loadNuxtConfig: klona/full stack overflow on jiti JSON-array default import (self-ref .default)

[s00d]

Environment

• Nuxt / @nuxt/kit 4.5.1 (repro). Kit 4.5.0 often survives because it used klona (lite).
• Relevant change: loadNuxtConfig does klona(resolved.config) via klona/full (no cycle detection).

Reproduction

// locales.json — a JSON array
// [{ "code": "en" }, { "code": "de" }]

// nuxt.config.ts
import locales from './locales.json'

export default defineNuxtConfig({
  // any module option that holds the array is enough; i18n shown as real-world case
  i18n: { locales },
})

Then nuxt prepare → Maximum call stack size exceeded in klona/full.

Control: locales: locales.map((l) => ({ ...l })) → OK.

Minimal jiti check (Nuxt loads config with interopDefault: true):

import { createJiti } from 'jiti'
const jiti = createJiti(import.meta.url, { interopDefault: true })
const mod = jiti('./locales.json')
Array.isArray(mod)       // true
mod.default === mod      // true  ← cycle

Native import … with { type: 'json' } does not add that default.

Describe the bug

1. jiti + interopDefault attaches default to a JSON array module pointing at itself.
2. Kit 4.5.1 clones the full resolved config with klona/full, which walks .default forever.
3. Crash happens in loadNuxtConfig before any module setup, so modules cannot sanitize in time.

Path from a patched depth-limited klona looked like: .i18n.locales.default.default…default.0.

Suggested directions

• Make config clone cycle-safe (WeakSet / use lite where full isn’t needed), and/or
• Avoid attaching default onto array exports in the jiti path used for nuxt.config.

Workaround for apps: shallow-clone the array before putting it in config.

Seen with nuxt-i18n-micro i18n.locales from a JSON array import; module-side normalize only helps after a successful load.

[coderabbitai]

⚠️ Possible Duplicate Issue(s)

• nuxt prepare fails with "Maximum call stack size exceeded" in klona since 4.5.1 when config embeds a jiti-imported JSON module #35913

🔗 Related PRs

#35729 - fix(kit): avoid mutating layer configs when resolving options [merged]
#35825 - fix(kit): re-order local layers before resolving config [open]
#35914 - fix(kit): clone resolved config with klona rather than klona/full [merged]
#35936 - refactor(kit): inline c12 and untyped, make jiti/giget optional peers [merged]
#35943 - perf(nuxt,kit)!: make jiti an optional peer dependency [merged]

---

📝 Issue Planner

_{Check the box below or use the @coderabbitai plan command to generate an implementation plan and prompts that you can use with your favorite coding assistant.}

• Create Plan

---

🧪 Issue enrichment is currently in open beta.

You can configure auto-planning by selecting labels in the issue_enrichment configuration.

To disable automatic issue enrichment, add the following to your .coderabbit.yaml:

issue_enrichment:
  auto_enrich:
    enabled: false

💬 Have feedback or questions? Drop into our discord!

[s00d]

Duplicate of #35913 — same root cause (klona/full + jiti JSON default self-ref).

Fixed in #35914 (klona instead of klona/full), merged 2026-07-30. Latest npm release is still 4.5.1 (2026-07-27), so the fix is on main but not published yet. Closing as duplicate.