fix(sentry): stop reporting expected notFound/redirect as errors

src/instrument.server.mjs

@@ -1,5 +1,8 @@
 import * as Sentry from '@sentry/tanstackstart-react'
-import { redactByokRequestHeaders } from './utils/sentry-redaction'
+import {
+  filterSentryEvent,
+  redactByokRequestHeaders,
+} from './utils/sentry-redaction'
 
 if (!Sentry.getClient())
   Sentry.init({
@@ -25,6 +28,6 @@ if (!Sentry.getClient())
         return null
       return breadcrumb
     },
-    beforeSend: redactByokRequestHeaders,
+    beforeSend: filterSentryEvent,
     beforeSendTransaction: redactByokRequestHeaders,
   })

src/router.tsx

@@ -9,7 +9,10 @@ import {
   installStaleAppReloadHandlers,
   consumeStaleAppRecovery,
 } from './utils/stale-app-reload'
-import { redactByokRequestHeaders } from './utils/sentry-redaction'
+import {
+  isRouterControlFlow,
+  redactByokRequestHeaders,
+} from './utils/sentry-redaction'
 import type { DocsNavTabId } from './utils/docsNavTabs'
 import type { CustomToolTabId } from './libraries/custom-tool-tabs'
 
@@ -25,6 +28,7 @@ if (typeof document !== 'undefined') {
     // Set 'tracePropagationTargets' to control for which URLs distributed tracing should be enabled
     tracePropagationTargets: ['localhost', /^https:\/\/tanstack\.com\//],
     beforeSend(event, hint) {
+      if (isRouterControlFlow(hint.originalException)) return null
       redactByokRequestHeaders(event)
       // Only suppress the exact error that triggered a reload. Errors during
       // the reload cooldown still need reporting.

src/utils/sentry-redaction.ts

@@ -1,3 +1,5 @@
+import { isNotFound, isRedirect } from '@tanstack/react-router'
+
 type EventWithRequestHeaders = {
   request?: {
     headers?: Record<string, string>
@@ -14,6 +16,10 @@ type EventWithRequestHeaders = {
   exception?: { values?: { value?: string }[] }
 }
 
+type EventHintWithOriginalException = {
+  originalException?: unknown
+}
+
 export function redactByokRequestHeaders<
   TEvent extends EventWithRequestHeaders,
 >(event: TEvent) {
@@ -59,3 +65,19 @@ export function redactByokRequestHeaders<
 
   return event
 }
+
+/**
+ * TanStack Router/Start throws `notFound()` and `redirect()` objects as
+ * control flow. They are not real errors and should never be reported.
+ */
+export function isRouterControlFlow(value: unknown): boolean {
+  return isNotFound(value) || isRedirect(value)
+}
+
+export function filterSentryEvent<TEvent extends EventWithRequestHeaders>(
+  event: TEvent,
+  hint?: EventHintWithOriginalException,
+): TEvent | null {
+  if (isRouterControlFlow(hint?.originalException)) return null
+  return redactByokRequestHeaders(event)
+}

tests/sentry-redaction.test.ts

@@ -1,6 +1,10 @@
 import assert from 'node:assert/strict'
 import test from 'node:test'
-import { redactByokRequestHeaders } from '../src/utils/sentry-redaction'
+import { notFound, redirect } from '@tanstack/react-router'
+import {
+  filterSentryEvent,
+  redactByokRequestHeaders,
+} from '../src/utils/sentry-redaction'
 
 test('Sentry events never include BYOK request headers', () => {
   const event = {
@@ -17,3 +21,23 @@ test('Sentry events never include BYOK request headers', () => {
   assert.equal(redactByokRequestHeaders(event), event)
   assert.deepEqual(event.request.headers, { Accept: 'application/json' })
 })
+
+test('Sentry filters actual Router control flow and keeps real failures redacted', () => {
+  for (const originalException of [notFound(), redirect({ href: '/' })]) {
+    assert.equal(filterSentryEvent({}, { originalException }), null)
+  }
+  for (const originalException of [
+    new Error('failure'),
+    new Response(null, { status: 500 }),
+    { isRedirect: true },
+    undefined,
+  ]) {
+    const event = {
+      request: {
+        headers: { 'x-byok-openai': 'secret', Accept: 'application/json' },
+      },
+    }
+    assert.equal(filterSentryEvent(event, { originalException }), event)
+    assert.deepEqual(event.request.headers, { Accept: 'application/json' })
+  }
+})