robertorobles opened a new issue, #73175:
URL: https://github.com/apache/airflow/issues/73175
### Description
In Airflow 3.x, `TaskInstance.xcom_pull()` executed from inside a running
task goes through `airflow.sdk.api.client.py::XComOperations.get()`. When the
requested key/task_id doesn't have a matching XCom, the API server returns a
`404`, which is caught and handled gracefully — the call still returns `None`,
matching Airflow 2.x behavior — but before returning, it logs:
```python
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 every task that does a "check if this XCom exists" style
`xcom_pull` (a very common and valid pattern — pulling with a `default`, or
checking optional upstream output) emits a task-log `ERROR` line even though
nothing failed and no exception propagates. This is confusing for
on-call/monitoring setups that alert on ERROR-level task logs, and
misrepresents an expected, handled condition as an error.
This behavior was introduced by #45344 (closing #45341), which fixed a real
bug — task crashes on missing XCom — by catching the 404 and returning `None`.
That PR's discussion focused entirely on not crashing; the log *level* wasn't
discussed.
### Suggested fix
Downgrade these to `log.warning` (or lower) in `airflow/sdk/api/client.py`,
since the surrounding code explicitly treats the condition as expected/handled,
not an error:
- `XComOperations.get()` (~line 535, "XCom not found")
- `XComOperations.get_sequence_item()` (~line 606, "XCom not found")
(Possibly also `"Asset not found"` at ~line 674 for the same reason, though
that's a separate call site — happy to split if preferred.)
### Workaround
`[logging] namespace_levels = airflow.sdk.api.client=CRITICAL` in
`airflow.cfg` silences it, but that's an all-or-nothing hammer on the whole
client logger (also silences genuine connectivity/auth errors from the same
module).
### Environment
Observed on Airflow **3.2.2**, but the code path is unchanged as of `main`
as far as I can tell.
### Are you willing to submit a PR?
- [ ] Yes I am willing to submit a PR!
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