fix(css): remove ?used hack (fixes #6421, #8245, #8461)

packages/playground/css/__tests__/css.spec.ts

@@ -417,9 +417,5 @@ test("relative path rewritten in Less's data-uri", async () => {
 test('PostCSS source.input.from includes query', async () => {
   const code = await page.textContent('.postcss-source-input')
   // should resolve assets
-  expect(code).toContain(
-    isBuild
-      ? '/postcss-source-input.css?used&query=foo'
-      : '/postcss-source-input.css?query=foo'
-  )
+  expect(code).toContain('/postcss-source-input.css?query=foo')
 })

packages/vite/src/node/importGlob.ts

@@ -9,7 +9,6 @@ import {
   preloadMarker,
   preloadMethod
 } from './plugins/importAnalysisBuild'
-import { isCSSRequest } from './plugins/css'
 import {
   blankReplacer,
   cleanUrl,
@@ -150,16 +149,14 @@ export async function transformImportGlob(
         await fsp.readFile(path.join(base, files[i]), 'utf-8')
       )},`
     } else {
-      const importeeUrl = isCSSRequest(importee) ? `${importee}?used` : importee
       if (isEager) {
         const identifier = `__glob_${importIndex}_${i}`
-        // css imports injecting a ?used query to export the css string
         importsString += `import ${
           isEagerDefault ? `` : `* as `
-        }${identifier} from ${JSON.stringify(importeeUrl)};`
+        }${identifier} from ${JSON.stringify(importee)};`
         entries += ` ${JSON.stringify(file)}: ${identifier},`
       } else {
-        let imp = `import(${JSON.stringify(importeeUrl)})`
+        let imp = `import(${JSON.stringify(importee)})`
         if (!normalizeUrl && preload) {
           imp =
             `(${isModernFlag}` +

packages/vite/src/node/plugins/css.ts

@@ -102,7 +102,6 @@ const htmlProxyRE = /(\?|&)html-proxy\b/
 const commonjsProxyRE = /\?commonjs-proxy/
 const inlineRE = /(\?|&)inline\b/
 const inlineCSSRE = /(\?|&)inline-css\b/
-const usedRE = /(\?|&)used\b/
 const varRE = /^var\(/i
 
 const enum PreprocessLang {
@@ -370,18 +369,19 @@ export function cssPostPlugin(config: ResolvedConfig): Plugin {
       }
 
       let code: string
-      if (usedRE.test(id)) {
-        if (modulesCode) {
-          code = modulesCode
-        } else {
-          let content = css
-          if (config.build.minify) {
-            content = await minifyCSS(content, config)
-          }
-          code = `export default ${JSON.stringify(content)}`
-        }
+      if (modulesCode) {
+        code = modulesCode
       } else {
-        code = `export default ''`
+        let content = css
+        if (config.build.minify) {
+          content = await minifyCSS(content, config)
+        }
+        // marking as pure to make it tree-shakable by minifier
+        // but the module itself is still treated as a non tree-shakable module
+        // because moduleSideEffects is 'no-treeshake'
+        code = `export default /* #__PURE__ */ (() => ${JSON.stringify(
+          content
+        )})()`
       }
 
       return {

packages/vite/src/node/plugins/importAnalysisBuild.ts

@@ -5,11 +5,11 @@ import { init, parse as parseImports } from 'es-module-lexer'
 import type { OutputChunk, SourceMap } from 'rollup'
 import type { RawSourceMap } from '@ampproject/remapping'
 import { transformImportGlob } from '../importGlob'
-import { bareImportRE, combineSourcemaps } from '../utils'
+import { combineSourcemaps } from '../utils'
 import type { Plugin } from '../plugin'
 import type { ResolvedConfig } from '../config'
 import { genSourceMapUrl } from '../server/sourcemap'
-import { isCSSRequest, removedPureCssFilesCache } from './css'
+import { removedPureCssFilesCache } from './css'
 
 /**
  * A flag for injected helpers. This flag will be set to `false` if the output
@@ -148,7 +148,6 @@ export function buildImportAnalysisPlugin(config: ResolvedConfig): Plugin {
           e: end,
           ss: expStart,
           se: expEnd,
-          n: specifier,
           d: dynamicIndex
         } = imports[index]
 
@@ -195,23 +194,6 @@ export function buildImportAnalysisPlugin(config: ResolvedConfig): Plugin {
           const replacement = `${preloadMethod}(() => ${original},${isModernFlag}?"${preloadMarker}":void 0)`
           str().overwrite(expStart, expEnd, replacement, { contentOnly: true })
         }
-
-        // Differentiate CSS imports that use the default export from those that
-        // do not by injecting a ?used query - this allows us to avoid including
-        // the CSS string when unnecessary (esbuild has trouble tree-shaking
-        // them)
-        if (
-          specifier &&
-          isCSSRequest(specifier) &&
-          source.slice(expStart, start).includes('from') &&
-          // edge case for package names ending with .css (e.g normalize.css)
-          !(bareImportRE.test(specifier) && !specifier.includes('/'))
-        ) {
-          const url = specifier.replace(/\?|$/, (m) => `?used${m ? '&' : ''}`)
-          str().overwrite(start, end, dynamicIndex > -1 ? `'${url}'` : url, {
-            contentOnly: true
-          })
-        }
       }
 
       if (