fix(auth): hostedui extract error_description query pararm

[atierian]

Issue #

• Not getting correct error message from Google signin. #3176

Description

If an error query parameter is included in the HostedUI callback, we currently throw a .service error with the value of the error key, omitting important information that may be needed by the caller. With this change, we now attempt to extract and use the value from error_description; if it doesn't exist, we fall back to the error we know is there. The fall back to error is necessary because error_description is optional according to the spec.

This change brings Amplify Swift in parity with Android, Flutter, and JS.

• Amplify Android
• Amplify Flutter
• Amplify JS

In the linked issue, we can see a specific use case the current behavior is blocking - client side logic based on information contained in an error thrown by a PreSignUp_ExternalProvider Lambda trigger. [Service Documentation]

Testing

In addition to the added test cases, this change was manually tested with a PreSignUp Lambda trigger:

exports.handler = (event, context, callback) => {
    const payload = JSON.stringify(
        { code: "409", custom_code: "002", message: "<placeholder>" }
    );
    const error = Error(payload);
    callback(error, event);
};

and the following client side code:

do {
    _ = try await Amplify.Auth.signInWithWebUI(
        for: .google, // this can be any social provider
        presentationAnchor: window
    )
} catch let error as AuthError {
>> breakpoint
} catch {
    print("Unexpected error: \(error)")
}

Breaking in the first catch block and po'ing the error -

Targeting v2.16.0 (current latest release), we see:

(lldb) po error
▿ AuthError: invalid_request
Recovery suggestion: Received an error message from the service
  ▿ service : 3 elements
    - .0 : "invalid_request"
    - .1 : "Received an error message from the service"
    - .2 : nil

Targeting branch hostedui_errordescription, we see:

(lldb) po error
▿ AuthError: invalid_request PreSignUp+failed+with+error+{"code":"409","custom_code":"002","message":"<placeholder>"}.+
Recovery suggestion: Received an error message from the service
  ▿ service : 3 elements
    - .0 : "invalid_request PreSignUp+failed+with+error+{\"code\":\"409\",\"custom_code\":\"002\",\"message\":\"<placeholder>\"}.+"
    - .1 : "Received an error message from the service"
    - .2 : nil

General Checklist

• Added new tests to cover change, if needed
• Build succeeds with all target using Swift Package Manager
• All unit tests pass
• All integration tests pass
• Security oriented best practices and standards are followed (e.g. using input sanitization, principle of least privilege, etc)
• Documentation update for the change if required
• PR title conforms to conventional commit style
• New or updated tests include Given When Then inline code documentation and are named accordingly testThing_condition_expectation()
• If breaking change, documentation/changelog update with migration instructions

By submitting this pull request, I confirm that my contribution is made under the terms of the Apache 2.0 license.

[codecov-commenter]

Codecov Report

Merging #3183 (a124bd5) into main (9d6fa8b) will increase coverage by 13.55%.
Report is 21 commits behind head on main.
The diff coverage is 0.00%.

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@@             Coverage Diff             @@
##             main    #3183       +/-   ##
===========================================
+ Coverage   50.61%   64.17%   +13.55%     
===========================================
  Files         385     1067      +682     
  Lines        7203    36132    +28929     
===========================================
+ Hits         3646    23186    +19540     
- Misses       3557    12946     +9389     

Flag	Coverage Δ
API_plugin_unit_test	66.52% <ø> (?)
AWSPluginsCore	69.55% <ø> (?)
Amplify	48.01% <ø> (-0.02%)	⬇️
Analytics_plugin_unit_test	86.39% <ø> (?)
Auth_plugin_unit_test	74.54% <0.00%> (?)
CoreMLPredictions_plugin_unit_test	59.44% <ø> (?)
DataStore_plugin_unit_test	80.09% <ø> (?)
Geo_plugin_unit_test	54.06% <ø> (?)
Logging_plugin_unit_test	62.61% <ø> (ø)
Predictions_plugin_unit_test	35.17% <ø> (?)
PushNotifications_plugin_unit_test	69.43% <ø> (ø)
Storage_plugin_unit_test	54.10% <ø> (?)
unit_tests	64.17% <0.00%> (+13.55%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files Changed	Coverage Δ
.../HostedUI/HostedUIASWebAuthenticationSession.swift	0.00% <0.00%> (ø)

... and 682 files with indirect coverage changes

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[harsh62]

LGTM