Open Radar

 
Summary:
If you have a newly setup device or one that has been reset, the first call to
[MIDINetworkSession defaultSession].enabled = YES;
won't take effect, the session won't be enabled. If you query the value of the property you will find it to be false. If you restart the application and try to enable the session again it will succeed, as will every other attempt until you reset the device again.

Steps to Reproduce:
Reset an iOS device, then start an application that wants to enable the [MIDINetworkSession defaultSession].

Consider the following example:

MIDIClientRef client;
MIDIPortRef inputPort;
MIDIClientCreate(CFSTR("Client"), NULL, NULL, &client);
MIDIInputPortCreate(client, CFSTR("Input Port"), NULL, NULL, &inputPort);
        MIDIPortConnectSource(inputPort, [MIDINetworkSession defaultSession].sourceEndpoint, NULL);

[MIDINetworkSession defaultSession].enabled = YES;
NSLog(@"Status: %d", [MIDINetworkSession defaultSession].enabled);

In this example I omitted the callback functions, but thats not relevant here.

Expected Results:
To be able to enable the defaultSession at the first try.

Actual Results:
If you run the provided example on a device where the defaultSession was not enabled previously (it's a newly setup device or was reset, or no MIDI application was used before) you won't be able to enable the session. The code will run, the port will open, but the app won't be able to communicate.

If you restart the app however, and in fact from that point on you can successfully enable the session until again you reset the devices settings.

Version:
iOS 7.1.2, iOS 8.0.2, iOS 8.1