changelog.yml

name: changelog

on:
  pull_request:
    types:
      - opened
      - synchronize
      - reopened
      - ready_for_review
      - edited
      - labeled
      - unlabeled

permissions:
  contents: read
  pull-requests: read

jobs:
  require-changelog:
    runs-on: ubuntu-latest
    steps:
      - name: Enforce changelog policy
        uses: actions/github-script@v7
        with:
          script: |
            const pr = context.payload.pull_request;
            if (!pr) {
              core.info("No pull request payload found.");
              return;
            }

            if (pr.draft) {
              core.notice("Draft PR: changelog enforcement will run again when the PR is marked ready for review.");
              return;
            }

            const labels = new Set((pr.labels || []).map((label) => label.name));
            if (labels.has("skip-changelog")) {
              core.notice("Skipping changelog check because the PR has the skip-changelog label.");
              return;
            }

            const files = await github.paginate(github.rest.pulls.listFiles, {
              owner: context.repo.owner,
              repo: context.repo.repo,
              pull_number: pr.number,
              per_page: 100,
            });

            const changedFiles = files.map((file) => file.filename);
            if (changedFiles.includes("CHANGELOG.md")) {
              core.notice("CHANGELOG.md was updated in this PR.");
              return;
            }

            const exemptFiles = new Set([
              "README.md",
              "CHANGELOG.md",
              "LICENSE",
              "mkdocs.yml",
              "uv.lock",
              ".gitignore",
              ".pre-commit-config.yaml",
            ]);
            const exemptPrefixes = [
              ".github/",
              "docs/",
              "tests/",
            ];

            const requiresChangelog = changedFiles.filter((file) => {
              if (exemptFiles.has(file)) {
                return false;
              }
              if (exemptPrefixes.some((prefix) => file.startsWith(prefix))) {
                return false;
              }
              return true;
            });

            if (requiresChangelog.length === 0) {
              core.notice("Only docs/tests/CI/internal files changed, so no changelog entry is required.");
              return;
            }

            const details = requiresChangelog.slice(0, 20).map((file) => `- ${file}`).join("\n");
            core.setFailed(
              [
                "This PR changes user-facing or package-relevant files but does not update CHANGELOG.md.",
                "Add a changelog entry, or apply the skip-changelog label if the change is intentionally internal.",
                "",
                "Files that triggered this check:",
                details,
              ].join("\n"),
            );