add comment and update mechanism

Author: nicohrubec

dev-packages/e2e-tests/test-applications/tanstackstart-react/tests/errors.test.ts

@@ -51,7 +51,7 @@ test('Sends server-side function error to Sentry with auto-instrumentation', asy
           type: 'Error',
           value: 'Sentry Server Function Test Error',
           mechanism: {
-            type: 'auto.function.tanstackstart',
+            type: 'auto.middleware.tanstackstart.server_function',
             handled: false,
           },
         },
@@ -82,7 +82,7 @@ test('Sends API route error to Sentry with auto-instrumentation', async ({ page
           type: 'Error',
           value: 'Sentry API Route Test Error',
           mechanism: {
-            type: 'auto.function.tanstackstart',
+            type: 'auto.middleware.tanstackstart.request',
             handled: false,
           },
         },
@@ -93,6 +93,8 @@ test('Sends API route error to Sentry with auto-instrumentation', async ({ page
   expect(errorEvent.transaction).toBe('GET /api/error');
 });
 
+// the sentry global middleware does not capture errors from SSR loader errors since they are serialized before they reach the middleware layer
+// this test verifies that the error is in fact not sent to Sentry
 test('Does not send SSR loader error to Sentry', async ({ baseURL, page }) => {
   let errorEventOccurred = false;
 

packages/tanstackstart-react/src/server/globalMiddleware.ts

@@ -2,15 +2,17 @@ import { addNonEnumerableProperty, captureException } from '@sentry/core';
 import type { TanStackMiddlewareBase } from '../common/types';
 import { SENTRY_INTERNAL } from './middleware';
 
-async function sentryMiddlewareHandler({ next }: { next: () => Promise<unknown> }): Promise<unknown> {
-  try {
-    return await next();
-  } catch (e) {
-    captureException(e, {
-      mechanism: { type: 'auto.function.tanstackstart', handled: false },
-    });
-    throw e;
-  }
+function createSentryMiddlewareHandler(mechanismType: string) {
+  return async function sentryMiddlewareHandler({ next }: { next: () => Promise<unknown> }): Promise<unknown> {
+    try {
+      return await next();
+    } catch (e) {
+      captureException(e, {
+        mechanism: { type: mechanismType, handled: false },
+      });
+      throw e;
+    }
+  };
 }
 
 /**
@@ -19,8 +21,10 @@ async function sentryMiddlewareHandler({ next }: { next: () => Promise<unknown>
  */
 export const sentryGlobalRequestMiddleware: TanStackMiddlewareBase = {
   '~types': undefined,
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  options: { server: sentryMiddlewareHandler as (...args: any[]) => any },
+   
+  options: {
+    server: createSentryMiddlewareHandler('auto.middleware.tanstackstart.request') as (...args: any[]) => any,
+  },
 };
 
 /**
@@ -29,8 +33,10 @@ export const sentryGlobalRequestMiddleware: TanStackMiddlewareBase = {
  */
 export const sentryGlobalFunctionMiddleware: TanStackMiddlewareBase = {
   '~types': undefined,
-  // eslint-disable-next-line @typescript-eslint/no-explicit-any
-  options: { server: sentryMiddlewareHandler as (...args: any[]) => any },
+   
+  options: {
+    server: createSentryMiddlewareHandler('auto.middleware.tanstackstart.server_function') as (...args: any[]) => any,
+  },
 };
 
 // Mark as internal so the Vite auto-instrumentation plugin skips these middleware

packages/tanstackstart-react/test/server/globalMiddleware.test.ts

@@ -28,7 +28,7 @@ describe('sentryGlobalRequestMiddleware', () => {
     await expect(serverFn({ next })).rejects.toThrow('test error');
 
     expect(captureExceptionSpy).toHaveBeenCalledWith(error, {
-      mechanism: { type: 'auto.function.tanstackstart', handled: false },
+      mechanism: { type: 'auto.middleware.tanstackstart.request', handled: false },
     });
   });
 
@@ -48,6 +48,23 @@ describe('sentryGlobalRequestMiddleware', () => {
 });
 
 describe('sentryGlobalFunctionMiddleware', () => {
+  afterEach(() => {
+    vi.clearAllMocks();
+  });
+
+  it('captures error with correct mechanism when next() throws', async () => {
+    const error = new Error('test error');
+    const next = vi.fn().mockRejectedValue(error);
+
+    const serverFn = sentryGlobalFunctionMiddleware.options.server!;
+
+    await expect(serverFn({ next })).rejects.toThrow('test error');
+
+    expect(captureExceptionSpy).toHaveBeenCalledWith(error, {
+      mechanism: { type: 'auto.middleware.tanstackstart.server_function', handled: false },
+    });
+  });
+
   it('has __SENTRY_INTERNAL__ flag set', () => {
     expect((sentryGlobalFunctionMiddleware as unknown as Record<string, unknown>)['__SENTRY_INTERNAL__']).toBe(true);
   });