amoghrajesh opened a new pull request, #48440:
URL: https://github.com/apache/airflow/pull/48440
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closes: #48408
The issue has nothing much to do with cross dags, it wont matter at all.
The root of the problem was that None was returned because
`include_prior_dates` wasn't implemented in task sdk.
This PR attempts to do that.
## Key changes
1. Moving away from the `xcom_query` as now I need to pass runtime parameter
to it, include_prior_dates. Although it is used by other API so not removing it
2. `logical_date` is a field that marks the start of a data interval and for
manual runs, can be empty, leading to the functionality of filtering by prior
dates failing. The query was:
```
dr = session.query(DagRun.logical_date).filter(DagRun.run_id ==
run_id).subquery()
query = query.filter(cls.logical_date <= dr.c.logical_date)
```
This was running into an issue because `logical_date` was empty for manual
runs.
Note, this has changed since 2.10.x as we used to have "execution_date" back
then which wasnt empty.
2.10.x:
3.0:
So a good fallback would be to use `run_after` instead when the
`logical_date` is None. I have implemented that using `coalesce`.
3. Added the `include_prior_dates` as a parameter for the SDK client
## Testing
Used the dag:
```
# from airflow.sdk import dag
from airflow.decorators import dag, task
@dag()
def cross_dag_xcom_upstream():
@task
def push_to_xcom():
return "Hello!"
push_to_xcom()
cross_dag_xcom_upstream()
@dag()
def cross_dag_xcom_downstream():
@task
def pull_from_xcom(**context):
print("The context task instance is", context["task_instance"])
my_data = context["task_instance"].xcom_pull(
dag_id="cross_dag_xcom_upstream",
task_ids="push_to_xcom",
key="return_value",
include_prior_dates=True,
)
return my_data
pull_from_xcom()
cross_dag_xcom_downstream()
```
Run the first DAG:
<img width="1726" alt="image"
src="https://github.com/user-attachments/assets/2f728ca4-b64f-4d53-9fc9-f7596ab31a8e";
/>
Run the second DAG:
<img width="1726" alt="image"
src="https://github.com/user-attachments/assets/38122234-4c72-48ff-be18-e3ca2ebb47c6";
/>
Observe that it doesn't get None anymore.
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