/**
* Worktree Detection Utility
*
* Detects if the current working directory is a git worktree and extracts
* information about the parent repository.
*
* Git worktrees have a `.git` file (not directory) containing:
* gitdir: /path/to/parent/.git/worktrees/<name>
*/
import { statSync, readFileSync } from 'fs';
import path from 'path';
export interface WorktreeInfo {
isWorktree: boolean;
worktreeName: string | null; // e.g., "yokohama"
parentRepoPath: string | null; // e.g., "/Users/alex/main"
parentProjectName: string | null; // e.g., "main"
}
const NOT_A_WORKTREE: WorktreeInfo = {
isWorktree: false,
worktreeName: null,
parentRepoPath: null,
parentProjectName: null
};
/**
* Detect if a directory is a git worktree and extract parent info.
*
* @param cwd - Current working directory (absolute path)
* @returns WorktreeInfo with parent details if worktree, otherwise isWorktree=false
*/
export function detectWorktree(cwd: string): WorktreeInfo {
const gitPath = path.join(cwd, '.git');
// Check if .git is a file (worktree) or directory (main repo)
let stat;
try {
stat = statSync(gitPath);
} catch {
// No .git at all - not a git repo
return NOT_A_WORKTREE;
}
if (!stat.isFile()) {
// .git is a directory = main repo, not a worktree
return NOT_A_WORKTREE;
}
// Parse .git file to find parent repo
let content: string;
try {
content = readFileSync(gitPath, 'utf-8').trim();
} catch {
return NOT_A_WORKTREE;
}
// Format: gitdir: /path/to/parent/.git/worktrees/<name>
const match = content.match(/^gitdir:\s*(.+)$/);
if (!match) {
return NOT_A_WORKTREE;
}
const gitdirPath = match[1];
// Extract: /path/to/parent from /path/to/parent/.git/worktrees/name
// Handle both Unix and Windows paths
const worktreesMatch = gitdirPath.match(/^(.+)[/\\]\.git[/\\]worktrees[/\\]([^/\\]+)$/);
if (!worktreesMatch) {
return NOT_A_WORKTREE;
}
const parentRepoPath = worktreesMatch[1];
const worktreeName = path.basename(cwd);
const parentProjectName = path.basename(parentRepoPath);
return {
isWorktree: true,
worktreeName,
parentRepoPath,
parentProjectName
};
}
