[robertorobles]

closes: #73175

Description

TaskInstance.xcom_pull() from within a running task goes through airflow.sdk.api.client.py::XComOperations.get() (and get_sequence_item()). When the requested key/task_id has no matching XCom, the API server returns a 404, which is caught and handled gracefully: the call returns None, matching Airflow 2.x behavior, and no exception propagates to the task.

Before returning, though, this was logged at ERROR level:

log.error(
    "XCom not found",
    dag_id=dag_id, run_id=run_id, task_id=task_id, key=key,
    map_index=map_index, detail=e.detail, status_code=e.response.status_code,
)

This means any task using the common, valid pattern of pulling an optional upstream XCom (e.g. with a default, or just checking whether something was pushed) emits a task-log ERROR even though nothing failed. This is confusing for monitoring/alerting setups that key off ERROR-level task logs, and misrepresents an expected, already-handled condition as an error.

This behavior was introduced in #45344 (closing #45341), which fixed a real bug — the task crashing entirely on a missing XCom — by catching the 404 and returning None. That PR's discussion focused on not crashing; the log level itself wasn't discussed.

Change

Downgrade the two "XCom not found" log.error(...) calls in XComOperations.get() and XComOperations.get_sequence_item() to log.warning(...). No behavior change — the call still returns None/an ErrorResponse as before, only the log level changes.

Scope is intentionally limited to these two XCom call sites (as opposed to also touching the unrelated "Asset not found" log in the same file), to keep this focused and easy to review.

Are you willing to submit a PR?

• Yes I am willing to submit a PR!

[boring-cyborg]

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[robertorobles]

Closing this as a duplicate — #73198 was opened shortly before this one for the same issue (#73175) and additionally includes test coverage for the changed log level, which this PR was missing. Let's consolidate review effort there.

[robertorobles]

Superseded by #73198.