[Bug]: IPeripheral's connection state is not updated after .Scan() running again

[sleushunou]

Component/Nuget

BluetoothLE Client (Shiny.BluetoothLE)

What operating system(s) are effected?

• [X] iOS (13+ supported)
• [ ] Mac Catalyst
• [ ] Android (8+ supported)

Version(s) of Operation Systems

Tested on iOS 16 iPhone 12

Hosting Model

• [ ] MAUI
• [X] Native/Classic Xamarin
• [ ] Manual

Steps To Reproduce

Run .Scan() Receive IPeripheral from result of .Scan() Run .Scan() again Try to connect to received at step 2 IPeripheral and observe IPeripheral::WhenStatusChanged()

Expected Behavior

IPeripheral::WhenStatusChanged() - status changed when peripheral is connected

Actual Behavior

IPeripheral::WhenStatusChanged() - status not changed when peripheral is connected, subscription handler is not called when BUT IBleDelegate::OnPeripheralStateChanged() - state changed when peripheral is connected ✔️

Exception or Log output

instead of logs. seems like problem is here: this.Clear(); List of cached IPeripheral's on BleManager cleared every time after starting a new scan, and when connection status is changed, BleManager calls p.ReceiveStateChange(status);, where p - another, newly created, instance of IPeripheral that refers on the same physical device, and first instance of IPeripheral does not receive state change

public IObservable<ScanResult> Scan(ScanConfig? scanConfig = null) => Observable.Create<ScanResult>(ob =>
{
    if (this.IsScanning)
        throw new InvalidOperationException("There is already an existing scan");

    this.Clear();
    ......
}

void Clear() => this.peripherals
    .Where(x => x.Value.Status != ConnectionState.Connected)
    .ToList()
    .ForEach(x => this.peripherals.TryRemove(x.Key, out var device));

void RunStateChange(CBPeripheral peripheral, bool connected, NSError? error)
{
    this.logger.PeripheralStateChange(peripheral.Identifier, connected, error?.LocalizedDescription ?? "None");

    var p = this.GetPeripheral(peripheral);
    var status = connected ? ConnectionState.Connected : ConnectionState.Disconnected;
    p.ReceiveStateChange(status);

    this.services.RunDelegates<IBleDelegate>(x => x.OnPeripheralStateChanged(p), this.logger);
}

readonly ConcurrentDictionary<string, Peripheral> peripherals = new();
Peripheral GetPeripheral(CBPeripheral peripheral) => this.peripherals.GetOrAdd(
    peripheral.Identifier.ToString(),
    x => new Peripheral(this, peripheral, this.operations, this.peripheralLogger)
);

Code Sample

    private  IDisposable _subscription;

    private async Task Test(IBleManager bleManager)
    {
        var scanResult = await bleManager
            .Scan(new ScanConfig())
            .FirstAsync()
            .ToTask()
            .ConfigureAwait(false);

        var peripheral = scanResult.Peripheral;

        var scanResult2 = await bleManager
            .Scan(new ScanConfig())
            .FirstAsync()
            .ToTask()
            .ConfigureAwait(false);

        _subscription = peripheral.WhenStatusChanged().Subscribe(OnStatusChanged);
        peripheral.Connect(new ConnectionConfig(false));
    }

    private void OnStatusChanged(ConnectionState state)
    {

    }

Code of Conduct

• [X] I have supplied a reproducible sample that is NOT FROM THE SHINY SAMPLES!
• [X] I am a Sponsor OR I am using the LATEST stable/beta version from nuget (v3.0 stable - ALPHAS are not taking issues - Sponsors can still send v2 issues)
• [X] I am Sponsor OR My GitHub account is 30+ days old
• [X] I understand that if I am checking these boxes and I am not actually following what they are saying, I will be removed from this repository!

[sleushunou]

https://developer.apple.com/library/archive/documentation/NetworkingInternetWeb/Conceptual/CoreBluetooth_concepts/BestPracticesForInteractingWithARemotePeripheralDevice/BestPracticesForInteractingWithARemotePeripheralDevice.html#//apple_ref/doc/uid/TP40013257-CH6-SW1

According to the Apple guide, scanning should be active only when it is really needed to save battery power.

business case: Once we have found all of our expected devices, we stop scanning. But, if we want to add another device to the device list, we run the scan again.

[sleushunou]

Are you actually connected to the devices while running a scan though?

usually not, but a business case is theoretically possible when we are connected to one device and are trying to find a second one

[aritchie]

Please read the previous issue. Don't keep a reference to peripheral across scans unless they're connected