css url alias not resolved

[mrsvt]

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Describe the bug

<style>
.img {
  width: 200px;
  height: 200px;
  background: url("@/assets/logo.png") center / contain no-repeat;
}
</style>

The alias (@) is not resolved to its correct path defined in vite.config.js:

import path from "path";
import vue from "@vitejs/plugin-vue";

/**
 * @type {import('vite').UserConfig}
 */
export default {
  resolve: {
    alias: {
      "@": path.join(__dirname, "src"),
    },
  },
  plugins: [vue()],
};

I tried to fix it in assets.ts with the following:

-  const file = url.startsWith('/')
-    ? path.join(config.root, url)
-    : path.join(path.dirname(importer), url)
+  let file
+  if (url.startsWith('/')) {
+    file = path.join(config.root, url)
+  } else {
+    const resolved = (await pluginContext.resolve(url, importer))?.id
+    file = resolved || path.join(path.dirname(importer), url)
+  }

and in css.ts with the following:

-    ? (url, importer) => {
+    ? async (url, importer) => {
        if (url.startsWith('/')) {
          return config.base + url.slice(1)
        } else {
-          const filePath = normalizePath(
-            path.resolve(path.dirname(importer || id), url)
-          )
+          const resolved = (await this.resolve(url, importer || id))?.id
+          const filePath =
+            resolved ||
+            normalizePath(path.resolve(path.dirname(importer || id), url))
          return fileToDevUrl(filePath, config)
        }
      }

Reproduction

https://github.com/sayuti-daniel/vite-css-url-alias

System Info

• vite version: 2.0.0-beta.70
• Operating System: MacOS Catalina (10.15.7)
• Node version: v14.15.0
• Package manager (npm/yarn/pnpm) and version: npm 6.14.8

Logs (Optional if provided reproduction)

1. Run vite or vite build with the --debug flag.
2. Provide the error log here.