Fix i18n current locale (#12839)

mtwilliams-code · ematipico · web-flow · commit 57be3494e2bd · 2025-01-10T15:32:58.000Z
Co-authored-by: Emanuele Stoppa &lt;my.burning@gmail.com&gt;
diff --git a/.changeset/happy-pianos-report.md b/.changeset/happy-pianos-report.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fix Astro.currentLocale returning the incorrect locale when using fallback rewrites in SSR mode
diff --git a/packages/astro/src/core/render-context.ts b/packages/astro/src/core/render-context.ts
@@ -605,8 +605,17 @@ export class RenderContext {
 				computedLocale = computeCurrentLocale(referer, locales, defaultLocale);
 			}
 		} else {
-			const pathname =
-				routeData.pathname && !isRoute404or500(routeData) ? routeData.pathname : url.pathname;
+			// For SSG we match the route naively, for dev we handle fallback on 404, for SSR we find route from fallbackRoutes
+			let pathname = routeData.pathname;
+			if (!routeData.pattern.test(url.pathname)) {
+				for (const fallbackRoute of routeData.fallbackRoutes) {
+					if (fallbackRoute.pattern.test(url.pathname)) {
+						pathname = fallbackRoute.pathname;
+						break;
+					}
+				}
+			}
+			pathname = pathname && !isRoute404or500(routeData) ? pathname : url.pathname;
 			computedLocale = computeCurrentLocale(pathname, locales, defaultLocale);
 		}
 
diff --git a/packages/astro/test/fixtures/i18n-routing-fallback/src/pages/index.astro b/packages/astro/test/fixtures/i18n-routing-fallback/src/pages/index.astro
@@ -1,3 +1,6 @@
+---
+const locale = Astro.currentLocale
+---
 <html>
 <head>
 	<title>Astro</title>
@@ -7,6 +10,10 @@
 </head>
 <body>
 	Hello
+	<p>
+
+	locale - {locale}
+	</p>
 </body>
 </html>
 
diff --git a/packages/astro/test/i18n-routing.test.js b/packages/astro/test/i18n-routing.test.js
@@ -1,6 +1,6 @@
+import * as cheerio from 'cheerio';
 import * as assert from 'node:assert/strict';
 import { after, afterEach, before, describe, it } from 'node:test';
-import * as cheerio from 'cheerio';
 import testAdapter from './test-adapter.js';
 import { loadFixture } from './test-utils.js';
 
@@ -2014,13 +2014,13 @@ describe('Fallback rewrite dev server', () => {
 				locales: ['en', 'fr', 'es', 'it', 'pt'],
 				routing: {
 					prefixDefaultLocale: false,
+					fallbackType: 'rewrite',
 				},
 				fallback: {
 					fr: 'en',
 					it: 'en',
 					es: 'pt',
 				},
-				fallbackType: 'rewrite',
 			},
 		});
 		devServer = await fixture.startDevServer();
@@ -2032,6 +2032,7 @@ describe('Fallback rewrite dev server', () => {
 	it('should correctly rewrite to en', async () => {
 		const html = await fixture.fetch('/fr').then((res) => res.text());
 		assert.match(html, /Hello/);
+		assert.match(html, /locale - fr/);
 		// assert.fail()
 	});
 
@@ -2085,6 +2086,7 @@ describe('Fallback rewrite SSG', () => {
 	it('should correctly rewrite to en', async () => {
 		const html = await fixture.readFile('/fr/index.html');
 		assert.match(html, /Hello/);
+		assert.match(html, /locale - fr/);
 		// assert.fail()
 	});
 
@@ -2138,6 +2140,7 @@ describe('Fallback rewrite SSR', () => {
 		const response = await app.render(request);
 		assert.equal(response.status, 200);
 		const html = await response.text();
+		assert.match(html, /locale - fr/);
 		assert.match(html, /Hello/);
 	});
 

-Original file line number
+Diff line change
@@ @@ -0,0 +1,5 @@ @@
 +---
 +'astro': patch
 +---
++
 +Fix Astro.currentLocale returning the incorrect locale when using fallback rewrites in SSR mode