feat(merge): gstack-merge regime-aware merge helper + tests

Pure regime logic in lib/merge.ts (detect/submit-plan/classify-land/handoff
schema+validation) behind a thin bin/gstack-merge CLI (detect/submit/wait/
write-state/read-state). Supports none, GitHub native merge queue, and the
trunk.io merge queue with a comment-first submit chain. 41 deterministic
tests (30 unit + 11 CLI).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
This commit is contained in:
Garry Tan 2026-05-31 09:13:16 -07:00
parent 9562ad4e70
commit e7741d9841
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bin/gstack-merge Executable file
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#!/usr/bin/env bun
// gstack-merge — regime-aware merge driver for /land and /land-and-deploy.
//
// Owns the four risky merge operations as a thin CLI over the pure logic in
// lib/merge.ts (which is unit-tested). Supports three regimes: none, GitHub
// native merge queue, and trunk.io merge queue.
//
// Subcommands:
// detect [--base B] [--pr N] [--json]
// submit --regime R --pr N [--base B] [--priority P]
// wait --pr N --base B [--regime R] [--timeout S] [--interval S]
// [--enqueue-timeout S] [--once]
// write-state --pr N --base B --slug SLUG [--regime R] [--sha-timeout S]
// read-state --slug SLUG --pr N --repo OWNER/NAME [--max-age-ms N] [--json]
//
// Contract: detect/wait/read-state never mutate git/PR state. submit and
// write-state are the only state-touching subcommands.
import { spawnSync } from 'node:child_process';
import { existsSync, readFileSync, writeFileSync, mkdirSync, renameSync } from 'node:fs';
import { homedir } from 'node:os';
import { join } from 'node:path';
import {
detectRegime,
planSubmit,
classifyLand,
buildLandState,
validateConsume,
isTrunkQueueCheck,
trunkQueueCheckName,
type Regime,
type PrCheck,
} from '../lib/merge';
// --- arg parsing --------------------------------------------------------
function parseArgs(argv: string[]): { cmd: string; flags: Record<string, string>; bools: Set<string> } {
const cmd = argv[0] || '';
const flags: Record<string, string> = {};
const bools = new Set<string>();
for (let i = 1; i < argv.length; i++) {
const a = argv[i];
if (a.startsWith('--')) {
const key = a.slice(2);
const next = argv[i + 1];
if (next !== undefined && !next.startsWith('--')) {
flags[key] = next;
i++;
} else {
bools.add(key);
}
}
}
return { cmd, flags, bools };
}
// --- shell helpers ------------------------------------------------------
function run(cmd: string, args: string[]): { code: number; stdout: string; stderr: string } {
const r = spawnSync(cmd, args, { encoding: 'utf-8', timeout: 60000 });
return { code: r.status ?? 1, stdout: (r.stdout || '').trim(), stderr: (r.stderr || '').trim() };
}
function ghJson<T>(args: string[]): T | null {
const r = run('gh', args);
if (!r.stdout) return null;
try {
return JSON.parse(r.stdout) as T;
} catch {
return null;
}
}
function which(bin: string): boolean {
return run('command', ['-v', bin]).code === 0 || run('sh', ['-c', `command -v ${bin}`]).code === 0;
}
function sleep(ms: number): Promise<void> {
return new Promise((r) => setTimeout(r, ms));
}
// --- data gatherers -----------------------------------------------------
interface PrView {
number?: number;
state?: string;
mergeCommit?: { oid?: string } | null;
headRefOid?: string;
headRefName?: string;
baseRefName?: string;
autoMergeRequest?: unknown;
}
function prView(pr: string | undefined): PrView | null {
const args = ['pr', 'view'];
if (pr) args.push(pr);
args.push('--json', 'number,state,mergeCommit,headRefOid,headRefName,baseRefName,autoMergeRequest');
return ghJson<PrView>(args);
}
function prChecks(pr: string | undefined): PrCheck[] {
const args = ['pr', 'checks'];
if (pr) args.push(pr);
// gh pr checks exits non-zero when checks are failing/pending; we still want the JSON.
args.push('--json', 'name,state,bucket');
const r = run('gh', args);
if (!r.stdout) return [];
try {
return JSON.parse(r.stdout) as PrCheck[];
} catch {
return [];
}
}
function repoSlug(): string {
const r = ghJson<{ nameWithOwner?: string }>(['repo', 'view', '--json', 'nameWithOwner']);
return r?.nameWithOwner || '';
}
function readTrunkYaml(): string | null {
const p = join(process.cwd(), '.trunk', 'trunk.yaml');
if (existsSync(p)) {
try { return readFileSync(p, 'utf-8'); } catch { return null; }
}
return null;
}
/** Parse "Merge queue: X" from the ## Merge Configuration section of CLAUDE.md. */
function readConfigRegime(): string | null {
const p = join(process.cwd(), 'CLAUDE.md');
if (!existsSync(p)) return null;
let body: string;
try { body = readFileSync(p, 'utf-8'); } catch { return null; }
const m = body.match(/##\s*Merge Configuration[\s\S]*?(?=\n##\s|\n#\s|$)/);
if (!m) return null;
const line = m[0].match(/Merge queue:\s*([a-zA-Z]+)/);
return line ? line[1].toLowerCase() : null;
}
/** Best-effort GitHub-native merge-queue detection via the GraphQL API. */
function githubMergeQueueEnabled(slug: string, base: string): boolean {
if (!slug.includes('/')) return false;
const [owner, name] = slug.split('/');
const q = `query($o:String!,$n:String!,$b:String!){repository(owner:$o,name:$n){mergeQueue(branch:$b){id}}}`;
const r = run('gh', ['api', 'graphql', '-f', `query=${q}`, '-f', `o=${owner}`, '-f', `n=${name}`, '-f', `b=${base}`]);
if (r.code !== 0 || !r.stdout) return false;
try {
const j = JSON.parse(r.stdout);
return !!j?.data?.repository?.mergeQueue?.id;
} catch {
return false;
}
}
/** Does origin/<base> contain the head commit? (fetches first). */
function baseContainsHead(base: string, headRefOid: string): boolean {
if (!headRefOid) return false;
run('git', ['fetch', 'origin', base]);
return run('git', ['merge-base', '--is-ancestor', headRefOid, `origin/${base}`]).code === 0;
}
function findQueueCheck(checks: PrCheck[], base: string): PrCheck | null {
return (
checks.find((c) => c.name === trunkQueueCheckName(base)) ||
checks.find((c) => isTrunkQueueCheck(c.name)) ||
null
);
}
// --- subcommands --------------------------------------------------------
async function cmdDetect(flags: Record<string, string>, bools: Set<string>): Promise<number> {
const pr = flags.pr;
const slug = repoSlug();
const base = flags.base || prView(pr)?.baseRefName || 'main';
const checks = prChecks(pr);
const result = detectRegime({
base,
checks,
trunkYaml: readTrunkYaml(),
configRegime: readConfigRegime(),
githubMergeQueue: githubMergeQueueEnabled(slug, base),
});
if (bools.has('json')) {
process.stdout.write(JSON.stringify({ ...result, base }) + '\n');
} else {
process.stdout.write(`MERGE_REGIME=${result.regime}\nMERGE_REGIME_SOURCE=${result.source}\nBASE=${base}\n`);
}
return 0;
}
function cmdSubmit(flags: Record<string, string>): number {
const pr = flags.pr;
const regime = (flags.regime || 'none') as Regime;
if (!pr) { process.stderr.write('submit: --pr is required\n'); return 2; }
const plan = planSubmit(regime, Number(pr), {
trunkCliAvailable: which('trunk'),
trunkToken: !!process.env.TRUNK_API_TOKEN,
priority: flags.priority,
});
for (const cand of plan.candidates) {
process.stdout.write(`→ ${cand.desc}: ${cand.cmd} ${cand.args.join(' ')}\n`);
let r: { code: number; stdout: string; stderr: string };
if (cand.cmd === 'trunk-rest') {
r = submitViaRest(Number(pr), flags.base || '', flags.priority);
} else {
r = run(cand.cmd, cand.args);
}
if (r.code === 0) {
process.stdout.write(`SUBMIT_OK=${regime}\nSUBMIT_VIA=${cand.desc}\n`);
if (r.stdout) process.stdout.write(r.stdout + '\n');
return 0;
}
process.stderr.write(` (failed: ${r.stderr || r.stdout || 'exit ' + r.code})\n`);
}
process.stderr.write(`SUBMIT_FAILED=${regime} — no candidate succeeded\n`);
return 1;
}
function submitViaRest(pr: number, base: string, priority?: string): { code: number; stdout: string; stderr: string } {
const token = process.env.TRUNK_API_TOKEN;
if (!token) return { code: 1, stdout: '', stderr: 'TRUNK_API_TOKEN not set' };
const slug = repoSlug();
const [owner, name] = slug.split('/');
const payload = JSON.stringify({
repo: { host: 'github.com', owner, name },
pr: { number: pr },
targetBranch: base || undefined,
...(priority ? { priority } : {}),
});
return run('curl', [
'-sS', '-X', 'POST', 'https://api.trunk.io/v1/submitPullRequest',
'-H', `x-api-token: ${token}`,
'-H', 'Content-Type: application/json',
'-d', payload,
]);
}
async function cmdWait(flags: Record<string, string>): Promise<number> {
const pr = flags.pr;
const base = flags.base;
if (!pr || !base) { process.stderr.write('wait: --pr and --base are required\n'); return 2; }
const regime = (flags.regime || 'none') as Regime;
const intervalMs = (Number(flags.interval) || 30) * 1000;
const timeoutMs = (Number(flags.timeout) || 1800) * 1000; // 30 min
const enqueueMs = (Number(flags['enqueue-timeout']) || 120) * 1000;
const once = flags.once !== undefined || process.argv.includes('--once');
const classifyNow = () => {
const v = prView(pr) || {};
const checks = prChecks(pr);
const queueCheck = findQueueCheck(checks, base);
const oid = v.mergeCommit?.oid || null;
return classifyLand({
state: v.state || 'OPEN',
mergeCommitOid: oid,
baseContainsHead: oid ? true : baseContainsHead(base, v.headRefOid || ''),
queueCheck,
autoMergeEnabled: v.autoMergeRequest != null,
});
};
if (once) {
const c = classifyNow();
process.stdout.write(`LAND_STATUS=${c.status}\nLAND_REASON=${c.reason}\n`);
return c.status === 'landed' ? 0 : c.status === 'pending' ? 0 : 1;
}
const start = Date.now();
// Trunk phase 1: confirm the comment actually enqueued (the queue check
// appears) — a posted "/trunk merge" comment is silently inert if the
// GitHub App isn't installed or "GitHub commands" is off.
if (regime === 'trunk') {
let enqueued = false;
while (Date.now() - start < enqueueMs) {
const v = prView(pr) || {};
if ((v.state || '').toUpperCase() === 'MERGED') { enqueued = true; break; }
if (findQueueCheck(prChecks(pr), base)) { enqueued = true; break; }
await sleep(Math.min(intervalMs, 15000));
}
if (!enqueued) {
process.stderr.write(
'TRUNK_ENQUEUE_TIMEOUT — posted "/trunk merge" but no "' + trunkQueueCheckName(base) +
'" check appeared. Is the Trunk GitHub App installed and "GitHub commands" enabled?\n',
);
return 1;
}
process.stdout.write('Trunk picked up the PR — waiting for the queue to finish.\n');
}
// Phase 2: resolution.
let lastNarrate = Date.now();
while (Date.now() - start < timeoutMs) {
const c = classifyNow();
if (c.status === 'landed') {
process.stdout.write(`LAND_STATUS=landed\nLAND_REASON=${c.reason}\n`);
return 0;
}
if (c.status === 'ejected') {
process.stderr.write(`LAND_STATUS=ejected\nLAND_REASON=${c.reason}\n`);
return 1;
}
if (c.status === 'closed') {
process.stderr.write(`LAND_STATUS=closed\nLAND_REASON=${c.reason}\n`);
return 1;
}
if (Date.now() - lastNarrate > 120000) {
const mins = Math.round((Date.now() - start) / 60000);
process.stdout.write(`Still waiting to land... (${mins}m so far)\n`);
lastNarrate = Date.now();
}
await sleep(intervalMs);
}
process.stderr.write(`LAND_STATUS=timeout\nLAND_REASON=did not land within ${Math.round(timeoutMs / 60000)}m\n`);
return 1;
}
async function cmdWriteState(flags: Record<string, string>): Promise<number> {
const pr = flags.pr;
const base = flags.base;
const slug = flags.slug;
if (!pr || !base || !slug) { process.stderr.write('write-state: --pr, --base, --slug are required\n'); return 2; }
const regime = (flags.regime || 'none') as Regime;
const shaTimeoutMs = (Number(flags['sha-timeout']) || 90) * 1000;
// Poll until MERGED with a non-null merge SHA (the SHA can lag the state
// flip on squash/queue merges). Fall back to the base tip only in the
// genuine rebase-null case (MERGED + base contains head but oid stays null).
const start = Date.now();
let v: PrView | null = null;
let oid: string | null = null;
while (Date.now() - start < shaTimeoutMs) {
v = prView(pr);
const state = (v?.state || '').toUpperCase();
oid = v?.mergeCommit?.oid || null;
if (state === 'MERGED' && oid) break;
if (state === 'CLOSED') { process.stderr.write('write-state: PR is CLOSED, not merged\n'); return 1; }
await sleep(5000);
}
v = v || prView(pr) || {};
const state = (v.state || '').toUpperCase();
const headRefOid = v.headRefOid || '';
const contains = baseContainsHead(base, headRefOid);
if (state !== 'MERGED' || !(oid || contains)) {
process.stderr.write('write-state: landing not confirmed (PR not MERGED on base) — refusing to write handoff\n');
return 1;
}
let sha = oid || '';
let shaNote = '';
if (!sha) {
// rebase-null edge: use the base tip as the best available revert target.
const tip = run('git', ['rev-parse', `origin/${base}`]).stdout;
sha = tip;
shaNote = ' (no mergeCommit.oid — using base tip; rebase-merge repo)';
}
const state2 = buildLandState({
pr: Number(pr),
sha,
headRefOid,
base,
head_branch: v.headRefName || '',
repo: repoSlug(),
regime,
ts: new Date().toISOString(),
});
const dir = join(homedir(), '.gstack', 'projects', slug);
mkdirSync(dir, { recursive: true });
const dest = join(dir, 'last-land.json');
const tmp = `${dest}.${process.pid}.tmp`;
writeFileSync(tmp, JSON.stringify(state2, null, 2) + '\n', { mode: 0o600 });
renameSync(tmp, dest);
process.stdout.write(`LANDED: pr=#${pr} sha=${sha} regime=${regime} base=${base}${shaNote}\n`);
process.stdout.write(`HANDOFF_FILE=${dest}\n`);
return 0;
}
function cmdReadState(flags: Record<string, string>, bools: Set<string>): number {
const slug = flags.slug;
const pr = flags.pr;
const repo = flags.repo;
if (!slug || !pr || !repo) { process.stderr.write('read-state: --slug, --pr, --repo are required\n'); return 2; }
const dest = join(homedir(), '.gstack', 'projects', slug, 'last-land.json');
let state: any = null;
if (existsSync(dest)) {
try { state = JSON.parse(readFileSync(dest, 'utf-8')); } catch { state = null; }
}
const v = validateConsume(state, {
pr: Number(pr),
repo,
maxAgeMs: flags['max-age-ms'] ? Number(flags['max-age-ms']) : undefined,
}, Date.now());
if (!v.ok) {
process.stderr.write(`READ_STATE_INVALID=${v.reason}\n`);
return 1;
}
if (bools.has('json')) {
process.stdout.write(JSON.stringify(state) + '\n');
} else {
process.stdout.write(`LAND_SHA=${state.sha}\nLAND_BASE=${state.base}\nLAND_REGIME=${state.regime}\nLAND_HEAD=${state.head_branch}\n`);
}
return 0;
}
// --- main ---------------------------------------------------------------
async function main(): Promise<number> {
const { cmd, flags, bools } = parseArgs(process.argv.slice(2));
switch (cmd) {
case 'detect': return cmdDetect(flags, bools);
case 'submit': return cmdSubmit(flags);
case 'wait': return cmdWait(flags);
case 'write-state': return cmdWriteState(flags);
case 'read-state': return cmdReadState(flags, bools);
default:
process.stderr.write('usage: gstack-merge <detect|submit|wait|write-state|read-state> [flags]\n');
return 2;
}
}
if (import.meta.main) {
main().then((code) => process.exit(code)).catch((err) => {
process.stderr.write(`gstack-merge: ${err?.message || err}\n`);
process.exit(3);
});
}

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lib/merge.ts Normal file
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// lib/merge.ts — pure merge-regime logic for /land and /land-and-deploy.
//
// This module is the single source of truth for the four risky merge
// operations, kept pure (no I/O) so they can be unit-tested with fixtures:
//
// detectRegime — none | github | trunk, from gh/check/config signals
// planSubmit — ordered list of submit commands per regime (trunk = comment-first)
// classifyLand — landed | ejected | pending | closed, from PR state + checks
// buildLandState / validateConsume — the last-land.json handoff contract
//
// The CLI wrapper (bin/gstack-merge) gathers the live data via gh/git/fs and
// calls these functions. Keeping logic here means an E2E that inspects a
// command tests prompt text, but the unit tests here test behavior.
export type Regime = 'none' | 'github' | 'trunk';
export const LAND_STATE_SCHEMA_VERSION = 1;
// --- Regime detection ---------------------------------------------------
export interface PrCheck {
/** Check name, e.g. "Trunk Merge Queue (main)". */
name?: string;
/** gh exposes `state` (e.g. SUCCESS) and/or `bucket` (pass/fail/pending). */
state?: string;
bucket?: string;
}
export interface DetectInput {
/** Base branch the PR targets, e.g. "main". */
base: string;
/** Output of `gh pr checks --json name,state,bucket`. */
checks: PrCheck[];
/** Contents of .trunk/trunk.yaml if present, else null. */
trunkYaml: string | null;
/** Explicit "Merge queue: X" from CLAUDE.md ## Merge Configuration, else null. */
configRegime?: string | null;
/** True when branch protection on `base` has a GitHub-native merge queue. */
githubMergeQueue?: boolean;
}
export interface DetectResult {
regime: Regime;
/** How the regime was decided — for honest narration. */
source: 'config' | 'trunk-status-check' | 'trunk-yaml' | 'github-branch-protection' | 'default';
}
const VALID_REGIMES: Regime[] = ['none', 'github', 'trunk'];
/** Name of the GitHub status check Trunk posts on PRs, e.g. "Trunk Merge Queue (main)". */
export function trunkQueueCheckName(base: string): string {
return `Trunk Merge Queue (${base})`;
}
/** Match any "Trunk Merge Queue (<branch>)" check regardless of branch. */
export function isTrunkQueueCheck(name: string | undefined): boolean {
return !!name && /^Trunk Merge Queue \(.+\)$/.test(name);
}
/**
* Decide the merge regime. Precedence:
* 1. explicit config key (the project owns its config)
* 2. live Trunk status check on the PR (the authoritative live signal)
* 3. .trunk/trunk.yaml `merge:` section (secondary NOT `.trunk/` presence
* alone, which `trunk check` also creates)
* 4. GitHub-native merge queue from branch protection
* 5. none
*/
export function detectRegime(input: DetectInput): DetectResult {
const cfg = (input.configRegime || '').trim().toLowerCase();
if (VALID_REGIMES.includes(cfg as Regime)) {
return { regime: cfg as Regime, source: 'config' };
}
if (input.checks.some((c) => isTrunkQueueCheck(c.name))) {
return { regime: 'trunk', source: 'trunk-status-check' };
}
// Secondary: a `merge:` section in .trunk/trunk.yaml means merge-queue is
// configured for this repo (distinct from a bare .trunk/ that only carries
// `trunk check` linter config).
if (input.trunkYaml && /^\s*merge\s*:/m.test(input.trunkYaml)) {
return { regime: 'trunk', source: 'trunk-yaml' };
}
if (input.githubMergeQueue) {
return { regime: 'github', source: 'github-branch-protection' };
}
return { regime: 'none', source: 'default' };
}
// --- Submit planning ----------------------------------------------------
export interface SubmitCandidate {
/** Program to run. */
cmd: string;
/** Args (pr number substituted). */
args: string[];
/** Human description for narration. */
desc: string;
}
export interface SubmitPlan {
regime: Regime;
/** Candidates to try in order; first that runs cleanly wins. */
candidates: SubmitCandidate[];
/** Whether `--delete-branch` is owned by us (false for trunk — Trunk owns it). */
deleteBranch: boolean;
}
export interface SubmitOpts {
/** `trunk` CLI is installed + on PATH. */
trunkCliAvailable?: boolean;
/** $TRUNK_API_TOKEN is set (enables the REST fallback). */
trunkToken?: boolean;
/** Optional priority word for trunk (urgent|high|medium|low|lowest). */
priority?: string;
}
/**
* Build the ordered submit plan for a regime.
*
* trunk is **comment-first**: `gh pr comment "/trunk merge"` needs zero new
* auth (gh is already required and Trunk's "GitHub commands" toggle is
* default-ON), so it works the moment Trunk's GitHub App is installed. The
* trunk CLI and REST are opportunistic upgrades.
*/
export function planSubmit(regime: Regime, pr: number, opts: SubmitOpts = {}): SubmitPlan {
const prRef = String(pr);
if (regime === 'none') {
return {
regime,
deleteBranch: true,
candidates: [
{ cmd: 'gh', args: ['pr', 'merge', prRef, '--squash', '--delete-branch'], desc: 'direct squash merge' },
],
};
}
if (regime === 'github') {
return {
regime,
deleteBranch: true,
candidates: [
{ cmd: 'gh', args: ['pr', 'merge', prRef, '--auto', '--delete-branch'], desc: 'GitHub auto-merge / merge queue' },
// If --auto is not enabled on the repo, fall back to a direct squash.
{ cmd: 'gh', args: ['pr', 'merge', prRef, '--squash', '--delete-branch'], desc: 'direct squash merge (auto unavailable)' },
],
};
}
// trunk — comment-first, then CLI, then REST. NEVER `gh pr merge`, NEVER
// --delete-branch (Trunk owns the merge and branch cleanup).
const commentBody = opts.priority ? `/trunk merge --priority=${opts.priority}` : '/trunk merge';
const candidates: SubmitCandidate[] = [
{ cmd: 'gh', args: ['pr', 'comment', prRef, '--body', commentBody], desc: 'enqueue via GitHub comment (/trunk merge)' },
];
if (opts.trunkCliAvailable) {
const cliArgs = ['merge', prRef];
if (opts.priority) cliArgs.push('--priority', opts.priority);
candidates.push({ cmd: 'trunk', args: cliArgs, desc: 'enqueue via trunk CLI' });
}
if (opts.trunkToken) {
// REST fallback is executed specially by the CLI wrapper (curl with token);
// represented here so callers/tests see the full ordered chain.
candidates.push({ cmd: 'trunk-rest', args: [prRef], desc: 'enqueue via Trunk REST API' });
}
return { regime, deleteBranch: false, candidates };
}
// --- Landing classification ---------------------------------------------
export type LandStatus = 'landed' | 'ejected' | 'pending' | 'closed';
export interface ClassifyInput {
/** PR state: OPEN | MERGED | CLOSED. */
state: string;
/** `gh pr view --json mergeCommit -q .mergeCommit.oid`, null if absent. */
mergeCommitOid: string | null;
/** True if `git branch -r --contains <headRefOid>` shows the base branch. */
baseContainsHead: boolean;
/** The Trunk/GitHub merge-queue check on the PR, if present. */
queueCheck?: { name?: string; state?: string; bucket?: string } | null;
/** Whether GitHub auto-merge is enabled (autoMergeRequest non-null). */
autoMergeEnabled?: boolean;
}
const EJECTED_STATES = new Set(['FAILURE', 'ERROR', 'CANCELLED', 'CANCELED', 'FAIL']);
/**
* Decide whether a PR has landed. Uniform across all three regimes:
*
* landed = MERGED AND (mergeCommit.oid non-null OR base contains the head)
* pending = MERGED but SHA not yet visible (squash/rebase lag), or still in queue
* ejected = queue check failed/cancelled while PR is still OPEN
* closed = CLOSED without merging
*
* The (oid OR baseContainsHead) guard handles rebase-merge repos where
* mergeCommit.oid stays null H3.
*/
export function classifyLand(input: ClassifyInput): { status: LandStatus; reason: string } {
const state = (input.state || '').toUpperCase();
if (state === 'MERGED') {
if (input.mergeCommitOid || input.baseContainsHead) {
return { status: 'landed', reason: 'PR is MERGED and the commit is on the base branch' };
}
return { status: 'pending', reason: 'PR is MERGED but the merge SHA is not visible yet (squash/rebase lag)' };
}
if (state === 'CLOSED') {
return { status: 'closed', reason: 'PR was closed without merging' };
}
// state OPEN
const cs = (input.queueCheck?.state || input.queueCheck?.bucket || '').toUpperCase();
if (input.queueCheck && EJECTED_STATES.has(cs)) {
return { status: 'ejected', reason: `merge-queue check reported ${cs}` };
}
return { status: 'pending', reason: 'PR is still open (in queue or merge pending)' };
}
// --- Handoff state (last-land.json) -------------------------------------
export interface LandState {
schema_version: number;
pr: number;
sha: string;
headRefOid: string;
base: string;
head_branch: string;
repo: string; // owner/name
regime: Regime;
ts: string; // ISO 8601
}
export interface BuildLandStateInput {
pr: number;
sha: string;
headRefOid: string;
base: string;
head_branch: string;
repo: string;
regime: Regime;
/** ISO timestamp — injected so this stays pure/deterministic in tests. */
ts: string;
}
/** Assemble a validated LandState. Throws if the landing SHA is missing. */
export function buildLandState(input: BuildLandStateInput): LandState {
if (!input.sha) {
throw new Error('refusing to write last-land.json with an empty merge SHA — landing not confirmed');
}
return {
schema_version: LAND_STATE_SCHEMA_VERSION,
pr: input.pr,
sha: input.sha,
headRefOid: input.headRefOid,
base: input.base,
head_branch: input.head_branch,
repo: input.repo,
regime: input.regime,
ts: input.ts,
};
}
export interface ConsumeExpectation {
pr: number;
repo: string;
/** Max age in ms before the state is considered stale. Default 6h. */
maxAgeMs?: number;
}
const DEFAULT_MAX_AGE_MS = 6 * 60 * 60 * 1000;
/**
* Validate a last-land.json the parent is about to consume. Guards against
* stale-state-drives-wrong-deploy (H5): the file must be for THIS pr+repo,
* recent, schema-compatible, and carry a non-null SHA.
*/
export function validateConsume(
state: Partial<LandState> | null,
expected: ConsumeExpectation,
nowMs: number,
): { ok: boolean; reason?: string } {
if (!state) return { ok: false, reason: 'no last-land.json found' };
if (state.schema_version !== LAND_STATE_SCHEMA_VERSION) {
return { ok: false, reason: `schema_version mismatch (got ${state.schema_version}, want ${LAND_STATE_SCHEMA_VERSION})` };
}
if (!state.sha) return { ok: false, reason: 'last-land.json has no merge SHA' };
if (state.pr !== expected.pr) {
return { ok: false, reason: `last-land.json is for PR #${state.pr}, not #${expected.pr}` };
}
if (state.repo !== expected.repo) {
return { ok: false, reason: `last-land.json is for repo ${state.repo}, not ${expected.repo}` };
}
const ts = state.ts ? Date.parse(state.ts) : NaN;
if (Number.isNaN(ts)) return { ok: false, reason: 'last-land.json has an invalid timestamp' };
const maxAge = expected.maxAgeMs ?? DEFAULT_MAX_AGE_MS;
if (nowMs - ts > maxAge) {
return { ok: false, reason: `last-land.json is stale (${Math.round((nowMs - ts) / 60000)} min old)` };
}
return { ok: true };
}

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// Deterministic end-to-end coverage of the bin/gstack-merge CLI (arg parsing,
// file IO, and the lib/merge.ts wiring through the real binary). Free + fast —
// no claude -p, no network. The submit/wait/classify *logic* is unit-tested in
// gstack-merge.test.ts; this proves the executable plumbs it correctly and that
// the handoff contract (write → consume, with null/stale/foreign rejection)
// round-trips through the actual CLI surface /land and /land-and-deploy call.
import { describe, test, expect, beforeEach, afterEach } from 'bun:test';
import { spawnSync } from 'node:child_process';
import { mkdtempSync, rmSync, mkdirSync, writeFileSync } from 'node:fs';
import { tmpdir } from 'node:os';
import { join } from 'node:path';
const BIN = join(import.meta.dir, '..', 'bin', 'gstack-merge');
function runCli(args: string[], opts: { cwd?: string; home?: string } = {}) {
const r = spawnSync('bun', [BIN, ...args], {
encoding: 'utf-8',
cwd: opts.cwd || process.cwd(),
env: { ...process.env, ...(opts.home ? { HOME: opts.home } : {}) },
timeout: 30000,
});
return { code: r.status ?? 1, stdout: r.stdout || '', stderr: r.stderr || '' };
}
let tmp: string;
beforeEach(() => { tmp = mkdtempSync(join(tmpdir(), 'gstack-merge-cli-')); });
afterEach(() => { rmSync(tmp, { recursive: true, force: true }); });
describe('gstack-merge CLI: detect', () => {
test('an explicit "Merge queue: trunk" config wins (no git/gh needed)', () => {
// A non-git temp dir: gh/git calls return nothing, so the config key is the
// only signal — exactly the precedence /land relies on.
writeFileSync(join(tmp, 'CLAUDE.md'), '# proj\n\n## Merge Configuration\n- Merge queue: trunk\n');
const r = runCli(['detect', '--base', 'main', '--json'], { cwd: tmp });
expect(r.code).toBe(0);
const out = JSON.parse(r.stdout.trim());
expect(out.regime).toBe('trunk');
expect(out.source).toBe('config');
});
test('config "Merge queue: github" is honored', () => {
writeFileSync(join(tmp, 'CLAUDE.md'), '## Merge Configuration\n- Merge queue: github\n');
const r = runCli(['detect', '--base', 'main', '--json'], { cwd: tmp });
expect(JSON.parse(r.stdout.trim()).regime).toBe('github');
});
test('no config + no signals → none', () => {
const r = runCli(['detect', '--base', 'main', '--json'], { cwd: tmp });
expect(r.code).toBe(0);
expect(JSON.parse(r.stdout.trim()).regime).toBe('none');
});
});
describe('gstack-merge CLI: handoff round-trip (write → consume)', () => {
const SLUG = 'acme-widget';
const REPO = 'acme/widget';
function seedHandoff(home: string, overrides: Record<string, unknown> = {}) {
const dir = join(home, '.gstack', 'projects', SLUG);
mkdirSync(dir, { recursive: true });
const state = {
schema_version: 1,
pr: 42,
sha: 'deadbeefcafe',
headRefOid: 'cafef00d',
base: 'main',
head_branch: 'feat/x',
repo: REPO,
regime: 'trunk',
ts: new Date().toISOString(),
...overrides,
};
writeFileSync(join(dir, 'last-land.json'), JSON.stringify(state, null, 2));
}
test('read-state accepts a matching recent handoff and emits the SHA', () => {
seedHandoff(tmp);
const r = runCli(['read-state', '--slug', SLUG, '--pr', '42', '--repo', REPO], { home: tmp });
expect(r.code).toBe(0);
expect(r.stdout).toContain('LAND_SHA=deadbeefcafe');
expect(r.stdout).toContain('LAND_REGIME=trunk');
});
test('read-state rejects a handoff for a different PR (no cross-PR deploy)', () => {
seedHandoff(tmp);
const r = runCli(['read-state', '--slug', SLUG, '--pr', '99', '--repo', REPO], { home: tmp });
expect(r.code).toBe(1);
expect(r.stderr).toContain('READ_STATE_INVALID');
});
test('read-state rejects a handoff for a different repo', () => {
seedHandoff(tmp);
const r = runCli(['read-state', '--slug', SLUG, '--pr', '42', '--repo', 'other/repo'], { home: tmp });
expect(r.code).toBe(1);
expect(r.stderr).toContain('READ_STATE_INVALID');
});
test('read-state rejects a stale handoff', () => {
seedHandoff(tmp, { ts: '2020-01-01T00:00:00.000Z' });
const r = runCli(['read-state', '--slug', SLUG, '--pr', '42', '--repo', REPO], { home: tmp });
expect(r.code).toBe(1);
expect(r.stderr).toContain('READ_STATE_INVALID');
});
test('read-state rejects a handoff with an empty SHA (the null-SHA STOP)', () => {
seedHandoff(tmp, { sha: '' });
const r = runCli(['read-state', '--slug', SLUG, '--pr', '42', '--repo', REPO], { home: tmp });
expect(r.code).toBe(1);
expect(r.stderr).toContain('READ_STATE_INVALID');
});
test('read-state reports missing when there is no handoff at all', () => {
const r = runCli(['read-state', '--slug', 'nope', '--pr', '1', '--repo', REPO], { home: tmp });
expect(r.code).toBe(1);
expect(r.stderr).toContain('READ_STATE_INVALID');
});
});
describe('gstack-merge CLI: argument handling', () => {
test('unknown subcommand exits 2 with usage', () => {
const r = runCli(['frobnicate']);
expect(r.code).toBe(2);
expect(r.stderr).toContain('usage: gstack-merge');
});
test('submit without --pr exits 2', () => {
const r = runCli(['submit', '--regime', 'none']);
expect(r.code).toBe(2);
});
});

263
test/gstack-merge.test.ts Normal file
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import { describe, test, expect } from 'bun:test';
import {
detectRegime,
planSubmit,
classifyLand,
buildLandState,
validateConsume,
isTrunkQueueCheck,
trunkQueueCheckName,
LAND_STATE_SCHEMA_VERSION,
type LandState,
} from '../lib/merge';
describe('detectRegime', () => {
test('explicit config key wins over everything', () => {
const r = detectRegime({
base: 'main',
configRegime: 'github',
checks: [{ name: trunkQueueCheckName('main'), state: 'PENDING' }], // would say trunk
trunkYaml: 'merge:\n required_statuses: [ci]',
githubMergeQueue: false,
});
expect(r.regime).toBe('github');
expect(r.source).toBe('config');
});
test('invalid config key is ignored and falls through to live signals', () => {
const r = detectRegime({
base: 'main',
configRegime: 'banana',
checks: [{ name: 'Trunk Merge Queue (main)' }],
trunkYaml: null,
});
expect(r.regime).toBe('trunk');
expect(r.source).toBe('trunk-status-check');
});
test('trunk status check on the PR → trunk (even on a non-main base)', () => {
const r = detectRegime({
base: 'develop',
checks: [{ name: 'Trunk Merge Queue (develop)', state: 'TESTING' }],
trunkYaml: null,
});
expect(r.regime).toBe('trunk');
expect(r.source).toBe('trunk-status-check');
});
test('.trunk/trunk.yaml with a merge: section → trunk (secondary signal)', () => {
const r = detectRegime({
base: 'main',
checks: [{ name: 'build' }, { name: 'test' }],
trunkYaml: 'version: 0.1\nmerge:\n required_statuses:\n - build\n',
});
expect(r.regime).toBe('trunk');
expect(r.source).toBe('trunk-yaml');
});
test('bare .trunk/trunk.yaml WITHOUT a merge: section is NOT trunk (check-only false positive guard)', () => {
const r = detectRegime({
base: 'main',
checks: [{ name: 'build' }],
trunkYaml: 'version: 0.1\ncli:\n version: 1.22.0\nlint:\n enabled:\n - eslint\n',
});
expect(r.regime).toBe('none');
expect(r.source).toBe('default');
});
test('github branch-protection merge queue → github', () => {
const r = detectRegime({
base: 'main',
checks: [{ name: 'build' }],
trunkYaml: null,
githubMergeQueue: true,
});
expect(r.regime).toBe('github');
expect(r.source).toBe('github-branch-protection');
});
test('no signals → none', () => {
const r = detectRegime({ base: 'main', checks: [], trunkYaml: null });
expect(r.regime).toBe('none');
expect(r.source).toBe('default');
});
});
describe('isTrunkQueueCheck', () => {
test('matches the queue check name for any branch', () => {
expect(isTrunkQueueCheck('Trunk Merge Queue (main)')).toBe(true);
expect(isTrunkQueueCheck('Trunk Merge Queue (release/v2)')).toBe(true);
});
test('does not match unrelated checks', () => {
expect(isTrunkQueueCheck('Trunk Check')).toBe(false);
expect(isTrunkQueueCheck('build')).toBe(false);
expect(isTrunkQueueCheck(undefined)).toBe(false);
});
});
describe('planSubmit', () => {
test('none → single direct squash with branch delete', () => {
const p = planSubmit('none', 42);
expect(p.deleteBranch).toBe(true);
expect(p.candidates).toHaveLength(1);
expect(p.candidates[0].args).toEqual(['pr', 'merge', '42', '--squash', '--delete-branch']);
});
test('github → auto-merge first, squash fallback', () => {
const p = planSubmit('github', 42);
expect(p.deleteBranch).toBe(true);
expect(p.candidates[0].args).toContain('--auto');
expect(p.candidates[1].args).toContain('--squash');
});
test('trunk is comment-first and never deletes the branch', () => {
const p = planSubmit('trunk', 7, { trunkCliAvailable: false, trunkToken: false });
expect(p.deleteBranch).toBe(false);
expect(p.candidates).toHaveLength(1);
expect(p.candidates[0].cmd).toBe('gh');
expect(p.candidates[0].args).toEqual(['pr', 'comment', '7', '--body', '/trunk merge']);
// No gh pr merge anywhere in the trunk plan.
expect(p.candidates.some((c) => c.args.includes('merge') && c.cmd === 'gh' && c.args.includes('pr') && c.args[1] === 'merge')).toBe(false);
});
test('trunk adds CLI then REST as opportunistic fallbacks, in order', () => {
const p = planSubmit('trunk', 7, { trunkCliAvailable: true, trunkToken: true });
expect(p.candidates.map((c) => c.cmd)).toEqual(['gh', 'trunk', 'trunk-rest']);
});
test('trunk priority threads into the comment body and CLI', () => {
const p = planSubmit('trunk', 7, { trunkCliAvailable: true, priority: 'high' });
expect(p.candidates[0].args).toContain('/trunk merge --priority=high');
expect(p.candidates[1].args).toEqual(['merge', '7', '--priority', 'high']);
});
});
describe('classifyLand', () => {
test('MERGED with a merge SHA → landed', () => {
const c = classifyLand({ state: 'MERGED', mergeCommitOid: 'abc123', baseContainsHead: false });
expect(c.status).toBe('landed');
});
test('MERGED with null SHA but base contains head → landed (rebase-merge case, H3)', () => {
const c = classifyLand({ state: 'MERGED', mergeCommitOid: null, baseContainsHead: true });
expect(c.status).toBe('landed');
});
test('MERGED but SHA not visible and base does not yet contain head → pending (squash lag)', () => {
const c = classifyLand({ state: 'MERGED', mergeCommitOid: null, baseContainsHead: false });
expect(c.status).toBe('pending');
});
test('OPEN with a failed queue check → ejected', () => {
const c = classifyLand({
state: 'OPEN',
mergeCommitOid: null,
baseContainsHead: false,
queueCheck: { name: 'Trunk Merge Queue (main)', state: 'FAILURE' },
});
expect(c.status).toBe('ejected');
});
test('OPEN with a cancelled queue check → ejected', () => {
const c = classifyLand({
state: 'OPEN',
mergeCommitOid: null,
baseContainsHead: false,
queueCheck: { name: 'Trunk Merge Queue (main)', bucket: 'CANCELLED' },
});
expect(c.status).toBe('ejected');
});
test('OPEN with a still-testing queue check → pending', () => {
const c = classifyLand({
state: 'OPEN',
mergeCommitOid: null,
baseContainsHead: false,
queueCheck: { name: 'Trunk Merge Queue (main)', state: 'IN_PROGRESS' },
});
expect(c.status).toBe('pending');
});
test('CLOSED → closed', () => {
const c = classifyLand({ state: 'CLOSED', mergeCommitOid: null, baseContainsHead: false });
expect(c.status).toBe('closed');
});
});
describe('buildLandState', () => {
const base = {
pr: 12,
sha: 'deadbeef',
headRefOid: 'cafe',
base: 'main',
head_branch: 'feat/x',
repo: 'owner/name',
regime: 'trunk' as const,
ts: '2026-05-31T00:00:00.000Z',
};
test('assembles a schema-versioned state', () => {
const s = buildLandState(base);
expect(s.schema_version).toBe(LAND_STATE_SCHEMA_VERSION);
expect(s.sha).toBe('deadbeef');
expect(s.repo).toBe('owner/name');
// scope is intentionally absent (T2 — parent recomputes diff-scope).
expect('scope' in s).toBe(false);
});
test('refuses to build with an empty SHA (handoff would silently kill revert)', () => {
expect(() => buildLandState({ ...base, sha: '' })).toThrow(/empty merge SHA/);
});
});
describe('validateConsume', () => {
const now = Date.parse('2026-05-31T01:00:00.000Z');
const good: LandState = {
schema_version: LAND_STATE_SCHEMA_VERSION,
pr: 12,
sha: 'deadbeef',
headRefOid: 'cafe',
base: 'main',
head_branch: 'feat/x',
repo: 'owner/name',
regime: 'trunk',
ts: '2026-05-31T00:30:00.000Z',
};
test('accepts a matching recent state', () => {
expect(validateConsume(good, { pr: 12, repo: 'owner/name' }, now).ok).toBe(true);
});
test('rejects when no state file', () => {
const v = validateConsume(null, { pr: 12, repo: 'owner/name' }, now);
expect(v.ok).toBe(false);
});
test('rejects a state for a different PR (stale-state-drives-wrong-deploy, H5)', () => {
const v = validateConsume(good, { pr: 99, repo: 'owner/name' }, now);
expect(v.ok).toBe(false);
expect(v.reason).toMatch(/PR #12/);
});
test('rejects a state for a different repo', () => {
const v = validateConsume(good, { pr: 12, repo: 'other/name' }, now);
expect(v.ok).toBe(false);
});
test('rejects a stale state past max age', () => {
const stale = { ...good, ts: '2026-05-30T00:00:00.000Z' };
const v = validateConsume(stale, { pr: 12, repo: 'owner/name' }, now);
expect(v.ok).toBe(false);
expect(v.reason).toMatch(/stale/);
});
test('rejects an empty SHA', () => {
const v = validateConsume({ ...good, sha: '' }, { pr: 12, repo: 'owner/name' }, now);
expect(v.ok).toBe(false);
});
test('rejects a schema_version mismatch', () => {
const v = validateConsume({ ...good, schema_version: 99 }, { pr: 12, repo: 'owner/name' }, now);
expect(v.ok).toBe(false);
});
});