harness);
+		client.ensureRoomKnown(50);
+		await flush();
+		client.ensureMessagesLoaded(50);
+		await flush();
+
+		harness.fetchMessages.mockResolvedValue({
+			messages: [
+				message({ id: 1, roomId: 50 }),
+				message({ id: 2, roomId: 50 }),
+			],
+		});
+		client.ensureMessagesLoaded(50);
+		await flush();
+
+		// nothing was pushed to the observer while the room's page was not open
+		expect(harness.fetchMessages).toHaveBeenCalledTimes(2);
+		expect(client.getSnapshot().messagesByRoomId.get(50)).toHaveLength(2);
+	});
+
 	test("an observed room the user's list later carries is superseded by the list version", async () => {
 		const observed = room({ id: 50 });
 		const harness = createHarness({ observedRoom: observed });

app/features/chat/chat-client.ts

@@ -67,7 +67,7 @@ export interface ChatClient {
 	refreshRooms: () => Promise<void>;
 	/** Fetches a room's info as an observed room when the user's own room list does not carry it (observer access via a route's `chatRooms`). */
 	ensureRoomKnown: (roomId: number) => void;
-	/** Fetches the room's history unless it is already loaded or loading. */
+	/** Fetches the room's history unless it is already loaded or loading. An observed room's held history is refetched instead of trusted: messages only reach an observer while the route surfacing the room keeps its subscription. */
 	ensureMessagesLoaded: (roomId: number) => void;
 	/** Reconnect catch-up: refetches the room list and every loaded history. */
 	catchUp: () => void;
@@ -455,7 +455,8 @@ export function createChatClient(deps: ChatClientDeps): ChatClient {
 			void loadObservedRoom(roomId);
 		},
 		ensureMessagesLoaded: (roomId) => {
-			if (messagesByRoomId.has(roomId)) return;
+			const canHaveMissedMessages = roomById(roomId)?.observed ?? false;
+			if (messagesByRoomId.has(roomId) && !canHaveMissedMessages) return;
 			void loadMessages(roomId);
 		},
 		catchUp: () => {

changelog/2026-08-29-observer-chat-history.md

@@ -0,0 +1,4 @@
+---
+type: bug
+---
+Fix tournament staff not seeing chat messages sent while they were on another page

e2e/chat.spec.ts

@@ -25,6 +25,7 @@ import { MobileNav } from "./pages/layout/mobile-nav";
 import { SideNav } from "./pages/layout/side-nav";
 import { SendouQLookingPage } from "./pages/sendouq/sendouq-looking-page";
 import { SendouQMatchPage } from "./pages/sendouq/sendouq-match-page";
+import { TournamentBracketsPage } from "./pages/tournament/tournament-brackets-page";
 import { TournamentMatchPage } from "./pages/tournament/tournament-match-page";
 
 test.describe("Chat", () => {
@@ -383,6 +384,56 @@ test.describe("Chat", () => {
 		}
 	});
 
+	test("An observer coming back to a match chat sees what was said while they were away", async ({
+		page,
+		browser,
+		workerBaseURL,
+		factories,
+	}) => {
+		const { tournament, matchId } = await createInProgressMatch(factories, {
+			name: "Chat Cup",
+			friendId: NZAP_TEST_ID,
+		});
+
+		const participant = await openSecondUser(
+			browser,
+			workerBaseURL,
+			NZAP_TEST_ID,
+		);
+		try {
+			await new TournamentMatchPage(participant.page).goto({
+				tournamentId: tournament.id,
+				matchId,
+			});
+			const participantChat = new ChatSidebar(participant.page).chat();
+
+			// the tournament's author, and so an observer of the match chat
+			await impersonate(page);
+			const brackets = new TournamentBracketsPage(page);
+			await brackets.goto(tournament.id);
+
+			const matchPage = await brackets.openMatch(matchId);
+			const chat = new ChatSidebar(page);
+
+			await expect(chat.locators.openChats).toHaveCount(1);
+
+			// an observer is only pushed the room's messages while on the page that
+			// surfaced it, so what is said from here on never reaches their history
+			await matchPage.backToBracket();
+
+			await participantChat.send("said while you were on the bracket");
+			await expect(participantChat.locators.pendingMessages).toHaveCount(0);
+
+			await brackets.openMatch(matchId);
+
+			await expect(
+				chat.chat().message("said while you were on the bracket"),
+			).toBeVisible();
+		} finally {
+			await participant.close();
+		}
+	});
+
 	test("A closed room is readable by staff and denied to its participants", async ({
 		page,
 		browser,