Fix browser back button crash on tournament page

app/features/tournament-bracket/core/Bracket.test.ts

@@ -322,6 +322,42 @@ describe("swiss standings - losses against tied", () => {
 	});
 });
 
+describe("live standings - teams the tournament does not know", () => {
+	// client-side the bracket's match data can be fresher than the layout's teams
+	test.each(["swiss", "round_robin"] as const)(
+		"leaves them out (%s)",
+		(type) => {
+			const tournament = testTournament({
+				ctx: {
+					settings: {
+						bracketProgression: [
+							{
+								type,
+								name: "Bracket",
+								requiresCheckIn: false,
+								settings: {},
+								sources: [],
+							},
+						],
+					},
+					teams: [tournamentCtxTeam(1), tournamentCtxTeam(2)],
+				},
+				data: Engine.create({
+					type,
+					seeding: [1, 2, 3],
+					settings: { groupCount: 1, roundCount: 3 },
+				}),
+			});
+
+			const standings = tournament.bracketByIdx(0)!.liveStandings;
+
+			expect(standings.map((standing) => standing.team.id).sort()).toEqual([
+				1, 2,
+			]);
+		},
+	);
+});
+
 describe("swiss standings - cross group ties", () => {
 	// Two Swiss groups of four playing one round. Group 1 is won by seed 3 (who beat
 	// seed 7), group 2 by seed 6 (who upset seed 2). Both are 1st of their group, and

app/features/tournament-bracket/core/Bracket/RoundRobinBracket.ts

@@ -279,6 +279,8 @@ export class RoundRobinBracket extends Bracket {
 
 			placements.push(
 				...teams
+					// client-side the layout's teams can lag behind freshly loaded match data, mostly preview tournaments (prevent crash)
+					.filter((team) => this.tournament.teamById(team.id))
 					.sort((a, b) => {
 						// TIEBREAKER 0) dropped out teams are always last
 						const aDroppedOut = droppedOutTeams.includes(a.id);

app/features/tournament-bracket/core/Bracket/SwissBracket.ts

@@ -376,6 +376,8 @@ export class SwissBracket extends Bracket {
 
 			placements.push(
 				...teams
+					// client-side the layout's teams can lag behind freshly loaded match data, mostly preview tournaments (prevent crash)
+					.filter((team) => this.tournament.teamById(team.id))
 					.sort((a, b) => {
 						// TIEBREAKER 0) dropped out teams are always last
 						const aDroppedOut = droppedOutTeams.includes(a.id);

app/features/tournament-bracket/routes/to.$id.brackets.tsx

@@ -16,6 +16,7 @@ import {
 	useLoaderData,
 	useLocation,
 	useOutletContext,
+	useRevalidator,
 } from "react-router";
 import { Alert } from "~/components/Alert";
 import { LinkButton, SendouButton } from "~/components/elements/Button";
@@ -102,6 +103,7 @@ function TournamentBracketsView() {
 	useScrollToMatchOnLoad();
 
 	const bracket = tournament.bracketByIdx(data.bracketIdx);
+	useRevalidateOnUnknownTeams(bracket);
 
 	useTopicRevalidation(
 		tournamentChannel(tournament.ctx.id),
@@ -281,6 +283,19 @@ function useScrollToMatchOnLoad() {
 	}, [scrollToMatchId]);
 }
 
+/** The layout does not revalidate on navigations within the tournament, so it can lack teams registered since it loaded. */
+function useRevalidateOnUnknownTeams(bracket: BracketType | null) {
+	const { revalidate } = useRevalidator();
+	const hasUnknownTeams =
+		bracket?.participantTournamentTeamIds.some(
+			(teamId) => !bracket.tournament.teamById(teamId),
+		) ?? false;
+
+	React.useEffect(() => {
+		if (hasUnknownTeams) revalidate();
+	}, [hasUnknownTeams, revalidate]);
+}
+
 function getAbDivisionsStartError(
 	bracket: BracketType,
 	tournament: Tournament,

changelog/2026-10-02-brackets-page-crash-new-teams.md

@@ -0,0 +1,5 @@
+---
+navItem: medal
+type: bug
+---
+Fix the tournament brackets page crashing when returning to it after new teams had registered (using browser back button)