'NoneType' object has no attribute 'wait' with airflow db shell on SQLite

[marclamberti]

Apache Airflow version: 2.0.0b3

Kubernetes version (if you are using kubernetes) (use kubectl version):

Environment:

• Cloud provider or hardware configuration:
• OS (e.g. from /etc/os-release): Ubuntu 20.04.1 LTS
• Kernel (e.g. uname -a): Linux airflowvm 5.4.0-56-generic Adding ftp hook #62-Ubuntu SMP Mon Nov 23 19:20:19 UTC 2020 x86_64 x86_64 x86_64 GNU/Linux
• Install tools:
• Others:

What happened:

After connecting to SQLite with airflow db shell
And exiting the shell with.quit

I got the following error:

[2020-12-04 07:31:28,506] {process_utils.py:149} INFO - Executing cmd: sqlite3 /home/airflow/airflow/airflow.db
SQLite version 3.31.1 2020-01-27 19:55:54
Enter ".help" for usage hints.
sqlite> ;
sqlite> .quit
Traceback (most recent call last):
  File "/home/airflow/sandbox/bin/airflow", line 8, in <module>
    sys.exit(main())
  File "/home/airflow/sandbox/lib/python3.8/site-packages/airflow/__main__.py", line 40, in main
    args.func(args)
  File "/home/airflow/sandbox/lib/python3.8/site-packages/airflow/cli/cli_parser.py", line 50, in command
    return func(*args, **kwargs)
  File "/home/airflow/sandbox/lib/python3.8/site-packages/airflow/utils/cli.py", line 86, in wrapper
    return f(*args, **kwargs)
  File "/home/airflow/sandbox/lib/python3.8/site-packages/airflow/cli/commands/db_command.py", line 78, in shell
    execute_interactive(["sqlite3", url.database]).wait()
AttributeError: 'NoneType' object has no attribute 'wait'

What you expected to happen:

No error when exiting the session.
Looks like this execute_interactive(["sqlite3", url.database]) returns None

How to reproduce it:

airflow db shell
sqlite> .quit

Anything else we need to know:

I love this new command :)