nextjs - 💡(How to fix) Fix Sentry Spotlight sourcemaps work with Webpack but fail under Turbopack in Next.js (Next.js 16 + @sentry/nextjs) [1 participants]

### Current vs. Expected behavior

# 🐛 Sentry Spotlight sourcemaps fail under Turbopack in Next.js (Webpack works correctly)

---

## 📄 Description

When using `@sentry/nextjs` with Next.js 16, source maps and Spotlight integration work correctly in Webpack dev mode, but fail under Turbopack.

Even though Turbopack source maps are enabled via experimental flags, Sentry Spotlight does not resolve stack traces to original source files. Instead, it shows minified or chunked output.

---

## ⚙️ Next.js Configuration

### `next.config.ts`

```ts
import { withSentryConfig } from "@sentry/nextjs";
import type { NextConfig } from "next";
import bundleAnalyzer from "@next/bundle-analyzer";

const baseConfig: NextConfig = {
  reactStrictMode: false,

  async headers() {
    return [secHeaders];
  },

  experimental: {
    turbopackSourceMaps: true,
    turbopackInputSourceMaps: true,
  },
};

let nextConfig = baseConfig;

if (process.env.NEXT_PUBLIC_SENTRY_DISABLED !== "true") {
  nextConfig = withSentryConfig(nextConfig, {
    org: process.env.SENTRY_ORGANIZATION,
    project: process.env.SENTRY_PROJECT,
    authToken: process.env.SENTRY_AUTH_TOKEN,

    silent: !process.env.CI,
    widenClientFileUpload: true,

    // tunnelRoute intentionally disabled
    // tunnelRoute: "/monitoring",

    webpack: {
      reactComponentAnnotation: {
        enabled: true,
      },
      treeshake: {
        removeDebugLogging: true,
      },
    },

    telemetry: false,

    sourcemaps: {
      disable: false,
    },
  });
}

export default nextConfig;

webpack(config, { dev, isServer }) {
  if (dev && !isServer) {
    config.devtool = "source-map";
  }
  return config;
},

## 🧩 Environment

- Next.js: 15.x
- @sentry/nextjs: latest
- Node.js: 24+
- Bundlers:
  - Webpack (`next dev --webpack`)
  - Turbopack (`next dev`)
- Repro: local development