`sentry-replay_id=` baggage header is not present when trace starts in the backend with SSR app

[Fwang36]

Environment

SaaS (https://sentry.io/)

Steps to Reproduce

I tested this in a Laravel, and a Python SSR app, so I'm not sure if this applies to every sdk.

When a trace is started in the backend the baggage headers do not contain a sentry-replay_id=. This causes error events that happen in the backend sdk in the same trace to not be connected to the replay, even though the Trace view shows a full connection.

Steps to reproduce -

1. Create SSR app
2. install javascript sdk for the frontend
3. Follow a Distributed Tracing guide - Python's sentry_sdk.get_baggage() or Laravel's {!! \Sentry\Laravel\Integration::sentryMeta() !!}
4. Start a trace from the backend to the frontend and check the header's being attached missing the sentry-replay_id=

Error linking seems to work only when the trace is started from the frontend javascript sdk.

baggage of trace started from backend

Example Of replay where the initial trace started from the backend where errors in trace to not appear in Replay

Expected Result

For the replays to be linked to the errors just like we do for transactions and error events

baggage of trace started from frontend

Actual Result

When traces start in the backend, they do not contain a sentry-replay_id in the baggage header

Product Area

Replays

[getsantry]

Assigning to @getsentry/support for routing ⏲️

[getsantry]

Routing to @getsentry/product-owners-replays for triage ⏲️

[bruno-garcia]

I'll move it to sentry-javascript repo

[mydea]

hey,

yeah, this is a known issue. This is a duplicate of #9490 - we have this on our radar and do want to work on this, but just haven't gotten around to doing this yet. I'll close this for now, you can follow the progress on this in the issue I linked - thank you!