[knowprasad]

Description

In \opentelemetry.baggage.propagation.W3CBaggagePropagator.extract, the implementation extracted only the first element from \getter.get(carrier, self._BAGGAGE_HEADER_NAME). When a carrier contains multiple \�aggage\ header entries (for example, when using frameworks that return a list of headers or when multiple integrations such as Sentry and OpenTelemetry inject separate baggage headers), all entries after the first were discarded.

Per the W3C Baggage specification:

A server receiving multiple Baggage header fields MUST combine them into a single list by appending each in field value order, separated by a comma (,).

And RFC 9110 Section 5.3:

A recipient MAY combine multiple field lines within each field section that have the same field name by appending each subsequent field line value to the combined value in order, separated by a comma and optional whitespace.

This PR updates \W3CBaggagePropagator.extract\ to:

1. Retrieve all header entries from \getter.get(carrier, self._BAGGAGE_HEADER_NAME).
2. Combine multiple header strings by joining with commas ,\ in field value order.
3. Add regression tests in \ est_w3cbaggagepropagator.py\ verifying multi-header extraction, comma-separated combinations, duplicate key handling (where later values win), and empty/whitespace entries.

Fixes #5811

Type of change

• Bug fix (non-breaking change which fixes an issue)

Checklist:

• Followed the style guidelines of this project
• Changelog entry added to .changelog/5811.fixed\
• Added unit tests covering multiple baggage headers
• Signed-off-by commit added (DCO)

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Waiting on reviewers · refreshed 2026-10-23 04:00 UTC

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