Upgrade JWT Kit to 5.2.0 with Breaking Changes Migration

[0xRohit]

Summary

This PR upgrades the JWT Kit dependency from 4.13.0 to 5.2.0 and migrates all code to use the new JWT Kit 5.x APIs. The migration maintains full backward compatibility for the OAuth authentication flow while adopting the improved security and performance features of JWT Kit 5.x.

Changes Overview

Dependencies

• Package.swift: Updated JWT Kit dependency from 4.13.0 to 5.2.0

Core OAuth Implementation

• OAuthServiceAccount.swift:

  • Migrated RSA key creation from RSAKey.private() to
    Insecure.RSA.PrivateKey(pem:)
  • Replaced JWTSigner.rs256() with JWTKeyCollection approach
  • Updated generateJWT() method to be async
  • Modified refresh() method to handle async JWT generation using Task/Promise pattern

• OAuthPayload.swift:

  • Updated verify() method signature from verify(using signer: JWTSigner) to verify(using algorithm: some JWTAlgorithm) async throws

• OAuthAccessToken.swift:

  • Added Sendable protocol conformance for Swift 6 compatibility

Code Quality Improvements

• StorageObjectAPI.swift:
  • Fixed deprecation warning by replacing body.length with body.contentLength

Testing

• CredentialTests.swift:
  • Added comprehensive JWT generation test to verify new API functionality
  • Test validates RSA key creation, JWT payload signing, and token structure

Breaking Changes

Component	Before (JWT Kit 4.x)	After (JWT Kit 5.x)
RSA Key Creation	RSAKey.private(pem:)	Insecure.RSA.PrivateKey(pem:)
JWT Signing	JWTSigner.rs256(key:).sign()	JWTKeyCollection().sign()
JWT Verification	verify(using: JWTSigner)	verify(using: JWTAlgorithm) async

Testing

• All builds pass without compilation errors or warnings
• JWT token generation functionality verified with new test
• OAuth authentication flow maintains full compatibility
• Swift 6 concurrency compliance verified

Migration Impact

For Library Users

• No breaking changes - All public APIs remain the same
• OAuth authentication continues to work identically
• Service account JWT generation maintains same behavior

For Library Maintainers

• JWT Kit 5.x provides improved security with Swift Crypto backend
• Better async/await support for modern Swift concurrency
• Enhanced type safety and performance improvements

File Changes Summary

Core/Sources/Configuration/OAuth/OAuthAccessToken.swift | 2 +-
Core/Sources/Configuration/OAuth/OAuthPayload.swift | 2 +-
Core/Sources/Configuration/OAuth/OAuthServiceAccount.swift | 53 ++++++++--------
Core/Tests/CredentialTests.swift | 64 ++++++++++++++++++-
Package.swift | 2 +-
Storage/Sources/API/StorageObjectAPI.swift | 2 +-

6 files changed, 98 insertions(+), 27 deletions(-)

Verification Steps

1. Build Verification: swift build passes cleanly
2. Test Verification: swift test passes with new JWT functionality
   test
3. API Compatibility: All existing OAuth flows work unchanged
4. Code Quality: No compiler warnings or deprecations

Type of Change

• Dependencies update
• Breaking changes migration
• Code quality improvements
• Test coverage addition

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