tar-stream 3.2.0: pack

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 tar-stream.pack in pkg:npm/tar-stream@3.2.0
Kind: HOW

Use EXACTLY these public packages and versions:
  - pkg:npm/tar-stream@3.2.0
Demonstrate these symbols/APIs:
  - tar-stream.pack

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:sha256:0c3a8ba94805b0d00598e9cde542bcf86e9c3ae43f279f34b0d77c890d428264","contract":["tar.pack returns a readable stream that yields 512-byte aligned blocks and terminates with a 1024-byte zero block after finalize","pack.entry buffers string or Buffer payload with custom header metadata and writes padded tar blocks","pack.entry returns a writable sink stream when payload is omitted and finalizes after streaming exactly header.size bytes","pack.entry destroys the pack stream and reports size mismatch when streamed bytes do not match header.size","pack.entry queues concurrent entry streams and processes them sequentially","pack.entry throws an error when called on an already finalized pack stream","pack.entry writes directory entries with type directory, default 0755 mode, and zero size","writing payload to a void directory entry emits an error rejecting bodies for that entry"],"goal":"verify tar-stream.pack in pkg:npm/tar-stream@3.2.0","kind":"HOW","packages":["pkg:npm/tar-stream@3.2.0"],"schemaVersion":1,"symbols":["tar-stream.pack"]},"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/tar-stream@3.2.0"],"schemaVersion":1,"subject":"pkg:npm/tar-stream@3.2.0","symbols":["tar-stream.pack"],"verifierAdapter":"node-typescript@1"}

{
  "name": "sample-tar-stream-pack",
  "version": "1.0.0",
  "lockfileVersion": 3,
  "requires": true,
  "packages": {
    "": {
      "name": "sample-tar-stream-pack",
      "version": "1.0.0",
      "dependencies": {
        "tar-stream": "3.2.0"
      }
    },
    "node_modules/b4a": {
      "version": "1.9.0",
      "resolved": "https://registry.npmjs.org/b4a/-/b4a-1.9.0.tgz",
      "integrity": "sha512-dpfcF9fDNR6++cthXR67iyhgqWy9CBouAvIWhIntzBG6cvK/cnIPiZQjBwi/ZqjjBEDGfoNDtmB0kTjroOJ3pQ==",
      "license": "Apache-2.0",
      "peerDependencies": {
        "react-native-b4a": "*"
      },
      "peerDependenciesMeta": {
        "react-native-b4a": {
          "optional": true
        }
      }
    },
    "node_modules/bare-events": {
      "version": "2.9.2",
      "resolved": "https://registry.npmjs.org/bare-events/-/bare-events-2.9.2.tgz",
      "integrity": "sha512-AIPKioV7/Y/8KfZ3AAhjPJxLLbY49S64Ym5DakZlUg75qQiTgUq9hEJoEwa4eUezPUlXRy/i5NpsKvo9jgKmoA==",
      "license": "Apache-2.0",
      "peerDependencies": {
        "bare-abort-controller": "*"
      },
      "peerDependenciesMeta": {
        "bare-abort-controller": {
          "optional": true
        }
      }
    },
    "node_modules/bare-fs": {
      "version": "4.8.1",
      "resolved": "https://registry.npmjs.org/bare-fs/-/bare-fs-4.8.1.tgz",
      "integrity": "sha512-N1nnXdHZAOSstz0XiHikGS4HGMH4CnSwhqWdGQQMqqdvp4Jybm9sE3R1WVnpWVd4SFkc8ryPDBLViNLwiEqECg==",
      "license": "Apache-2.0",
      "dependencies": {
        "bare-events": "^2.5.4",
        "bare-path": "^3.0.0",
        "bare-stream": "^2.6.4",
        "bare-url": "^2.2.2",
        "fast-fifo": "^1.3.2"
      },
      "engines": {
        "bare": ">=1.28.0"
      },
      "peerDependencies": {
        "bare-buffer": "*"
      },
      "peerDependenciesMeta": {
        "bare-buffer": {
          "optional": true
        }
      }
    },
    "node_modules/bare-path": {
      "version": "3.1.2",
      "resolved": "https://registry.npmjs.org/bare-path/-/bare-path-3.1.2.tgz",
      "integrity": "sha512-ZyKbsuuqK6Ag0K8pX6V5Txq6XeJRvY+wXucnFGRjiyVYP9YWDpIQugk/b+enRYrEYBJaqLzghRQpXPMR7341Nw==",
      "license": "Apache-2.0"
    },
    "node_modules/bare-stream": {
      "version": "2.13.4",
      "resolved": "https://registry.npmjs.org/bare-stream/-/bare-stream-2.13.4.tgz",
      "integrity": "sha512-PcrQ8lVLbiJscNm1Kez+Yp4Gy4AHGcN1lzwjvf5NybWen7VvEgUfyfnXYJ2zNqWnzOfCb1Abq6lH8ti0syQszA==",
      "license": "Apache-2.0",
      "dependencies": {
        "b4a": "^1.8.1",
        "streamx": "^2.25.0",
        "teex": "^1.0.1"
      },
      "peerDependencies": {
        "bare-abort-controller": "*",
        "bare-buffer": "*",
        "bare-events": "*"
      },
      "peerDependenciesMeta": {
        "bare-abort-controller": {
          "optional": true
        },
        "bare-buffer": {
          "optional": true
        },
        "bare-events": {
          "optional": true
        }
      }
    },
    "node_modules/bare-url": {
      "version": "2.5.4",
      "resolved": "https://registry.npmjs.org/bare-url/-/bare-url-2.5.4.tgz",
      "integrity": "sha512-Gxa7UVWBr0/edU1b+TJhn/AZvMQUj9OGspvYsaTYQrAbZA4BOTZGL3LiZxvD+CeMlDH4juwD84+eTAp/bLYW5g==",
      "license": "Apache-2.0",
      "dependencies": {
        "bare-path": "^3.0.0"
      }
    },
    "node_modules/events-universal": {
      "version": "1.0.1",
      "resolved": "https://registry.npmjs.org/events-universal/-/events-universal-1.0.1.tgz",
      "integrity": "sha512-LUd5euvbMLpwOF8m6ivPCbhQeSiYVNb8Vs0fQ8QjXo0JTkEHpz8pxdQf0gStltaPpw0Cca8b39KxvK9cfKRiAw==",
      "license": "Apache-2.0",
      "dependencies": {
        "bare-events": "^2.7.0"
      }
    },
    "node_modules/fast-fifo": {
      "version": "1.3.2",
      "resolved": "https://registry.npmjs.org/fast-fifo/-/fast-fifo-1.3.2.tgz",
      "integrity": "sha512-/d9sfos4yxzpwkDkuN7k2SqFKtYNmCTzgfEpz82x34IM9/zc8KGxQoXg1liNC/izpRM/MBdt44Nmx41ZWqk+FQ==",
      "license": "MIT"
    },
    "node_modules/streamx": {
      "version": "2.28.1",
      "resolved": "https://registry.npmjs.org/streamx/-/streamx-2.28.1.tgz",
      "integrity": "sha512-zEzXb0s5Cds7tqMH6rhZ05lcJydCWiQPEwiNngVqzsxCc962vLY4Uw+mW7od8kDH258k2Uz/JrOkdIAAhSh9VA==",
      "license": "MIT",
      "dependencies": {
        "events-universal": "^1.0.0",
        "fast-fifo": "^1.3.2",
        "text-decoder": "^1.1.0"
      }
    },
    "node_modules/tar-stream": {
      "version": "3.2.0",
      "resolved": "https://registry.npmjs.org/tar-stream/-/tar-stream-3.2.0.tgz",
      "integrity": "sha512-ojzvCvVaNp6aOTFmG7jaRD0meowIAuPc3cMMhSgKiVWws1GyHbGd/xvnyuRKcKlMpt3qvxx6r0hreCNITP9hIg==",
      "license": "MIT",
      "dependencies": {
        "b4a": "^1.6.4",
        "bare-fs": "^4.5.5",
        "fast-fifo": "^1.2.0",
        "streamx": "^2.15.0"
      }
    },
    "node_modules/teex": {
      "version": "1.0.1",
      "resolved": "https://registry.npmjs.org/teex/-/teex-1.0.1.tgz",
      "integrity": "sha512-eYE6iEI62Ni1H8oIa7KlDU6uQBtqr4Eajni3wX7rpfXD8ysFx8z0+dri+KWEPWpBsxXfxu58x/0jvTVT1ekOSg==",
      "license": "MIT",
      "dependencies": {
        "streamx": "^2.12.5"
      }
    },
    "node_modules/text-decoder": {
      "version": "1.2.7",
      "resolved": "https://registry.npmjs.org/text-decoder/-/text-decoder-1.2.7.tgz",
      "integrity": "sha512-vlLytXkeP4xvEq2otHeJfSQIRyWxo/oZGEbXrtEEF9Hnmrdly59sUbzZ/QgyWuLYHctCHxFF4tRQZNQ9k60ExQ==",
      "license": "Apache-2.0",
      "dependencies": {
        "b4a": "^1.6.4"
      }
    }
  }
}

{
  "name": "sample-tar-stream-pack",
  "version": "1.0.0",
  "private": true,
  "dependencies": {
    "tar-stream": "3.2.0"
  }
}

{
  "schemaVersion": 1,
  "goal": "verify tar-stream.pack in pkg:npm/tar-stream@3.2.0",
  "kind": "HOW",
  "packages": [
    "pkg:npm/tar-stream@3.2.0"
  ],
  "symbols": [
    "tar-stream.pack"
  ]
}

import assert from 'node:assert/strict';
import { Buffer } from 'node:buffer';
import tar from 'tar-stream';

// 1. tar.pack returns a readable stream that yields 512-byte aligned blocks and terminates with a 1024-byte zero block after finalize
await new Promise((resolve, reject) => {
	const pack = tar.pack();
	const chunks = [];

	pack.on('data', (chunk) => chunks.push(chunk));
	pack.on('end', () => {
		try {
			const tarBuf = Buffer.concat(chunks);
			assert.ok(tarBuf.length >= 1024);
			assert.equal(tarBuf.length % 512, 0);
			const trailer = tarBuf.subarray(tarBuf.length - 1024);
			assert.deepEqual(trailer, Buffer.alloc(1024, 0));
			resolve();
		} catch (err) {
			reject(err);
		}
	});
	pack.on('error', reject);

	pack.finalize();
});

// 2. pack.entry buffers string or Buffer payload with custom header metadata and writes padded tar blocks
await new Promise((resolve, reject) => {
	const pack = tar.pack();
	const chunks = [];

	pack.on('data', (chunk) => chunks.push(chunk));
	pack.on('end', () => {
		try {
			const tarBuf = Buffer.concat(chunks);
			assert.equal(tarBuf.length % 512, 0);

			// Inspect header at offset 0
			const name = tarBuf
				.subarray(0, 100)
				.toString('utf8')
				.replace(/\0.*$/, '');
			assert.equal(name, 'test-file.txt');

			const sizeOctal = tarBuf
				.subarray(124, 136)
				.toString('utf8')
				.replace(/\0.*$/, '')
				.trim();
			assert.equal(parseInt(sizeOctal, 8), 14);

			const magic = tarBuf.subarray(257, 263).toString('utf8');
			assert.ok(magic.startsWith('ustar'));

			// Check content at offset 512
			const content = tarBuf.subarray(512, 512 + 14).toString('utf8');
			assert.equal(content, 'hello tar pack');

			// Check padding between 512+14 and 1024
			const padding = tarBuf.subarray(512 + 14, 1024);
			assert.deepEqual(padding, Buffer.alloc(512 - 14, 0));

			resolve();
		} catch (err) {
			reject(err);
		}
	});
	pack.on('error', reject);

	pack.entry(
		{ name: 'test-file.txt', mode: 0o644, mtime: new Date(1700000000000) },
		'hello tar pack',
		(err) => {
			if (err) return reject(err);
			pack.finalize();
		},
	);
});

// 3. pack.entry returns a writable sink stream when payload is omitted and finalizes after streaming exactly header.size bytes
await new Promise((resolve, reject) => {
	const pack = tar.pack();
	const chunks = [];

	pack.on('data', (chunk) => chunks.push(chunk));
	pack.on('end', () => {
		try {
			const tarBuf = Buffer.concat(chunks);
			assert.equal(tarBuf.length % 512, 0);

			const name = tarBuf
				.subarray(0, 100)
				.toString('utf8')
				.replace(/\0.*$/, '');
			assert.equal(name, 'streamed.txt');

			const content = tarBuf.subarray(512, 512 + 11).toString('utf8');
			assert.equal(content, 'stream-data');
			resolve();
		} catch (err) {
			reject(err);
		}
	});
	pack.on('error', reject);

	const entryStream = pack.entry({ name: 'streamed.txt', size: 11 }, (err) => {
		if (err) return reject(err);
		pack.finalize();
	});

	assert.equal(typeof entryStream.write, 'function');
	entryStream.write(Buffer.from('stream-'));
	entryStream.end(Buffer.from('data'));
});

// 4. pack.entry destroys the pack stream and reports size mismatch when streamed bytes do not match header.size
await new Promise((resolve, reject) => {
	const pack = tar.pack();
	let packError = null;
	let entryError = null;

	function check() {
		try {
			assert.ok(packError instanceof Error);
			assert.match(packError.message, /size mismatch/i);
			assert.ok(entryError instanceof Error);
			assert.match(entryError.message, /size mismatch/i);
			resolve();
		} catch (e) {
			reject(e);
		}
	}

	pack.on('error', (err) => {
		packError = err;
		if (entryError) check();
	});

	const entryStream = pack.entry({ name: 'mismatch.txt', size: 20 }, () => {});

	entryStream.on('error', (err) => {
		entryError = err;
		if (packError) check();
	});

	entryStream.write(Buffer.from('short'));
	entryStream.end();
});

// 5. pack.entry queues concurrent entry streams and processes them sequentially
await new Promise((resolve, reject) => {
	const pack = tar.pack();
	const chunks = [];

	pack.on('data', (chunk) => chunks.push(chunk));
	pack.on('end', () => {
		try {
			const tarBuf = Buffer.concat(chunks);
			assert.equal(tarBuf.length % 512, 0);
			const name1 = tarBuf.subarray(0, 100).toString('utf8').replace(/\0.*$/, '');
			assert.equal(name1, 'first.txt');
			const name2 = tarBuf.subarray(1024, 1124).toString('utf8').replace(/\0.*$/, '');
			assert.equal(name2, 'second.txt');
			resolve();
		} catch (err) {
			reject(err);
		}
	});
	pack.on('error', reject);

	const s1 = pack.entry({ name: 'first.txt', size: 5 }, (err) => {
		if (err) reject(err);
	});
	const s2 = pack.entry({ name: 'second.txt', size: 6 }, (err) => {
		if (err) reject(err);
		pack.finalize();
	});

	s1.write(Buffer.from('hello'));
	s1.end();
	s2.write(Buffer.from('world!'));
	s2.end();
});

// 6. pack.entry throws an error when called on an already finalized pack stream
{
	const pack = tar.pack();
	pack.finalize();
	assert.throws(
		() => {
			pack.entry({ name: 'late.txt' });
		},
		{
			name: 'Error',
			message: /already finalized or destroyed/,
		},
	);
}

// 7. pack.entry writes directory entries with type directory, default 0755 mode, and zero size
await new Promise((resolve, reject) => {
	const pack = tar.pack();
	const chunks = [];

	pack.on('data', (chunk) => chunks.push(chunk));
	pack.on('end', () => {
		try {
			const tarBuf = Buffer.concat(chunks);
			const name = tarBuf
				.subarray(0, 100)
				.toString('utf8')
				.replace(/\0.*$/, '');
			assert.equal(name, 'some-dir/');

			const modeOctal = tarBuf
				.subarray(100, 108)
				.toString('utf8')
				.replace(/\0.*$/, '')
				.trim();
			assert.equal(parseInt(modeOctal, 8), 0o755);

			const typeflag = String.fromCharCode(tarBuf[156]);
			assert.equal(typeflag, '5');

			const sizeOctal = tarBuf
				.subarray(124, 136)
				.toString('utf8')
				.replace(/\0.*$/, '')
				.trim();
			assert.equal(parseInt(sizeOctal, 8), 0);

			resolve();
		} catch (err) {
			reject(err);
		}
	});
	pack.on('error', reject);

	pack.entry({ name: 'some-dir/', type: 'directory' }, (err) => {
		if (err) return reject(err);
		pack.finalize();
	});
});

// 8. writing payload to a void directory entry emits an error rejecting bodies for that entry
await new Promise((resolve, reject) => {
	const pack = tar.pack();
	let packError = null;
	let sinkError = null;

	function check() {
		try {
			assert.ok(packError instanceof Error);
			assert.match(packError.message, /No body allowed for this entry/);
			assert.ok(sinkError instanceof Error);
			assert.match(sinkError.message, /No body allowed for this entry/);
			resolve();
		} catch (e) {
			reject(e);
		}
	}

	pack.on('error', (err) => {
		packError = err;
		if (sinkError) check();
	});

	const voidSink = pack.entry({ name: 'some-dir/', type: 'directory' });

	voidSink.on('error', (err) => {
		sinkError = err;
		if (packError) check();
	});

	voidSink.write(Buffer.from('unexpected'));
});