Background

Follow-up to #644, which excluded CHANGELOG.md from the changed-files ms.date freshness check (scripts/linting/Invoke-MsDateFreshnessCheck.ps1) so release-please PRs are not blocked by a stale frontmatter date. That fix is correct but defensive — the underlying issue is that release-please does not refresh ms.date when it regenerates CHANGELOG.md.

Proposal (Option 1)

Add a step to the release workflow that runs after googleapis/release-please-action and, when a release PR was opened or updated, rewrites the ms.date frontmatter field in CHANGELOG.md and pushes the change back to the release PR branch.

Sketch:

- uses: googleapis/release-please-action@v4
  id: release
  with:
    config-file: release-please-config.json
    manifest-file: release-please-manifest.json

- name: Stamp ms.date in CHANGELOG.md
  if: steps.release.outputs.prs_created == 'true' || steps.release.outputs.pr != ''
  env:
    PR_BRANCH: ${{ fromJSON(steps.release.outputs.pr).headBranchName }}
  run: |
    git fetch origin "$PR_BRANCH"
    git checkout "$PR_BRANCH"
    today=$(date -u +%Y-%m-%d)
    sed -i -E "s/^ms\.date: .*/ms.date: ${today}/" CHANGELOG.md
    git config user.name  "github-actions[bot]"
    git config user.email "41898282+github-actions[bot]@users.noreply.github.com"
    git add CHANGELOG.md
    git diff --cached --quiet || git commit -m "chore: refresh CHANGELOG ms.date"
    git push origin "$PR_BRANCH"

Acceptance Criteria

• Release-please PRs land with ms.date in CHANGELOG.md set to the date the PR was last regenerated (UTC).
• The release workflow handles the no-op case (no release PR open) without failing.
• The commit-back step uses the github-actions[bot] identity and a conventional commit message so it does not pollute the changelog itself.
• Once verified working, consider removing the CHANGELOG.md entry from $excludePatterns in scripts/linting/Invoke-MsDateFreshnessCheck.ps1 so the freshness check covers the changelog again.

Alternatives Considered

• Option 2 — release-please custom updater plugin. Heavier than warranted for a single frontmatter field.
• Option 3 — drop ms.date from CHANGELOG.md entirely. Viable if the docs pipeline does not require the field on generated files; per-release headers already encode dates.

References

• fix(scripts): exclude CHANGELOG.md from changed-files msdate check #644 — exclusion fix that this issue supersedes
• chore(main): release 0.8.0 #450 — release-please PR that originally surfaced the problem