Function detectWorktreeMainRepoPath

src/utils/sandbox/sandbox-adapter.ts:437–460

* Detect if cwd is a git worktree and resolve the main repo path. * Called once during initialize() and cached for the session. * In a worktree, .git is a file (not a directory) containing "gitdir: ...". * If .git is a directory, readFile throws EISDIR and we return null.

(cwd: string)

 * If .git is a directory, readFile throws EISDIR and we return null.
 */
async function detectWorktreeMainRepoPath(cwd: string): Promise<string | null> {
  const gitPath = join(cwd, '.git')
  try {
    const gitContent = await readFile(gitPath, { encoding: 'utf8' })
    const gitdirMatch = gitContent.match(/^gitdir:\s*(.+)$/m)
    if (!gitdirMatch?.[1]) {
      return null
    }
    // gitdir may be relative (rare, but git accepts it) — resolve against cwd
    const gitdir = resolve(cwd, gitdirMatch[1].trim())
    // gitdir format: /path/to/main/repo/.git/worktrees/worktree-name
    // Match the /.git/worktrees/ segment specifically — indexOf('.git') alone
    // would false-match paths like /home/user/.github-projects/...
    const marker = `${sep}.git${sep}worktrees${sep}`
    const markerIndex = gitdir.lastIndexOf(marker)
    if (markerIndex > 0) {
      return gitdir.substring(0, markerIndex)
    }
    return null
  } catch {
    // Not in a worktree, .git is a directory (EISDIR), or can't read .git file
    return null
  }
}

/**
 * Check if dependencies are available (memoized)