turn getRetiringFederationSize to return an optional

[julianlen]

Description

Motivation and Context

How Has This Been Tested?

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• I have updated the documentation accordingly.
• Tests for the changes have been added (for bug fixes / features)
• Requires Activation Code (Hard Fork)

• Other information:

[github-actions]

Dependency Review

✅ No vulnerabilities or license issues or OpenSSF Scorecard issues found.

Scanned Files

None

[Copilot]

Pull request overview

This PR refactors the getRetiringFederationSize() method to return an Optional<Integer> instead of a primitive int, eliminating the need to use magic number -1 to represent a non-existent retiring federation. The change improves type safety and makes the API more explicit about the possibility of absent values.

Key Changes:

• Modified the return type of getRetiringFederationSize() from int to Optional<Integer> across the interface and implementation layers
• Updated all test cases to verify optional emptiness instead of checking for the magic number response code
• Added proper unwrapping of the Optional at the Bridge layer boundary, converting back to the magic number for backward compatibility

Reviewed changes

Copilot reviewed 8 out of 8 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
FederationSupport.java	Updated interface signature to return Optional<Integer>
FederationSupportImpl.java	Simplified implementation to return Optional directly instead of falling back to error code
BridgeSupport.java	Updated return type to propagate Optional<Integer>
Bridge.java	Added unwrapping logic with fallback to FEDERATION_NON_EXISTENT code for backward compatibility
FederationSupportImplTest.java	Updated assertions to check for empty Optional instead of error code
BridgeSupportTest.java	Updated mock setup to return Optional
BridgeSupportIT.java	Updated integration test assertions to verify Optional presence/absence
BridgeIT.java	Updated mock to return Optional.of(1234)

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[jeremy-then]

LGTM.

[julia-zack]

left one super minor comment

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
100.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud