feat(nextjs): auto-enable development export conditions in dev mode

The SDK's webpack config now automatically adds 'development' to
resolve.conditionNames when running 'next dev'. This enables:
- Spotlight auto-enablement from NEXT_PUBLIC_SENTRY_SPOTLIGHT env var
- Other development-only SDK features

Users no longer need manual webpack configuration for Spotlight to work.

Author: BYK

dev-packages/e2e-tests/test-applications/nextjs-15-spotlight/next.config.js

@@ -7,19 +7,6 @@ const nextConfig = {
   env: {
     NEXT_PUBLIC_SENTRY_SPOTLIGHT: 'true',
   },
-
-  // Configure webpack to use 'development' export condition in dev mode
-  // This enables Sentry SDK's development-only features like Spotlight auto-enablement
-  webpack: (config, { dev }) => {
-    if (dev) {
-      // Add 'development' to the front of conditionNames to prioritize dev exports
-      config.resolve.conditionNames = [
-        'development',
-        ...(config.resolve.conditionNames || ['import', 'module', 'browser', 'require', 'node', 'default']),
-      ];
-    }
-    return config;
-  },
 };
 
 module.exports = withSentryConfig(nextConfig, {

packages/nextjs/src/config/webpack.ts

@@ -97,6 +97,16 @@ export function constructWebpackConfigFunction({
     // `newConfig.module.rules` is required, so we don't have to keep asserting its existence
     const newConfig = setUpModuleRules(rawNewConfig);
 
+    // In development mode, add 'development' to resolve conditions so that
+    // @sentry/* packages use their development exports (which include features like Spotlight auto-enablement)
+    if (isDev) {
+      newConfig.resolve = newConfig.resolve || {};
+      newConfig.resolve.conditionNames = [
+        'development',
+        ...(newConfig.resolve.conditionNames || ['import', 'module', 'browser', 'require', 'node', 'default']),
+      ];
+    }
+
     // Add a loader which will inject code that sets global values
     addValueInjectionLoader({
       newConfig,