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BR: MidiOutput::createNewDeviceleaks devices if you use the same name twice

#1

MidiOutput::createNewDeviceleaks devices if you use the same name twice.

    o1 = juce::MidiOutput::createNewDevice ("Command8 Port 1");
    o2 = juce::MidiOutput::createNewDevice ("Command8 Port 1");

The second call returns nullptr but the MIDI port is created, and there is no way to shut it down now (except exit the process).

#2

Which platform are you seeing this on? I don’t get this behaviour on Big Sur.

#3

I’m on Big Sur as well. What I am seeing is:

auto err = CreatorFunctionsToUse::createSource (ump::PacketProtocol::MIDI_1_0, client, name.cfString, &endpoint);

This succeeds and creates a new midi port and places it in endpoint

if (! CHECK_ERROR (MIDIObjectSetIntegerProperty (endpoint, kMIDIPropertyUniqueID, (SInt32) deviceIdentifier)))

This fails, because the ID isn’t unique. And then the function bails out, leaking the endpoint

My “fix” to get me up and running:

        for (int i = 0; i < 10; i++)
        {
            if (CHECK_ERROR (MIDIObjectSetIntegerProperty (endpoint, kMIDIPropertyUniqueID, (SInt32) deviceIdentifier + i)))
                break;

            if (i == 9)
                return {};
        }

I’m not sure if you actually want to allow multiple MIDI devices with the same name. I had another program that failed when accessing ports with the same name, so I was just creating a quick test program to generate the ports, since I don’t have two of the same midi devices. I was surprised to see the two ports in the other program, yet get a nullptr for the second device in juce.

#4

Thanks for providing more details. I still can’t reproduce the issue by creating multiple devices with the same name (Big Sur Beta 11.3) but I can see how endpoints/ports might be leaked if an error is emitted during initialisation of a MidiInput or MidiOutput.

I’ve added a potential fix for the issue here:

Please let me know if this patch doesn’t resolve the issue for you, and I’ll take another look.

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