SongPal: do not crash if active_source is not (yet) available - fixes #20343

[Censored3]

Description:

Related issue (if applicable): fixes #20343

Pull request in home-assistant.io with documentation (if applicable): home-assistant/home-assistant.io#<home-assistant.io PR number goes here>

Example entry for configuration.yaml (if applicable):

Checklist:

• The code change is tested and works locally.
• Local tests pass with tox. Your PR cannot be merged unless tests pass
• There is no commented out code in this PR.

If user exposed functionality or configuration variables are added/changed:

• Documentation added/updated in home-assistant.io

If the code communicates with devices, web services, or third-party tools:

• New dependencies have been added to the REQUIREMENTS variable (example).
• New dependencies are only imported inside functions that use them (example).
• New or updated dependencies have been added to requirements_all.txt by running script/gen_requirements_all.py.
• New files were added to .coveragerc.

If the code does not interact with devices:

• Tests have been added to verify that the new code works.

[Censored3]

With this implemented, source is populated after a while... Maybe it's a timing issue

[rytilahti]

I thought that this shoulnd't ever happen async_update is always called at least once, but looking at it now I think this can happen when there is no active source (lines 252-253). Good catch! Could you please update the description to explain the problem you are encountering? Do you get a stacktrace?

edit: stacktrace in the linked bug report, so ignore my questions.

[rytilahti]

Could you add a single-line comment here describing the necessity of using getattr instead of regular attribute access here, then it's okay to merge.

[Censored3]

Sure - here you go. Is this comment sufficient?

[rytilahti]

That's good, thanks! I changed the title to be a bit more descriptive :-)

[Censored3]

Great, happy to help.

Thx btw for adding active source reading; really something I was missing!

[rytilahti]

Glad to hear someone else besides me is using the platform :-) But wasn't that feature always there? Or do you mean the push-based, immediate updates? I think the problem itself may be caused partially by that codepath (if the device responds no active source during the initialization, the variable will get updated first after a source changed notification is received from the device).

[Censored3]

Ah well I vaguely remember something about it being there, but at least wasn't working for my devices... Maybe the updated python-songpal dep took care of it. I'm happy either way ;-)