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Improve error message for Python decorator invoking function with same name as the task name #49875
Description
Body
Given code:
from datetime import datetime
from airflow import DAG
from airflow.decorators import task
from time import sleep
default_args = {
'owner': 'airflow',
'start_date': datetime(2023, 2, 1)
}
with DAG('scheduler', schedule="@daily", catchup=True, default_args=default_args):
@task()
def sleep():
sleep(3600)
sleep()
It fails with:
TypeError: too many positional arguments
File "/opt/airflow/task-sdk/src/airflow/sdk/execution_time/task_runner.py", line 829 in run
File "/opt/airflow/task-sdk/src/airflow/sdk/execution_time/task_runner.py", line 1092 in _execute_task
File "/opt/airflow/task-sdk/src/airflow/sdk/bases/operator.py", line 408 in wrapper
File "/opt/airflow/task-sdk/src/airflow/sdk/bases/decorator.py", line 251 in execute
File "/opt/airflow/task-sdk/src/airflow/sdk/bases/operator.py", line 408 in wrapper
File "/opt/airflow/providers/standard/src/airflow/providers/standard/operators/python.py", line 212 in execute
File "/opt/airflow/providers/standard/src/airflow/providers/standard/operators/python.py", line 235 in execute_callable
File "/opt/airflow/task-sdk/src/airflow/sdk/execution_time/callback_runner.py", line 81 in run
File "/files/dags/scheduler.py", line 15 in sleep
File "/opt/airflow/task-sdk/src/airflow/sdk/bases/decorator.py", line 363 in __call__
File "/opt/airflow/task-sdk/src/airflow/sdk/bases/operator.py", line 513 in apply_defaults
File "/opt/airflow/providers/standard/src/airflow/providers/standard/decorators/python.py", line 58 in __init__
File "/opt/airflow/task-sdk/src/airflow/sdk/bases/operator.py", line 513 in apply_defaults
File "/opt/airflow/task-sdk/src/airflow/sdk/bases/decorator.py", line 239 in __init__
File "/usr/local/lib/python3.9/inspect.py", line 3045 in bind
File "/usr/local/lib/python3.9/inspect.py", line 2966 in _bind
The reason for this failure is because the python task has the exact name as the python function. My real code was more complex than the example I share here.. it took me several minutes to figure out what was the issue. Not sure if we can fix it but if we can improve the error message we should
Committer
- I acknowledge that I am a maintainer/committer of the Apache Airflow project.
Activity
giannistbs commentedon Apr 28, 2025
Hello! Can i work on this?
ashb commentedon Apr 28, 2025
What is your plan?
kiran2706 commentedon May 23, 2025
@ashb - Can I take a shot at this?
My plan is to implement it by intercepting function calls in TaskDecorator.call, and inspecting the call stack to detect potential self-invocations caused by naming collisions between the function and the task object.
If detected, I'll log a clear warning or optionally raise an informative error to help users debug it faster.
Let me know if you have any suggestions before I start
cc: @potiuk
vatsrahul1001 commentedon Aug 28, 2025
I can repro this as well
suman-himanshu commentedon Aug 29, 2025
I am able to reproduce this issue at my end.
ashb commentedon Sep 24, 2025
Ideally though we do that without inspecting the callstack in "happy" path cases, as looking at the call stack is expensive.
gitbita99 commentedon Apr 8, 2026
Hi @ashb , I would like to work in this issue
Problem: When users shadow imports with task name, they get a cryptic
TypeError: too many positional arguments.Solution: Add exception handling in
DecoratedOperator.__init__to provide a helpful hint message - only when the error occurs (No overhead).The fix catches the TypeError during signature binding, adds guidance / hint and returns it.
I have a working implementation ready. Could you please assign this issue to me?
Gourigupta2004 commentedon Jun 28, 2026
Hi @eladkal,
I would like to investigate and work on this issue. Please assign this to me
Thanks
potiuk commentedon Jun 29, 2026
We do not assign issues (see contributing guides) - but feel free to work on it.
Rename task decorator newsfragment for PR check (apache#49875)
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