Connection state transitions directly to CONNECTED after GATT_ERROR during onServicesDiscovered.

[mobilestromer-ctrl]

Hello, what we saw is that the peripheral connection state transitions to CONNECTED before DISCONNECTED (on Android side) while a GATT_ERROR occurs during the handshake from onServicesDiscovered. What we would expect is that it transitions to DISCONNECTING/DISCONNECTED instead, so we should reliably know if the connection was properly established. Thank you!

[twyatt]

What version of Kable, and what platform?

[mobilestromer-ctrl]

We are using 0.39.2, this happens in the context of a kmm project, with the ble functionality being shared, but only when running it on Android devices. For more context, we implemented a "handshake" mechanism inside onServicesDiscovered that throws status: GATT_AUTH_FAIL(137) in case the user is not authorised to use the dongle. But after throwing this error, kable transitions to CONNECTED state, than to DISCONNECTED.

[twyatt]

Are you saying that you throw an exception from within the onServicesDiscovered lambda, and when doing so, Kable transitions to Connected state?

[mobilestromer-ctrl]

So inside the onServicesDiscovered we read a characteristic from our dongle (reading this characteristic triggers pairing with the dongle). But if the dongle is not in pairing mode, or we tap cancel on the pairing popup, reading this characteristic throws GATT_AUTH_FAIL(137) from Kable. Which is totally fine as we did not bond with the dongle. However, when throwing this error, the exposed connection state of the peripheral (dongle) also transitions first to CONNECTED than to DISCONNECTED (we expect it transitioning to DISCONNECTING/DISCONNECTED directly), which is not what we want, as the bonding process throws an error and so from our understanding the CONNECTED state should not be reached. I will atach some logs for reference:

11:25:49.801 onCharacteristicRead
service: <SERVICE_UUID>
characteristic: <CHARACTERISTIC_UUID>
status: GATT_AUTH_FAIL(137)
data: 00

11:25:49.803 Configuring characteristic observations

11:25:49.805 Connected

[twyatt]

It sounds like your device requires and/or you're performing bonding? Which is not yet supported: #111

[mobilestromer-ctrl]

I understand that bonding is not supported, but we expect a DISCONNECTING/DISCONNECTED state to be returned when an error is thrown during characteristic observations stage.

[twyatt]

we expect a DISCONNECTING/DISCONNECTED state to be returned when an error is thrown during characteristic observations stage

That's a good point. I'll try to find some time to look into it.

[mobilestromer-ctrl]

Hello, any news on the matter?