Implement AutoFill Credential Provider Extension in iOS14 - swift

Question

I'm trying to implement the AutoFill Credential Provider Extension, however I'm having some problems following the video of the WWDC where they presented this feature.
Is there someone that has already done it that could help me?
Right now, I added the AutoFill Credential Provider capability as well as the AutoFill Credential Provider extension, which right now looks like this:
import AuthenticationServices
class CredentialProviderViewController: ASCredentialProviderViewController {
override func prepareCredentialList(for serviceIdentifiers: [ASCredentialServiceIdentifier]) {
}
override func provideCredentialWithoutUserInteraction(for credentialIdentity: ASPasswordCredentialIdentity) {
let databaseIsUnlocked = true
if (databaseIsUnlocked) {
let passwordCredential = ASPasswordCredential(user: "j_appleseed", password: "apple1234")
self.extensionContext.completeRequest(withSelectedCredential: passwordCredential, completionHandler: nil)
} else {
self.extensionContext.cancelRequest(withError: NSError(domain: ASExtensionErrorDomain, code:ASExtensionError.userInteractionRequired.rawValue))
}
}
override func prepareInterfaceToProvideCredential(for credentialIdentity: ASPasswordCredentialIdentity) {
}
#IBAction func cancel(_ sender: AnyObject?) {
self.extensionContext.cancelRequest(withError: NSError(domain: ASExtensionErrorDomain, code: ASExtensionError.userCanceled.rawValue))
}
#IBAction func passwordSelected(_ sender: AnyObject?) {
let passwordCredential = ASPasswordCredential(user: "j_appleseed", password: "apple1234")
self.extensionContext.completeRequest(withSelectedCredential: passwordCredential, completionHandler: nil)
}
}
All of this was pre-written, but on the line
} else {
self.extensionContext.cancelRequest(withError: NSError(domain: ASExtensionErrorDomain, code:ASExtensionError.userInteractionRequired.rawValue))
}
I get the yellow warning "Will never be executed". Can someone help me understand how this extension works? Or is there a guide that I can follow? I can't find any nor on this website nor elsewhere on the internet.

Answer 1

There's not much in the way of documentation or sample code, and no tutorials that I can find. Essentially there is the video you already linked to, and the documentation for the ASCredentialProviderViewController class, which is here:
https://developer.apple.com/documentation/authenticationservices/ascredentialproviderviewcontroller?language=objc
But in your code, it should be quite clear why the line you quoted will never be executed. See my comments below:
let databaseIsUnlocked = true
if (databaseIsUnlocked) //this is always true, because you've just set it to be true
{
let passwordCredential = ASPasswordCredential(user: "j_appleseed", password: "apple1234")
self.extensionContext.completeRequest(withSelectedCredential: passwordCredential, completionHandler: nil)
} else { //so there is no "else"
self.extensionContext.cancelRequest(withError: NSError(domain: ASExtensionErrorDomain, code:ASExtensionError.userInteractionRequired.rawValue))
}
Presumably Apple thought people might want to replace "databaseIsUnlocked = true" with a check to see if their database is unlocked. If that doesn't apply to you, you can ignore that bit.