iOS Passcode fallback never presented after failed TouchID

[CAJazzer]

Using the Demo app on my iOS device, the "verify with passcode fallback" call simply reverts to the catch alert() in doVerifyFingerprint() after 3 failed attempts using touch. No err is displayed (undefined), only the title and okButtonText.
my iOS version: 12.1.3

[EddyVerbruggen]

I just tested the embedded demo app on my iPad Pro and it behaves as expected: after failing to scan the finger 3 times the promise is rejected. Can you give it a try?

[CAJazzer]

Thanks,

Same results.

I downloaded (cloned) the demo, then used Xcode to set a valid certificate and run the project on my iPhone 6s & on my iPad Air.

The problem is I never get the passcode screen.

Using the “verify with passcode” button, after 3 tries all I get is the alert dialog:

Biometric ID NOT
OK / canceled

Mmkay

"Never get the passcode fallback"

[marcocasadio]

hi, the same for me

[bradmartin]

I looked into this. Might need to use the DeviceOwnerAuthentication of LAPolicy for the passcode fallback. Not 100% certain on this ATM.

[EddyVerbruggen]

I've just tested with Face ID on my iPhone X and it seems to work as expected. The only thing I can think of is this check failing so it fell through to the 'verify with custom callback' method.

So I've applied a small change where this fall through will still trigger the passcode fallback by applying the policy @bradmartin suggested.