pr-issue-reference.yml

name: PR Issue Reference

on:
  pull_request_target:
    types:
      - opened
      - edited
      - reopened
      - synchronize
      - ready_for_review

permissions:
  contents: read
  issues: read
  pull-requests: read

jobs:
  require-issue-reference:
    runs-on: ubuntu-latest
    steps:
      - name: Require a same-repository issue reference
        env:
          GITHUB_TOKEN: ${{ github.token }}
        shell: bash
        run: |
          set -euo pipefail

          node <<'NODE'
          const fs = require('node:fs');
          const https = require('node:https');

          const event = JSON.parse(fs.readFileSync(process.env.GITHUB_EVENT_PATH, 'utf8'));
          const token = process.env.GITHUB_TOKEN;
          const pr = event.pull_request;
          const repository = event.repository.full_name;
          const [owner, repo] = repository.split('/');
          const text = `${pr.title ?? ''}\n${pr.body ?? ''}`;

          const escapeRegExp = (value) => value.replace(/[.*+?^${}()|[\]\\]/g, '\\$&');
          const numbers = new Set();

          const addNumber = (value) => {
            const number = Number(value);
            if (Number.isSafeInteger(number) && number > 0) {
              numbers.add(number);
            }
          };

          for (const match of text.matchAll(/(^|[^\w/-])#([1-9]\d*)\b/g)) {
            addNumber(match[2]);
          }

          for (const match of text.matchAll(/\bGH-([1-9]\d*)\b/gi)) {
            addNumber(match[1]);
          }

          const sameRepo = escapeRegExp(repository);
          for (const match of text.matchAll(new RegExp(`\\b${sameRepo}#([1-9]\\d*)\\b`, 'gi'))) {
            addNumber(match[1]);
          }

          for (const match of text.matchAll(
            new RegExp(`https://github\\.com/${sameRepo}/issues/([1-9]\\d*)\\b`, 'gi'),
          )) {
            addNumber(match[1]);
          }

          numbers.delete(Number(pr.number));

          const requestIssue = (number) =>
            new Promise((resolve, reject) => {
              const request = https.request(
                {
                  hostname: 'api.github.com',
                  method: 'GET',
                  path: `/repos/${owner}/${repo}/issues/${number}`,
                  headers: {
                    Accept: 'application/vnd.github+json',
                    Authorization: `Bearer ${token}`,
                    'User-Agent': 'git-warp-pr-issue-reference-guard',
                    'X-GitHub-Api-Version': '2022-11-28',
                  },
                },
                (response) => {
                  let body = '';
                  response.setEncoding('utf8');
                  response.on('data', (chunk) => {
                    body += chunk;
                  });
                  response.on('end', () => {
                    if (response.statusCode === 404) {
                      resolve({ kind: 'missing', number });
                      return;
                    }
                    if (response.statusCode !== 200) {
                      reject(
                        new Error(`GitHub API returned ${response.statusCode} for #${number}: ${body}`),
                      );
                      return;
                    }
                    const issue = JSON.parse(body);
                    if (issue.pull_request !== undefined) {
                      resolve({ kind: 'pull-request', number, title: issue.title });
                      return;
                    }
                    resolve({ kind: 'issue', number, title: issue.title });
                  });
                },
              );
              request.on('error', reject);
              request.end();
            });

          async function main() {
            const candidates = [...numbers].sort((left, right) => left - right);
            if (candidates.length === 0) {
              console.error('This PR must reference at least one same-repository GitHub Issue.');
              console.error(`Accepted forms: #123, GH-123, ${repository}#123, or https://github.com/${repository}/issues/123.`);
              process.exit(1);
            }

            for (const number of candidates) {
              const result = await requestIssue(number);
              if (result.kind === 'issue') {
                console.log(`Found issue reference #${result.number}: ${result.title}`);
                process.exit(0);
              }
              if (result.kind === 'pull-request') {
                console.log(`Ignoring #${result.number}: it is a pull request, not an issue.`);
                continue;
              }
              console.log(`Ignoring #${result.number}: no such same-repository issue exists.`);
            }

            console.error('This PR references numbers, but none resolve to a same-repository GitHub Issue.');
            console.error('References to pull requests do not satisfy this gate.');
            process.exit(1);
          }

          main().catch((error) => {
            console.error(error);
            process.exit(1);
          });
          NODE