GitNexus/gitnexus/test/unit/windows-long-path-prefix.test.ts

/**
 * #2667 — the Windows extended-length (`\\?\`) prefix must never survive into a
 * path GitNexus compares or keys on.
 *
 * `stripWindowsLongPathPrefix` is a POSIX no-op, so these assertions only bite on
 * windows-latest; the file is registered in `scripts/cross-platform-tests.ts` for
 * exactly that reason. Like `analyzer-identity-path-normalization.test.ts`, it holds
 * ONLY pure-function assertions with an explicit `platform` argument — no fixture,
 * no filesystem — so it stays green on every runner.
 */
import { describe, it, expect } from 'vitest';
import path from 'path';
import { stripWindowsLongPathPrefix } from '../../src/lib/utils.js';

describe('stripWindowsLongPathPrefix (#2667)', () => {
  it('strips the prefix from a drive path', () => {
    expect(stripWindowsLongPathPrefix('\\\\?\\D:\\Projects\\repo', 'win32')).toBe(
      'D:\\Projects\\repo',
    );
  });

  it('rewrites the UNC form back to its `\\\\server\\share` shape', () => {
    expect(stripWindowsLongPathPrefix('\\\\?\\UNC\\server\\share\\repo', 'win32')).toBe(
      '\\\\server\\share\\repo',
    );
  });

  // The namespace `\\?\` addresses is case-insensitive, so a caller can spell
  // the token in any case. Matching only `UNC` left `\\?\unc\…` prefixed, which
  // is the #2667 registry mismatch all over again on a network share.
  it('rewrites the UNC form whatever case the token is spelled in', () => {
    expect(stripWindowsLongPathPrefix('\\\\?\\unc\\server\\share\\repo', 'win32')).toBe(
      '\\\\server\\share\\repo',
    );
    expect(stripWindowsLongPathPrefix('\\\\?\\Unc\\server\\share\\repo', 'win32')).toBe(
      '\\\\server\\share\\repo',
    );
  });

  it('leaves a volume-GUID path untouched — its remainder is not a usable path', () => {
    expect(stripWindowsLongPathPrefix('\\\\?\\Volume{1a2b3c4d}\\repo', 'win32')).toBe(
      '\\\\?\\Volume{1a2b3c4d}\\repo',
    );
  });

  it('leaves the `\\\\.\\` device namespace untouched', () => {
    // Most of what it addresses is not a filesystem path at all.
    expect(stripWindowsLongPathPrefix('\\\\.\\D:\\repo', 'win32')).toBe('\\\\.\\D:\\repo');
    expect(stripWindowsLongPathPrefix('\\\\.\\PhysicalDrive0', 'win32')).toBe(
      '\\\\.\\PhysicalDrive0',
    );
  });

  // Degenerate extended paths: stripping these would emit something worse than
  // the input. `\\?\UNC` has no share to keep, so a blind slice yields the bare
  // root `\\`; `\\?\D:foo` is drive-RELATIVE, so a blind slice yields `D:foo`,
  // which is not absolute and would resolve against the process cwd. Both are
  // left untouched so they simply fail to match a registry entry.
  it('leaves a UNC prefix with no share component untouched', () => {
    expect(stripWindowsLongPathPrefix('\\\\?\\UNC\\', 'win32')).toBe('\\\\?\\UNC\\');
    expect(stripWindowsLongPathPrefix('\\\\?\\UNC', 'win32')).toBe('\\\\?\\UNC');
  });

  it('leaves a drive-relative extended path untouched, so output stays absolute', () => {
    expect(stripWindowsLongPathPrefix('\\\\?\\D:foo', 'win32')).toBe('\\\\?\\D:foo');
    expect(path.win32.isAbsolute(stripWindowsLongPathPrefix('\\\\?\\D:\\foo', 'win32'))).toBe(true);
  });

  it('is a no-op on already-canonical drive and UNC paths', () => {
    expect(stripWindowsLongPathPrefix('D:\\Projects\\repo', 'win32')).toBe('D:\\Projects\\repo');
    expect(stripWindowsLongPathPrefix('\\\\server\\share\\repo', 'win32')).toBe(
      '\\\\server\\share\\repo',
    );
  });

  it('is idempotent — it runs wherever a comparison key is built', () => {
    const once = stripWindowsLongPathPrefix('\\\\?\\D:\\Projects\\repo', 'win32');
    expect(stripWindowsLongPathPrefix(once, 'win32')).toBe(once);

    const uncOnce = stripWindowsLongPathPrefix('\\\\?\\UNC\\server\\share\\repo', 'win32');
    expect(stripWindowsLongPathPrefix(uncOnce, 'win32')).toBe(uncOnce);
  });

  // Near-miss spellings must fail closed rather than be half-normalized: none of
  // these is the extended-length prefix, so none may be sliced.
  it('leaves near-miss namespace spellings untouched', () => {
    expect(stripWindowsLongPathPrefix('\\\\??\\D:\\repo', 'win32')).toBe('\\\\??\\D:\\repo');
    expect(stripWindowsLongPathPrefix('\\\\?\\\\D:\\repo', 'win32')).toBe('\\\\?\\\\D:\\repo');
    expect(stripWindowsLongPathPrefix('\\?\\D:\\repo', 'win32')).toBe('\\?\\D:\\repo');
    expect(stripWindowsLongPathPrefix('\\\\?\\GLOBALROOT\\Device\\X', 'win32')).toBe(
      '\\\\?\\GLOBALROOT\\Device\\X',
    );
  });

  it('handles degenerate and empty input without throwing', () => {
    expect(stripWindowsLongPathPrefix('', 'win32')).toBe('');
    expect(stripWindowsLongPathPrefix('\\\\?\\', 'win32')).toBe('\\\\?\\');
    expect(stripWindowsLongPathPrefix('\\\\', 'win32')).toBe('\\\\');
    expect(stripWindowsLongPathPrefix('D:', 'win32')).toBe('D:');
  });

  // The helper matches the backslash spelling only, by design — `path.resolve`
  // folds `//?/` into it first. A half-converted path is left alone rather than
  // sliced on one separator convention and rejoined on the other.
  it('leaves a forward-slash or mixed-separator prefix untouched', () => {
    expect(stripWindowsLongPathPrefix('//?/D:/repo', 'win32')).toBe('//?/D:/repo');
    expect(stripWindowsLongPathPrefix('//?/UNC/server/share', 'win32')).toBe(
      '//?/UNC/server/share',
    );
    // Backslash prefix with a forward-slash body IS sliced — the prefix matched.
    expect(stripWindowsLongPathPrefix('\\\\?\\D:\\a/b/c', 'win32')).toBe('D:\\a/b/c');
  });

  it('is a no-op off Windows, where `\\\\?\\…` is an ordinary filename', () => {
    expect(stripWindowsLongPathPrefix('\\\\?\\D:\\repo', 'linux')).toBe('\\\\?\\D:\\repo');
    expect(stripWindowsLongPathPrefix('/home/node/repo', 'linux')).toBe('/home/node/repo');
  });

  // The leak this normalization exists to prevent. `path.win32.relative` cannot
  // express a relative path between a prefixed and an un-prefixed form of the SAME
  // directory — they share no root — so it returns the absolute target instead.
  // That absolute string is exactly what #2667 reported inside node IDs
  // (`Function:\\?\D:\…\market.move:…`), and it is the same defect class as the
  // cross-drive `isInside` bug fixed in #2688.
  it('makes a mixed-prefix relativization relative again', () => {
    const prefixed = '\\\\?\\D:\\repo';
    const child = 'D:\\repo\\a\\b.move';

    expect(path.win32.relative(prefixed, child)).toBe(child);
    expect(path.win32.relative(stripWindowsLongPathPrefix(prefixed, 'win32'), child)).toBe(
      'a\\b.move',
    );
  });

  // Why `canonicalizePath`'s `catch` branch leaked and its realpath branch did
  // not. The repo-manager regression tests for that branch can only run on
  // windows-latest, so pin the underlying platform fact here, where it runs
  // everywhere: `path.resolve` carries the prefix through untouched, which is
  // all the fallback branch used to do. Also pins the forward-slash spelling
  // that the helper deliberately does not match, because `resolve` folds it
  // into the backslash form first.
  it('pins that path.resolve preserves the prefix (the fallback branch #2667 leaked through)', () => {
    expect(path.win32.resolve('\\\\?\\D:\\repo\\sub')).toBe('\\\\?\\D:\\repo\\sub');
    expect(path.win32.resolve('//?/D:/repo/sub')).toBe('\\\\?\\D:\\repo\\sub');

    expect(stripWindowsLongPathPrefix(path.win32.resolve('\\\\?\\D:\\repo\\sub'), 'win32')).toBe(
      'D:\\repo\\sub',
    );
  });
});