Amplify.Auth.signIn() using String(format:) with mismatched type specifiers.

[kevinleadoutlabs]

Describe the bug

I'm getting these errors right after signIn executes (see below)
String(format:locale:arguments:): Provided argument types ["Swift.Double"] (with inferred specifiers ["%lf"]) do not match the format string's specifiers [Error Domain=NSCocoaErrorDomain Code=2048 "Format '%lli' does not match expected '%lf'" UserInfo={NSDebugDescription=Format '%lli' does not match expected '%lf'}]
String(format:locale:arguments:): Provided argument types ["Swift.Double"] (with inferred specifiers ["%lf"]) do not match the format string's specifiers [Error Domain=NSCocoaErrorDomain Code=2048 "Format '%lli' does not match expected '%lf'" UserInfo={NSDebugDescription=Format '%lli' does not match expected '%lf'}]
String(format:locale:arguments:): Provided argument types ["Swift.Double"] (with inferred specifiers ["%lf"]) do not match the format string's specifiers [Error Domain=NSCocoaErrorDomain Code=2048 "Format '%lli' does not match expected '%lf'" UserInfo={NSDebugDescription=Format '%lli' does not match expected '%lf'}]
String(format:locale:arguments:): Provided argument types ["Swift.Double"] (with inferred specifiers ["%lf"]) do not match the format string's specifiers [Error Domain=NSCocoaErrorDomain Code=2048 "Format '%lli' does not match expected '%lf'" UserInfo={NSDebugDescription=Format '%lli' does not match expected '%lf'}]

Somewhere it seems like you're passing Doubles into Int64 (%lli format is expected) - just a guess.

Steps To Reproduce

let signInResult = try await Amplify.Auth.signIn(
                    username: username,
                    password: password
                )

Expected behavior

no errors...

Amplify Framework Version

2.51.1

Amplify Categories

Auth

Dependency manager

Swift PM

Swift version

6.2

CLI version

N/A

Xcode version

26.0.1

Relevant log output

String(format:locale:arguments:): Provided argument types ["Swift.Double"] (with inferred specifiers ["%lf"]) do not match the format string's specifiers [Error Domain=NSCocoaErrorDomain Code=2048 "Format '%lli' does not match expected '%lf'" UserInfo={NSDebugDescription=Format '%lli' does not match expected '%lf'}]
String(format:locale:arguments:): Provided argument types ["Swift.Double"] (with inferred specifiers ["%lf"]) do not match the format string's specifiers [Error Domain=NSCocoaErrorDomain Code=2048 "Format '%lli' does not match expected '%lf'" UserInfo={NSDebugDescription=Format '%lli' does not match expected '%lf'}]
String(format:locale:arguments:): Provided argument types ["Swift.Double"] (with inferred specifiers ["%lf"]) do not match the format string's specifiers [Error Domain=NSCocoaErrorDomain Code=2048 "Format '%lli' does not match expected '%lf'" UserInfo={NSDebugDescription=Format '%lli' does not match expected '%lf'}]
String(format:locale:arguments:): Provided argument types ["Swift.Double"] (with inferred specifiers ["%lf"]) do not match the format string's specifiers [Error Domain=NSCocoaErrorDomain Code=2048 "Format '%lli' does not match expected '%lf'" UserInfo={NSDebugDescription=Format '%lli' does not match expected '%lf'}]

Is this a regression?

No

Regression additional context

No response

Platforms

No response

OS Version

26.0.1

Device

iPhone 7 Simulator

Specific to simulators

No response

Additional context

No response

[harsh62]

Some follow up quetions:

• Can you share the entire verbose log when this error happens?

• And did your sign in actually succeed?

• What kind of Auth Flow did you try? Like User Auth or SRP Auth?

• Can you share the username and password you tried?

• Any other unique setup you might have?

[kevinleadoutlabs]

That's pretty much all you get. I set breakpoints and tracked it to that specific call. None of my code is moving on either side of that call.
Signin succeeded... this is an annoyance not a critical issue
Went with whatever the new default is... I think User Auth?
Nothing special about username and password... they are authenticating. username is an email.
Nothing else unique. Tried on multiple laptops some with very fresh implementations and others where I've had some old and new libraries. same results. Not that I want to guess but... this may be doing it: func prepareJsonPayload(
username: String,
contextData: [String: String],
userPoolId: String
) throws -> String {
let timestamp = String(format: "%lli", floor(Date().timeIntervalSince1970 * 1_000))
let payload = [
"contextData": contextData,
"username": username,
"userPoolId": userPoolId,
"timestamp": timestamp
] as [String: Any]
let jsonData = try JSONSerialization.data(withJSONObject: payload)
guard let jsonString = String(data: jsonData, encoding: .utf8) else {
throw ASFError.stringConversion
}
return jsonString
}

[vincent-peng]

@harsh62 Same issue happened on our end too.

Here some insights:
• Can you share the entire verbose log when this error happens?
Exact same steps with the issue, after calling Amplify.Auth.signIn(username: username,password: password)

String(format:locale:arguments:): Provided argument types ["Swift.Double"] (with inferred specifiers ["%lf"]) do not match the format string's specifiers [Error Domain=NSCocoaErrorDomain Code=2048 "Format '%lli' does not match expected '%lf'" UserInfo={NSDebugDescription=Format '%lli' does not match expected '%lf'}]

• And did your sign in actually succeed?
Yes, Login succeed.

• What kind of Auth Flow did you try? Like User Auth or SRP Auth?
We are using SRP Auth.

[kevinleadoutlabs]

Cool glad you could repro it. I was able to pinpoint it to that code above in your library... I think you have more of these in your code as well.

[tylerjroach]

Thank you for the info. As far as I understand, there are no reports of this causing any failures, correct? Either way, we will look at resolving.

[kevinleadoutlabs]

correct. no failures.