test: add packageJson BOM processing test case

playground/resolve/__tests__/resolve.spec.ts

@@ -248,3 +248,7 @@ test.runIf(isBuild)('public dir is not copied', async () => {
     fs.existsSync(path.resolve(testDir, 'dist/should-not-be-copied')),
   ).toBe(false)
 })
+
+test('import utf8-bom package', async () => {
+  expect(await page.textContent('.utf8-bom-package')).toMatch('[success]')
+})

playground/resolve/index.html

@@ -176,6 +176,9 @@ <h2>resolve package that contains # in path</h2>
 <h2>resolve non normalized absolute path</h2>
 <p class="non-normalized"></p>
 
+<h2>utf8-bom-package</h2>
+<p class="utf8-bom-package">fail</p>
+
 <script type="module">
   import '@generated-content-virtual-file'
   function text(selector, text) {
@@ -399,6 +402,9 @@ <h2>resolve non normalized absolute path</h2>
 
   import nonNormalizedAbsolute from '@non-normalized'
   text('.non-normalized', nonNormalizedAbsolute)
+
+  import { msg as utf8BomPackage } from '@vitejs/test-utf8-bom-package'
+  text('.utf8-bom-package', utf8BomPackage)
 </script>
 
 <style>

playground/resolve/package.json

@@ -40,6 +40,7 @@
     "@vitejs/test-resolve-exports-with-module-condition-required": "link:./exports-with-module-condition-required",
     "@vitejs/test-resolve-linked": "workspace:*",
     "@vitejs/test-resolve-imports-pkg": "link:./imports-path/other-pkg",
-    "@vitejs/test-resolve-sharp-dir": "link:./sharp-dir"
+    "@vitejs/test-resolve-sharp-dir": "link:./sharp-dir",
+    "@vitejs/test-utf8-bom-package": "link:./utf8-bom-package"
   }
 }

playground/resolve/utf8-bom-package/index.mjs

@@ -0,0 +1,3 @@
+import '@babel/runtime/helpers/esm/slicedToArray'
+
+export const msg = '[success]'

playground/resolve/utf8-bom-package/package.json

@@ -0,0 +1,8 @@
+{
+  "name": "@vitejs/test-utf8-bom-package",
+  "private": true,
+  "version": "1.0.0",
+  "exports": {
+    ".": "./index.mjs"
+  }
+}