chore(ci): add concurrency control to all workflows#56
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Why: org-wide CI is queue-bound — 93 jobs perpetually queued across
the org, oldest 23 hours old on spar, ~30-40% of compute spent on
runs against superseded commits. Adding workflow-level concurrency
cancels superseded PR runs (the cheapest, lowest-risk fix) and is a
prerequisite for the runner-migration work tracked separately.
What: a single workflow file in this repo, `.github/workflows/ci.yml`.
Default variant — group by workflow + head_ref (or ref on non-PR
events), cancel-in-progress only on `pull_request` events. The
sbom/provenance jobs in this workflow are gated on
`github.ref == 'refs/heads/main'`; the conditional cancel
(`${{ github.event_name == 'pull_request' }}`) leaves them untouched
on push-to-main while still cancelling stale PR runs.
Classification:
- ci.yml → default variant (filename not in the
release/compliance/sign keyword list; main-only attestation jobs
are protected by the conditional cancel-in-progress).
Out of scope (per the brief): runner migration, job parallelisation,
cache strategy, permissions hardening — tracked separately, depend
on this PR landing first.
Verification:
- YAML parses (python -c "import yaml; yaml.safe_load(...)").
- Diff is 4 lines, only under .github/workflows/.
- After merge, the next PR push will demonstrate cancel behaviour;
main push will demonstrate non-cancellation.
Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…tion test) Verifying the concurrency block from the parent commit by pushing two no-op commits in quick succession; the second should cancel this run. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
…test) The previous push's run should be cancelled by this one if the concurrency block is wired correctly. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>
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Summary
Adds a workflow-level `concurrency:` block to `.github/workflows/ci.yml`. Cancels superseded PR runs; never cancels runs on `main`, tags, or scheduled events. Org-wide pattern landing across 11 repos to clear the queue backlog.
Why
Org has 93 jobs perpetually queued; oldest is 23h old on `spar`. Without concurrency control, every `git push` to a PR branch starts a fresh run while previous runs on superseded commits keep executing. Concurrency control is the cheapest, lowest-risk fix and a strict prerequisite for any later runner migration.
Variant applied
Diff
4-line addition. Strictly scoped to `.github/workflows/` per the brief.
```yaml
concurrency:
group: ${{ github.workflow }}-${{ github.head_ref || github.ref }}
cancel-in-progress: ${{ github.event_name == 'pull_request' }}
```
Verification
Out of scope
Runner migration, job parallelisation, cache strategy, permissions hardening — tracked separately, depend on this PR landing first.
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