NearbyMessages finds messages from lost BLE devices

[pNre]

Hi, I've been noticing an odd behavior during my test of the NearbyMessages library. Here are the steps I've been following:

• Star the app
• The app starts a subscription for messages from BLE devices (an USB BLE Eddystone-EID beacon), setting deviceTypesToDiscover = kGNSDeviceUsingNearby | kGNSDeviceBLEBeacon
• subscriptionWithMessageFoundHandler is called with the expected message when the beacon is ranged
• Send the app to the background
• messageLostHandler is called with the expected message
• Power off the beacon
• Resume the app
• subscriptionWithMessageFoundHandler is called again with the same messages from the offline beacon
• messageLostHandler isn't called again

What I expect here is for subscriptionWithMessageFoundHandler to not be called again if the beacon is no longer in range. The same thing happens using the sample app from this repo.

Do you have any advice? Thanks

[dan-webb]

Hello,

I've reproduced what you're seeing, and it's a bug. I'm working on a fix, and it will ship with the next release.

A possible workaround: When your app is backgrounded, deallocate the GNSMessageManager; when it is foregrounded, re-create it. The stale beacon state is store in this object, so creating a new one will start fresh. (Use the UIApplicationDidEnterBackgroundNotification and UIApplicationWillEnterForegroundNotification notifications.)

Thanks for the bug report, and apologies for the hassle!

• Dan