label-prs.yml

name: Label PRs

on:
    pull_request_target:
        types: [opened, edited, reopened, synchronize]

permissions:
    contents: read
    pull-requests: write

concurrency:
    group: label-prs-${{ github.event.pull_request.number }}
    cancel-in-progress: true

jobs:
    label:
        runs-on: ubuntu-latest
        if: ${{ github.event.pull_request.user.type != 'Bot' }}
        steps:
            - name: Apply category label from conventional-commit title
              uses: actions/github-script@v9
              with:
                  script: |
                      const TYPE_TO_LABEL = {
                        feat: "type: feature",
                        fix: "type: fix",
                        perf: "type: performance",
                        refactor: "type: refactor",
                        docs: "type: docs",
                        build: "type: build",
                        ci: "type: build",
                        chore: "type: chore",
                      };

                      function labelFor(title) {
                        const m = (title || "").match(/^([a-zA-Z]+)(?:\([^)]*\))?!?:/);
                        return m ? (TYPE_TO_LABEL[m[1].toLowerCase()] || null) : null;
                      }

                      const pr = context.payload.pull_request;
                      const label = labelFor(pr.title);
                      if (!label) {
                        core.info(`No category mapping for title "${pr.title}" — leaving labels unchanged.`);
                        return;
                      }

                      const owner = context.repo.owner;
                      const repo = context.repo.repo;
                      const issue_number = pr.number;
                      const managed = new Set(Object.values(TYPE_TO_LABEL));
                      const current = (pr.labels || []).map((l) => l.name);

                      for (const name of current) {
                        if (managed.has(name) && name !== label) {
                          await github.rest.issues
                            .removeLabel({ owner, repo, issue_number, name })
                            .catch(() => {});
                        }
                      }

                      if (current.includes(label)) {
                        core.info(`"${label}" already present.`);
                      } else {
                        await github.rest.issues.addLabels({ owner, repo, issue_number, labels: [label] });
                        core.info(`Applied "${label}".`);
                      }