cases/getsentry/getsentry_sentry_python_sentry_ruby_102dddf76ba8/prompt.md

Custom baggage is overwritten with Sentry values on outgoing requests.

Python SDK

Currently, any library that is patched by Sentry tries to append the baggage header whenever possible, for example httpx. When an outgoing request already has custom data in the baggage header, the destination of the call does not receive the original custom baggage. Other integrations use a similar approach to the httpx one and may be affected too.

To reproduce:

• Initialize a project with sentry-sdk==1.26.0 and httpx.
• Initialize Sentry with sentry_sdk.init(default_integrations=True, auto_enabling_integrations=True).
• Make a call with an httpx client such as client.get("/path", headers={"baggage": "custom=value"}).

Ruby SDK

Sentry::Utils::HttpTracing#set_propagation_headers overwrites propagation headers on outgoing HTTP requests. While this is fine for the Sentry-specific sentry-trace header, the baggage header is a W3C standard shared across multiple systems. Pre-existing baggage entries may be set by OpenTelemetry, application code, or other instrumentation.

To reproduce:

• Set a custom baggage header on an outgoing HTTP request, for example routingKey=myvalue,tenantId=123.
• Ensure propagate_traces is enabled and the target URL matches trace_propagation_targets.
• Make the request using Net::HTTP, Faraday, or Excon.
• Inspect the outgoing request headers.

Expected Result

When a baggage header already exists on the outgoing request, Sentry should merge its entries with the existing value by joining them with a comma (,), as per the W3C Baggage specification. The Sentry baggage and the original custom baggage values should both be present.

Actual Result

Sentry baggage overwrites the whole baggage value, leaving Sentry values only. The original custom entries are lost.