[TASK] Phase 2 - Matrix Build Strategy for Multi-Java Releases

Description

Implement matrix build strategy to enable a single release workflow run to build and deploy multiple Java version variants in parallel using GitHub Actions.

Epic: #34484 (Java Version Override Support in CI/CD)

Dependencies:

• #34586 (Phase 1 - Basic override support) - In PR review (#34612)
• #34637 (Phase 1.5 - Sequential dual release) - Pending

Background

GitHub Actions has a fundamental limitation: cannot use strategy.matrix with uses: (reusable workflows). This requires careful architectural decisions about how to implement parallel multi-Java builds.

Implementation Options

Four approaches are viable, each with different trade-offs:

Option	Approach	Parallelism	Complexity	Effort
A	Job Duplication	✅ Yes	Medium	Medium
B1	Sequential Wrapper	❌ No (~2x time)	Low	Low
B2	Parallel Wrapper	✅ Yes	Low	Low-Medium
C	True Matrix (Composite Actions)	✅ Yes	High	High

Recommended: Option B2 (Parallel Wrapper) - best balance of parallelism with minimal refactoring.

Decision Document

📄 See linked Google Doc for detailed analysis and decision gathering

Acceptance Criteria

• Architecture decision documented and approved
• Matrix configuration design finalized (2 variants max: default + alternate)
• Release workflow (cicd_6-release.yml) supports enable-matrix input
• Parallel execution of Java variant builds when matrix enabled
• Output aggregation for Docker tags (Slack notification)
• Shared steps run once (SBOM, plugin update, labels)
• Backward compatibility: enable-matrix: false works identically to current
• Optional: Extend to trunk/nightly workflows (manual dispatch)
• Optional: Label-based matrix trigger for PR workflow (java-matrix label)
• Documentation created (docs/JAVA_MATRIX_BUILD_GUIDE.md)

Priority

Medium

Additional Context

Key Files to Modify

• .github/workflows/cicd_6-release.yml - Add matrix inputs
• .github/workflows/cicd_comp_build-phase.yml - Support matrix-derived inputs
• .github/workflows/cicd_comp_deployment-phase.yml - Support matrix-derived inputs
• .github/workflows/cicd_comp_release-phase.yml - Add Artifactory version suffix
• .github/actions/core-cicd/deployment/deploy-jfrog/action.yml - Add version suffix input

Simplified Configuration (2 variants only)

inputs:
  enable-matrix:
    description: 'Enable dual Java version build'
    type: boolean
    default: false
  alternate-java-version:
    description: 'Alternate Java version (SDKMAN format)'
    type: string
    default: '25.0.1-open'
  alternate-artifact-suffix:
    description: 'Suffix for alternate Java artifacts'
    type: string
    default: '-java25'

Related Issues

• Epic: #34484
• Phase 1: #34586 (PR #34612)
• Phase 1.5: #34637

Start by reviewing the four implementation options and the linked decision document, then inspect .github/workflows/cicd_6-release.yml and the listed build, deployment, release, and deploy-jfrog files. Done means an approved architecture, parallel Java variants with aggregated Docker tags, shared steps run once, enable-matrix disabled remains backward compatible, and the Java matrix guide is created.