kosteev opened a new issue, #49540:
URL: https://github.com/apache/airflow/issues/49540
### Apache Airflow version
3.0.0
### If "Other Airflow 2 version" selected, which one?
_No response_
### What happened?
With the following DAG:
```
from __future__ import annotations
import logging
from datetime import datetime
from airflow.decorators import task
from airflow.models.dag import DAG
log = logging.getLogger(__name__)
with DAG(
"xcom_test",
schedule="* * * * *", # Override to match your needs,
start_date=datetime(2021, 1, 1),
catchup=False,
tags=["example", "sheets"],
) as dag:
@task
def xcom_string():
return "string"
@task
def xcom_dict():
return {"a": "b"}
@task
def xcom_list():
return [("a", "b"), ("c", "d")]
@task
def read_xcom(**kwargs):
xcom_string_task_value = kwargs["task_instance"].xcom_pull("xcom_string")
print("xcom_string_task", type(xcom_string_task_value),
xcom_string_task_value)
xcom_string_task_value_ids =
kwargs["task_instance"].xcom_pull(task_ids=["xcom_string"], key="return_value")
print("xcom_string_task_ids", type(xcom_string_task_value_ids),
xcom_string_task_value_ids, xcom_string_task_value_ids[0])
xcom_dict_task_value = kwargs["task_instance"].xcom_pull("xcom_dict")
print("xcom_dict_task", type(xcom_dict_task_value), xcom_dict_task_value)
xcom_dict_task_value_ids =
kwargs["task_instance"].xcom_pull(task_ids=["xcom_dict"], key="return_value")
print("xcom_dict_task_ids", type(xcom_dict_task_value_ids),
xcom_dict_task_value_ids, xcom_dict_task_value_ids[0])
xcom_list_task_value = kwargs["task_instance"].xcom_pull("xcom_list")
print("xcom_list_task", type(xcom_list_task_value), xcom_list_task_value)
xcom_list_task_value_ids =
kwargs["task_instance"].xcom_pull(task_ids=["xcom_list"], key="return_value")
print("xcom_list_task_ids", type(xcom_list_task_value_ids),
xcom_list_task_value_ids, xcom_list_task_value_ids[0])
xcom_string = xcom_string()
xcom_dict = xcom_dict()
xcom_list = xcom_list()
read_xcom_task = read_xcom()
xcom_string >> xcom_dict >> xcom_list >> read_xcom_task
```
In Airflow 2, the output is:
```
[2025-04-22, 08:13:20 UTC] {logging_mixin.py:190} INFO - xcom_string_task
<class 'str'> string
[2025-04-22, 08:13:20 UTC] {logging_mixin.py:190} INFO -
xcom_string_task_ids <class 'airflow.models.xcom.LazyXComSelectSequence'>
LazySelectSequence([1 item]) string
[2025-04-22, 08:13:20 UTC] {logging_mixin.py:190} INFO - xcom_dict_task
<class 'dict'> {'a': 'b'}
[2025-04-22, 08:13:20 UTC] {logging_mixin.py:190} INFO - xcom_dict_task_ids
<class 'airflow.models.xcom.LazyXComSelectSequence'> LazySelectSequence([1
item]) {'a': 'b'}
[2025-04-22, 08:13:20 UTC] {logging_mixin.py:190} INFO - xcom_list_task
<class 'list'> [['a', 'b'], ['c', 'd']]
[2025-04-22, 08:13:20 UTC] {logging_mixin.py:190} INFO - xcom_list_task_ids
<class 'airflow.models.xcom.LazyXComSelectSequence'> LazySelectSequence([1
item]) [['a', 'b'], ['c', 'd']]
[2025-04-22, 08:13:20 UTC] {python.py:240} INFO - Done. Returned value was:
None
```
In Airflow 3:
### What you think should happen instead?
The same behavior in Airflow 2 and 3.
For the case (task_ids=["{task_id}"]), the difference is that in Airflow 2
the result will be list of values, in Airflow 3 the result will be the value
itself.
### How to reproduce
See section above
### Operating System
Linux
### Versions of Apache Airflow Providers
_No response_
### Deployment
Other
### Deployment details
_No response_
### Anything else?
_No response_
### Are you willing to submit PR?
- [ ] Yes I am willing to submit a PR!
### Code of Conduct
- [x] I agree to follow this project's [Code of
Conduct](https://github.com/apache/airflow/blob/main/CODE_OF_CONDUCT.md)
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
