registry: fix code quality issues flagged by sonarqube static analysis

[iamabhilaksh]

registry: fix code quality issues flagged by sonarqube static analysis

Summary

Fixes code quality issues in the registry module flagged by static analysis tools. The changes
reduce code duplication, improve resource safety, clarify intent through inline comments, and
eliminate a credential-scanning false positive in tests. No functional behaviour is changed.

Changes

Modified Files

• AbstractRegistry.java — Remove redundant abstract method declarations (6 lines removed)

  • getAuthUsername() and getAuthToken() were re-declared with @Override on AbstractRegistry
    but are already defined on the AuthProvider interface it implements; the duplicate declarations
    are removed

• BearerTokenExchange.java — Reduce nesting, add constants, fix comment (72 lines changed)

  • Added TOKEN_FIELD = "token" and ACCESS_TOKEN_FIELD = "access_token" constants to eliminate
    magic strings referenced in multiple places
  • Extracted inner try (CloseableHttpResponse ...) block into a private executeTokenRequest()
    method, removing one level of nesting from getBearerToken()
  • Fixed split comment // Token can be in ... (GCP Artifact Registry) \n// field — reworded
    into a single line within the 100-char checkstyle limit:
    // Token field is "token" (Docker Hub, AWS ECR) or "access_token" (GCP Artifact Registry)

• LayerExtractor.java — Improve executor error handling and merge duplicate conditions
  (70 lines changed)

  • Wrapped executor.submit(...) in a try-catch block that closes PipedOutputStream and
    throws UnknownException if submission fails, preventing the caller from blocking indefinitely
    on a pipe that will never be written to
  • Merged two consecutive if (...) continue; checks into a single combined condition with ||,
    eliminating the duplicate continue statement flagged by static analysis

• OciRegistryClient.java — Extract methods, add constant, restore comments (134 lines changed)

  • Added MANIFEST_ERROR_FORMAT constant to avoid repeating the identical String.format template
    across the three HTTP-error branches (404, 401, default)
  • Extracted fetchManifest() internals into:
    • buildFetchManifestRequest() — builds the HttpGet with auth and Accept headers
    • executeFetchManifestRequest() — executes, checks status, enforces size limit, and parses
    • computeManifestDigest() — returns the Docker-Content-Digest header value or computes
      SHA-256 from the response body when the header is absent (e.g. AWS ECR)
  • Simplified nested if (reference.startsWith(DIGEST_PREFIX)) { if (!reference.equals(...)) }
    into a single combined condition
  • Restored three clarifying comments that were dropped during extraction:
    • // Check manifest size limit to prevent resource exhaustion
    • // Validate digest if fetching by digest reference (e.g., repo@sha256:...)
    • // Docker-Content-Digest header may be absent (e.g., AWS ECR); calculate from response body
  • Now routes all HTTP error status codes through the existing mapHttpStatusToException() helper
    instead of repeating the if/else chain

• OciRegistryClientTest.java — Replace hardcoded Base64 credential with dynamic encoding
  (6 lines changed)

  • "Basic dXNlcjp0b2tlbg==" was a hardcoded Base64-encoded credential triggering secret-scanning
    false positives; replaced with "Basic " + Base64.getEncoder().encodeToString(...) so the
    value is computed at runtime

---

Testing Details

Unit Tests (136/136 passed)

---

References

• OCI Distribution Specification
• go-containerregistry reference implementation —
  used to cross-verify manifest size limit (100 MB), digest validation behaviour, and the
  Docker-Content-Digest fallback pattern

[codecov-commenter]

Codecov Report

❌ Patch coverage is 77.77778% with 18 lines in your changes missing coverage. Please review.
✅ Project coverage is 82.33%. Comparing base (03f6a8c) to head (5b34008).

Files with missing lines	Patch %	Lines
...ce/multicloudj/registry/driver/LayerExtractor.java	58.33%	9 Missing and 1 partial ⚠️
...multicloudj/registry/driver/OciRegistryClient.java	83.78%	4 Missing and 2 partials ⚠️
...lticloudj/registry/driver/BearerTokenExchange.java	90.00%	0 Missing and 2 partials ⚠️

❌ Your patch status has failed because the patch coverage (77.77%) 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              @@
##               main     #319      +/-   ##
============================================
- Coverage     82.36%   82.33%   -0.04%     
- Complexity      625      626       +1     
============================================
  Files           191      191              
  Lines         11503    11504       +1     
  Branches       1525     1521       -4     
============================================
- Hits           9475     9472       -3     
- Misses         1357     1361       +4     
  Partials        671      671              

Flag	Coverage Δ
unittests	82.33% <77.77%> (-0.04%)	⬇️

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