The error "TOO MANY OPEN CONNECTIONS" is returned in onDeviceFailedToConnect

[LuoPeiQin]

Reproduction environment: Phone: Google Pixel 6 (other Google phones should be the same) Android version: Android 14

Reproduction steps: Method One:

1. Connect to a Bluetooth device and disconnect after ten seconds;
2. Wait ten seconds and then reconnect to this Bluetooth device, then loop steps 1 and 2;
3. After repeating steps 1 and 2 about twenty times, the "TOO MANY OPEN CONNECTIONS" message will appear, and at this point, no Bluetooth devices can be connected unless Bluetooth or the App is restarted; Method Two:
4. Simultaneously connect multiple devices and disconnect after ten seconds;
5. Reconnect multiple devices and repeat steps 1 and 2;
6. The issue can be reproduced within about five minutes;

I did not encounter this problem on an OPPO phone with the latest Android 15 system. Could this issue be related to any recent code changes by Google? How should I resolve this issue?

I am eagerly awaiting replies from everyone and the author. Thank you very much.

[LuoPeiQin]

After the issue occurred, I checked the Heap Dump of the Profiler and found that all BleManager instances were held by BluetoothGatt, but in fact, the disconnect calls were all BleManager.

[philips77]

Hi, Do you know what type is BleManagerHandler$4 exactly? This seems to be a list / map holding instances of BluetoothGatt objects.

[LuoPeiQin]

	private final BluetoothGattCallback gattCallback = new BluetoothGattCallback() {

		@Override
		public void onConnectionStateChange(@NonNull final BluetoothGatt gatt,
											final int status, final int newState) {
			log(Log.DEBUG, () ->
					"[Callback] Connection state changed with status: " + status +
							" and new state: " + newState + " (" + ParserUtils.stateToString(newState) + ")");

			if (status == BluetoothGatt.GATT_SUCCESS && newState == BluetoothProfile.STATE_CONNECTED) {
				// Sometimes, when a notification/indication is received after the device got
				// disconnected, the Android calls onConnectionStateChanged again, with state
				// STATE_CONNECTED.
				// See: https://github.com/NordicSemiconductor/Android-BLE-Library/issues/43
				if (bluetoothDevice == null) {
					Log.e(TAG, "Device received notification after disconnection.");
					log(Log.DEBUG, () -> "gatt.close()");
					try {
						gatt.close();
					} catch (final Throwable t) {
						// ignore
					}
					return;
				}

After comparative analysis, it was found that BleManagerHandler$4 corresponds to the code mentioned above, but the specific cause has yet to be determined.

Thank you very much for providing such an excellent open-source library.