Replace internal cssScopeTo implementation to vite.cssScopeTo

.changeset/hungry-sheep-sneeze.md

@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Updates internal CSS chunking behavior for Astro components' scoped styles. This may result in slightly more CSS chunks created, but should allow the scoped styles to only be included on pages that use them.

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

@@ -1,12 +1,11 @@
 import type { GetModuleInfo } from 'rollup';
-import type { BuildOptions, ResolvedConfig, Rollup, Plugin as VitePlugin } from 'vite';
+import type { BuildOptions, ResolvedConfig, Plugin as VitePlugin } from 'vite';
 import { isBuildableCSSRequest } from '../../../vite-plugin-astro-server/util.js';
 import type { BuildInternals } from '../internal.js';
 import type { AstroBuildPlugin, BuildTarget } from '../plugin.js';
 import type { PageBuildData, StaticBuildOptions, StylesheetAsset } from '../types.js';
 
 import { hasAssetPropagationFlag } from '../../../content/index.js';
-import type { AstroPluginCssMetadata } from '../../../vite-plugin-astro/index.js';
 import * as assetName from '../css-asset-name.js';
 import {
 	getParentExtendedModuleInfos,
@@ -156,32 +155,6 @@ function rollupPluginAstroBuildCSS(options: PluginOptions): VitePlugin[] {
 		},
 	};
 
-	/**
-	 * This plugin is a port of https://github.com/vitejs/vite/pull/16058. It enables removing unused
-	 * scoped CSS from the bundle if the scoped target (e.g. Astro files) were not bundled.
-	 * Once/If that PR is merged, we can refactor this away, renaming `meta.astroCss` to `meta.vite`.
-	 */
-	const cssScopeToPlugin: VitePlugin = {
-		name: 'astro:rollup-plugin-css-scope-to',
-		renderChunk(_, chunk, __, meta) {
-			for (const id in chunk.modules) {
-				// If this CSS is scoped to its importers exports, check if those importers exports
-				// are rendered in the chunks. If they are not, we can skip bundling this CSS.
-				const modMeta = this.getModuleInfo(id)?.meta as AstroPluginCssMetadata | undefined;
-				const cssScopeTo = modMeta?.astroCss?.cssScopeTo;
-				if (cssScopeTo && !isCssScopeToRendered(cssScopeTo, Object.values(meta.chunks))) {
-					// If this CSS is not used, delete it from the chunk modules so that Vite is unable
-					// to trace that it's used
-					delete chunk.modules[id];
-					const moduleIdsIndex = chunk.moduleIds.indexOf(id);
-					if (moduleIdsIndex > -1) {
-						chunk.moduleIds.splice(moduleIdsIndex, 1);
-					}
-				}
-			}
-		},
-	};
-
 	const singleCssPlugin: VitePlugin = {
 		name: 'astro:rollup-plugin-single-css',
 		enforce: 'post',
@@ -273,7 +246,7 @@ function rollupPluginAstroBuildCSS(options: PluginOptions): VitePlugin[] {
 		},
 	};
 
-	return [cssBuildPlugin, cssScopeToPlugin, singleCssPlugin, inlineStylesheetsPlugin];
+	return [cssBuildPlugin, singleCssPlugin, inlineStylesheetsPlugin];
 }
 
 /***** UTILITY FUNCTIONS *****/
@@ -321,25 +294,3 @@ function appendCSSToPage(
 		}
 	}
 }
-
-/**
- * `cssScopeTo` is a map of `importer`s to its `export`s. This function iterate each `cssScopeTo` entries
- * and check if the `importer` and its `export`s exists in the final chunks. If at least one matches,
- * `cssScopeTo` is considered "rendered" by Rollup and we return true.
- */
-function isCssScopeToRendered(
-	cssScopeTo: Record<string, string[]>,
-	chunks: Rollup.RenderedChunk[],
-) {
-	for (const moduleId in cssScopeTo) {
-		const exports = cssScopeTo[moduleId];
-		// Find the chunk that renders this `moduleId` and get the rendered module
-		const renderedModule = chunks.find((c) => c.moduleIds.includes(moduleId))?.modules[moduleId];
-		// Return true if `renderedModule` exists and one of its exports is rendered
-		if (renderedModule?.renderedExports.some((e) => exports.includes(e))) {
-			return true;
-		}
-	}
-
-	return false;
-}

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

@@ -188,7 +188,18 @@ async function ssrBuild(
 						const encoded = encodeName(name);
 						return [prefix, encoded, suffix].join('');
 					},
-					assetFileNames: `${settings.config.build.assets}/[name].[hash][extname]`,
+					assetFileNames(chunkInfo) {
+						const { names } = chunkInfo;
+						const name = names[0] ?? '';
+
+						// Sometimes chunks have the `@_@astro` suffix due to SSR logic. Remove it!
+						// TODO: refactor our build logic to avoid this
+						if (name.includes(ASTRO_PAGE_EXTENSION_POST_PATTERN)) {
+							const [sanitizedName] = name.split(ASTRO_PAGE_EXTENSION_POST_PATTERN);
+							return `${settings.config.build.assets}/${sanitizedName}.[hash][extname]`;
+						}
+						return `${settings.config.build.assets}/[name].[hash][extname]`;
+					},
 					...viteConfig.build?.rollupOptions?.output,
 					entryFileNames(chunkInfo) {
 						if (chunkInfo.facadeModuleId?.startsWith(ASTRO_PAGE_RESOLVED_MODULE_ID)) {

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

@@ -2,11 +2,7 @@ import type { SourceDescription } from 'rollup';
 import type * as vite from 'vite';
 import type { Logger } from '../core/logger/core.js';
 import type { AstroSettings } from '../types/astro.js';
-import type {
-	PluginCssMetadata as AstroPluginCssMetadata,
-	PluginMetadata as AstroPluginMetadata,
-	CompileMetadata,
-} from './types.js';
+import type { PluginMetadata as AstroPluginMetadata, CompileMetadata } from './types.js';
 
 import { defaultClientConditions, defaultServerConditions, normalizePath } from 'vite';
 import type { AstroConfig } from '../types/public/config.js';
@@ -16,7 +12,7 @@ import { handleHotUpdate } from './hmr.js';
 import { parseAstroRequest } from './query.js';
 import { loadId } from './utils.js';
 export { getAstroMetadata } from './metadata.js';
-export type { AstroPluginMetadata, AstroPluginCssMetadata };
+export type { AstroPluginMetadata };
 
 interface AstroPluginOptions {
 	settings: AstroSettings;
@@ -138,17 +134,9 @@ export default function astro({ settings, logger }: AstroPluginOptions): vite.Pl
 
 					return {
 						code: result.code,
-						// This metadata is used by `cssScopeToPlugin` to remove this module from the bundle
-						// if the `filename` default export (the Astro component) is unused.
-						meta: result.isGlobal
-							? undefined
-							: ({
-									astroCss: {
-										cssScopeTo: {
-											[filename]: ['default'],
-										},
-									},
-								} satisfies AstroPluginCssMetadata),
+						// `vite.cssScopeTo` is a Vite feature that allows this CSS to be treeshaken
+						// if the Astro component's default export is not used
+						meta: result.isGlobal ? undefined : { vite: { cssScopeTo: [filename, 'default'] } },
 					};
 				}
 				case 'script': {

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

@@ -18,27 +18,6 @@ export interface PluginMetadata {
 	};
 }
 
-export interface PluginCssMetadata {
-	astroCss: {
-		/**
-		 * For Astro CSS virtual modules, it can scope to the main Astro module's default export
-		 * so that if those exports are treeshaken away, the CSS module will also be treeshaken.
-		 *
-		 * Example config if the CSS id is `/src/Foo.astro?astro&type=style&lang.css`:
-		 * ```js
-		 * cssScopeTo: {
-		 *   '/src/Foo.astro': ['default']
-		 * }
-		 * ```
-		 *
-		 * The above is the only config we use today, but we're exposing as a `Record` to follow the
-		 * upstream Vite implementation: https://github.com/vitejs/vite/pull/16058. When/If that lands,
-		 * we can also remove our custom implementation.
-		 */
-		cssScopeTo: Record<string, string[]>;
-	};
-}
-
 export interface CompileMetadata {
 	/** Used for HMR to compare code changes */
 	originalCode: string;

packages/astro/test/0-css.test.js

@@ -9,10 +9,19 @@ import { after, before, describe, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import { loadFixture } from './test-utils.js';
 
-/** @type {import('./test-utils').Fixture} */
-let fixture;
+async function getCssContent($, fixture) {
+	const contents = await Promise.all(
+		$('link[rel=stylesheet][href^=/_astro/]').map((_, el) =>
+			fixture.readFile(el.attribs.href.replace(/^\/?/, '/')),
+		),
+	);
+	return contents.join('').replace(/\s/g, '').replace('/n', '');
+}
 
 describe('CSS', function () {
+	/** @type {import('./test-utils').Fixture} */
+	let fixture;
+
 	before(async () => {
 		fixture = await loadFixture({ root: './fixtures/0-css/' });
 	});
@@ -30,10 +39,7 @@ describe('CSS', function () {
 				// get bundled CSS (will be hashed, hence DOM query)
 				html = await fixture.readFile('/index.html');
 				$ = cheerio.load(html);
-				const bundledCSSHREF = $('link[rel=stylesheet][href^=/_astro/]').attr('href');
-				bundledCSS = (await fixture.readFile(bundledCSSHREF.replace(/^\/?/, '/')))
-					.replace(/\s/g, '')
-					.replace('/n', '');
+				bundledCSS = await getCssContent($, fixture);
 			},
 			{
 				timeout: 45000,
@@ -99,8 +105,7 @@ describe('CSS', function () {
 			it('Styles through barrel files should only include used Astro scoped styles', async () => {
 				const barrelHtml = await fixture.readFile('/barrel-styles/index.html');
 				const barrel$ = cheerio.load(barrelHtml);
-				const barrelBundledCssHref = barrel$('link[rel=stylesheet][href^=/_astro/]').attr('href');
-				const style = await fixture.readFile(barrelBundledCssHref.replace(/^\/?/, '/'));
+				const style = await getCssContent(barrel$, fixture);
 				assert.match(style, /\.comp-a\[data-astro-cid/);
 				assert.match(style, /\.comp-c\{/);
 				assert.doesNotMatch(style, /\.comp-b/);

packages/astro/test/astro-css-bundling.test.js

@@ -63,9 +63,9 @@ describe('CSS Bundling', function () {
 			}
 		});
 
-		it('there are 4 css files', async () => {
+		it('there are 5 css files', async () => {
 			const dir = await fixture.readdir('/_astro');
-			assert.equal(dir.length, 4);
+			assert.equal(dir.length, 5);
 		});
 
 		it('CSS includes hashes', async () => {
@@ -96,9 +96,9 @@ describe('CSS Bundling', function () {
 			await fixture.build({ mode: 'production' });
 		});
 
-		it('there are 4 css files', async () => {
+		it('there are 5 css files', async () => {
 			const dir = await fixture.readdir('/assets');
-			assert.equal(dir.length, 4);
+			assert.equal(dir.length, 5);
 		});
 
 		it('CSS does not include hashes', async () => {

packages/astro/test/config-vite.test.js

@@ -20,7 +20,7 @@ describe('Vite Config', async () => {
 	it('Allows overriding bundle naming options in the build', async () => {
 		const html = await fixture.readFile('/index.html');
 		const $ = cheerio.load(html);
-		assert.match($('link').attr('href'), /\/assets\/testing-[a-z\d]+\.css/);
+		assert.match($('link').attr('href'), /\/assets\/testing-.+\.css/);
 	});
 });
 

packages/astro/test/css-inline-stylesheets.test.js

@@ -113,7 +113,7 @@ describe('Setting inlineStylesheets to auto in static output', () => {
 
 		// the count of style/link tags depends on our css chunking logic
 		// this test should be updated if it changes
-		assert.equal($('style').length, 3);
+		assert.equal($('style').length, 2);
 		assert.equal($('link[rel=stylesheet]').length, 1);
 	});
 
@@ -162,7 +162,7 @@ describe('Setting inlineStylesheets to auto in server output', () => {
 
 		// the count of style/link tags depends on our css chunking logic
 		// this test should be updated if it changes
-		assert.equal($('style').length, 3);
+		assert.equal($('style').length, 2);
 		assert.equal($('link[rel=stylesheet]').length, 1);
 	});
 

packages/astro/test/css-order-import.test.js

@@ -147,9 +147,9 @@ describe('CSS ordering - import order', () => {
 			const content = await Promise.all(
 				getLinks(html).map((href) => getLinkContent(href, fixture)),
 			);
-			let [link1, link2] = content;
+			let [link1, , link3] = content;
 			assert.ok(link1.css.includes('f0f8ff')); // aliceblue minified
-			assert.ok(link2.css.includes('ff0')); // yellow minified
+			assert.ok(link3.css.includes('ff0')); // yellow minified
 		});
 	});
 });

packages/astro/test/css-order.test.js

@@ -90,7 +90,7 @@ describe('CSS production ordering', () => {
 			);
 
 			assert.ok(content.length, 3, 'there are 3 stylesheets');
-			const [, sharedStyles, pageStyles] = content;
+			const [, pageStyles, sharedStyles] = content;
 
 			assert.ok(/red/.exec(sharedStyles.css));
 			assert.ok(/#00f/.exec(pageStyles.css));

packages/astro/test/postcss.test.js

@@ -4,6 +4,15 @@ import * as cheerio from 'cheerio';
 import eol from 'eol';
 import { loadFixture } from './test-utils.js';
 
+async function getCssContent($, fixture) {
+	const contents = await Promise.all(
+		$('link[rel=stylesheet][href^=/_astro/]').map((_, el) =>
+			fixture.readFile(el.attribs.href.replace(/^\/?/, '/')),
+		),
+	);
+	return contents.join('').replace(/\s/g, '').replace('/n', '');
+}
+
 describe('PostCSS', () => {
 	let fixture;
 	let bundledCSS;
@@ -19,10 +28,7 @@ describe('PostCSS', () => {
 			// get bundled CSS (will be hashed, hence DOM query)
 			const html = await fixture.readFile('/index.html');
 			const $ = cheerio.load(html);
-			const bundledCSSHREF = $('link[rel=stylesheet][href^=/_astro/]').attr('href');
-			bundledCSS = (await fixture.readFile(bundledCSSHREF.replace(/^\/?/, '/')))
-				.replace(/\s/g, '')
-				.replace('/n', '');
+			bundledCSS = await getCssContent($, fixture);
 		},
 		{ timeout: 45000 },
 	);

packages/astro/test/remote-css.test.js

@@ -3,6 +3,15 @@ import { before, describe, it } from 'node:test';
 import * as cheerio from 'cheerio';
 import { loadFixture } from './test-utils.js';
 
+async function getCssContent($, fixture) {
+	const contents = await Promise.all(
+		$('link[rel=stylesheet][href^=/_astro/]').map((_, el) =>
+			fixture.readFile(el.attribs.href.replace(/^\/?/, '/')),
+		),
+	);
+	return contents.join('').replace(/\s/g, '').replace('/n', '');
+}
+
 describe('Remote CSS', () => {
 	let fixture;
 
@@ -19,8 +28,7 @@ describe('Remote CSS', () => {
 		const html = await fixture.readFile('/index.html');
 		const $ = cheerio.load(html);
 
-		const relPath = $('link').attr('href');
-		const css = await fixture.readFile(relPath);
+		const css = await getCssContent($, fixture);
 
 		assert.match(css, /https:\/\/unpkg.com\/open-props/);
 		assert.match(css, /body/);

packages/integrations/tailwind/test/fixtures/basic/astro.config.js

@@ -8,5 +8,8 @@ export default defineConfig({
       configFile: fileURLToPath(new URL('./tailwind.config.js', import.meta.url)),
       nesting: true
     }),
-  ]
+  ],
+  build: {
+    inlineStylesheets: 'never'
+  }
 });