nextjs: Next 16 request yields a route-less http.server segment named only by method, plus the route-named one #25370

Environment

• @sentry/nextjs 11.7.0 (default span streaming), @sentry/node 11.7.0
• next 16.4.0, App Router, proxy.ts present, output: 'standalone', next build with Turbopack, run with node server.js
• Sentry.init in instrumentation.ts with tracesSampleRate: 1, no ignoreSpans, no custom sampler

What happens

Each request produces three separate segment spans in the same trace, none with a parent:

Captured by pointing the DSN at a local HTTP sink (one request each to /login and /api/users/me). For /login, the bare GET starts within a millisecond of middleware GET and ends when it ends; GET /login starts when the bare GET ends. The bare GET has url.path set but no http.route or next.route, and enhanceHandleRequestRootSpan only names a span from next.route/http.route, so it keeps the method as its name. Every route's bare GET looks the same.

Why it matters

• http.server is counted twice per request, so transaction counts, failure rates and p95 over span.op:http.server are skewed.
• When the named segment is dropped (for example by Sentry's "Filter out health check transactions" inbound filter, which matches GET /api/health), the bare GET for that request is still ingested, so a filtered route still shows up as GET.

What I tried

ignoreSpans: [{ name: /^(GET|POST)$/, op: 'http.server' }] drops a span created with that name and op in a unit test (startSpan), but removes nothing from the real Next server. I did not find out why. My guess is that the name or op is set after the filter runs, but I have not confirmed that.

Not tested

I did not run the same app without proxy.ts, so "the bare root is the proxy phase" is inferred from timing and the middleware GET sibling, not confirmed.

Expected

One http.server segment per request, named by route, with the proxy/middleware work as a child or as a clearly separate segment that is not also op http.server.