msd-core/tests/helpers/cold-runtime-lib-fixture.cjs

'use strict';

/**
 * Build a hermetic "cold tree" install fixture for #3582 — a copy of hooks/
 * plus msd-core/bin/ensure-runtime-build.cjs with the compiled
 * msd-core/bin/lib/*.cjs directory and tsconfig.build.json deliberately
 * ABSENT, mirroring a raw plugin-marketplace / git-clone install that never
 * ran `npm run build:lib`.
 *
 * Deliberately NOT `tests/helpers/copy-script-fixture.cjs`'s
 * `copyScriptWithDeps`: that helper walks the require graph and copies every
 * dependency it finds — including msd-core/bin/lib/*.cjs, which exist in
 * THIS repo's already-built tree — so it would faithfully reproduce a WARM
 * tree, the opposite of what a cold-tree test needs. This helper copies only
 * hooks/ and the seam module itself, and never touches msd-core/bin/lib/ or
 * tsconfig.build.json — so `ensureRuntimeBuild()` inside the fixture
 * deterministically throws `RuntimeBuildError` ("tsconfig.build.json not
 * found") the first time any fixture hook reaches it, without ever deleting
 * or touching the real repo's msd-core/bin/lib/.
 */

const fs = require('node:fs');
const path = require('node:path');

const REPO_ROOT = path.resolve(__dirname, '..', '..');

/**
 * Pure name-filter decision for a single hooks/ top-level entry: should it be
 * copied into the cold-tree fixture? Excludes the build output dir and any
 * transient build-hooks.js staging dir (both by NAME ONLY — see the
 * no-stat-on-a-skipped-name rationale in buildColdInstallTree below).
 * @param {string} name
 * @returns {boolean}
 */
function shouldCopyHookEntry(name) {
  return name !== 'dist' && !name.startsWith('.dist-staging');
}

/**
 * @param {object} [opts]
 * @param {string} [opts.repoRoot]  TEST-ONLY: source tree root to copy hooks/
 *   and msd-core/bin/ensure-runtime-build.cjs from, in place of the real
 *   REPO_ROOT. Lets a test point this fixture at a hermetic fake tree instead
 *   of mutating the live repo's hooks/ directory (which other test files may
 *   be concurrently reading). Defaults to REPO_ROOT.
 * @returns {{ dir: string, hooksDir: string, cleanup: () => void }}
 */
function buildColdInstallTree(opts = {}) {
  const repoRoot = opts.repoRoot || REPO_ROOT;
  const dir = fs.mkdtempSync(path.join(require('node:os').tmpdir(), 'msd-cold-tree-'));

  // hooks/ — entire directory (top-level hook scripts + hooks/lib/*.js +
  // managed-hooks-registry.cjs + hooks.json). hooks/dist/ (gitignored,
  // build-hooks.js output) is excluded — it is not present in a raw
  // marketplace checkout either.
  //
  // This is NOT a single recursive fs.cpSync(hooks/, ...) with a `filter`
  // callback. The live hooks/ directory is not stable during a test run:
  // scripts/build-hooks.js writes atomically via a per-PID staging dir
  // (hooks/.dist-staging-<pid>, gitignored — see .gitignore:21) that it
  // creates and then removes once the atomic rename into hooks/dist/ is
  // done, and up to nine test files invoke build-hooks.js concurrently from
  // their `before()` hooks. A recursive cpSync enumerates hooks/, may
  // observe another process's transient .dist-staging-<pid> entry, and can
  // then lstat/copy it AFTER that process has already deleted it — an
  // intermittent ENOENT ("no such file or directory, lstat
  // '.../hooks/.dist-staging-<pid>'"). Excluding only the basename 'dist'
  // does not help: '.dist-staging-<pid>' is a different name.
  //
  // Fix: enumerate hooks/ ourselves and skip transient entries BY NAME
  // ONLY, before ever touching them — no stat/lstat on a name we're going
  // to skip. Skipping by name (rather than filtering after readdir handed
  // control to fs.cpSync's own traversal) is what closes the race: a
  // vanishing .dist-staging-<pid> dir is never accessed at all once its
  // name has excluded it.
  const hooksDestDir = path.join(dir, 'hooks');
  fs.mkdirSync(hooksDestDir, { recursive: true });
  for (const entry of fs.readdirSync(path.join(repoRoot, 'hooks'), { withFileTypes: true })) {
    if (!shouldCopyHookEntry(entry.name)) continue;
    // #3900 (same-class guard, found in review): the live repo tree is walked
    // here — a daemon's socket/FIFO inside hooks/ would reach cpSync and
    // throw ENXIO (a FIFO would block). Dirent type check, not name-only.
    if (!entry.isFile() && !entry.isDirectory()) continue;
    fs.cpSync(path.join(repoRoot, 'hooks', entry.name), path.join(hooksDestDir, entry.name), {
      recursive: true,
    });
  }

  // msd-core/bin/ensure-runtime-build.cjs — the seam itself. Deliberately
  // NOT msd-core/bin/lib/ (absent — isBuilt() reads false) and NOT
  // tsconfig.build.json at the fixture root (absent — ensureRuntimeBuild's
  // "cannot auto-build" branch fires deterministically).
  fs.mkdirSync(path.join(dir, 'msd-core', 'bin'), { recursive: true });
  fs.copyFileSync(
    path.join(repoRoot, 'msd-core', 'bin', 'ensure-runtime-build.cjs'),
    path.join(dir, 'msd-core', 'bin', 'ensure-runtime-build.cjs'),
  );

  function cleanup() {
    fs.rmSync(dir, { recursive: true, force: true, maxRetries: 3 });
  }

  return { dir, hooksDir: path.join(dir, 'hooks'), cleanup };
}

module.exports = { buildColdInstallTree, REPO_ROOT, shouldCopyHookEntry };