fix(i18n): review fallback system

.changeset/flat-jobs-punch.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fix a flaw in the i18n fallback logic, where the routes didn't preserve their metadata, such as hoisted scripts

packages/astro/src/@types/astro.ts

@@ -2434,16 +2434,21 @@ export interface RouteData {
 	prerender: boolean;
 	redirect?: RedirectConfig;
 	redirectRoute?: RouteData;
+	fallbackRoutes: RouteData[];
 }
 
 export type RedirectRouteData = RouteData & {
 	redirect: string;
 };
 
-export type SerializedRouteData = Omit<RouteData, 'generate' | 'pattern' | 'redirectRoute'> & {
+export type SerializedRouteData = Omit<
+	RouteData,
+	'generate' | 'pattern' | 'redirectRoute' | 'fallbackRoutes'
+> & {
 	generate: undefined;
 	pattern: string;
 	redirectRoute: SerializedRouteData | undefined;
+	fallbackRoutes: SerializedRouteData[];
 	_meta: {
 		trailingSlash: AstroConfig['trailingSlash'];
 	};

packages/astro/src/core/app/index.ts

@@ -127,6 +127,13 @@ export class App {
 		}
 		return pathname;
 	}
+
+	#getPathnameFromRequest(request: Request): string {
+		const url = new URL(request.url);
+		const pathname = prependForwardSlash(this.removeBase(url.pathname));
+		return pathname;
+	}
+
 	match(request: Request, _opts: MatchOptions = {}): RouteData | undefined {
 		const url = new URL(request.url);
 		// ignore requests matching public assets
@@ -151,7 +158,8 @@ export class App {
 		}
 
 		Reflect.set(request, clientLocalsSymbol, locals ?? {});
-		const defaultStatus = this.#getDefaultStatusCode(routeData.route);
+		const pathname = this.#getPathnameFromRequest(request);
+		const defaultStatus = this.#getDefaultStatusCode(routeData, pathname);
 		const mod = await this.#getModuleForRoute(routeData);
 
 		const pageModule = (await mod.page()) as any;
@@ -369,8 +377,15 @@ export class App {
 		});
 	}
 
-	#getDefaultStatusCode(route: string): number {
-		route = removeTrailingForwardSlash(route);
+	#getDefaultStatusCode(routeData: RouteData, pathname: string): number {
+		if (!routeData.pattern.exec(pathname)) {
+			for (const fallbackRoute of routeData.fallbackRoutes) {
+				if (fallbackRoute.pattern.test(pathname)) {
+					return 302;
+				}
+			}
+		}
+		const route = removeTrailingForwardSlash(routeData.route);
 		if (route.endsWith('/404')) return 404;
 		if (route.endsWith('/500')) return 500;
 		return 200;

packages/astro/src/core/build/buildPipeline.ts

@@ -164,17 +164,15 @@ export class BuildPipeline extends Pipeline {
 			}
 		}
 
-		for (const [path, pageDataList] of this.#internals.pagesByComponents.entries()) {
-			for (const pageData of pageDataList) {
-				if (routeIsRedirect(pageData.route)) {
-					pages.set(pageData, path);
-				} else if (
-					routeIsFallback(pageData.route) &&
-					(i18nHasFallback(this.getConfig()) ||
-						(routeIsFallback(pageData.route) && pageData.route.route === '/'))
-				) {
-					pages.set(pageData, path);
-				}
+		for (const [path, pageData] of this.#internals.pagesByComponent.entries()) {
+			if (routeIsRedirect(pageData.route)) {
+				pages.set(pageData, path);
+			} else if (
+				routeIsFallback(pageData.route) &&
+				(i18nHasFallback(this.getConfig()) ||
+					(routeIsFallback(pageData.route) && pageData.route.route === '/'))
+			) {
+				pages.set(pageData, path);
 			}
 		}