feat(nextjs): Add disableSentryWebpackConfig flag

packages/nextjs/src/config/types.ts

@@ -486,6 +486,18 @@ export type SentryBuildOptions = {
    */
   disableManifestInjection?: boolean;
 
+  /**
+   * Disables automatic injection of Sentry's Webpack configuration.
+   *
+   * By default, the Sentry Next.js SDK injects its own Webpack configuration to enable features such as
+   * source map upload and automatic instrumentation. Set this option to `true` if you want to prevent
+   * the SDK from modifying your Webpack config (for example, if you want to handle Sentry integration manually
+   * or if you are on an older version of Next.js while using Turbopack).
+   *
+   * @default false
+   */
+  disableSentryWebpackConfig?: boolean;
+
   /**
    * Contains a set of experimental flags that might change in future releases. These flags enable
    * features that are still in development and may be modified, renamed, or removed without notice.

packages/nextjs/src/config/withSentryConfig.ts

@@ -311,9 +311,10 @@ function getFinalConfigObject(
             ],
           },
         }),
-    webpack: !isTurbopack
-      ? constructWebpackConfigFunction(incomingUserNextConfigObject, userSentryOptions, releaseName, routeManifest)
-      : undefined,
+    webpack:
+      isTurbopack || userSentryOptions.disableSentryWebpackConfig
+        ? incomingUserNextConfigObject.webpack // just return the original webpack config
+        : constructWebpackConfigFunction(incomingUserNextConfigObject, userSentryOptions, releaseName, routeManifest),
     ...(isTurbopackSupported && isTurbopack
       ? {
           turbopack: constructTurbopackConfig({

packages/nextjs/test/config/withSentryConfig.test.ts

@@ -145,6 +145,130 @@ describe('withSentryConfig', () => {
     });
   });
 
+  describe('webpack configuration behavior', () => {
+    const originalTurbopack = process.env.TURBOPACK;
+
+    afterEach(() => {
+      vi.restoreAllMocks();
+      process.env.TURBOPACK = originalTurbopack;
+    });
+
+    it('uses constructed webpack function when Turbopack is disabled and disableSentryWebpackConfig is false/undefined', () => {
+      delete process.env.TURBOPACK;
+
+      // default behavior
+      const finalConfigUndefined = materializeFinalNextConfig(exportedNextConfig);
+      expect(finalConfigUndefined.webpack).toBeInstanceOf(Function);
+
+      const sentryOptions = {
+        disableSentryWebpackConfig: false,
+      };
+      const finalConfigFalse = materializeFinalNextConfig(exportedNextConfig, undefined, sentryOptions);
+      expect(finalConfigFalse.webpack).toBeInstanceOf(Function);
+    });
+
+    it('preserves original webpack config when disableSentryWebpackConfig is true (regardless of Turbopack)', () => {
+      const originalWebpackFunction = vi.fn();
+      const configWithWebpack = {
+        ...exportedNextConfig,
+        webpack: originalWebpackFunction,
+      };
+
+      const sentryOptions = {
+        disableSentryWebpackConfig: true,
+      };
+
+      delete process.env.TURBOPACK;
+      const finalConfigWithoutTurbopack = materializeFinalNextConfig(configWithWebpack, undefined, sentryOptions);
+      expect(finalConfigWithoutTurbopack.webpack).toBe(originalWebpackFunction);
+
+      process.env.TURBOPACK = '1';
+      vi.spyOn(util, 'getNextjsVersion').mockReturnValue('15.3.0');
+      const finalConfigWithTurbopack = materializeFinalNextConfig(configWithWebpack, undefined, sentryOptions);
+      expect(finalConfigWithTurbopack.webpack).toBe(originalWebpackFunction);
+    });
+
+    it('preserves original webpack config when Turbopack is enabled (ignores disableSentryWebpackConfig flag)', () => {
+      process.env.TURBOPACK = '1';
+      vi.spyOn(util, 'getNextjsVersion').mockReturnValue('15.3.0');
+
+      const originalWebpackFunction = vi.fn();
+      const configWithWebpack = {
+        ...exportedNextConfig,
+        webpack: originalWebpackFunction,
+      };
+
+      const sentryOptionsWithFalse = {
+        disableSentryWebpackConfig: false,
+      };
+      const finalConfigWithFalse = materializeFinalNextConfig(configWithWebpack, undefined, sentryOptionsWithFalse);
+      expect(finalConfigWithFalse.webpack).toBe(originalWebpackFunction);
+
+      const finalConfigWithUndefined = materializeFinalNextConfig(configWithWebpack);
+      expect(finalConfigWithUndefined.webpack).toBe(originalWebpackFunction);
+
+      const sentryOptionsWithTrue = {
+        disableSentryWebpackConfig: true,
+      };
+      const finalConfigWithTrue = materializeFinalNextConfig(configWithWebpack, undefined, sentryOptionsWithTrue);
+      expect(finalConfigWithTrue.webpack).toBe(originalWebpackFunction);
+    });
+
+    it('preserves original webpack config when Turbopack is enabled and disableSentryWebpackConfig is true', () => {
+      process.env.TURBOPACK = '1';
+      vi.spyOn(util, 'getNextjsVersion').mockReturnValue('15.3.0');
+
+      const sentryOptions = {
+        disableSentryWebpackConfig: true,
+      };
+
+      const originalWebpackFunction = vi.fn();
+      const configWithWebpack = {
+        ...exportedNextConfig,
+        webpack: originalWebpackFunction,
+      };
+
+      const finalConfig = materializeFinalNextConfig(configWithWebpack, undefined, sentryOptions);
+
+      expect(finalConfig.webpack).toBe(originalWebpackFunction);
+    });
+
+    it('preserves undefined webpack when Turbopack is enabled, disableSentryWebpackConfig is true, and no original webpack config exists', () => {
+      process.env.TURBOPACK = '1';
+      vi.spyOn(util, 'getNextjsVersion').mockReturnValue('15.3.0');
+
+      const sentryOptions = {
+        disableSentryWebpackConfig: true,
+      };
+
+      const configWithoutWebpack = {
+        ...exportedNextConfig,
+      };
+      delete configWithoutWebpack.webpack;
+
+      const finalConfig = materializeFinalNextConfig(configWithoutWebpack, undefined, sentryOptions);
+
+      expect(finalConfig.webpack).toBeUndefined();
+    });
+
+    it('includes turbopack config when Turbopack is supported and enabled', () => {
+      process.env.TURBOPACK = '1';
+      vi.spyOn(util, 'getNextjsVersion').mockReturnValue('15.3.0');
+
+      const finalConfig = materializeFinalNextConfig(exportedNextConfig);
+
+      expect(finalConfig.turbopack).toBeDefined();
+    });
+
+    it('does not include turbopack config when Turbopack is not enabled', () => {
+      delete process.env.TURBOPACK;
+
+      const finalConfig = materializeFinalNextConfig(exportedNextConfig);
+
+      expect(finalConfig.turbopack).toBeUndefined();
+    });
+  });
+
   describe('release injection behavior', () => {
     afterEach(() => {
       vi.restoreAllMocks();