feat(archive): add tar and tar.gz converters

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

test/converters/archive.test.js

@@ -3,6 +3,7 @@ import fs from 'node:fs/promises';
 import path from 'node:path';
 import os from 'node:os';
 import AdmZip from 'adm-zip';
+import * as tar from 'tar';
 import { registerArchiveConverters, assertNoPathEscape } from '../../src/converters/archive.js';
 import { resolve, listTargetFormats } from '../../src/converters/registry.js';
 
@@ -94,3 +95,41 @@ describe('archive converters — zip-slip protection', () => {
     await expect(entry.convert(maliciousPath, outputPath)).rejects.toThrow(/escapes/);
   });
 });
+
+describe('archive converters — tar / tar.gz', () => {
+  it('registers tar and tar.gz as targets for each other', () => {
+    expect(listTargetFormats('tar')).toContain('tar.gz');
+    expect(listTargetFormats('tar.gz')).toContain('tar');
+  });
+
+  it('converts zip -> tar, preserving nested paths and content', async () => {
+    const inputPath = path.join(tmpDir, 'for-tar.zip');
+    buildZipFixture(inputPath);
+    const outputPath = path.join(tmpDir, 'output.tar');
+    const entry = resolve('zip', 'tar');
+
+    await entry.convert(inputPath, outputPath);
+
+    const listDir = await fs.mkdtemp(path.join(os.tmpdir(), 'tar-check-'));
+    await tar.extract({ file: outputPath, cwd: listDir });
+    expect(await fs.readFile(path.join(listDir, 'hello.txt'), 'utf8')).toBe('hello world');
+    expect(await fs.readFile(path.join(listDir, 'nested', 'inner.txt'), 'utf8')).toBe('nested content');
+    await fs.rm(listDir, { recursive: true, force: true });
+  });
+
+  it('converts tar -> tar.gz and back to tar, preserving content', async () => {
+    const tarPath = path.join(tmpDir, 'roundtrip.tar');
+    await tar.create({ file: tarPath, cwd: srcFixtureDir }, ['hello.txt', 'nested']);
+
+    const gzPath = path.join(tmpDir, 'roundtrip.tar.gz');
+    await resolve('tar', 'tar.gz').convert(tarPath, gzPath, { quality: 9 });
+
+    const backToTarPath = path.join(tmpDir, 'roundtrip-back.tar');
+    await resolve('tar.gz', 'tar').convert(gzPath, backToTarPath);
+
+    const listDir = await fs.mkdtemp(path.join(os.tmpdir(), 'tar-gz-check-'));
+    await tar.extract({ file: backToTarPath, cwd: listDir });
+    expect(await fs.readFile(path.join(listDir, 'hello.txt'), 'utf8')).toBe('hello world');
+    await fs.rm(listDir, { recursive: true, force: true });
+  });
+});