amoghrajesh opened a new pull request, #57614:
URL: https://github.com/apache/airflow/pull/57614
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## Problem
When migrating from Airflow 2.x to 3.0, the migration
`0049_3_0_0_remove_pickled_data_from_xcom_table` was failing.
This occurred when XCOM data contained the string "NaN" as part of a value,
for example:
```json
{"craft": "Tiangong", "name": "Ye GuangfuNaN"}
```
The migration was using a simple `REPLACE()` function that replaced all
occurrences of `'NaN'` with `'"nan"'`, which broke the JSON structure when
`NaN` appeared inside string values. The broken JSON would become:
```json
{"craft": "Tiangong", "name": "Ye Guangfu"nan""}
```
And things would break.
I changed the `NaN` sanitization to use regex with word boundaries to match
only standalone `NaN` tokens (like `"key": NaN`) while preserving `NaN` that
appears inside string values.
- PostgreSQL: Uses `regexp_replace` with word boundaries (`\bNaN\b`)
(https://neon.com/postgresql/postgresql-string-functions/regexp_replace)
- MySQL: Uses `REGEXP_REPLACE` with word boundaries (`[[:<:]]NaN[[:>:]]`)
(https://dev.mysql.com/doc/refman/8.4/en/regexp.html)
- SQLite: Kept simple with original `REPLACE()` approach as sqlite doesn't
have regex support(?)
## Testing
1. Installed 2.11 Airflow using: `breeze start-airflow --backend postgres
--executor CeleryExecutor --use-airflow-version 2.11.0 --db-reset`
2. Ran this DAG:
```python
from airflow import Dataset
from airflow.decorators import dag, task
from pendulum import datetime
import requests
# Define the basic parameters of the DAG, like schedule and start_date
@dag(
start_date=datetime(2024, 1, 1),
schedule="@daily",
catchup=False,
doc_md=__doc__,
default_args={"owner": "Astro", "retries": 3},
tags=["example"],
)
def example_astronauts():
@task
def get_astronauts(**context) -> list[dict]:
number_of_people_in_space = 1
list_of_people_in_space = [
{"craft": "Tiangong", "name": "Ye GuangfuNaN"},
]
context["ti"].xcom_push(
key="number_of_people_in_space", value=number_of_people_in_space
)
return list_of_people_in_space
@task
def print_astronaut_craft(greeting: str, person_in_space: dict) -> None:
"""
This task creates a print statement with the name of an
Astronaut in space and the craft they are flying on from
the API request results of the previous task, along with a
greeting which is hard-coded in this example.
"""
craft = person_in_space["craft"]
name = person_in_space["name"]
print(f"{name} is currently in space flying on the {craft}!
{greeting}")
print_astronaut_craft.partial(greeting="Hello! :)").expand(
person_in_space=get_astronauts() # Define dependencies using
TaskFlow API syntax
)
# Instantiate the DAG
example_astronauts()
```
<img width="3454" height="1460" alt="image (51)"
src="https://github.com/user-attachments/assets/93246d11-f865-472d-9f69-4b7b040777d1";
/>
3. Upgraded airflow to 3.11 using breeze: `breeze start-airflow --backend
postgres --executor CeleryExecutor --use-airflow-version 3.1.1`
No migration error:
```
Performing upgrade to the metadata database
postgresql+psycopg2://postgres:***@postgres/airflow
2025-10-31T10:40:09.197045Z [info ] Context impl PostgresqlImpl.
[alembic.runtime.migration] loc=migration.py:211
2025-10-31T10:40:09.197133Z [info ] Will assume transactional DDL.
[alembic.runtime.migration] loc=migration.py:214
2025-10-31T10:40:09.197938Z [info ] Context impl PostgresqlImpl.
[alembic.runtime.migration] loc=migration.py:211
2025-10-31T10:40:09.197991Z [info ] Will assume transactional DDL.
[alembic.runtime.migration] loc=migration.py:214
2025-10-31T10:40:09.198247Z [info ] Creating Airflow database tables
from the ORM [airflow.utils.db] loc=db.py:684
2025-10-31T10:40:09.198296Z [info ] Creating context
[airflow.utils.db] loc=db.py:689
2025-10-31T10:40:09.200174Z [info ] Binding engine
[airflow.utils.db] loc=db.py:691
2025-10-31T10:40:09.200245Z [info ] Pool status: Pool size: 5
Connections in pool: 0 Current Overflow: -3 Current Checked out connections: 2
[airflow.utils.db] loc=db.py:693
2025-10-31T10:40:09.200284Z [info ] Creating metadata
[airflow.utils.db] loc=db.py:695
2025-10-31T10:40:09.424717Z [info ] Getting alembic config
[airflow.utils.db] loc=db.py:698
2025-10-31T10:40:09.425147Z [info ] Stamping migration head
[airflow.utils.db] loc=db.py:705
2025-10-31T10:40:09.426209Z [info ] Context impl PostgresqlImpl.
[alembic.runtime.migration] loc=migration.py:211
2025-10-31T10:40:09.426272Z [info ] Will assume transactional DDL.
[alembic.runtime.migration] loc=migration.py:214
2025-10-31T10:40:09.450286Z [info ] Running stamp_revision ->
cc92b33c6709 [alembic.runtime.migration] loc=migration.py:622
2025-10-31T10:40:09.451776Z [info ] Airflow database tables created
[airflow.utils.db] loc=db.py:708
```
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