fix(vite): respect baseURL for public assets in dev (#28482)

packages/vite/src/plugins/public-dirs.ts

@@ -1,17 +1,51 @@
 import { existsSync } from 'node:fs'
 import { useNitro } from '@nuxt/kit'
 import { createUnplugin } from 'unplugin'
+import type { UnpluginOptions } from 'unplugin'
 import { withLeadingSlash, withTrailingSlash } from 'ufo'
 import { dirname, relative } from 'pathe'
 import MagicString from 'magic-string'
+import { isCSSRequest } from 'vite'
 
 const PREFIX = 'virtual:public?'
 const CSS_URL_RE = /url\((\/[^)]+)\)/g
+const CSS_URL_SINGLE_RE = /url\(\/[^)]+\)/
 
-export const VitePublicDirsPlugin = createUnplugin((options: { sourcemap?: boolean }) => {
+interface VitePublicDirsPluginOptions {
+  dev?: boolean
+  sourcemap?: boolean
+  baseURL?: string
+}
+
+export const VitePublicDirsPlugin = createUnplugin((options: VitePublicDirsPluginOptions) => {
   const { resolveFromPublicAssets } = useResolveFromPublicAssets()
 
+  const devTransformPlugin: UnpluginOptions = {
+    name: 'nuxt:vite-public-dir-resolution-dev',
+    vite: {
+      transform (code, id) {
+        if (!isCSSRequest(id) || !CSS_URL_SINGLE_RE.test(code)) { return }
+
+        const s = new MagicString(code)
+        for (const [full, url] of code.matchAll(CSS_URL_RE)) {
+          if (url && resolveFromPublicAssets(url)) {
+            s.replace(full, `url(${options.baseURL}${url})`)
+          }
+        }
+
+        if (s.hasChanged()) {
           return {
+            code: s.toString(),
+            map: options.sourcemap ? s.generateMap({ hires: true }) : undefined,
+          }
+        }
+      },
+    },
+  }
+
+  return [
+    ...(options.dev && options.baseURL && options.baseURL !== '/' ? [devTransformPlugin] : []),
+    {
       name: 'nuxt:vite-public-dir-resolution',
       vite: {
         load: {
@@ -71,7 +105,8 @@ export const VitePublicDirsPlugin = createUnplugin((options: { sourcemap?: boole
           }
         },
       },
-  }
+    },
+  ]
 })
 
 export function useResolveFromPublicAssets () {

packages/vite/src/vite.ts

@@ -99,7 +99,11 @@ export const bundle: NuxtBuilder['bundle'] = async (nuxt) => {
         },
         plugins: [
           // add resolver for files in public assets directories
-          VitePublicDirsPlugin.vite({ sourcemap: !!nuxt.options.sourcemap.server }),
+          VitePublicDirsPlugin.vite({
+            dev: nuxt.options.dev,
+            sourcemap: !!nuxt.options.sourcemap.server,
+            baseURL: nuxt.options.app.baseURL,
+          }),
           composableKeysPlugin.vite({
             sourcemap: !!nuxt.options.sourcemap.server || !!nuxt.options.sourcemap.client,
             rootDir: nuxt.options.rootDir,