feat: add GitHub repo rule detector script

scripts/repo-rule-detector.mjs

@@ -0,0 +1,106 @@
+#!/usr/bin/env node
+/**
+ * repo-rule-detector.mjs
+ *
+ * Detect GitHub repository rules that commonly affect dev flow:
+ * - require PRs for main
+ * - required status checks
+ * - required reviews
+ * - admin enforcement
+ * - allowed merge methods (merge commit / squash / rebase)
+ *
+ * Usage:
+ *   node scripts/repo-rule-detector.mjs owner/repo
+ *   node scripts/repo-rule-detector.mjs owner/repo --branch main
+ *
+ * Requires:
+ *   - gh auth
+ */
+
+import { execFileSync } from 'node:child_process';
+
+function sh(args) {
+  return execFileSync('gh', args, { encoding: 'utf8' }).trim();
+}
+
+function parseArgs(argv) {
+  const out = { repo: null, branch: 'main' };
+  const rest = [];
+  for (let i = 2; i < argv.length; i++) {
+    const a = argv[i];
+    if (a === '--branch') { out.branch = argv[++i]; continue; }
+    rest.push(a);
+  }
+  if (rest.length < 1) throw new Error('Missing repo argument: owner/repo');
+  out.repo = rest[0];
+  return out;
+}
+
+function main() {
+  const { repo, branch } = parseArgs(process.argv);
+
+  const repoInfo = JSON.parse(sh(['api', `repos/${repo}`]));
+
+  // Branch protection (classic)
+  let bp = null;
+  try {
+    bp = JSON.parse(sh(['api', `repos/${repo}/branches/${branch}/protection` ]));
+  } catch {
+    bp = null;
+  }
+
+  // Repo rulesets (new)
+  let rulesets = [];
+  try {
+    rulesets = JSON.parse(sh(['api', `repos/${repo}/rulesets`, '--paginate']));
+  } catch {
+    rulesets = [];
+  }
+
+  const relevantRulesets = rulesets
+    .filter(rs => rs?.enforcement && rs.enforcement !== 'disabled')
+    .filter(rs => {
+      const targets = rs?.conditions?.ref_name?.include ?? [];
+      return targets.length === 0 || targets.includes('~DEFAULT_BRANCH') || targets.includes(branch) || targets.includes(`refs/heads/${branch}`);
+    })
+    .map(rs => ({
+      id: rs.id,
+      name: rs.name,
+      enforcement: rs.enforcement,
+      target: rs?.conditions?.ref_name ?? null
+    }));
+
+  const allowedMergeMethods = {
+    mergeCommit: !!repoInfo.allow_merge_commit,
+    squash: !!repoInfo.allow_squash_merge,
+    rebase: !!repoInfo.allow_rebase_merge
+  };
+
+  const out = {
+    repo: repoInfo.full_name,
+    url: repoInfo.html_url,
+    defaultBranch: repoInfo.default_branch,
+    branch,
+    allowedMergeMethods,
+    branchProtection: bp ? {
+      enabled: true,
+      requiredStatusChecks: bp.required_status_checks ? {
+        strict: bp.required_status_checks.strict,
+        contexts: bp.required_status_checks.contexts,
+        checks: bp.required_status_checks.checks
+      } : null,
+      requiredPullRequestReviews: bp.required_pull_request_reviews ? {
+        requiredApprovingReviewCount: bp.required_pull_request_reviews.required_approving_review_count,
+        requireCodeOwnerReviews: bp.required_pull_request_reviews.require_code_owner_reviews,
+        dismissStaleReviews: bp.required_pull_request_reviews.dismiss_stale_reviews
+      } : null,
+      enforceAdmins: bp.enforce_admins?.enabled ?? null,
+      restrictions: bp.restrictions ?? null
+    } : { enabled: false },
+    rulesets: relevantRulesets
+  };
+
+  console.log(JSON.stringify(out, null, 2));
+}
+
+main();