Add cache and parallel run to Git Count Contributors

[attiasas]

feat(git): Add parallel scanning and caching to Git Count Contributors

Summary

Introduces parallel repository scanning and a file-based cache layer to the git count-contributors command, significantly improving performance for large organizations with many repositories. Repositories are now scanned concurrently (configurable via --threads, default 10) and results are cached to disk (configurable via --cache-validity, default 3 days) to avoid redundant API calls on repeated runs.

Changes

• Parallel scanning: Refactored scanAndCollectCommitsInfo to scan repositories concurrently using gofrog/parallel.Runner. Each repo is scanned independently, and results are merged after all tasks complete.
• File-based cache: New cache.go module persists per-repo scan results as JSON files under ~/.jfrog/contributors-cache/<hash>/. Cache entries are keyed by a SHA256 hash of (scm-type, scm-api-url, owner, months) to avoid collisions. Writes are atomic (tmp + rename).
• New CLI flags:
  • --cache-validity — number of days a cached result remains valid (0 = skip cache, default 3).
  • --threads — number of parallel threads for scanning (default 10).
• Result types: Introduced repoScanResult and vcsServerScanResult structs to cleanly aggregate parallel results, along with mergeContributors, mergeDetailedContributors, and mergeDetailedRepos helper functions.
• Utility: Added GetContributorsCacheDir() in utils/paths.go.
• Tests: Added unit tests for cache round-trip, expiry, merge helpers, and parallel scanning via a new mockVcsClient test double.

Files changed

File	Status
cli/docs/flags.go	Modified — new CacheValidity, GitThreads flags
cli/gitcommands.go	Modified — parse new flags into params
commands/git/contributors/cache.go	Added — cache read/write/sanitize logic
commands/git/contributors/cache_test.go	Added — cache unit tests
commands/git/contributors/countcontributors.go	Modified — parallel scan, result structs, merge helpers
commands/git/contributors/countcontributors_test.go	Modified — merge and parallel scan tests
commands/git/contributors/mock_vcs_client_test.go	Added — full VcsClient mock for tests
utils/paths.go	Modified — GetContributorsCacheDir helper

Testing

• New unit tests cover cache write/read, cache expiry, zero-max-age bypass, missing cache files, all three merge helpers (empty src, non-overlapping, collision), and end-to-end parallel scanning with a mock VCS client.
• Existing tests continue to pass.

Notes

• Cache entries use the same months parameter in the key, so changing --months automatically invalidates stale cache.
• Setting --cache-validity 0 fully bypasses caching (no file I/O at all).

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• The pull request is targeting the dev branch.
• The code has been validated to compile successfully by running go vet ./....
• The code has been formatted properly using go fmt ./....
• All static analysis checks passed.
• All tests have passed. If this feature is not already covered by the tests, new tests have been added.
• Updated the Contributing page / ReadMe page / CI Workflow files if needed.
• All changes are detailed at the description. if not already covered at JFrog Documentation, new documentation have been added.

[github-actions]

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