Swift runtime failure: Unexpectedly found nil while unwrapping an Optional value

[LiveSmartDev]

I found this issue with older SesameSDK too.

[takao-akiyoshi]

Unexpectedly found nil while unwrapping an Optional value also occurs elsewhere in the SDK by calling CHDeviceManager.getCHDevices.
And quite often this crash occurs!

[takao-akiyoshi]

I faced same error at other point too.

[JOiCh]

We have added error handling to ensure that the function does not crash due to nil values when unwrapping optional values. Upon preliminary investigation, it appears that there may be an issue with the return values from devices. Our team is actively investigating and debugging this issue. We sincerely apologize for the wait and appreciate your patience.

[takao-akiyoshi]

Thanks for the reply!

I confirmed you added nil handling at getCHDevices. (1c25196 )
I'll test with latest SDK later.

I guess it needs to add nil handling at readHistoryCommand and toCHDeviceKey as same as the above commit.(#52 (comment), #52 (comment))
Would you check readHistoryCommand and toCHDeviceKey ?

[takao-akiyoshi]

I found a same error at CHDeviceManager.parse too.
I think it's better to make sure not to create Device instance without deviceId than to add nil handling at many points.

[tangguoEddy]

We have not been successful in reproducing the aforementioned issue. Would it be possible for you to proffer additional information?

[takao-akiyoshi]

I guess these crash has been occurred only calling getCHDevices .
But, it seems to occur at a high frequency at certain times and sometimes works consistently.
Thus, would you call the method again and again until you get this issue?

Perhaps it saves wrong device data (such as no DeviceID) to CoreData sometimes in SDK.

[tangguoEddy]

Our appreciation for the intelligence you've conveyed is abundant; we shall perpetuate our keen surveillance. Additionally, if your acumen purveys any enhancements with regards to our coding, we earnestly encourage you to submit a pull request to Candy House.

[takao-akiyoshi]

I would like to submit a pull request if I could, but it needs understanding to specifications to BLE message between SESAME device and SDK.　(I can't know these specifications)
Cuz I guess the cause of this issue is such as followings.

• Incorrect data received from the device.
• Lack of error handling when incorrect data is received.

[takao-akiyoshi]

The cause of this issue is probably accessing CoreData at same time.
For example, it calls CHDeviceManager.shared.receiveCHDeviceKeys and immediately after calls CHDeviceManager.shared.getCHDevices with multi thread.

Thus, I think it can solve on a App-side.
But, this case is parse error for SESAME histories data. Thus, it needs to fix on SDK-side

[tangguoEddy]

The cause of this issue is probably accessing CoreData at same time. For example, it calls CHDeviceManager.shared.receiveCHDeviceKeys and immediately after calls CHDeviceManager.shared.getCHDevices with multi thread.

Thus, I think it can solve on a App-side. But, this case is parse error for SESAME histories data. Thus, it needs to fix on SDK-side

Thank you for your feedback. We have also noticed this thread safety issue with CoreData, and will schedule a fix.

[takao-akiyoshi]

It seems to get history data which type is "0".

[takao-akiyoshi]

@tangguoEddy
Would you review above PR and merge if you approve it.