generate-changelog: exit code 3 (no commits) causes false failure after release merge

[marc0olo]

Problem

The generate_changelog workflow fires on every push to main, including when a release PR is merged. When a release PR lands, the tag (e.g. v5.4.0) is created as part of that same commit. Commitizen then runs in --incremental mode, finds no commits after the newly-created tag, and exits with code 3 — failing the job.

Example failed run: https://github.com/dfinity/icp-js-core/actions/runs/25162483015/job/73761141579

Relevant log lines:

No commits found
##[error]Process completed with exit code 3.

Root cause

In actions/generate-changelog/action.yaml, the cz changelog command is run without any exit-code handling:

run: cz changelog --incremental --merge-prerelease --file-name="$FILE_NAME" --version-scheme semver2

Commitizen exit code 3 means "NoneReleased" / nothing to changelog — it is a no-op, not an error.

Possible solutions

Option A — Handle exit code 3 in actions/generate-changelog/action.yaml (recommended)

Treat exit code 3 as success at the action level, since it precisely means "nothing to do":

run: |
  cz changelog --incremental --merge-prerelease --file-name="$FILE_NAME" --version-scheme semver2 || {
    code=$?; [ "$code" -eq 3 ] && { echo "No new commits since last tag, skipping."; exit 0; }; exit $code
  }

Fixes the root cause at the right level and handles any "no commits" scenario generically.

Option B — Skip the job when triggered by a release commit (in the reusable workflow)

Add a pre-check in .github/workflows/generate-changelog.yaml that detects a release commit and skips changelog generation:

- name: Check for release commit
  id: check
  run: |
    msg=$(git log -1 --format=%s)
    [[ "$msg" =~ ^chore:[[:space:]]release ]] && echo "skip=true" >> $GITHUB_OUTPUT || true

- name: Generate changelog
  if: steps.check.outputs.skip != 'true'
  uses: dfinity/ci-tools/actions/generate-changelog@...

More targeted but depends on the release commit message format staying stable.

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Happy to open a PR for whichever approach is preferred.