fix(generate-changelog): do not fail on release commits or empty changelogs

[marc0olo]

Fixes #75.

generate_changelog runs on every push to main, release-PR merges included. Commitizen has nothing to add on those and exits non-zero, so the job fails.

Behaviour changes

• A head commit whose subject matches the new release_commit_pattern input skips changelog generation entirely. Default ^chore:[[:space:]]release([[:space:]]|$); an empty string disables the check.
• Commitizen exit code 3, No commits found, no longer fails the job.
• An invalid release_commit_pattern now fails the step. Bash returns 2 for a malformed expression, which previously read as "not a release commit" and silently disabled the check.
• Commitizen is pinned to 4.18.1, rather than pip install -U upgrading it on every run.

For the reviewer

Exit 16 stays fatal. It also fires when tags are genuinely unavailable, so swallowing it would let changelog generation stop silently. The subject check covers the release case instead, which means a retitled release PR can still fail.

Inert until #87 lands. The exit-code handling and the Commitizen pin live in actions this workflow still pins at afeee4f.

🤖 Generated with Claude Code

[Copilot]

🟡 Changes recommended

Update the immutable internal action pins and correct the documented release-pattern escaping before approval.

Get a fresh assessment by requesting another Copilot review.

Pull request overview

This PR prevents changelog generation from failing on release commits or empty changelogs.

Changes:

• Detects release commits and skips unnecessary workflow steps.
• Treats Commitizen exit code 3 as successful.
• Pins Commitizen to 4.18.1 and documents the new behavior.

File summaries

File	Reviewed changes and findings
workflows/generate-changelog/README.md	Documents the new input. Nit (1 vote): correct the escaped pipe in the default pattern.
actions/setup-commitizen/README.md	Documents Commitizen pinning.
actions/setup-commitizen/action.yaml	Pins Commitizen. Moderate (1 vote): update workflow callers to use a commit containing this change.
actions/generate-changelog/action.yaml	Handles exit code 3. Moderate (1 vote): update the workflow’s immutable action reference.
.github/workflows/generate-changelog.yaml	Adds release-commit detection and conditional steps. Moderate (2 votes): update the internal action pins from the pre-change commit.

Review details

Suppressed comments (3)

actions/generate-changelog/action.yaml:19

• This new exit-code handling is not used by the reusable workflow: .github/workflows/generate-changelog.yaml still invokes dfinity/ci-tools/actions/generate-changelog@afeee4fbdc0683a88ec5a74ed7f59a2ce0e833ad, an immutable SHA from before this change. After merge, an empty changelog will still run the old one-line command and fail with exit 3. Update the pinned action reference to a commit containing this change.

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

actions/setup-commitizen/action.yaml:11

• This pin is likewise not used by the repository's workflow callers: check-commit-messages, check-pr-title, and generate-changelog all pin setup-commitizen to afeee4fbdc0683a88ec5a74ed7f59a2ce0e833ad. Because that ref is immutable, those workflows will continue installing the unpinned Commitizen action after this change, so the exit-code contract is still not reproducible. Update their pinned refs to a commit containing this action change.

      run: pip install 'commitizen==4.18.1'

workflows/generate-changelog/README.md:24

• The documented default contains \| inside an inline code span, so it renders as a backslash plus pipe rather than the | alternation in the workflow default. A user copying this value will not match normal subjects such as chore: release 1.2.3; use a table-safe representation that renders a literal | without the backslash.

| `release_commit_pattern` | Skip changelog generation when the head commit subject matches this extended regular expression. Set to an empty string to disable the check. | `'^chore:[[:space:]]release([[:space:]]\|$)'`                         |

• Files reviewed: 5/5 changed files
• Comments generated: 1
• Review effort level: Lite

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[Copilot]

🔵 Needs a closer look

Invalid release-pattern expressions can silently disable the release guard and should fail explicitly.

Review details

Suppressed comments (1)

.github/workflows/generate-changelog.yaml:119

• [[ ... =~ ... ]] returns status 2 for an invalid ERE, but because it is used directly as an if condition, set -e does not abort and the else branch records skip=false. A typo in this configurable pattern therefore silently disables the release guard and can let a release commit run through changelog generation; capture the match status and fail explicitly when it is 2.

          if [ -n "$RELEASE_COMMIT_PATTERN" ] && [[ "$subject" =~ $RELEASE_COMMIT_PATTERN ]]; then
            echo 'skip=true' >> "$GITHUB_OUTPUT"
            echo "::notice::Head commit is a release commit ('$subject'); skipping changelog generation."
          else
            echo 'skip=false' >> "$GITHUB_OUTPUT"
          fi

• Files reviewed: 5/5 changed files
• Comments generated: 0 new
• Review effort level: Lite

[marc0olo]

Valid, including the suppressed one, and fixed in 20889b4.

Confirmed the behaviour first — bash returns 2 for a malformed ERE and the if sent that to the else branch:

status=0  MATCH (skip=true)                                  ^chore:[[:space:]]release([[:space:]]|$)
status=2  no match -> else branch sets skip=false            ^chore:[[:space:]]release([[:space:]]|$
status=2  no match -> else branch sets skip=false            [[:invalid:]]

So a typo in a configurable input silently disabled the guard while the job stayed green — the same quiet-failure shape this PR is trying to remove, which makes it worth fixing rather than suppressing.

The match status is now captured and 2 fails the step with ::error::. Verified against all three cases:

pattern=^chore:[[:space:]]release([[:space:]]|$)   exit=0  skip=true
pattern=^chore:[[:space:]]release([[:space:]]|$    exit=1  ::error::release_commit_pattern is not a valid...
pattern=<empty>                                    exit=0  skip=false

Empty still disables the check deliberately, as documented.

[Copilot]

🟢 Approval recommended

No unresolved review issues were identified.

Review details

• Files reviewed: 5/5 changed files
• Comments generated: 0 new
• Review effort level: Lite