Streamline & simplify __eq__ methods in models Dag and BaseOperator

[XD-DENG]

• Change-1: Use getattr() instead of dict as dict doesn't return correct values for properties (sample code reproducing the issue is given below). This was fixed for dag model, but was not fixed for baseoperator model.

• Change-2: Avoid unnecessary condition check (the removed condition checks are covered by _comps)

Sample Code Reproducing Issue in Change-1

class C:

    def __init__(self, elements):
        self._elements = elements

    @property
    def elements(self):
        return self._elements

    def test(self):
        print(self.__dict__.get("elements", None))
        print(getattr(self, "elements", None))

a = C([1,2,3])
a.test()

Output:

None
[1, 2, 3]

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[github-actions]

The Workflow run is cancelling this PR. It has some failed jobs matching ^Pylint$,^Static checks,^Build docs$,^Spell check docs$,^Backport packages$,^Provider packages,^Checks: Helm tests$,^Test OpenAPI*.

[mik-laj]

From what I can remember, it's optimization so we can check the most common case much faster.

[mik-laj]

See: 36e76fa and https://github.com/apache/airflow/pull/4322/files#r241802863

[XD-DENG]

That optimisation may not make sense given two reasons below:

• all() function has the "exit fast" property, i.e., whenever there is any False element, it will return False immediately, rather than traversing all elements in the iterable. reference
• For dag model, dag_id is the 1st element in _comps; For BaseOperator, task_id is the 1st element in _comps.

So after the change I make here, there should be zero impact on the performance (actually it improves the performance very minorly: it helps avoid comparing dag_id in dag model's __eq__for two times. Similar for BaseOperator).

Kindly let me know if it makes sense to you?

[mik-laj]

SGTM.

[github-actions]

The PR most likely needs to run full matrix of tests because it modifies parts of the core of Airflow. However, committers might decide to merge it quickly and take the risk. If they don't merge it quickly - please rebase it to the latest master at your convenience, or amend the last commit of the PR, and push it with --force-with-lease.