Improve checkUserNameValidity method in SelfRegistrationMgtClient

[amanda-ariyaratne]

Proposed changes in this pull request

This PR updates the SelfRegistrationMgtClient to ensure that tenant-qualified usernames are converted to tenant-aware usernames before being processed.
If not, post call [1] returns a 400 Bad Request because isExistingUser method in kernel is called with the tenant appended username [2]. Consequently, the tenant appended username is passed to [3]. Therefore, the tenant appended username is searched in the database which returns an empty results set [4]. But if the tenant name is removed from the username, an existing user can be found.

[1] https://github.com/wso2/carbon-identity-framework/blob/master/components/identity-mgt/org.wso2.carbon.identity.mgt.endpoint.util/src/main/java/org/wso2/carbon/identity/mgt/endpoint/util/client/SelfRegistrationMgtClient.java#L286

[2] https://github.com/wso2-extensions/identity-governance/blob/master/components/org.wso2.carbon.identity.recovery/src/main/java/org/wso2/carbon/identity/recovery/signup/UserSelfRegistrationManager.java#L1401

[3] https://github.com/wso2/carbon-kernel/blob/4.10.x/core/org.wso2.carbon.user.core/src/main/java/org/wso2/carbon/user/core/common/AbstractUserStoreManager.java#L6650

[4] https://github.com/wso2/carbon-kernel/blob/314e0e33e824c57173bfcbbf82ab831b5e6d075d/core/org.wso2.carbon.user.core/src/main/java/org/wso2/carbon/user/core/jdbc/UniqueIDJDBCUserStoreManager.java#L1418

Related Issues

• "Display message if username unavailable" config is hidden in the self registration configs product-is#22407

When should this PR be merged

[Please describe any preconditions that need to be addressed before we
can merge this pull request.]

Follow up actions

[List any possible follow-up actions here; for instance, testing data
migrations, software that we need to install on staging and production
environments.]

Checklist (for reviewing)

General

• Is this PR explained thoroughly? All code changes must be accounted for in the PR description.
• Is the PR labeled correctly?

Functionality

• Are all requirements met? Compare implemented functionality with the requirements specification.
• Does the UI work as expected? There should be no Javascript errors in the console; all resources should load. There should be no unexpected errors. Deliberately try to break the feature to find out if there are corner cases that are not handled.

Code

• Do you fully understand the introduced changes to the code? If not ask for clarification, it might uncover ways to solve a problem in a more elegant and efficient way.
• Does the PR introduce any inefficient database requests? Use the debug server to check for duplicate requests.
• Are all necessary strings marked for translation? All strings that are exposed to users via the UI must be marked for translation.

Tests

• Are there sufficient test cases? Ensure that all components are tested individually; models, forms, and serializers should be tested in isolation even if a test for a view covers these components.
• If this is a bug fix, are tests for the issue in place? There must be a test case for the bug to ensure the issue won’t regress. Make sure that the tests break without the new code to fix the issue.
• If this is a new feature or a significant change to an existing feature? has the manual testing spreadsheet been updated with instructions for manual testing?

Security

• Confirm this PR doesn't commit any keys, passwords, tokens, usernames, or other secrets.
• Are all UI and API inputs run through forms or serializers?
• Are all external inputs validated and sanitized appropriately?
• Does all branching logic have a default case?
• Does this solution handle outliers and edge cases gracefully?
• Are all external communications secured and restricted to SSL?

Documentation

• Are changes to the UI documented in the platform docs? If this PR introduces new platform site functionality or changes existing ones, the changes should be documented.
• Are changes to the API documented in the API docs? If this PR introduces new API functionality or changes existing ones, the changes must be documented.
• Are reusable components documented? If this PR introduces components that are relevant to other developers (for instance a mixin for a view or a generic form) they should be documented in the Wiki.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[jenkins-is-staging]

PR builder started
Link: https://github.com/wso2/product-is/actions/runs/13259538254

[codecov]

Codecov Report

Attention: Patch coverage is 0% with 1 line in your changes missing coverage. Please review.

Project coverage is 46.88%. Comparing base (7dcc4ab) to head (8c7a03d).
Report is 27 commits behind head on master.

Files with missing lines	Patch %	Lines
...ndpoint/util/client/SelfRegistrationMgtClient.java	0.00%	1 Missing ⚠️

❌ Your patch status has failed because the patch coverage (0.00%) is below the target coverage (80.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@             Coverage Diff              @@
##             master    #6480      +/-   ##
============================================
- Coverage     47.03%   46.88%   -0.15%     
- Complexity    15219    15319     +100     
============================================
  Files          1748     1748              
  Lines        105562   106576    +1014     
  Branches      19415    19697     +282     
============================================
+ Hits          49646    49972     +326     
- Misses        48879    49500     +621     
- Partials       7037     7104      +67     

Flag	Coverage Δ
unit	30.48% <0.00%> (+0.02%)	⬆️

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

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[jenkins-is-staging]

PR builder completed
Link: https://github.com/wso2/product-is/actions/runs/13259538254
Status: success

[jenkins-is-staging]

Approving the pull request based on the successful pr build https://github.com/wso2/product-is/actions/runs/13259538254