[pull] main from withastro:main

.changeset/all-badgers-peel.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes `getRelativeLocaleUrl`, `getAbsoluteLocaleUrl`, and `getAbsoluteLocaleUrlList` to strip trailing slashes when `trailingSlash: 'never'` is configured

.changeset/itchy-snails-march.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes CSS from `client:only` islands leaking to unrelated pages when Rollup bundles non-CSS-importing modules into the same chunk as CSS-importing modules

.changeset/long-cloths-smoke.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fixes HMR not triggering for files inside the `src/middleware/` directory during dev

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

@@ -177,6 +177,11 @@ function rollupPluginAstroBuildCSS(options: PluginOptions): VitePlugin[] {
 				// client:only component and if so, add its CSS to the page it belongs to.
 				if (this.environment?.name === ASTRO_VITE_ENVIRONMENT_NAMES.client) {
 					for (const id of Object.keys(chunk.modules)) {
+						// Only walk from CSS modules to find client:only parents. When Rollup
+						// merges unrelated modules into the same chunk, walking from every module
+						// would incorrectly attribute the chunk's CSS to pages reached through
+						// modules that have no CSS dependency.
+						if (!isCSSRequest(id)) continue;
 						for (const pageData of getParentClientOnlys(id, this, internals)) {
 							for (const importedCssImport of meta.importedCss) {
 								const cssToInfoRecord = (pagesToCss[pageData.moduleSpecifier] ??= {});

packages/astro/src/core/middleware/vite-plugin.ts

@@ -20,6 +20,13 @@ export const MIDDLEWARE_MODULE_ID = 'virtual:astro:middleware';
 const MIDDLEWARE_RESOLVED_MODULE_ID = '\0' + MIDDLEWARE_MODULE_ID;
 const NOOP_MIDDLEWARE = '\0noop-middleware';
 
+export function isMiddlewarePath(relativePath: string): boolean {
+	return (
+		relativePath.startsWith(`${MIDDLEWARE_PATH_SEGMENT_NAME}.`) ||
+		relativePath.startsWith(`${MIDDLEWARE_PATH_SEGMENT_NAME}/`)
+	);
+}
+
 export function vitePluginMiddleware({ settings }: { settings: AstroSettings }): VitePlugin {
 	let resolvedMiddlewareId: string | undefined = undefined;
 	const hasIntegrationMiddleware =
@@ -43,8 +50,7 @@ export function vitePluginMiddleware({ settings }: { settings: AstroSettings }):
 				// Check if the changed file is a middleware file under srcDir
 				if (!normalizedPath.startsWith(normalizedSrcDir)) return;
 				const relativePath = normalizedPath.slice(normalizedSrcDir.length);
-				// Dot ensures we match "middleware.ts" but not e.g. "middleware-utils.ts"
-				if (!relativePath.startsWith(`${MIDDLEWARE_PATH_SEGMENT_NAME}.`)) return;
+				if (!isMiddlewarePath(relativePath)) return;
 
 				for (const name of [
 					ASTRO_VITE_ENVIRONMENT_NAMES.ssr,

packages/astro/src/i18n/index.ts

@@ -1,4 +1,8 @@
-import { appendForwardSlash, joinPaths } from '@astrojs/internal-helpers/path';
+import {
+	appendForwardSlash,
+	joinPaths,
+	removeTrailingForwardSlash,
+} from '@astrojs/internal-helpers/path';
 import type { RoutingStrategies } from '../core/app/common.js';
 import type { SSRManifest } from '../core/app/types.js';
 import { shouldAppendForwardSlash } from '../core/build/util.js';
@@ -106,7 +110,7 @@ export function getLocaleRelativeUrl({
 	if (shouldAppendForwardSlash(trailingSlash, format)) {
 		relativePath = appendForwardSlash(joinPaths(...pathsToJoin));
 	} else {
-		relativePath = joinPaths(...pathsToJoin);
+		relativePath = removeTrailingForwardSlash(joinPaths(...pathsToJoin));
 	}
 
 	if (relativePath === '') {

packages/astro/test/client-only-css-chunk-leak.test.ts

@@ -0,0 +1,39 @@
+import assert from 'node:assert/strict';
+import { before, describe, it } from 'node:test';
+import { load as cheerioLoad } from 'cheerio';
+import { type Fixture, loadFixture } from './test-utils.ts';
+
+describe('client:only CSS chunk leak', () => {
+	let fixture: Fixture;
+
+	before(async () => {
+		fixture = await loadFixture({
+			root: './fixtures/client-only-css-chunk-leak/',
+		});
+		await fixture.build();
+	});
+
+	it('does not leak CSS to pages that do not use CSS-importing client:only components', async () => {
+		const html = await fixture.readFile('/about/index.html');
+		const $ = cheerioLoad(html);
+
+		const stylesheets = $('link[rel=stylesheet]');
+		// The about page only uses CurrentTime (no CSS imports).
+		// It should have no stylesheets from the shared chunk.
+		assert.equal(stylesheets.length, 0, 'About page should have no stylesheet links');
+	});
+
+	it('includes CSS on the page that uses the CSS-importing client:only component', async () => {
+		const html = await fixture.readFile('/index.html');
+		const $ = cheerioLoad(html);
+
+		const stylesheets = await Promise.all(
+			$('link[rel=stylesheet]').map((_, el) => {
+				return fixture.readFile(el.attribs.href);
+			}),
+		);
+		const css = stylesheets.join('');
+
+		assert.match(css, /\.heavy-widget/, 'Home page should include .heavy-widget CSS');
+	});
+});

packages/astro/test/fixtures/client-only-css-chunk-leak/astro.config.mjs

@@ -0,0 +1,23 @@
+import { defineConfig } from 'astro/config';
+import react from '@astrojs/react';
+
+export default defineConfig({
+  integrations: [react()],
+  build: { inlineStylesheets: 'never' },
+  vite: {
+    build: {
+      rollupOptions: {
+        output: {
+          // Force StyledPanel (which imports CSS) and formatLabel (a pure utility)
+          // into the same chunk. This simulates what Rollup's default heuristics
+          // do naturally in large apps.
+          manualChunks(id) {
+            if (id.includes('StyledPanel') || id.includes('formatLabel')) {
+              return 'shared-utils';
+            }
+          },
+        },
+      },
+    },
+  },
+});

packages/astro/test/fixtures/client-only-css-chunk-leak/package.json

@@ -0,0 +1,11 @@
+{
+  "name": "@test/client-only-css-chunk-leak",
+  "version": "0.0.0",
+  "private": true,
+  "dependencies": {
+    "astro": "workspace:*",
+    "@astrojs/react": "workspace:*",
+    "react": "^19.0.0",
+    "react-dom": "^19.0.0"
+  }
+}

packages/astro/test/fixtures/client-only-css-chunk-leak/src/components/CurrentTime.tsx

@@ -0,0 +1,5 @@
+import { formatLabel } from './formatLabel';
+
+export default function CurrentTime() {
+  return <span>{formatLabel('time')}</span>;
+}

packages/astro/test/fixtures/client-only-css-chunk-leak/src/components/HeavyWidget.tsx

@@ -0,0 +1,6 @@
+import StyledPanel from './StyledPanel';
+import { formatLabel } from './formatLabel';
+
+export default function HeavyWidget() {
+  return <StyledPanel>{formatLabel('Widget')}</StyledPanel>;
+}

packages/astro/test/fixtures/client-only-css-chunk-leak/src/components/StyledPanel.css

@@ -0,0 +1 @@
+.heavy-widget { color: red; font-size: 72px; background: limegreen; padding: 2rem; }

packages/astro/test/fixtures/client-only-css-chunk-leak/src/components/StyledPanel.tsx

@@ -0,0 +1,5 @@
+import './StyledPanel.css';
+
+export default function StyledPanel({ children }: { children: React.ReactNode }) {
+  return <div className="heavy-widget">{children}</div>;
+}

packages/astro/test/fixtures/client-only-css-chunk-leak/src/components/formatLabel.ts

@@ -0,0 +1,3 @@
+export function formatLabel(text: string): string {
+  return `[ ${text.toUpperCase()} ]`;
+}

packages/astro/test/fixtures/client-only-css-chunk-leak/src/layouts/Layout.astro

@@ -0,0 +1,14 @@
+---
+import CurrentTime from '../components/CurrentTime';
+---
+
+<html lang="en">
+  <head>
+    <meta charset="utf-8" />
+    <title>CSS Leak Test</title>
+  </head>
+  <body>
+    <CurrentTime client:only="react" />
+    <slot />
+  </body>
+</html>

packages/astro/test/fixtures/client-only-css-chunk-leak/src/pages/about.astro

@@ -0,0 +1,7 @@
+---
+import Layout from '../layouts/Layout.astro';
+---
+
+<Layout>
+  <h1>About</h1>
+</Layout>

packages/astro/test/fixtures/client-only-css-chunk-leak/src/pages/index.astro

@@ -0,0 +1,9 @@
+---
+import Layout from '../layouts/Layout.astro';
+import HeavyWidget from '../components/HeavyWidget';
+---
+
+<Layout>
+  <h1>Home</h1>
+  <HeavyWidget client:only="react" />
+</Layout>

packages/astro/test/units/i18n/astro_i18n.test.ts

@@ -263,6 +263,88 @@ describe('getLocaleRelativeUrl', () => {
 		);
 	});
 
+	it('should not add trailing slash when trailingSlash is "never" and path is empty or "/" (#17034)', () => {
+		const config = {
+			i18n: {
+				defaultLocale: 'en',
+				locales: ['en', 'pl'],
+			},
+		};
+
+		// path omitted vs path='' should produce the same result
+		assert.equal(
+			relativeUrl({
+				locale: 'pl',
+				base: '/',
+				...config.i18n,
+				trailingSlash: 'never',
+				format: 'directory',
+			}),
+			'/pl',
+		);
+		assert.equal(
+			relativeUrl({
+				locale: 'pl',
+				base: '/',
+				...config.i18n,
+				trailingSlash: 'never',
+				format: 'directory',
+				path: '',
+			}),
+			'/pl',
+		);
+		assert.equal(
+			relativeUrl({
+				locale: 'pl',
+				base: '/',
+				...config.i18n,
+				trailingSlash: 'never',
+				format: 'directory',
+				path: '/',
+			}),
+			'/pl',
+		);
+
+		// prependWith + trailing slash in path
+		assert.equal(
+			relativeUrl({
+				locale: 'pl',
+				base: '/',
+				...config.i18n,
+				trailingSlash: 'never',
+				format: 'directory',
+				path: 'docs/setup/',
+				prependWith: 'blog',
+			}),
+			'/blog/pl/docs/setup',
+		);
+
+		// absolute URL should also strip trailing slash
+		assert.equal(
+			absoluteUrl({
+				locale: 'pl',
+				base: '/',
+				...config.i18n,
+				trailingSlash: 'never',
+				format: 'directory',
+				path: '',
+				site: 'https://example.com',
+			}),
+			'https://example.com/pl',
+		);
+
+		// absoluteUrlList should be consistent across all locales
+		const list = absoluteUrlList({
+			base: '/',
+			...config.i18n,
+			trailingSlash: 'never',
+			format: 'directory',
+			path: '',
+			site: 'https://example.com',
+		});
+		assert.deepEqual(list, ['https://example.com', 'https://example.com/pl']);
+	});
+
 	it('should normalize locales by default', () => {
 		const config = {
 			base: '/blog',

packages/astro/test/units/middleware/middleware-hmr.test.ts

@@ -0,0 +1,37 @@
+import assert from 'node:assert/strict';
+import { describe, it } from 'node:test';
+import { isMiddlewarePath } from '../../../dist/core/middleware/vite-plugin.js';
+
+describe('middleware HMR path matching', () => {
+	it('matches middleware.ts (single-file pattern)', () => {
+		assert.ok(isMiddlewarePath('middleware.ts'));
+	});
+
+	it('matches middleware.js', () => {
+		assert.ok(isMiddlewarePath('middleware.js'));
+	});
+
+	it('matches middleware/index.ts (directory pattern)', () => {
+		assert.ok(isMiddlewarePath('middleware/index.ts'));
+	});
+
+	it('matches middleware/test.ts (file inside middleware directory)', () => {
+		assert.ok(isMiddlewarePath('middleware/test.ts'));
+	});
+
+	it('matches middleware/nested/deep.ts (nested file)', () => {
+		assert.ok(isMiddlewarePath('middleware/nested/deep.ts'));
+	});
+
+	it('does not match middleware-utils.ts (similarly named file)', () => {
+		assert.ok(!isMiddlewarePath('middleware-utils.ts'));
+	});
+
+	it('does not match pages/middleware.ts (wrong directory)', () => {
+		assert.ok(!isMiddlewarePath('pages/middleware.ts'));
+	});
+
+	it('does not match other unrelated files', () => {
+		assert.ok(!isMiddlewarePath('components/Header.astro'));
+	});
+});