From 12d0cc0e5860f63ea54c75e2b000d2692682b2d8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=BF=A0=20/=20green?= <green@sapphi.red>
Date: Mon, 9 May 2022 23:07:04 +0900
Subject: [PATCH] fix(css): preserve dynamic import css code (fix #5348)
 (#7746)

---
 .../src/node/plugins/importAnalysisBuild.ts    | 18 ++++++++++++------
 .../__tests__/css-codesplit.spec.ts            | 18 +++++++++++++++++-
 playground/css-codesplit/async.css             |  3 +++
 playground/css-codesplit/index.html            |  9 +++++++++
 playground/css-codesplit/inline.css            |  3 +++
 playground/css-codesplit/main.js               | 15 ++++++++++++---
 playground/css-codesplit/mod.module.css        |  3 +++
 7 files changed, 59 insertions(+), 10 deletions(-)
 create mode 100644 playground/css-codesplit/async.css
 create mode 100644 playground/css-codesplit/inline.css
 create mode 100644 playground/css-codesplit/mod.module.css

diff --git a/packages/vite/src/node/plugins/importAnalysisBuild.ts b/packages/vite/src/node/plugins/importAnalysisBuild.ts
index a4b091dc7..5b7d738c2 100644
--- a/packages/vite/src/node/plugins/importAnalysisBuild.ts
+++ b/packages/vite/src/node/plugins/importAnalysisBuild.ts
@@ -145,11 +145,15 @@ export function buildImportAnalysisPlugin(config: ResolvedConfig): Plugin {
           d: dynamicIndex
         } = imports[index]
 
-        if (dynamicIndex > -1 && insertPreload) {
+        const isDynamic = dynamicIndex > -1
+
+        if (isDynamic && insertPreload) {
           needPreloadHelper = true
-          const original = source.slice(expStart, expEnd)
-          const replacement = `${preloadMethod}(() => ${original},${isModernFlag}?"${preloadMarker}":void 0)`
-          str().overwrite(expStart, expEnd, replacement, { contentOnly: true })
+          str().prependLeft(expStart, `${preloadMethod}(() => `)
+          str().appendRight(
+            expEnd,
+            `,${isModernFlag}?"${preloadMarker}":void 0)`
+          )
         }
 
         // Differentiate CSS imports that use the default export from those that
@@ -159,14 +163,16 @@ export function buildImportAnalysisPlugin(config: ResolvedConfig): Plugin {
         if (
           specifier &&
           isCSSRequest(specifier) &&
-          source.slice(expStart, start).includes('from') &&
+          // always inject ?used query when it is a dynamic import
+          // because there is no way to check whether the default export is used
+          (source.slice(expStart, start).includes('from') || isDynamic) &&
           // already has ?used query (by import.meta.glob)
           !specifier.match(/\?used(&|$)/) &&
           // edge case for package names ending with .css (e.g normalize.css)
           !(bareImportRE.test(specifier) && !specifier.includes('/'))
         ) {
           const url = specifier.replace(/\?|$/, (m) => `?used${m ? '&' : ''}`)
-          str().overwrite(start, end, dynamicIndex > -1 ? `'${url}'` : url, {
+          str().overwrite(start, end, isDynamic ? `'${url}'` : url, {
             contentOnly: true
           })
         }
diff --git a/playground/css-codesplit/__tests__/css-codesplit.spec.ts b/playground/css-codesplit/__tests__/css-codesplit.spec.ts
index 95fe97a1b..789adba23 100644
--- a/playground/css-codesplit/__tests__/css-codesplit.spec.ts
+++ b/playground/css-codesplit/__tests__/css-codesplit.spec.ts
@@ -1,8 +1,23 @@
 import { findAssetFile, getColor, isBuild, readManifest } from '../../testUtils'
 
-test('should load both stylesheets', async () => {
+test('should load all stylesheets', async () => {
   expect(await getColor('h1')).toBe('red')
   expect(await getColor('h2')).toBe('blue')
+  expect(await getColor('.dynamic')).toBe('green')
+})
+
+test('should load dynamic import with inline', async () => {
+  const css = await page.textContent('.dynamic-inline')
+  expect(css).toMatch('.inline')
+
+  expect(await getColor('.inline')).not.toBe('yellow')
+})
+
+test('should load dynamic import with module', async () => {
+  const css = await page.textContent('.dynamic-module')
+  expect(css).toMatch('_mod_')
+
+  expect(await getColor('.mod')).toBe('yellow')
 })
 
 if (isBuild) {
@@ -10,6 +25,7 @@ if (isBuild) {
     expect(findAssetFile(/style.*\.js$/)).toBe('')
     expect(findAssetFile('main.*.js$')).toMatch(`/* empty css`)
     expect(findAssetFile('other.*.js$')).toMatch(`/* empty css`)
+    expect(findAssetFile(/async.*\.js$/)).toBe('')
   })
 
   test('should generate correct manifest', async () => {
diff --git a/playground/css-codesplit/async.css b/playground/css-codesplit/async.css
new file mode 100644
index 000000000..4902b2e7b
--- /dev/null
+++ b/playground/css-codesplit/async.css
@@ -0,0 +1,3 @@
+.dynamic {
+  color: green;
+}
diff --git a/playground/css-codesplit/index.html b/playground/css-codesplit/index.html
index 6b7b3bb2b..63bdb59e1 100644
--- a/playground/css-codesplit/index.html
+++ b/playground/css-codesplit/index.html
@@ -1,2 +1,11 @@
+<h1>This should be red</h1>
+<h2>This should be blue</h2>
+
+<p class="dynamic">This should be green</p>
+<p class="inline">This should not be yellow</p>
+<p class="dynamic-inline"></p>
+<p class="mod">This should be yellow</p>
+<p class="dynamic-module"></p>
+
 <script type="module" src="/main.js"></script>
 <div id="app"></div>
diff --git a/playground/css-codesplit/inline.css b/playground/css-codesplit/inline.css
new file mode 100644
index 000000000..b2a2b5f1e
--- /dev/null
+++ b/playground/css-codesplit/inline.css
@@ -0,0 +1,3 @@
+.inline {
+  color: yellow;
+}
diff --git a/playground/css-codesplit/main.js b/playground/css-codesplit/main.js
index 8c80df2c1..eb6e703f7 100644
--- a/playground/css-codesplit/main.js
+++ b/playground/css-codesplit/main.js
@@ -1,6 +1,15 @@
 import './style.css'
 import './main.css'
 
-document.getElementById(
-  'app'
-).innerHTML = `<h1>This should be red</h1><h2>This should be blue</h2>`
+import('./async.css')
+
+import('./inline.css?inline').then((css) => {
+  document.querySelector('.dynamic-inline').textContent = css.default
+})
+
+import('./mod.module.css').then((css) => {
+  document.querySelector('.dynamic-module').textContent = JSON.stringify(
+    css.default
+  )
+  document.querySelector('.mod').classList.add(css.default.mod)
+})
diff --git a/playground/css-codesplit/mod.module.css b/playground/css-codesplit/mod.module.css
new file mode 100644
index 000000000..7f8441048
--- /dev/null
+++ b/playground/css-codesplit/mod.module.css
@@ -0,0 +1,3 @@
+.mod {
+  color: yellow;
+}