fix(nextjs): Skip init inside a request of @sentry/cloudflare

Next.js calls `register()` inside the first request. When the Worker is
wrapped with `withSentry` from `@sentry/cloudflare`, the server and edge
`init` then installed the OpenTelemetry async context strategy on the storage
of that request, and every later request failed with
`context.getValue is not a function`.

On Cloudflare Workers, `init` now creates no client while a request of
`withSentry` from `@sentry/cloudflare` runs, because that client already
handles the request. The server `init` still adds the global event
processors and the turbopack tag.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: JPeer264

packages/nextjs/src/common/utils/responseEnd.ts

@@ -1,5 +1,5 @@
 import type { Span } from '@sentry/core';
-import { debug, fill, flush, GLOBAL_OBJ, setHttpStatus } from '@sentry/core';
+import { debug, fill, flush, getAsyncContextStrategy, getMainCarrier, GLOBAL_OBJ, setHttpStatus } from '@sentry/core';
 import { vercelWaitUntil } from '@sentry/core/server';
 import type { ServerResponse } from 'http';
 import { DEBUG_BUILD } from '../debug-build';
@@ -105,3 +105,20 @@ export function cloudflareWaitUntil(task: Promise<unknown>): void {
 export function isCloudflareWaitUntilAvailable(): boolean {
   return typeof _getOpenNextCloudflareContext()?.waitUntil === 'function';
 }
+
+/**
+ * Whether a request of `withSentry` from `@sentry/cloudflare` runs. A client of `init` would then replace its async
+ * context strategy while the request runs (#24603).
+ */
+export function isAsyncContextOwnedByCloudflare(): boolean {
+  const strategy = getAsyncContextStrategy(getMainCarrier());
+  // The AsyncLocalStorage strategy of `@sentry/cloudflare` has no `withActiveSpan`.
+  const asyncLocalStorage = strategy.getTracingChannelBinding?.()?.asyncLocalStorage as
+    | { getStore(): unknown }
+    | undefined;
+  return (
+    !strategy.withActiveSpan &&
+    asyncLocalStorage?.getStore() !== undefined &&
+    (GLOBAL_OBJ as { navigator?: { userAgent?: string } }).navigator?.userAgent === 'Cloudflare-Workers'
+  );
+}

packages/nextjs/src/edge/index.ts

@@ -3,6 +3,7 @@
 /* eslint-disable import/export */
 import {
   applySdkMetadata,
+  debug,
   getGlobalScope,
   getIsolationScope,
   getRootSpan,
@@ -30,7 +31,12 @@ import { dropMiddlewareTunnelRequests } from '../common/utils/dropMiddlewareTunn
 import { maybeForkIsolationScopeForRootSpan } from '../common/utils/forkIsolationScopeForRootSpan';
 import { getNormalizedRequestFromAttributes } from '../common/utils/getNormalizedRequestFromAttributes';
 import { isBuild } from '../common/utils/isBuild';
-import { flushSafelyWithTimeout, isCloudflareWaitUntilAvailable, waitUntil } from '../common/utils/responseEnd';
+import {
+  flushSafelyWithTimeout,
+  isAsyncContextOwnedByCloudflare,
+  isCloudflareWaitUntilAvailable,
+  waitUntil,
+} from '../common/utils/responseEnd';
 import { setUrlProcessingMetadata } from '../common/utils/setUrlProcessingMetadata';
 import { distDirRewriteFramesIntegration } from './distDirRewriteFramesIntegration';
 import { enhanceMiddlewareRootSpan } from '../common/enhanceMiddlewareRootSpan';
@@ -106,6 +112,14 @@ export function init(options: VercelEdgeOptions = {}): void {
   ];
   opts.ignoreSpans = [...(opts.ignoreSpans || []), ...nextjsIgnoreSpans];
 
+  if (isAsyncContextOwnedByCloudflare()) {
+    DEBUG_BUILD &&
+      debug.log(
+        'The client of `withSentry` handles this Worker, so `init` creates no client. Set the options in `withSentry`.',
+      );
+    return;
+  }
+
   // Use appropriate SDK metadata based on the runtime environment
   if (isRunningOnCloudflare) {
     applySdkMetadata(opts, 'nextjs', ['nextjs', 'cloudflare']);

packages/nextjs/src/server/index.ts

@@ -19,7 +19,7 @@ import { devErrorSymbolicationEventProcessor } from '../common/devErrorSymbolica
 import { isPrerenderControlFlowError } from '../common/nextNavigationErrorUtils';
 import { TRANSACTION_ATTR_SHOULD_DROP_TRANSACTION } from '../common/span-attributes-with-logic-attached';
 import { isBuild } from '../common/utils/isBuild';
-import { isCloudflareWaitUntilAvailable } from '../common/utils/responseEnd';
+import { isAsyncContextOwnedByCloudflare, isCloudflareWaitUntilAvailable } from '../common/utils/responseEnd';
 import { setUrlProcessingMetadata } from '../common/utils/setUrlProcessingMetadata';
 import { distDirRewriteFramesIntegration } from './distDirRewriteFramesIntegration';
 import { enhanceMiddlewareRootSpan } from '../common/enhanceMiddlewareRootSpan';
@@ -182,15 +182,18 @@ export function init(options: NodeOptions): NodeClient | undefined {
 
   DEBUG_BUILD && debug.log('Initializing SDK...');
 
-  if (sdkAlreadyInitialized()) {
+  // The client of `withSentry` from `@sentry/cloudflare` handles this request, so `init` creates none. The global
+  // parts below still apply.
+  const isOwnedByCloudflare = isAsyncContextOwnedByCloudflare();
+  if (sdkAlreadyInitialized() && !isOwnedByCloudflare) {
     DEBUG_BUILD && debug.log('SDK already initialized');
     return;
   }
 
   // Use appropriate SDK metadata based on the runtime environment
   applySdkMetadata(opts, 'nextjs', ['nextjs', cloudflareConfig ? 'cloudflare' : 'node']);
 
-  const client = nodeInit(opts);
+  const client = isOwnedByCloudflare ? undefined : nodeInit(opts);
 
   client?.on('beforeSampling', ({ spanAttributes }, samplingDecision) => {
     // There are situations where the Next.js Node.js server forwards requests for the Edge Runtime server (e.g. in
@@ -292,7 +295,14 @@ export function init(options: NodeOptions): NodeClient | undefined {
     // The statement above can throw because process is not defined on the client
   }
 
-  DEBUG_BUILD && debug.log('SDK successfully initialized');
+  if (isOwnedByCloudflare) {
+    DEBUG_BUILD &&
+      debug.log(
+        'The client of `withSentry` handles this Worker, so `init` creates no client. Set the options in `withSentry`.',
+      );
+  } else {
+    DEBUG_BUILD && debug.log('SDK successfully initialized');
+  }
 
   return client;
 }

packages/nextjs/test/edgeSdk.test.ts

@@ -1,5 +1,6 @@
 import type { Integration } from '@sentry/core';
-import { GLOBAL_OBJ } from '@sentry/core';
+import { getMainCarrier, GLOBAL_OBJ, withIsolationScope } from '@sentry/core';
+import { setAsyncLocalStorageAsyncContextStrategy } from '@sentry/server-utils';
 import * as SentryVercelEdge from '@sentry/vercel-edge';
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import { TRANSACTION_ATTR_SHOULD_DROP_TRANSACTION } from '../src/common/span-attributes-with-logic-attached';
@@ -21,6 +22,9 @@ describe('Edge init()', () => {
 
   afterEach(() => {
     vi.clearAllMocks();
+    vi.unstubAllGlobals();
+
+    getMainCarrier().__SENTRY__ = undefined;
   });
 
   it('inits the Vercel Edge SDK', () => {
@@ -52,6 +56,15 @@ describe('Edge init()', () => {
     );
   });
 
+  it('skips init on Cloudflare Workers in a request of `withSentry` from `@sentry/cloudflare`', () => {
+    vi.stubGlobal('navigator', { userAgent: 'Cloudflare-Workers' });
+    setAsyncLocalStorageAsyncContextStrategy();
+
+    withIsolationScope(() => init({}));
+
+    expect(vercelEdgeInit).not.toHaveBeenCalled();
+  });
+
   describe('integrations', () => {
     // Options passed by `@sentry/nextjs`'s `init` to `@sentry/vercel-edge`'s `init` after modifying them
     type ModifiedInitOptions = { integrations?: Integration[]; defaultIntegrations: Integration[] };

packages/nextjs/test/serverSdk.test.ts

@@ -1,5 +1,6 @@
 import type { Integration } from '@sentry/core';
-import { GLOBAL_OBJ, getMainCarrier } from '@sentry/core';
+import { GLOBAL_OBJ, getGlobalScope, getMainCarrier, withIsolationScope } from '@sentry/core';
+import { setAsyncLocalStorageAsyncContextStrategy } from '@sentry/server-utils';
 import { getCurrentScope } from '@sentry/node';
 import * as SentryNode from '@sentry/node';
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
@@ -18,10 +19,12 @@ function findIntegrationByName(integrations: Integration[] = [], name: string):
 describe('Server init()', () => {
   afterEach(() => {
     vi.clearAllMocks();
+    vi.unstubAllGlobals();
 
     getMainCarrier().__SENTRY__ = undefined;
 
     delete process.env.VERCEL;
+    delete (process as { turbopack?: boolean }).turbopack;
   });
 
   it('inits the Node SDK', () => {
@@ -67,6 +70,34 @@ describe('Server init()', () => {
     expect(nodeInit).toHaveBeenCalledTimes(1);
   });
 
+  it('skips init and sets the `turbopack` tag on Cloudflare Workers in a request of `withSentry` from `@sentry/cloudflare`', () => {
+    vi.stubGlobal('navigator', { userAgent: 'Cloudflare-Workers' });
+    setAsyncLocalStorageAsyncContextStrategy();
+    (process as { turbopack?: boolean }).turbopack = true;
+
+    withIsolationScope(() => init({}));
+
+    expect(nodeInit).not.toHaveBeenCalled();
+    expect(getGlobalScope().getScopeData().tags.turbopack).toBe(true);
+  });
+
+  it('inits on Cloudflare Workers outside of a request of `withSentry` from `@sentry/cloudflare`', () => {
+    vi.stubGlobal('navigator', { userAgent: 'Cloudflare-Workers' });
+    setAsyncLocalStorageAsyncContextStrategy();
+
+    init({});
+
+    expect(nodeInit).toHaveBeenCalledTimes(1);
+  });
+
+  it('inits outside of Cloudflare Workers when an AsyncLocalStorage strategy is installed', () => {
+    setAsyncLocalStorageAsyncContextStrategy();
+
+    withIsolationScope(() => init({}));
+
+    expect(nodeInit).toHaveBeenCalledTimes(1);
+  });
+
   // TODO: test `vercel` tag when running on Vercel
   // Can't just add the test and set env variables, since the value in `index.server.ts`
   // is resolved when importing.