[AIRFLOW-6864] Make airflow/jobs pylint compatible

[turbaszek]

This PR makes airflow/jobs pylint compatible and removes the cyclic dependency created by importing BackfillJob to access BackfillJob.ID_PREFIX

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Issue link: AIRFLOW-6864

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[turbaszek]

Depends on #7482

[mik-laj]

We currently have "airlfow/utils/state.py" which contains constants, so we can also create a new file that contains other enums/types/constants.

[mik-laj]

Do we need these constants? Maybe it would be better to use the DagRunType directly?

[turbaszek]

I am happy to do this in other PR.

[turbaszek]

I will leave it for other PR. It's not strictly related to this PR.

[ashb]

Good spot Kamil!

[kaxil]

There are merge conflicts

[turbaszek]

@kaxil @potiuk @mik-laj @ashb are we good to go?

[ashb]

@nuclearpinguin See https://github.com/apache/airflow/pull/7527/files#r383812108 -- this is my only outstanding query about this PR.

[turbaszek]

@nuclearpinguin See https://github.com/apache/airflow/pull/7527/files#r383812108 -- this is my only outstanding query about this PR.

This PR runs pylint over scheduler_job.py the one you mention does not. I suppose once I rebase I will have to fix it in more places. @ashb

[turbaszek]

************* Module airflow.jobs.scheduler_job
airflow/jobs/scheduler_job.py:1031:16: E1101: Method 'state' has no 'is_' member (no-member)

@ashb

I assume that the difference is that here DM.dag_id.is_(None) we are referencing dag_id attribute of sqla model. And here models.DagRun.state.is_(None) reference a method of DagRun:

    @declared_attr
    def state(self):
        return synonym('_state',
                       descriptor=property(self.get_state, self.set_state))

[ashb]

Ah, because we have ignored that file (or mostly ignored it) it's not yet showing up in Pylint. SQLA DelcarativeModels does funny things with the classes/instances that pylint can't detect.

I guess it's unavoidable, and we will have to ignore those few lines.

I think pylint-dev/pylint#3334 is the same issue we have (open, no feedback).