EQ shelf controls leaked when no sound IO or broadcast is configured

[ronso0]

Bug Description

warning [Main] The following 2 controls were leaked:
warning [Main] "[Mixer Profile]" "HiEQFrequency" QObject(0x0)
warning [Main] "[Mixer Profile]" "LoEQFrequency" QObject(0x0)

I noticed this repeatedly, now I managed to reproduce it:

• get warning that previous sound device for Main is n/a

  Mixxx was unable to open all the configured sound devices.

• click Reconfigure
• (no selection for Main), click Okay (or Apply + Okay)
• close Mixxx

Otoh, if I select a valid device, Apply/Okay, then clear the Main output, controls are not leaked :shrug:

FWIW making the controls std::unique_ptr<ControlPotmeter> has no effect. https://github.com/mixxxdj/mixxx/blob/8f647908af460e53fe8a860b6ce0964a93a55112/src/effects/effectsmanager.h#L115-L116

Version

at least 2.4 and later

OS

No response

[ronso0]

It seems the leaked controls are a side effect. After this

• click Reconfigure
• (no selection for Main), click Okay (or Apply + Okay)

we should actually see a the next dialog "Mixxx was configured without any output sound devices."

Conclusion:

Apply doesn't apply what we see Sound preferences, or rather the internal state is not displayed in the GUI, like missing but still 'configured' devices are not displayed in the comboboxes. edit: not quite, it's just that without changes (accept no main output) the 'modified' flag is still false and slotApply() does nothing.

Might be related to #6077

[ronso0]

(still no clue how that relates to the EQ controls)

[ronso0]

It seems the leaked controls are a side effect. After this

• click Reconfigure
• (no selection for Main), click Okay (or Apply + Okay)

FYI this also seems to be the reason why sometimes tracks don't load (overview progress stuck).

[daschuer]

13312 and #13333 are merged. Can we consider this one as fixed?

[ronso0]

13333 is unrelated, and #13312 only avoids the problematic situation.

I prefer to leave this open so someone may take a look and maybe finds the root cause. I suspect it's some missing nullptr check or something related to the main output and/or the output effect chain in EngineMixer.