The following Vite config options will be overridden by SvelteKit: root #13376

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1. teemingc

   added

   vite

   on Feb 13, 2025
2. damiensawyer commented on Apr 13, 2025

   

   damiensawyer

   on Apr 13, 2025

   More actions

   If anyone is interested, I got AI to write a patch script to help with this until it's fixed.

   Added this to package.json
   "scripts": {
   "postinstall": "node ./scripts/patch-script.js"
   }

   and created this file.

   #!/usr/bin/env node
   
   // This will be deleted when Svelte releases this fix https://github.com/sveltejs/kit/issues/13376
   
   import fs from 'fs';
   import path from 'path';
   import { fileURLToPath } from 'url';
   
   // Get current directory
   const __filename = fileURLToPath(import.meta.url);
   const __dirname = path.dirname(__filename);
   
   // Path to the file we need to modify
   const filePath = path.join(
     process.cwd(),
     'node_modules',
     '@sveltejs',
     'kit',
     'src',
     'exports',
     'vite',
     'index.js'
   );
   
   console.log(`Checking for SvelteKit file at: ${filePath}`);
   
   // Check if the file exists
   if (!fs.existsSync(filePath)) {
     console.log('SvelteKit file not found. The patch was not applied.');
     process.exit(0);
   }
   
   // Read the file
   let content = fs.readFileSync(filePath, 'utf8');
   
   // Look for the line we need to change
   const searchString = 'root: cwd,';
   const replaceString = 'root: posixify(cwd),';
   
   // Check if the file already contains the fix
   if (content.includes(replaceString)) {
     console.log('The SvelteKit file is already patched.');
     process.exit(0);
   }
   
   // Check if the line to change exists
   if (!content.includes(searchString)) {
     console.log('The line to patch was not found. Structure may have changed. Please check manually.');
     process.exit(1);
   }
   
   // Apply the change
   const patchedContent = content.replace(searchString, replaceString);
   
   // Write the file back
   fs.writeFileSync(filePath, patchedContent, 'utf8');
   
   console.log('Successfully patched SvelteKit vite/index.js to use posixify(cwd).');

   👎React with 👎4Reacted by Samuele Esposito, It's Me!, Garrett Smith and Patrick Joannisse
3. rebasecase commented on Aug 12, 2025

   

   rebasecase

   on Aug 12, 2025 · Hidden as duplicate

   show commentMore actions
4. niemyjski commented on Sep 21, 2025

   

   niemyjski

   on Sep 21, 2025

   Last edited by niemyjski

   More actions

   I'm also seeing this with storybook
5. tylergannon commented on Oct 25, 2025

   

   tylergannon

   on Oct 25, 2025

   Last edited by tylergannon

   More actions

   macOS too with latest tooling.

   package.json
6. thunze commented on Oct 31, 2025

   

   thunze

   on Oct 31, 2025

   Last edited by thunze

   More actions

   Seeing

   The following Vite config options will be overridden by SvelteKit:
     - base
   

   since upgrading to Vitest 4. Possibly related.

   👍React with 👍14Reacted by Brandon Pittman, Matheus Ferraz, tamas-torjek, theconektd, Jason L Perry, Garrett Smith, Caleb Evans, Matthew, David Dal Busco, Samuel Huang and 4 more
7. peterpeterparker commented on Nov 21, 2025

   

   peterpeterparker

   on Nov 21, 2025

   Last edited by peterpeterparker

   More actions

   The following Vite config options will be overridden by SvelteKit:

   • base

   - base is popping as well in my projects when I migrate from vitest v3 to v4.
8. huangsam commented on Nov 26, 2025

   

   huangsam

   on Nov 26, 2025

   More actions

   Seeing

   The following Vite config options will be overridden by SvelteKit:
     - base
   

   since upgrading to Vitest 5. Possibly related.

   Looking into this issue, it appears that Vitest >=4 sets the base path to '/' by default, which is not acceptable according to the SvelteKit docs which say:

   A root-relative path that must start, but not end with / (e.g. /base-path), unless it is the empty string...

   I realized this by simply appending these lines right after the console.error from the warn_overridden_config API:

   console.info("config", `'${config.base}'`); // Shows '/'
   console.info("resolved_config", `'${resolved_config.base}'`); // Shows ''

   I foresee a few options, in case that helps future maintainers or users who stumble upon this issue:

   • Wait for SvelteKit team to address the initial assumptions around Vitest
   • File a PR to refine the underlying assumptions around Vitest
   • Reach out to Vitest team regarding their breaking changes
   • Apply a local hack to the SvelteKit logic so that it suppresses that warning only for the base key
   • Keep vitest under 4.x for our specific projects

   ❤️React with ❤️2Reacted by Brandon Pittman and Matias Szylkowski
9. lewisacidic commented on Dec 16, 2025

   

   lewisacidic

   on Dec 16, 2025

   More actions

   An simple hack for the base issue is to reset base to '' in a plugin that runs before sveltekit. A super minimal vite.config.ts might look like:

   import { defineConfig } from 'vitest/config'
   import { sveltekit } from '@sveltejs/kit/vite'
   
   export default defineConfig({
     plugins: [
       // fix for vitest v4 setting base to '/'
       {
         name: 'reset-base',
         config() {
           return {
             base: '',
           }
         },
       },
       sveltekit(),
     ],
     test: {
       name: 'server',
       environment: 'node',
       include: ['src/**/*.{test,spec}.{js,ts}'],
     },
   })
   

   This stops the annoying bold red message.

   🎉React with 🎉2Reacted by Vince Lozada and Nuwan Karunarathna
10. teemingc

    assigned

    Copilot

    and

    teemingc

    on Jan 2, 2026
11. teemingc

    linked a pull request that will close this issuefix: avoid overridden Vite config warning with Vitest 4 #15121on Jan 14, 2026
12. teemingc

    linked a pull request that will close this issuefix: avoid overriding Vite default `base` when running Vitest 4 #14866on Jan 14, 2026
13. teemingc

    closed this as completedin #14866on Jan 14, 2026