vp create svelte generates config where vp check reports $props as no-undef

[crypt0box]

Describe the bug

vp create svelte can generate a project that fails vp check immediately.

The failure comes from the migrated Oxlint config preserving core no-undef for .svelte files. Valid Svelte 5 rune syntax such as $props() is reported as undefined:

eslint(no-undef): '$props' is not defined.

This appears to be a migration/config compatibility issue rather than an application code issue.

Current workaround

Manually disable no-undef for .svelte files in the generated vite.config.ts:

{
  files: ["*.svelte", "**/*.svelte"],
  rules: {
    "no-inner-declarations": "off",
    "no-self-assign": "off",
    "no-undef": "off",
  },
  jsPlugins: ["eslint-plugin-svelte"],
}

After this change, the $props() errors are no longer reported.

Proposed fix

When Vite+ migrates the ESLint config generated by sv create --add eslint into the lint block in vite.config.ts, normalize Svelte overrides so core no-undef is disabled for .svelte files.

For example, during the migrated Oxlint config sanitization step, if an override targets *.svelte / **/*.svelte, add:

rules: {
  "no-undef": "off",
}

This does not attempt to add full Svelte template linting support to Oxlint. It only prevents migrated core no-undef from flagging valid Svelte 5 rune globals such as $props() while Oxlint’s Svelte support is still partial.

One related observation: current sv create --add eslint --types ts disables no-undef globally for TypeScript projects, following typescript-eslint guidance. So another possible fix would be to preserve that top-level no-undef: "off" during migration. However, the minimal compatibility fix is to disable no-undef for migrated .svelte overrides.

---

This may be small enough that you might decide not to add a Vite+ migration-layer workaround and instead address it as part of broader Svelte
support in Oxlint / @oxlint/migrate. That would be understandable.

If you think this compatibility normalization belongs in Vite+, I would be happy to open a PR.

Also, thanks for building Vite+. I really like this tool.

Reproduction

https://github.com/crypt0box/vite-plus-svelte-eslint

Steps to reproduce

1. Create a Svelte project with Vite+:

vp create svelte

Choose TypeScript and ESLint.

2. Install dependencies if needed:

vp install

3. Run checks:

vp check

4. Observe that vp check fails on generated Svelte files:

error: Lint or type issues found

x eslint(no-undef): '$props' is not defined.
   ,-[src/routes/+layout.svelte:4:21]
 3 |
 4 |     let { children } = $props();
   :                        ^^^^^^
 5 | </script>
   `----

x eslint(no-undef): '$props' is not defined.
   ,-[src/lib/vitest-examples/Welcome.svelte:4:49]
 3 |
 4 |     let { host = 'SvelteKit', guest = 'Vitest' } = $props();
   :                                                    ^^^^^^
 5 | </script>
   `----

The generated vite.config.ts contains a top-level no-undef: "error" and a Svelte override that does not disable no-undef:

lint: {
  rules: {
    "no-undef": "error",
    // ...
  },
  overrides: [
    {
      files: ["*.svelte", "**/*.svelte"],
      rules: {
        "no-inner-declarations": "off",
        "no-self-assign": "off",
      },
      jsPlugins: ["eslint-plugin-svelte"],
    },
  ],
}

System Info

vp v0.2.1

Local vite-plus:
  vite-plus  v0.2.1

Tools:
  vite             v8.0.16
  rolldown         v1.1.1
  vitest           v4.1.9
  oxfmt            v0.55.0
  oxlint           v1.70.0
  oxlint-tsgolint  v0.23.0
  tsdown           v0.22.3

Environment:
  Package manager  pnpm v11.9.0
  Node.js          v24.18.0

Used Package Manager

pnpm

Validations

• Read the Contributing Guidelines.
• Check that there isn't already an issue for the same bug.
• Confirm this is a Vite+ issue and not an upstream issue (Vite, Vitest, tsdown, Rolldown, or Oxc).
• The provided reproduction is a minimal reproducible example.