fs.realpath 1.0.0: realpath

Clean-room public code sample — generation instructions

Write a brand-new, minimal, self-contained code sample in this clean-room directory.
Do not copy, paraphrase, or reference any existing project source. Work only from this spec.

A csx.json manifest scaffold already exists. Do not recreate it from memory. Preserve its case.goal, packages and symbols; fill its empty case.contract with exact assertions and correct its environment, commands and verifierAdapter for the files you generate.

Goal: verify fs.realpath.realpath in pkg:npm/fs.realpath@1.0.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/fs.realpath@1.0.0
Demonstrate these symbols/APIs:
  - fs.realpath.realpath

Rules:
  - One focused purpose; the smallest project that proves the goal.
  - Include a contract test (test/contract.*) that runs OFFLINE and exits 0 exactly when the goal behavior works.
  - Pin every dependency with a lockfile so resolution is reproducible.
  - No secrets, credentials, or tokens. No real URLs (only example.com or localhost). No absolute paths.
  - No personal names, emails, company names, or project identifiers of any kind.
  - No binaries and no generated output (node_modules, dist, target, venv, .git, .env).
  - Keep it under 200 files and 256KB packed.

{"case":{"caseId":"case:sha256:97dea7b21f1ea44976360d52279281d8a2bbd9973cbfbb829be5b79ff12a4747","constraints":{"executionContext":"node"},"contract":["Resolving a canonical file path with fs.realpath.realpath passes the resolved absolute path to the callback","Resolving a symbolic link with fs.realpath.realpath passes the canonical target path to the callback","Resolving nested symbolic links with fs.realpath.realpath passes the final target file path to the callback","Passing a cache object to fs.realpath.realpath resolves the path and invokes the callback","Resolving a non-existent path with fs.realpath.realpath passes an ENOENT error to the callback","fs.realpath.realpath is a function exported on the fs.realpath module matching the module default export"],"goal":"verify fs.realpath.realpath in pkg:npm/fs.realpath@1.0.0","kind":"HOW","packages":["pkg:npm/fs.realpath@1.0.0"],"schemaVersion":1,"symbols":["fs.realpath.realpath"]},"contractCommand":["node","test/contract.mjs"],"environment":{"arch":"x64","distro":"ubuntu","ecosystem":"npm","executionContext":"node","language":"javascript","libc":"glibc","libcVersion":"2.39","moduleSystem":"cjs","os":"linux","osVersionBucket":"24","packageManager":"npm","packageManagerVersion":"10.9.8","runtime":"node","runtimeVersion":"22.23.2","schemaVersion":1},"license":"MIT-0","packages":["pkg:npm/fs.realpath@1.0.0"],"schemaVersion":1,"subject":"pkg:npm/fs.realpath@1.0.0","symbols":["fs.realpath.realpath"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-fs-realpath-realpath",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-fs-realpath-realpath",
      "version": "1.0.0",
      "dependencies": {
        "fs.realpath": "1.0.0"
      }
    },
    "node_modules/fs.realpath": {
      "version": "1.0.0",
      "resolved": "https://registry.npmjs.org/fs.realpath/-/fs.realpath-1.0.0.tgz",
      "integrity": "sha512-OO0pH2lK6a0hZnAdau5ItzHPI6pUlvI7jMVnxUQRtw4owF2wk8lOSabtGDCTP4Ggrg2MbGnWO9X8K1t4+fGMDw==",
      "license": "ISC"
    }
  }
}

{
  "name": "sample-fs-realpath-realpath",
  "version": "1.0.0",
  "type": "module",
  "private": true,
  "dependencies": {
    "fs.realpath": "1.0.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify fs.realpath.realpath in pkg:npm/fs.realpath@1.0.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/fs.realpath@1.0.0"
  ],
  "symbols": [
    "fs.realpath.realpath"
  ]
}

import assert from 'node:assert/strict';
import fs from 'node:fs';
import os from 'node:os';
import path from 'node:path';
import fsRealpath from 'fs.realpath';

const { realpath } = fsRealpath;

const tmpBase = fs.mkdtempSync(path.join(os.tmpdir(), 'csx-fs-realpath-'));
const tmpDir = fs.realpathSync(tmpBase);

try {
	const targetFile = path.join(tmpDir, 'target.txt');
	fs.writeFileSync(targetFile, 'fs.realpath.realpath test content', 'utf8');

	const linkFile = path.join(tmpDir, 'link.txt');
	fs.symlinkSync(targetFile, linkFile);

	const nestedLinkFile = path.join(tmpDir, 'nested-link.txt');
	fs.symlinkSync(linkFile, nestedLinkFile);

	// 1. Resolving a canonical file path with fs.realpath.realpath passes the resolved absolute path to the callback
	await new Promise((resolve, reject) => {
		realpath(targetFile, (err, resolved) => {
			if (err) return reject(err);
			try {
				assert.equal(typeof resolved, 'string');
				assert.equal(resolved, targetFile);
				resolve();
			} catch (e) {
				reject(e);
			}
		});
	});

	// 2. Resolving a symbolic link with fs.realpath.realpath passes the canonical target path to the callback
	await new Promise((resolve, reject) => {
		realpath(linkFile, (err, resolved) => {
			if (err) return reject(err);
			try {
				assert.equal(resolved, targetFile);
				resolve();
			} catch (e) {
				reject(e);
			}
		});
	});

	// 3. Resolving nested symbolic links with fs.realpath.realpath passes the final target file path to the callback
	await new Promise((resolve, reject) => {
		realpath(nestedLinkFile, (err, resolved) => {
			if (err) return reject(err);
			try {
				assert.equal(resolved, targetFile);
				resolve();
			} catch (e) {
				reject(e);
			}
		});
	});

	// 4. Passing a cache object to fs.realpath.realpath resolves the path and invokes the callback
	const cache = {};
	await new Promise((resolve, reject) => {
		realpath(targetFile, cache, (err, resolved) => {
			if (err) return reject(err);
			try {
				assert.equal(resolved, targetFile);
				resolve();
			} catch (e) {
				reject(e);
			}
		});
	});

	// 5. Resolving a non-existent path with fs.realpath.realpath passes an ENOENT error to the callback
	const nonExistent = path.join(tmpDir, 'non-existent.txt');
	await new Promise((resolve, reject) => {
		realpath(nonExistent, (err, resolved) => {
			try {
				assert.ok(err, 'Expected error for non-existent path');
				assert.equal(err.code, 'ENOENT');
				assert.equal(resolved, undefined);
				resolve();
			} catch (e) {
				reject(e);
			}
		});
	});

	// 6. fs.realpath.realpath is a function exported on the fs.realpath module matching the module default export
	assert.equal(typeof realpath, 'function');
	assert.equal(fsRealpath, realpath);
} finally {
	fs.rmSync(tmpBase, { recursive: true, force: true });
}