Migration to nextjs 16 blocked by deprecated import in preview.js

[matthew-petty]

Is there a documented fix or workaround for the use of next/config in storybook? I have read in many places that it's compatible with next 16, but it looks like this deprecation warning is still firing. We are running 10.4.1

Storybook is emitting this warning during frontend builds/dev:

⚠ Runtime config is deprecated and will be removed in Next.js 16.
  Please remove the usage of "next/config" from your project.

Diagnosis

Our first-party code is clean — frontend/src and frontend/.storybook contain zero usages of next/config, publicRuntimeConfig, serverRuntimeConfig, or getConfig. The warning comes from a dev dependency:

• frontend/node_modules/@storybook/nextjs-vite/dist/config/preview.js:2

  import { setConfig } from "next/config";

• frontend/node_modules/vite-plugin-storybook-nextjs/dist/index.js:5046 already guards a related inject list with an isNext16orNewer check (...isNext16orNewer ? [] : ["next/config"]), so upstream is partially aware, but the preview-side import still fires unconditionally on Next 15.

[dosubot[bot]]

Hi @matthew-petty! I'm Dosu and I’m helping the storybook team.

This was addressed in PR #32547, which conditionally excludes the @storybook/nextjs-vite/config/preview file (the one importing next/config) when running Next.js ≥16 [1]. The fix uses semver to detect your installed Next.js version and only loads setConfig for projects on Next.js <16.

However, you mentioned you're on Next.js 15 — and on Next 15 the next/config import is still intentionally loaded because the config mechanism hasn't been removed yet (only deprecated). The warning itself is harmless on Next 15; it's Next.js telling you the API will be removed in 16, not that it's broken now.

A few things to clarify:

• If you're on Next 15: The warning is cosmetic. Storybook still needs setConfig for runtime config support on Next <16. There's no way to suppress it without patching the dependency.
• If you're actually migrating to Next 16: The fix in PR Next.js: Remove next/config usage in Next.js >=v16 projects #32547 should already be present in Storybook 10.4.1. Could you confirm which exact version of Next.js you're running (next --version or check package.json)? If it's a prerelease/canary of Next 16, ensure you're on the latest patch of Storybook — PR #32724 improved version detection for prerelease versions.

Could you share:

1. Your exact Next.js version (from package.json)
2. Whether the warning causes an actual build failure, or is just a console warning you'd like to silence?

If you're on a Next 16 release candidate and the guard isn't triggering, a minimal reproduction would help track down why the version check isn't excluding the preview file.

To reply, just mention @dosu.

---

Docs are dead. Just use Dosu.

[matthew-petty]

We're on next 15 and planning the upgrade. Thank you for providing this documentation. It would be helpful to have the semver gating documented somewhere.