fix(i18n): don't make virtual modules no-op

.changeset/short-points-hunt.md

@@ -0,0 +1,5 @@
+---
+"astro": patch
+---
+
+Fixes a case where the `i18n` virtual module was transformed into a no-op function when some functions were used inside a non-prerendered page.

packages/astro/src/core/build/plugins/plugin-chunks.ts

@@ -12,6 +12,10 @@ export function vitePluginChunks(): VitePlugin {
 					if (id.includes('astro/dist/runtime/server/')) {
 						return 'astro/server';
 					}
+					// Split the Astro runtime into a separate chunk for readability
+					if (id.includes('astro/dist/runtime')) {
+						return 'astro';
+					}
 				},
 			});
 		},

packages/astro/src/core/build/plugins/plugin-prerender.ts

@@ -5,6 +5,7 @@ import type { BuildInternals } from '../internal.js';
 import type { AstroBuildPlugin } from '../plugin.js';
 import type { StaticBuildOptions } from '../types.js';
 import { extendManualChunks } from './util.js';
+import { ASTRO_VIRTUAL_MODULE } from '../../constants.js';
 
 function vitePluginPrerender(opts: StaticBuildOptions, internals: BuildInternals): VitePlugin {
 	return {
@@ -13,12 +14,9 @@ function vitePluginPrerender(opts: StaticBuildOptions, internals: BuildInternals
 		outputOptions(outputOptions) {
 			extendManualChunks(outputOptions, {
 				after(id, meta) {
-					// Split the Astro runtime into a separate chunk for readability
-					if (id.includes('astro/dist/runtime')) {
-						return 'astro';
-					}
 					const pageInfo = internals.pagesByViteID.get(id);
 					let hasSharedModules = false;
+					let hasAstroVirtualModules = false;
 					if (pageInfo) {
 						// prerendered pages should be split into their own chunk
 						// Important: this can't be in the `pages/` directory!
@@ -43,12 +41,20 @@ function vitePluginPrerender(opts: StaticBuildOptions, internals: BuildInternals
 									// Given the previous statement, we only check if
 									// - the module is a page, and it's not pre-rendered
 									// - the module is the middleware
+									// - the module belongs to our virtual modules, which belong to `
 									// If one of these conditions is met, we need a separate chunk
 									for (const importer of moduleMeta.importedIds) {
 										// we don't want to analyze the same module again, so we skip it
 										if (importer !== id) {
 											const importerModuleMeta = meta.getModuleInfo(importer);
 											if (importerModuleMeta) {
+												if (
+													importerModuleMeta.meta &&
+													importerModuleMeta.meta[ASTRO_VIRTUAL_MODULE]
+												) {
+													hasAstroVirtualModules = true;
+													break;
+												}
 												// if the module is inside the pages
 												if (importerModuleMeta.id.includes('/pages')) {
 													// we check if it's not pre-rendered
@@ -70,6 +76,7 @@ function vitePluginPrerender(opts: StaticBuildOptions, internals: BuildInternals
 
 							opts.allPages;
 							pageInfo.hasSharedModules = hasSharedModules;
+							pageInfo.hasAstroVirtualModule = hasAstroVirtualModules;
 							pageInfo.route.prerender = true;
 							return 'prerender';
 						}

packages/astro/src/core/build/static-build.ts

@@ -374,7 +374,10 @@ async function cleanStaticOutput(
 ) {
 	const allStaticFiles = new Set();
 	for (const pageData of eachPageData(internals)) {
-		if (pageData.route.prerender && !pageData.hasSharedModules) {
+		if (
+			pageData.route.prerender &&
+			!(pageData.hasSharedModules || pageData.hasAstroVirtualModule)
+		) {
 			const { moduleSpecifier } = pageData;
 			const pageBundleId = internals.pageToBundleMap.get(moduleSpecifier);
 			const entryBundleId = internals.entrySpecifierToBundleMap.get(moduleSpecifier);

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

@@ -29,6 +29,10 @@ export interface PageBuildData {
 	hoistedScript: { type: 'inline' | 'external'; value: string } | undefined;
 	styles: Array<{ depth: number; order: number; sheet: StylesheetAsset }>;
 	hasSharedModules: boolean;
+	/**
+	 * Whether the page is using astro virtual modules
+	 */
+	hasAstroVirtualModule: boolean;
 }
 
 export type AllPagesData = Record<ComponentPath, PageBuildData>;

packages/astro/src/core/constants.ts

@@ -71,3 +71,21 @@ export const SUPPORTED_MARKDOWN_FILE_EXTENSIONS = [
 
 // The folder name where to find the middleware
 export const MIDDLEWARE_PATH_SEGMENT_NAME = 'middleware';
+
+/**
+ * This constant is used to mark internal astro virtual modules. Use this constant to attach it to the metadata of the virtual module, e.g.:
+ *
+ * ```js
+ * function resolveId(id) {
+ * 	if (id === virtualModuleId) {
+ *   	return {
+ *   		id,
+ *   		meta: {
+ *   			[ASTRO_VIRTUAL_MODULE]: true,
+ *   		},
+ *   	}
+ *   }
+ * }
+ * ```
+ */
+export const ASTRO_VIRTUAL_MODULE = 'astro-virtual-module';

packages/astro/src/i18n/vite-plugin-i18n.ts

@@ -2,6 +2,7 @@ import type * as vite from 'vite';
 import type { AstroConfig, AstroSettings } from '../@types/astro.js';
 import { AstroError } from '../core/errors/errors.js';
 import { AstroErrorData } from '../core/errors/index.js';
+import { ASTRO_VIRTUAL_MODULE } from '../core/constants.js';
 
 const virtualModuleId = 'astro:i18n';
 
@@ -44,10 +45,20 @@ export default function astroInternationalization({
 				},
 			};
 		},
-		resolveId(id) {
+		async resolveId(id) {
 			if (id === virtualModuleId) {
 				if (i18n === undefined) throw new AstroError(AstroErrorData.i18nNotEnabled);
-				return this.resolve('astro/virtual-modules/i18n.js');
+
+				const resolved = await this.resolve('astro/virtual-modules/i18n.js');
+				if (resolved) {
+					return {
+						id: resolved.id,
+						meta: {
+							[ASTRO_VIRTUAL_MODULE]: true,
+						},
+					};
+				}
+				return undefined;
 			}
 		},
 	};