feat(nextjs): Mark the late pageload link as a server_request link

Without a type, the link from a pageload to the server request whose trace
context arrived too late shows up in Sentry with no meaning. The type is
documented in getsentry/sentry-docs#20112.

Author: s1gr1d

packages/nextjs/src/client/routing/traceMetaTags.ts

@@ -1,3 +1,4 @@
+import { SENTRY_LINK_TYPE } from '@sentry/conventions/attributes';
 import type { Span } from '@sentry/core';
 import { extractTraceparentData } from '@sentry/core';
 import { GLOBAL_OBJ } from '@sentry/core';
@@ -7,6 +8,8 @@ import { WINDOW } from '@sentry/react';
 const TRACE_FLAG_SAMPLED = 0x1;
 const TRACE_FLAG_NONE = 0x0;
 
+const SERVER_REQUEST_LINK_TYPE = 'server_request';
+
 export interface TraceMetaTagValues {
   sentryTrace: string;
   baggage: string | undefined;
@@ -144,5 +147,6 @@ export function addTraceMetaTagLink(span: Span, { sentryTrace }: TraceMetaTagVal
       spanId: traceparent.parentSpanId,
       traceFlags: traceparent.parentSampled ? TRACE_FLAG_SAMPLED : TRACE_FLAG_NONE,
     },
+    attributes: { [SENTRY_LINK_TYPE]: SERVER_REQUEST_LINK_TYPE },
   });
 }

packages/nextjs/test/client/traceMetaTags.test.ts

@@ -1,4 +1,5 @@
 // @vitest-environment jsdom
+import { SENTRY_LINK_TYPE } from '@sentry/conventions/attributes';
 import type { Span } from '@sentry/core';
 import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
 import {
@@ -191,7 +192,7 @@ describe('waitForTraceMetaTag', () => {
 });
 
 describe('addTraceMetaTagLink', () => {
-  it('links the span described by the sentry-trace value and carries the sampled flag', () => {
+  it('links the server request described by the sentry-trace value and carries the sampled flag', () => {
     const span = { addLink: vi.fn() } as unknown as Span;
 
     addTraceMetaTagLink(span, { sentryTrace: HEAD_TRACE, baggage: undefined });
@@ -202,9 +203,11 @@ describe('addTraceMetaTagLink', () => {
 
     expect(span.addLink).toHaveBeenNthCalledWith(1, {
       context: { traceId: '11111111111111111111111111111111', spanId: '1111111111111111', traceFlags: 1 },
+      attributes: { [SENTRY_LINK_TYPE]: 'server_request' },
     });
     expect(span.addLink).toHaveBeenNthCalledWith(2, {
       context: { traceId: '33333333333333333333333333333333', spanId: '3333333333333333', traceFlags: 0 },
+      attributes: { [SENTRY_LINK_TYPE]: 'server_request' },
     });
   });