startNewTrace does not use same trace id for spans in callback

[mattjennings]

Is there an existing issue for this?

• I have checked for existing issues https://github.com/getsentry/sentry-javascript/issues
• I have reviewed the documentation https://docs.sentry.io/
• I am using the latest SDK release https://github.com/getsentry/sentry-javascript/releases

How do you use Sentry?

Sentry Saas (sentry.io)

Which SDK are you using?

@sentry/node

SDK Version

10.45.0

Framework Version

No response

Link to Sentry event

No response

Reproduction Example/SDK Setup

https://codesandbox.io/p/devbox/vigilant-rain-9f43ql?file=%2Findex.mjs

import crypto from "node:crypto";
import * as Sentry from "@sentry/node";

Sentry.init({
 tracesSampleRate: 1.0,
});

// sequential spans inside startNewTrace get different trace IDs
await Sentry.startNewTrace(async () => {
 const span1 = Sentry.startInactiveSpan({ op: "step.one", name: "Step One" });
 const traceId1 = span1.spanContext().traceId;
 span1.end();

 const span2 = Sentry.startInactiveSpan({ op: "step.two", name: "Step Two" });
 const traceId2 = span2.spanContext().traceId;
 span2.end();

 console.log("startNewTrace:");
 console.log(" span1 traceId:", traceId1);
 console.log(" span2 traceId:", traceId2);
 console.log(" same trace:", traceId1 === traceId2, "(expected true)");
});

// Workaround: continueTrace with a self-generated sentryTrace header
await Sentry.continueTrace(
 {
 sentryTrace: `${crypto.randomBytes(16).toString("hex")}-${crypto.randomBytes(8).toString("hex")}-1`,
 baggage: undefined,
 },
 async () => {
 const span1 = Sentry.startInactiveSpan({
 op: "step.one",
 name: "Step One",
 });
 const traceId1 = span1.spanContext().traceId;
 span1.end();

 const span2 = Sentry.startInactiveSpan({
 op: "step.two",
 name: "Step Two",
 });
 const traceId2 = span2.spanContext().traceId;
 span2.end();

 console.log("\ncontinueTrace (workaround):");
 console.log(" span1 traceId:", traceId1);
 console.log(" span2 traceId:", traceId2);
 console.log(" same trace:", traceId1 === traceId2, "(expected true)");
 },
);

await Sentry.close();

Steps to Reproduce

Run the provided js snippet in node with @sentry/node@10.45.0

Expected Result

All spans in the startNewTrace callback should share the same trace

Actual Result

Each span is assigned a new trace

Additional Context

I encountered this while trying to group a series of spans under a manually created trace. Used Claude to help debug and create this repro, the workaround is something I came up with that seemed to work but felt unintended.

Happy to provide any other information if needed.

Priority

_{React with 👍 to help prioritize this issue. Please use comments to provide useful context, avoiding +1 or me too, to help us triage it.}

[linear-code]

JS-1994

[mattjennings]

oops - it seems #18401 might be the same issue, but hopefully this repro helps as it seems that issue has gone stale.