DEBUG_ASSERT: Change Master Output to 'None'

[Uwe Klotz]

Branch: master (2.1 alpha)

I get a debug assertion when changing the Master Ouput to None:

Fatal [Main]: DEBUG ASSERT: "false" in file src/sounddevicenetwork.cpp, line 76
../mixxx_run.sh: line 32: 6450 Aborted (core dumped) "${MIXXX_DEV}/mixxx" --settingsPath "${MIXXX_CFG}" --resourcePath "${MIXXX_DEV}/res" --pluginPath "${MIXXX_PLUGINS}"

    // Create the callback function pointer.
    if (isClkRefDevice) {
        // Network device as clock Reference is not yet supported
        DEBUG_ASSERT(false);
    } else {

'None' is a valid selection and must be handled appropriately. Assertions should be used for detecting invalid program states, but must not be used for regular error handling.

[Daniel Schürmann (daschuer)]

The debug assert at this place is correct. Since I have assumed, that we will never get to this point.
We must prevent that we pick sounddevicenetwork as clock reference somewhere earlier.

[Uwe Klotz (uklotzde-deactivatedaccount)]

I disagree: "Always assert for the impossible", simple rule.

But it is possible. I described how to get to this point simply by selecting "None" in the drop down box. If the DEBUG_ASSERT is correct then we must never get there. Maybe the error has to be handled somewhere else, but something is missing here.

[Daniel Schürmann (daschuer)]

Äh, sorry. Why you disagree when we are the same opinion ;-)
This is a bug and needs to be fixed.

[Daniel Schürmann (daschuer)]

https://github.com/mixxxdj/mixxx/commit/f620e692865bf927c888c146c9993855a37d29ff

[Uwe Klotz (uklotzde-deactivatedaccount)]

Thanks for taking care, Daniel :)

Nothing serious, but the assertion indicated that Mixxx had reached an unexpected point in the code. This is a good example, why assertions are helpful for detecting unexpected behaviour or invalid code paths at runtime.

[Swiftb0y (swiftb0y)]

Mixxx now uses GitHub for bug tracking. This bug has been migrated to:
https://github.com/mixxxdj/mixxx/issues/8380