Incompatibility between Airflow 3.0.6 and FastAPI 0.121.0

[hnomichith]

Apache Airflow version

Other Airflow 2/3 version

If "Other Airflow 2/3 version" selected, which one?

3.0.6

What happened?

Hello,

Today, FastAPI released a new minor version, going from 0.120.4 to 0.121.0.

This new release has moved the is_async_gen_callable method from fastapi.dependants.utils to being a method on the fastapi.dependants.models.Dependant data class.

It triggered an error from a project using Airflow 3.0.6:

ImportError while loading conftest '/home/runner/work/scraping-toolbox/scraping-toolbox/scraping-toolbox-core/tests/conftest.py'.
tests/conftest.py:6: in <module>
    from airflow.utils.db import check, resetdb
.tox/py313-airflow30/lib/python3.13/site-packages/airflow/utils/db.py:59: in <module>
    from airflow.utils.db_manager import RunDBManager
.tox/py313-airflow30/lib/python3.13/site-packages/airflow/utils/db_manager.py:26: in <module>
    from airflow.api_fastapi.app import create_auth_manager
.tox/py313-airflow30/lib/python3.13/site-packages/airflow/api_fastapi/app.py:35: in <module>
    from airflow.api_fastapi.execution_api.app import create_task_execution_api_app
.tox/py313-airflow30/lib/python3.13/site-packages/airflow/api_fastapi/execution_api/app.py:27: in <module>
    from cadwyn import (
.tox/py313-airflow30/lib/python3.13/site-packages/cadwyn/__init__.py:3: in <module>
    from .applications import Cadwyn
.tox/py313-airflow30/lib/python3.13/site-packages/cadwyn/applications.py:31: in <module>
    from cadwyn.changelogs import CadwynChangelogResource, _generate_changelog
.tox/py313-airflow30/lib/python3.13/site-packages/cadwyn/changelogs.py:21: in <module>
    from cadwyn.route_generation import _get_routes
.tox/py313-airflow30/lib/python3.13/site-packages/cadwyn/route_generation.py:34: in <module>
    from cadwyn.schema_generation import (
.tox/py313-airflow30/lib/python3.13/site-packages/cadwyn/schema_generation.py:30: in <module>
    from fastapi.dependencies.utils import is_async_gen_callable, is_coroutine_callable, is_gen_callable
E   ImportError: cannot import name 'is_async_gen_callable' from 'fastapi.dependencies.utils' (/home/runner/work/scraping-toolbox/scraping-toolbox/scraping-toolbox-core/.tox/py313-airflow30/lib/python3.13/site-packages/fastapi/dependencies/utils.py)
py313-airflow30: exit 4 (4.45 seconds) /home/runner/work/scraping-toolbox/scraping-toolbox/scraping-toolbox-core> pytest pid=2405
  py313-airflow30: FAIL code 4 (25.57=setup[21.12]+cmd[4.45] seconds)
  evaluation failed :( (25.60 seconds)

I would guess the issue could be fixed here by adding a maximum version ; but we could also consider fixing the import.

What you think should happen instead?

Airflow 3.0 shouldn't have an incompatibility with FastAPI.

How to reproduce

• Create a new folder
• Start a new Python virtual environment with whatever tool you prefer (I used Mise and UV)
• I installed apache-airflow==3.0.6 with uv add apache-airflow==3.0.6.
• I checked fastapi version with uv pip show fastapi, it was indeed fastapi==0.121.0
• Then in the Python console, I reproducted the issue with from airflow.utils.db import check, resetdb

Operating System

Ubuntu 24.04.3 LTS

Versions of Apache Airflow Providers

apache-airflow-providers-common-compat==1.8.0
apache-airflow-providers-common-io==1.6.4
apache-airflow-providers-common-sql==1.28.2
apache-airflow-providers-smtp==2.3.1
apache-airflow-providers-standard==1.9.1

Deployment

Astronomer

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

• I agree to follow this project's Code of Conduct

[boring-cyborg]

Thanks for opening your first issue here! Be sure to follow the issue template! If you are willing to raise PR to address this issue please do so, no need to wait for approval.

[potiuk]

Correct. Fast API 0.121 does not work with cadwyn zmievsa/cadwyn#305 -> you can chime in there to raise it's priority. Also Airflow 3 does not really work well with FastAPI 0.118+ -> see fastapi/fastapi#14262 and Airflow 3.1 has (for now) FastAPI limited to <0.118 - only after yesterday's fix in 0.121 we can switch to >=0.121 but only after the cadwyn bug is fixed.

Converting to a discussion - this is not an Aiflow issue and will be fixed independently