next.js/packages/create-next-app/helpers/git.ts

import { execSync } from 'node:child_process'
import { join } from 'node:path'
import { rmSync } from 'node:fs'

function isInGitRepository(): boolean {
  try {
    execSync('git rev-parse --is-inside-work-tree', { stdio: 'ignore' })
    return true
  } catch (_) {}
  return false
}

function isInMercurialRepository(): boolean {
  try {
    execSync('hg --cwd . root', { stdio: 'ignore' })
    return true
  } catch (_) {}
  return false
}

function isDefaultBranchSet(): boolean {
  try {
    execSync('git config init.defaultBranch', { stdio: 'ignore' })
    return true
  } catch (_) {}
  return false
}

export function tryGitInit(root: string): boolean {
  let didInit = false
  try {
    execSync('git --version', { stdio: 'ignore' })
    if (isInGitRepository() || isInMercurialRepository()) {
      return false
    }

    execSync('git init', { stdio: 'ignore' })
    didInit = true

    if (!isDefaultBranchSet()) {
      execSync('git checkout -b main', { stdio: 'ignore' })
    }

    execSync('git add -A', { stdio: 'ignore' })
    execSync('git commit -m "Initial commit from Create Next App"', {
      stdio: 'ignore',
    })
    return true
  } catch (e) {
    if (didInit) {
      try {
        rmSync(join(root, '.git'), { recursive: true, force: true })
      } catch (_) {}
    }
    return false
  }
}