ci: cancel PR runs only for new commits - #129

Summary

Only a new head commit of a pull request now cancels its CI runs in progress: cancel-in-progress of the workflow-level concurrency block in .github/workflows/ci.yml is true only for pull_request with action synchronize on the first attempt, as in "Cancelled runs" of actions/gate/README.md in elixir-cloud-aai/.github (elixir-cloud-aai/.github#71):

cancel-in-progress: >-
  ${{ github.event_name == 'pull_request'
  && github.event.action == 'synchronize'
  && github.run_attempt == 1 }}

Before, a newer run on the same commit (e.g. for editing the description, also by Sourcery, or marking the pull request ready) cancelled the run in progress, and its failed CI passed was then the newest result on the commit, which blocked the merge (elixir-cloud-aai/.github#70). Runs for other actions, and reruns, now wait for the run in progress instead; a waiting run that is replaced starts no job, so it leaves no check. The gate keeps if: always(), so a needed job that failed or was cancelled still fails it. This pull request's own runs already use the new rule.

Runs for pushes to main now also get a group of their own (github.sha), as in the README, so that a waiting push run is no longer replaced by a newer one; pull request runs keep the group per ref. A comment above the block describes the rule.

Part of elixir-cloud-aai/.github#73

Verification

• actionlint and check-yaml (hooks of cloud-registry's pre-commit config, as this repository has none) on .github/workflows/ci.yml: passed.
• CI: all checks passed, including CI passed, on e3ea8c7.
• Sourcery: 1 thread (a body-edit run replacing a waiting title-edit run of a Dependabot pull request): answered, not changed (waiting runs were replaced before too; the title check's condition is outside this rollout), resolved.

Light lane: changes only the CI workflow's concurrency settings (no secrets, permissions or release workflow); I reviewed the diff myself.

Declined review findings

None.

Open questions

None.

🤖 Generated with Claude Code

https://claude.ai/code/session_011FSoqMpmDCfbACLj3uy6xV

Summary by Sourcery

Ensure CI cancellation is limited to new pull-request commits while preserving independent push runs and reliable merge checks.

Bug Fixes:

• Prevent CI runs for the same pull-request commit from being cancelled by metadata-only events or reruns, avoiding stale failed CI passed checks from blocking merges.

Enhancements:

• Retain cancellation only for first-attempt runs triggered by new pull-request commits and isolate push-to-main runs by commit so queued runs are not replaced.

CI:

• Update CI workflow concurrency grouping and cancellation rules to handle pull-request commits, other pull-request events, reruns, and pushes appropriately.