fix: bubble up errors in rewrites (#11136)

* fix: bubble up errors in rewrites

* docs

* remove commented code

* changesets

* fix string interpolation

.changeset/dull-lizards-jog.md

@@ -0,0 +1,5 @@
+---
+"astro": patch
+---
+
+Errors that are emitted during a rewrite are now bubbled up and shown to the user. A 404 response is not returned anymore.

.changeset/nervous-pens-retire.md

@@ -0,0 +1,7 @@
+---
+"astro": patch
+---
+
+It's not possible anymore to use `Astro.rewrite("/404")` inside static pages. This isn't counterproductive because Astro will end-up emitting a page that contains the HTML of 404 error page.
+
+It's still possible to use `Astro.rewrite("/404")` inside on-demand pages, or pages that opt-out from prerendering.

packages/astro/src/container/pipeline.ts

@@ -7,12 +7,13 @@ import type {
 } from '../@types/astro.js';
 import { type HeadElements, Pipeline } from '../core/base-pipeline.js';
 import type { SinglePageBuiltModule } from '../core/build/types.js';
-import { RouteNotFound } from '../core/errors/errors-data.js';
+import { InvalidRewrite404, RouteNotFound } from '../core/errors/errors-data.js';
 import { AstroError } from '../core/errors/index.js';
 import {
 	createModuleScriptElement,
 	createStylesheetElementSet,
 } from '../core/render/ssr-element.js';
+import { default404Page } from '../core/routing/astro-designed-error-pages.js';
 
 export class ContainerPipeline extends Pipeline {
 	/**
@@ -111,4 +112,12 @@ export class ContainerPipeline extends Pipeline {
 	// At the moment it's not used by the container via any public API
 	// @ts-expect-error It needs to be implemented.
 	async getComponentByRoute(_routeData: RouteData): Promise<ComponentInstance> {}
+
+	rewriteKnownRoute(pathname: string, _sourceRoute: RouteData): ComponentInstance {
+		if (pathname === '/404') {
+			return { default: default404Page } as any as ComponentInstance;
+		}
+
+		throw new AstroError(InvalidRewrite404);
+	}
 }

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

@@ -9,8 +9,11 @@ import type {
 import { Pipeline } from '../base-pipeline.js';
 import type { SinglePageBuiltModule } from '../build/types.js';
 import { DEFAULT_404_COMPONENT } from '../constants.js';
+import { RewriteEncounteredAnError } from '../errors/errors-data.js';
+import { AstroError } from '../errors/index.js';
 import { RedirectSinglePageBuiltModule } from '../redirects/component.js';
 import { createModuleScriptElement, createStylesheetElementSet } from '../render/ssr-element.js';
+import { DEFAULT_404_ROUTE } from '../routing/astro-designed-error-pages.js';
 
 export class AppPipeline extends Pipeline {
 	#manifestData: ManifestData | undefined;
@@ -82,36 +85,44 @@ export class AppPipeline extends Pipeline {
 
 	async tryRewrite(
 		payload: RewritePayload,
-		request: Request
+		request: Request,
+		sourceRoute: RouteData
 	): Promise<[RouteData, ComponentInstance]> {
 		let foundRoute;
 
 		for (const route of this.#manifestData!.routes) {
+			let finalUrl: URL | undefined = undefined;
+
 			if (payload instanceof URL) {
-				if (route.pattern.test(payload.pathname)) {
-					foundRoute = route;
-					break;
-				}
+				finalUrl = payload;
 			} else if (payload instanceof Request) {
-				const url = new URL(payload.url);
-				if (route.pattern.test(url.pathname)) {
-					foundRoute = route;
-					break;
-				}
+				finalUrl = new URL(payload.url);
 			} else {
-				const newUrl = new URL(payload, new URL(request.url).origin);
-				if (route.pattern.test(decodeURI(newUrl.pathname))) {
-					foundRoute = route;
-					break;
-				}
+				finalUrl = new URL(payload, new URL(request.url).origin);
+			}
+
+			if (route.pattern.test(decodeURI(finalUrl.pathname))) {
+				foundRoute = route;
+				break;
+			} else if (finalUrl.pathname === '/404') {
+				foundRoute = DEFAULT_404_ROUTE;
+				break;
 			}
 		}
 
 		if (foundRoute) {
-			const componentInstance = await this.getComponentByRoute(foundRoute);
-			return [foundRoute, componentInstance];
+			if (foundRoute.pathname === '/404') {
+				const componentInstance = this.rewriteKnownRoute(foundRoute.pathname, sourceRoute);
+				return [foundRoute, componentInstance];
+			} else {
+				const componentInstance = await this.getComponentByRoute(foundRoute);
+				return [foundRoute, componentInstance];
+			}
 		}
-		throw new Error('Route not found');
+		throw new AstroError({
+			...RewriteEncounteredAnError,
+			message: RewriteEncounteredAnError.message(payload.toString()),
+		});
 	}
 
 	async getModuleForRoute(route: RouteData): Promise<SinglePageBuiltModule> {
@@ -141,4 +152,13 @@ export class AppPipeline extends Pipeline {
 			);
 		}
 	}
+
+	// We don't need to check the source route, we already are in SSR
+	rewriteKnownRoute(pathname: string, _sourceRoute: RouteData): ComponentInstance {
+		if (pathname === '/404') {
+			return { default: () => new Response(null, { status: 404 }) } as ComponentInstance;
+		} else {
+			return { default: () => new Response(null, { status: 500 }) } as ComponentInstance;
+		}
+	}
 }

packages/astro/src/core/base-pipeline.ts

@@ -80,11 +80,14 @@ export abstract class Pipeline {
 	 *
 	 * - if not `RouteData` is found
 	 *
-	 * @param {RewritePayload} rewritePayload
+	 * @param {RewritePayload} rewritePayload The payload provided by the user
+	 * @param {Request} request The original request
+	 * @param {RouteData} sourceRoute The original `RouteData`
 	 */
 	abstract tryRewrite(
 		rewritePayload: RewritePayload,
-		request: Request
+		request: Request,
+		sourceRoute: RouteData
 	): Promise<[RouteData, ComponentInstance]>;
 
 	/**
@@ -92,6 +95,16 @@ export abstract class Pipeline {
 	 * @param routeData
 	 */
 	abstract getComponentByRoute(routeData: RouteData): Promise<ComponentInstance>;
+
+	/**
+	 * Attempts to execute a rewrite of a known Astro route:
+	 * - /404 -> src/pages/404.astro -> template
+	 * - /500 -> src/pages/500.astro
+	 *
+	 * @param pathname The pathname where the user wants to rewrite e.g. "/404"
+	 * @param sourceRoute The original route where the first request started. This is needed in case a pipeline wants to check if the current route is pre-rendered or not
+	 */
+	abstract rewriteKnownRoute(pathname: string, sourceRoute: RouteData): ComponentInstance;
 }
 
 // eslint-disable-next-line @typescript-eslint/no-empty-interface

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

@@ -44,8 +44,6 @@ import { getOutputFilename, isServerLikeOutput } from '../util.js';
 import { getOutDirWithinCwd, getOutFile, getOutFolder } from './common.js';
 import { cssOrder, mergeInlineCss } from './internal.js';
 import { BuildPipeline } from './pipeline.js';
-import { ASTRO_PAGE_MODULE_ID } from './plugins/plugin-pages.js';
-import { getVirtualModulePageName } from './plugins/util.js';
 import type {
 	PageBuildData,
 	SinglePageBuiltModule,

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

@@ -8,7 +8,7 @@ import type {
 import { getOutputDirectory } from '../../prerender/utils.js';
 import { BEFORE_HYDRATION_SCRIPT_ID, PAGE_SCRIPT_ID } from '../../vite-plugin-scripts/index.js';
 import type { SSRManifest } from '../app/types.js';
-import { RouteNotFound } from '../errors/errors-data.js';
+import { InvalidRewrite404, RewriteEncounteredAnError } from '../errors/errors-data.js';
 import { AstroError } from '../errors/index.js';
 import { routeIsFallback, routeIsRedirect } from '../redirects/helpers.js';
 import { RedirectSinglePageBuiltModule } from '../redirects/index.js';
@@ -18,6 +18,7 @@ import {
 	createModuleScriptsSet,
 	createStylesheetElementSet,
 } from '../render/ssr-element.js';
+import { DEFAULT_404_ROUTE } from '../routing/astro-designed-error-pages.js';
 import { isServerLikeOutput } from '../util.js';
 import { getOutDirWithinCwd } from './common.js';
 import { type BuildInternals, cssOrder, getPageData, mergeInlineCss } from './internal.js';
@@ -278,35 +279,43 @@ export class BuildPipeline extends Pipeline {
 
 	async tryRewrite(
 		payload: RewritePayload,
-		request: Request
+		request: Request,
+		sourceRoute: RouteData
 	): Promise<[RouteData, ComponentInstance]> {
 		let foundRoute: RouteData | undefined;
 		// options.manifest is the actual type that contains the information
 		for (const route of this.options.manifest.routes) {
+			let finalUrl: URL | undefined = undefined;
+
 			if (payload instanceof URL) {
-				if (route.pattern.test(payload.pathname)) {
-					foundRoute = route;
-					break;
-				}
+				finalUrl = payload;
 			} else if (payload instanceof Request) {
-				const url = new URL(payload.url);
-				if (route.pattern.test(url.pathname)) {
-					foundRoute = route;
-					break;
-				}
+				finalUrl = new URL(payload.url);
 			} else {
-				const newUrl = new URL(payload, new URL(request.url).origin);
-				if (route.pattern.test(decodeURI(newUrl.pathname))) {
-					foundRoute = route;
-					break;
-				}
+				finalUrl = new URL(payload, new URL(request.url).origin);
+			}
+
+			if (route.pattern.test(decodeURI(finalUrl.pathname))) {
+				foundRoute = route;
+				break;
+			} else if (finalUrl.pathname === '/404') {
+				foundRoute = DEFAULT_404_ROUTE;
+				break;
 			}
 		}
 		if (foundRoute) {
-			const componentInstance = await this.getComponentByRoute(foundRoute);
-			return [foundRoute, componentInstance];
+			if (foundRoute.pathname === '/404') {
+				const componentInstance = await this.rewriteKnownRoute(foundRoute.pathname, sourceRoute);
+				return [foundRoute, componentInstance];
+			} else {
+				const componentInstance = await this.getComponentByRoute(foundRoute);
+				return [foundRoute, componentInstance];
+			}
 		} else {
-			throw new AstroError(RouteNotFound);
+			throw new AstroError({
+				...RewriteEncounteredAnError,
+				message: RewriteEncounteredAnError.message(payload.toString()),
+			});
 		}
 	}
 
@@ -367,6 +376,13 @@ export class BuildPipeline extends Pipeline {
 
 		return RedirectSinglePageBuiltModule;
 	}
+
+	rewriteKnownRoute(_pathname: string, sourceRoute: RouteData): ComponentInstance {
+		if (!isServerLikeOutput(this.config) || sourceRoute.prerender) {
+			throw new AstroError(InvalidRewrite404);
+		}
+		throw new Error(`Unreachable, in SSG this route shouldn't be generated`);
+	}
 }
 
 function createEntryURL(filePath: string, outFolder: URL) {

packages/astro/src/core/constants.ts

@@ -30,7 +30,7 @@ export const ROUTE_TYPE_HEADER = 'X-Astro-Route-Type';
 /**
  * The value of the `component` field of the default 404 page, which is used when there is no user-provided 404.astro page.
  */
-export const DEFAULT_404_COMPONENT = 'astro-default-404';
+export const DEFAULT_404_COMPONENT = 'astro-default-404.astro';
 
 /**
  * A response with one of these status codes will be rewritten

packages/astro/src/core/errors/errors-data.ts

@@ -1117,6 +1117,29 @@ export const MissingMiddlewareForInternationalization = {
 		"Your configuration setting `i18n.routing: 'manual'` requires you to provide your own i18n `middleware` file.",
 } satisfies ErrorData;
 
+/**
+ * @docs
+ * @description
+ * The user tried to rewrite using a route that doesn't exist, or it emitted a runtime error during its rendering phase.
+ */
+export const RewriteEncounteredAnError = {
+	name: 'RewriteEncounteredAnError',
+	title: "Astro couldn't find the route to rewrite, or if was found but it emitted an error during the rendering phase.",
+	message: (route: string, stack?: string) => `The route ${route} that you tried to render doesn't exist, or it emitted an error during the rendering phase. ${stack ? stack : ""}.`
+} satisfies ErrorData;
+
+/**
+ * @docs
+ * @description
+ *
+ * The user tried to rewrite a 404 page inside a static page.
+ */
+export const InvalidRewrite404 = {
+	name: 'InvalidRewrite404',
+	title: "You attempted to rewrite a 404 inside a static page, and this isn't allowed.",
+	message: 'Rewriting a 404 is only allowed inside on-demand pages.',
+} satisfies ErrorData;
+
 /**
  * @docs
  * @description

packages/astro/src/core/render-context.ts

@@ -20,6 +20,7 @@ import { renderEndpoint } from '../runtime/server/endpoint.js';
 import { renderPage } from '../runtime/server/index.js';
 import {
 	ASTRO_VERSION,
+	DEFAULT_404_COMPONENT,
 	REROUTE_DIRECTIVE_HEADER,
 	ROUTE_TYPE_HEADER,
 	clientAddressSymbol,
@@ -38,6 +39,9 @@ import { type Pipeline, Slots, getParams, getProps } from './render/index.js';
  * It contains data unique to each request. It is responsible for executing middleware, calling endpoints, and rendering the page by gathering necessary data from a `Pipeline`.
  */
 export class RenderContext {
+	// The first route that this instance of the context attempts to render
+	originalRoute: RouteData;
+
 	private constructor(
 		readonly pipeline: Pipeline,
 		public locals: App.Locals,
@@ -50,7 +54,9 @@ export class RenderContext {
 		public params = getParams(routeData, pathname),
 		protected url = new URL(request.url),
 		public props: Props = {}
-	) {}
+	) {
+		this.originalRoute = routeData;
+	}
 
 	/**
 	 * A flag that tells the render content if the rewriting was triggered
@@ -124,18 +130,15 @@ export class RenderContext {
 		const lastNext = async (ctx: APIContext, payload?: RewritePayload) => {
 			if (payload) {
 				if (this.pipeline.manifest.rewritingEnabled) {
-					try {
-						const [routeData, component] = await pipeline.tryRewrite(payload, this.request);
-						this.routeData = routeData;
-						componentInstance = component;
-					} catch (e) {
-						return new Response('Not found', {
-							status: 404,
-							statusText: 'Not found',
-						});
-					} finally {
-						this.isRewriting = true;
-					}
+					// we intentionally let the error bubble up
+					const [routeData, component] = await pipeline.tryRewrite(
+						payload,
+						this.request,
+						this.originalRoute
+					);
+					this.routeData = routeData;
+					componentInstance = component;
+					this.isRewriting = true;
 				} else {
 					this.pipeline.logger.warn(
 						'router',
@@ -166,6 +169,7 @@ export class RenderContext {
 						result.cancelled = true;
 						throw e;
 					}
+
 					// Signal to the i18n middleware to maybe act on this response
 					response.headers.set(ROUTE_TYPE_HEADER, 'page');
 					// Signal to the error-page-rerouting infra to let this response pass through to avoid loops
@@ -218,29 +222,25 @@ export class RenderContext {
 
 		const rewrite = async (reroutePayload: RewritePayload) => {
 			pipeline.logger.debug('router', 'Called rewriting to:', reroutePayload);
-			try {
-				const [routeData, component] = await pipeline.tryRewrite(reroutePayload, this.request);
-				this.routeData = routeData;
-				if (reroutePayload instanceof Request) {
-					this.request = reroutePayload;
-				} else {
-					this.request = this.#copyRequest(
-						new URL(routeData.pathname ?? routeData.route, this.url.origin),
-						this.request
-					);
-				}
-				this.url = new URL(this.request.url);
-				this.cookies = new AstroCookies(this.request);
-				this.params = getParams(routeData, url.toString());
-				this.isRewriting = true;
-				return await this.render(component);
-			} catch (e) {
-				pipeline.logger.debug('router', 'Rewrite failed.', e);
-				return new Response('Not found', {
-					status: 404,
-					statusText: 'Not found',
-				});
+			const [routeData, component] = await pipeline.tryRewrite(
+				reroutePayload,
+				this.request,
+				this.originalRoute
+			);
+			this.routeData = routeData;
+			if (reroutePayload instanceof Request) {
+				this.request = reroutePayload;
+			} else {
+				this.request = this.#copyRequest(
+					new URL(routeData.pathname ?? routeData.route, this.url.origin),
+					this.request
+				);
 			}
+			this.url = new URL(this.request.url);
+			this.cookies = new AstroCookies(this.request);
+			this.params = getParams(routeData, url.toString());
+			this.isRewriting = true;
+			return await this.render(component);
 		};
 
 		return {
@@ -409,30 +409,26 @@ export class RenderContext {
 		};
 
 		const rewrite = async (reroutePayload: RewritePayload) => {
-			try {
-				pipeline.logger.debug('router', 'Calling rewrite: ', reroutePayload);
-				const [routeData, component] = await pipeline.tryRewrite(reroutePayload, this.request);
-				this.routeData = routeData;
-				if (reroutePayload instanceof Request) {
-					this.request = reroutePayload;
-				} else {
-					this.request = this.#copyRequest(
-						new URL(routeData.pathname ?? routeData.route, this.url.origin),
-						this.request
-					);
-				}
-				this.url = new URL(this.request.url);
-				this.cookies = new AstroCookies(this.request);
-				this.params = getParams(routeData, url.toString());
-				this.isRewriting = true;
-				return await this.render(component);
-			} catch (e) {
-				pipeline.logger.debug('router', 'Rerouting failed, returning a 404.', e);
-				return new Response('Not found', {
-					status: 404,
-					statusText: 'Not found',
-				});
+			pipeline.logger.debug('router', 'Calling rewrite: ', reroutePayload);
+			const [routeData, component] = await pipeline.tryRewrite(
+				reroutePayload,
+				this.request,
+				this.originalRoute
+			);
+			this.routeData = routeData;
+			if (reroutePayload instanceof Request) {
+				this.request = reroutePayload;
+			} else {
+				this.request = this.#copyRequest(
+					new URL(routeData.pathname ?? routeData.route, this.url.origin),
+					this.request
+				);
 			}
+			this.url = new URL(this.request.url);
+			this.cookies = new AstroCookies(this.request);
+			this.params = getParams(routeData, url.toString());
+			this.isRewriting = true;
+			return await this.render(component);
 		};
 
 		return {

packages/astro/src/core/routing/astro-designed-error-pages.ts

@@ -1,20 +1,38 @@
-import type { ManifestData } from '../../@types/astro.js';
+import type { ManifestData, RouteData } from '../../@types/astro.js';
+import notFoundTemplate from '../../template/4xx.js';
 import { DEFAULT_404_COMPONENT } from '../constants.js';
 
+export const DEFAULT_404_ROUTE: RouteData = {
+	component: DEFAULT_404_COMPONENT,
+	generate: () => '',
+	params: [],
+	pattern: /\/404/,
+	prerender: false,
+	pathname: '/404',
+	segments: [[{ content: '404', dynamic: false, spread: false }]],
+	type: 'page',
+	route: '/404',
+	fallbackRoutes: [],
+	isIndex: false,
+};
+
 export function ensure404Route(manifest: ManifestData) {
 	if (!manifest.routes.some((route) => route.route === '/404')) {
-		manifest.routes.push({
-			component: DEFAULT_404_COMPONENT,
-			generate: () => '',
-			params: [],
-			pattern: /\/404/,
-			prerender: false,
-			segments: [[{ content: '404', dynamic: false, spread: false }]],
-			type: 'page',
-			route: '/404',
-			fallbackRoutes: [],
-			isIndex: false,
-		});
+		manifest.routes.push(DEFAULT_404_ROUTE);
 	}
 	return manifest;
 }
+
+export async function default404Page({ pathname }: { pathname: string }) {
+	return new Response(
+		notFoundTemplate({
+			statusCode: 404,
+			title: 'Not found',
+			tabTitle: '404: Not Found',
+			pathname,
+		}),
+		{ status: 404, headers: { 'Content-Type': 'text/html; charset=utf-8' } }
+	);
+}
+// mark the function as an AstroComponentFactory for the rendering internals
+default404Page.isAstroComponentFactory = true;

packages/astro/src/vite-plugin-astro-server/pipeline.ts

@@ -11,20 +11,20 @@ import type {
 	SSRManifest,
 } from '../@types/astro.js';
 import { getInfoOutput } from '../cli/info/index.js';
-import type { HeadElements } from '../core/base-pipeline.js';
+import { type HeadElements } from '../core/base-pipeline.js';
 import { ASTRO_VERSION, DEFAULT_404_COMPONENT } from '../core/constants.js';
 import { enhanceViteSSRError } from '../core/errors/dev/index.js';
-import { RouteNotFound } from '../core/errors/errors-data.js';
+import { InvalidRewrite404, RewriteEncounteredAnError } from '../core/errors/errors-data.js';
 import { AggregateError, AstroError, CSSError, MarkdownError } from '../core/errors/index.js';
 import type { Logger } from '../core/logger/core.js';
 import type { ModuleLoader } from '../core/module-loader/index.js';
 import { Pipeline, loadRenderer } from '../core/render/index.js';
+import { DEFAULT_404_ROUTE, default404Page } from '../core/routing/astro-designed-error-pages.js';
 import { isPage, isServerLikeOutput, resolveIdToUrl, viteID } from '../core/util.js';
 import { PAGE_SCRIPT_ID } from '../vite-plugin-scripts/index.js';
 import { getStylesForURL } from './css.js';
 import { getComponentMetadata } from './metadata.js';
 import { createResolve } from './resolve.js';
-import { default404Page } from './response.js';
 import { getScriptsForURL } from './scripts.js';
 
 export class DevPipeline extends Pipeline {
@@ -193,7 +193,8 @@ export class DevPipeline extends Pipeline {
 
 	async tryRewrite(
 		payload: RewritePayload,
-		request: Request
+		request: Request,
+		sourceRoute: RouteData
 	): Promise<[RouteData, ComponentInstance]> {
 		let foundRoute;
 		if (!this.manifestData) {
@@ -201,35 +202,52 @@ export class DevPipeline extends Pipeline {
 		}
 
 		for (const route of this.manifestData.routes) {
+			let finalUrl: URL | undefined = undefined;
+
 			if (payload instanceof URL) {
-				if (route.pattern.test(payload.pathname)) {
-					foundRoute = route;
-					break;
-				}
+				finalUrl = payload;
 			} else if (payload instanceof Request) {
-				const url = new URL(payload.url);
-				if (route.pattern.test(url.pathname)) {
-					foundRoute = route;
-					break;
-				}
+				finalUrl = new URL(payload.url);
 			} else {
-				const newUrl = new URL(payload, new URL(request.url).origin);
-				if (route.pattern.test(decodeURI(newUrl.pathname))) {
-					foundRoute = route;
-					break;
-				}
+				finalUrl = new URL(payload, new URL(request.url).origin);
+			}
+
+			if (route.pattern.test(decodeURI(finalUrl.pathname))) {
+				foundRoute = route;
+				break;
+			} else if (finalUrl.pathname === '/404') {
+				foundRoute = DEFAULT_404_ROUTE;
+				break;
 			}
 		}
 
 		if (foundRoute) {
-			const componentInstance = await this.getComponentByRoute(foundRoute);
-			return [foundRoute, componentInstance];
+			if (foundRoute.pathname === '/404') {
+				const componentInstance = this.rewriteKnownRoute(foundRoute.pathname, sourceRoute);
+				return [foundRoute, componentInstance];
+			} else {
+				const componentInstance = await this.getComponentByRoute(foundRoute);
+				return [foundRoute, componentInstance];
+			}
 		} else {
-			throw new AstroError(RouteNotFound);
+			throw new AstroError({
+				...RewriteEncounteredAnError,
+				message: RewriteEncounteredAnError.message(payload.toString()),
+			});
 		}
 	}
 
 	setManifestData(manifestData: ManifestData) {
 		this.manifestData = manifestData;
 	}
+
+	rewriteKnownRoute(route: string, sourceRoute: RouteData): ComponentInstance {
+		if (isServerLikeOutput(this.config) && sourceRoute.prerender) {
+			if (route === '/404') {
+				return { default: default404Page } as any as ComponentInstance;
+			}
+		}
+
+		throw new AstroError(InvalidRewrite404);
+	}
 }

packages/astro/src/vite-plugin-astro-server/response.ts

@@ -23,20 +23,6 @@ export async function handle404Response(
 	writeHtmlResponse(res, 404, html);
 }
 
-export async function default404Page({ pathname }: { pathname: string }) {
-	return new Response(
-		notFoundTemplate({
-			statusCode: 404,
-			title: 'Not found',
-			tabTitle: '404: Not Found',
-			pathname,
-		}),
-		{ status: 404, headers: { 'Content-Type': 'text/html; charset=utf-8' } }
-	);
-}
-// mark the function as an AstroComponentFactory for the rendering internals
-default404Page.isAstroComponentFactory = true;
-
 export async function handle500Response(
 	loader: ModuleLoader,
 	res: http.ServerResponse,

packages/astro/src/vite-plugin-astro-server/route.ts

@@ -11,11 +11,12 @@ import { loadMiddleware } from '../core/middleware/loadMiddleware.js';
 import { RenderContext } from '../core/render-context.js';
 import { type SSROptions, getProps } from '../core/render/index.js';
 import { createRequest } from '../core/request.js';
+import { default404Page } from '../core/routing/astro-designed-error-pages.js';
 import { matchAllRoutes } from '../core/routing/index.js';
 import { normalizeTheLocale } from '../i18n/index.js';
 import { getSortedPreloadedMatches } from '../prerender/routing.js';
 import type { DevPipeline } from './pipeline.js';
-import { default404Page, handle404Response, writeSSRResult, writeWebResponse } from './response.js';
+import { handle404Response, writeSSRResult, writeWebResponse } from './response.js';
 
 type AsyncReturnType<T extends (...args: any) => Promise<any>> = T extends (
 	...args: any

packages/astro/test/fixtures/reroute/src/pages/blog/oops.astro

@@ -1,11 +0,0 @@
----
-return Astro.rewrite("/404")
----
-<html>
-<head>
-	<title>Blog hello</title>
-</head>
-<body>
-<h1>Blog hello</h1>
-</body>
-</html>

packages/astro/test/fixtures/rewrite-404-invalid/astro.config.mjs

@@ -0,0 +1,9 @@
+import { defineConfig } from 'astro/config';
+
+// https://astro.build/config
+export default defineConfig({
+	experimental: {
+		rewriting: true
+	},
+	site: "https://example.com"
+});

packages/astro/test/fixtures/rewrite-404-invalid/package.json

@@ -0,0 +1,8 @@
+{
+  "name": "@test/rewrite-404-invalid",
+  "version": "0.0.0",
+  "private": true,
+  "dependencies": {
+    "astro": "workspace:*"
+  }
+}

packages/astro/test/fixtures/rewrite-404-invalid/src/pages/rewrite-404.astro

@@ -0,0 +1,3 @@
+---
+return Astro.rewrite("/404")
+---

packages/astro/test/fixtures/rewrite-runtime-error/astro.config.mjs

@@ -0,0 +1,9 @@
+import { defineConfig } from 'astro/config';
+
+// https://astro.build/config
+export default defineConfig({
+	experimental: {
+		rewriting: true
+	},
+	site: "https://example.com"
+});

packages/astro/test/fixtures/rewrite-runtime-error/package.json

@@ -0,0 +1,8 @@
+{
+  "name": "@test/rewrite-runtime-errror",
+  "version": "0.0.0",
+  "private": true,
+  "dependencies": {
+    "astro": "workspace:*"
+  }
+}

packages/astro/test/fixtures/rewrite-runtime-error/src/pages/errors/from.astro

@@ -0,0 +1,4 @@
+---
+return Astro.rewrite('/errors/to');
+---
+<div></div>

packages/astro/test/fixtures/rewrite-runtime-error/src/pages/errors/to.astro

@@ -0,0 +1,4 @@
+---
+throw new Error('Custom error')
+---
+<div></div>

packages/astro/test/rewrite.test.js

@@ -55,11 +55,10 @@ describe('Dev reroute', () => {
 		assert.equal($('h1').text(), 'Index');
 	});
 
-	it('should render the 404 built-in page', async () => {
-		const html = await fixture.fetch('/blog/oops').then((res) => res.text());
-		const $ = cheerioLoad(html);
+	it('should return a 404', async () => {
+		const response = await fixture.fetch('/blog/oops');
 
-		assert.equal($('h1').text(), '404:  Not found');
+		assert.equal(response.status, 404);
 	});
 });
 
@@ -120,6 +119,21 @@ describe('Build reroute', () => {
 	});
 });
 
+describe('SSR route', () => {
+	it("should not build if a user tries to use rewrite('/404') in static pages", async () => {
+		try {
+			const fixture = await loadFixture({
+				root: './fixtures/rewrite-404-invalid/',
+			});
+			await fixture.build();
+			assert.fail('It should fail.');
+		} catch {
+			// it passes
+			assert.equal(true, true);
+		}
+	});
+});
+
 describe('SSR reroute', () => {
 	/** @type {import('./test-utils').Fixture} */
 	let fixture;
@@ -184,8 +198,7 @@ describe('SSR reroute', () => {
 	it('should render the 404 built-in page', async () => {
 		const request = new Request('http://example.com/blog/oops');
 		const response = await app.render(request);
-		const html = await response.text();
-		assert.equal(html, 'Not found');
+		assert.equal(response.status, 404);
 	});
 
 	it('should pass the POST data from one page to another', async () => {
@@ -246,3 +259,27 @@ describe('Middleware', () => {
 		assert.match($('h1').text(), /Index/);
 	});
 });
+
+describe('Runtime error', () => {
+	/** @type {import('./test-utils').Fixture} */
+	let fixture;
+	let devServer;
+
+	before(async () => {
+		fixture = await loadFixture({
+			root: './fixtures/rewrite-runtime-error/',
+		});
+		devServer = await fixture.startDevServer();
+	});
+
+	after(async () => {
+		await devServer.stop();
+	});
+
+	it('should render the index page when navigating /reroute ', async () => {
+		const html = await fixture.fetch('/errors/from').then((res) => res.text());
+		const $ = cheerioLoad(html);
+
+		assert.equal($('title').text(), 'Error');
+	});
+});

pnpm-lock.yaml

@@ -3466,6 +3466,18 @@ importers:
         specifier: workspace:*
         version: link:../../..
 
+  packages/astro/test/fixtures/rewrite-404-invalid:
+    dependencies:
+      astro:
+        specifier: workspace:*
+        version: link:../../..
+
+  packages/astro/test/fixtures/rewrite-runtime-error:
+    dependencies:
+      astro:
+        specifier: workspace:*
+        version: link:../../..
+
   packages/astro/test/fixtures/root-srcdir-css:
     dependencies:
       astro: