Show DAG parse error if 'timetable' and 'schedule_interval' are set together

[sdebruyn]

Apache Airflow version

2.2.5 (latest released)

What happened

In the UI I see 1 day, 00:00:00 under Schedule instead of the summary I've defined in my timetable:

    @property
    def summary(self) -> str:
        return "Daily (DailyTimetable)"

What you think should happen instead

According to the docs, overriding summary should change how the timetable is represented in the UI: https://airflow.apache.org/docs/apache-airflow/stable/howto/timetable.html#timetable-display-in-ui

How to reproduce

from airflow.timetables.base import DagRunInfo, DataInterval, TimeRestriction, Timetable


class DailyTimetable(Timetable):

    @property
    def summary(self) -> str:
        return "Daily (DailyTimetable)"

I can't share our implementation of this timetable, but I added the relevant code for the summary that is deployed.

Operating System

docker image apache/airflow:2.2.5-python3.9

Versions of Apache Airflow Providers

Apache Airflow 2.2.5

Deployment

Official Apache Airflow Helm Chart

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

[sdebruyn]

My bad, I accidentally set the schedule interval as well

[uranusjr]

Let me add an error for this so you don’t stumble on it again.

[uranusjr]

Actually it seems like we already have an exception?

>>> from airflow import DAG
>>> from airflow.timetables.simple import NullTimetable
>>> DAG("my-dag", schedule_interval="@once", timetable=NullTimetable())
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/opt/airflow/airflow/models/dag.py", line 426, in __init__
    raise TypeError("cannot specify both 'schedule_interval' and 'timetable'")
TypeError: cannot specify both 'schedule_interval' and 'timetable'

[sdebruyn]

It wasn't triggered for me since I set the timetable after the init

[uranusjr]

Modifying a DAG after it’s declared is not recommended or actively supported, so you should avoid that anyway. I’ll still add something to guard this, but don’t count for the validation to be fool-proof.