mirror-issue-labels.yml

name: Mirror Issue Labels to PR

on:
  pull_request:
    types: [opened, reopened, ready_for_review]

permissions: {}

concurrency:
  group: ${{ github.workflow }}-${{ github.event.pull_request.number || github.ref }}
  cancel-in-progress: true

jobs:
  mirror:
    name: Mirror linked issue labels to PR
    if: >-
      contains(github.event.pull_request.labels.*.name, 'coding-agent') ||
      github.event.pull_request.user.login == 'Copilot' ||
      github.actor == 'copilot-swe-agent[bot]'
    runs-on: ubuntu-latest
    permissions:
      pull-requests: write
      issues: read
    steps:
      - name: Copy labels from linked issue(s)
        uses: actions/github-script@v9
        with:
          script: |
            const body = context.payload.pull_request.body || '';

            // Strip HTML comments and fenced code blocks before matching, so
            // example "Closes #N" lines in template guidance don't trigger.
            const stripped = body
              .replace(/<!--[\s\S]*?-->/g, '')
              .replace(/```[\s\S]*?```/g, '');

            // Match "Closes #N", "Fixes #N", "Resolves #N" (case-insensitive,
            // with optional ing/d/s suffixes). Only same-repo references are mirrored.
            const pattern = /\b(?:close[sd]?|fix(?:e[sd])?|resolve[sd]?)\s+#(\d+)\b/gi;
            const issueNumbers = new Set();
            let m;
            while ((m = pattern.exec(stripped)) !== null) {
              issueNumbers.add(parseInt(m[1], 10));
            }

            if (issueNumbers.size === 0) {
              core.info('No "Closes #N" references found in PR body; nothing to mirror.');
              return;
            }

            const prNumber = context.payload.pull_request.number;
            const existingLabels = new Set(
              (context.payload.pull_request.labels || []).map(l => l.name)
            );

            const toAdd = new Set();
            for (const num of issueNumbers) {
              try {
                const { data: issue } = await github.rest.issues.get({
                  owner: context.repo.owner,
                  repo: context.repo.repo,
                  issue_number: num,
                });
                for (const label of issue.labels || []) {
                  const name = typeof label === 'string' ? label : label.name;
                  if (!name) continue;
                  if (existingLabels.has(name)) continue;
                  toAdd.add(name);
                }
              } catch (err) {
                core.warning(`Failed to fetch issue #${num}: ${err.message}`);
              }
            }

            if (toAdd.size === 0) {
              core.info('Linked issue(s) had no new labels to mirror.');
              return;
            }

            const labels = Array.from(toAdd);
            await github.rest.issues.addLabels({
              owner: context.repo.owner,
              repo: context.repo.repo,
              issue_number: prNumber,
              labels,
            });
            core.info(`Mirrored ${labels.length} label(s) to PR: ${labels.join(', ')}`);