Fixed rows count in the migration script

[alartum]

Changes:

• replaced .count() method with an already existing get_query_count method;

Motivation:

While performing the Apache Airflow update from 2.2.3 to 2.7.1 I faced an issue with the migration:

$ airflow db migrate
...
File "/home/airflow/.local/bin/airflow", line 8, in <module>
    sys.exit(main())
  File "/home/airflow/.local/lib/python3.10/site-packages/airflow/__main__.py", line 60, in main
    args.func(args)
  File "/home/airflow/.local/lib/python3.10/site-packages/airflow/cli/cli_config.py", line 49, in command
    return func(*args, **kwargs)
  File "/home/airflow/.local/lib/python3.10/site-packages/airflow/cli/commands/db_command.py", line 65, in upgradedb
    migratedb(args)
  File "/home/airflow/.local/lib/python3.10/site-packages/airflow/utils/cli.py", line 113, in wrapper
    return f(*args, **kwargs)
  File "/home/airflow/.local/lib/python3.10/site-packages/airflow/utils/providers_configuration_loader.py", line 56, in wrapped_function
    return func(*args, **kwargs)
  File "/home/airflow/.local/lib/python3.10/site-packages/airflow/cli/commands/db_command.py", line 104, in migratedb
    db.upgradedb(
  File "/home/airflow/.local/lib/python3.10/site-packages/airflow/utils/session.py", line 77, in wrapper
    return func(*args, session=session, **kwargs)
  File "/home/airflow/.local/lib/python3.10/site-packages/airflow/utils/db.py", line 1616, in upgradedb
    for err in _check_migration_errors(session=session):
  File "/home/airflow/.local/lib/python3.10/site-packages/airflow/utils/db.py", line 1499, in _check_migration_errors
    yield from check_fn(session=session)
  File "/home/airflow/.local/lib/python3.10/site-packages/airflow/utils/db.py", line 1460, in check_bad_references
    invalid_row_count = bad_rows_query.count()
AttributeError: 'Select' object has no attribute 'count'

The cause of the error is that SQLAlchemy changed the behavior of the select statement. It has already been addressed in other places using func.count(), so the problematic line looks more like a typo/oversight.

---

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[boring-cyborg]

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[ephraimbuddy]

Can we add a test to protect future changes here?

[alartum]

Sure, I will add it

[alartum]

@ephraimbuddy I've finally found the time to add the test, although it required more work than expected :)

[ephraimbuddy]

Nice to have but not required

[boring-cyborg]

Awesome work, congrats on your first merged pull request! You are invited to check our Issue Tracker for additional contributions.