install.js

'use strict'

//
// Compatibility with older node.js as path.exists got moved to `fs`.
//
const fs = require('node:fs')
const path = require('node:path')
const os = require('node:os')
const hook = path.join(__dirname, 'hook')
const root = path.resolve(__dirname, '..', '..', '..')
const exists = fs.existsSync || path.existsSync

//
// Gather the location of the possible hidden .git directory, the hooks
// directory which contains all git hooks and the absolute location of the
// `pre-commit` file. The path needs to be absolute in order for the symlinking
// to work correctly.
//

let git = getGitFolderPath(root)
let hooks
let precommit

// Function to recursively finding .git folder
function getGitFolderPath (currentPath) {
  const git = path.resolve(currentPath, '.git')

  if (!exists(git) || !fs.lstatSync(git).isDirectory()) {
    console.log('pre-commit:')
    console.log('pre-commit: Not found .git folder in', git)

    const newPath = path.resolve(currentPath, '..')

    // Stop if we on top folder
    if (currentPath === newPath) {
      return null
    }

    return getGitFolderPath(newPath)
  }

  console.log('pre-commit:')
  console.log('pre-commit: Found .git folder in', git)
  return git
}

//
// Resolve git directory for submodules
//
if (exists(git) && fs.lstatSync(git).isFile()) {
  const gitinfo = fs.readFileSync(git).toString()
  const gitdirmatch = /gitdir: (.+)/.exec(gitinfo)
  const gitdir = gitdirmatch.length === 2 ? gitdirmatch[1] : null

  if (gitdir !== null) {
    git = path.resolve(root, gitdir)
    hooks = path.resolve(git, 'hooks')
    precommit = path.resolve(hooks, 'pre-commit')
  }
}

//
// Bail out if we don't have an `.git` directory as the hooks will not get
// triggered. If we do have directory create a hooks folder if it doesn't exist.
//
if (!git) {
  console.log('pre-commit:')
  console.log('pre-commit: Not found any .git folder for installing pre-commit hook')
  process.exit(0)
}

hooks = path.resolve(git, 'hooks')
precommit = path.resolve(hooks, 'pre-commit')

if (!exists(hooks)) fs.mkdirSync(hooks)

//
// If there's an existing `pre-commit` hook we want to back it up instead of
// overriding it and losing it completely as it might contain something
// important.
//
if (exists(precommit) && !fs.lstatSync(precommit).isSymbolicLink()) {
  console.log('pre-commit:')
  console.log('pre-commit: Detected an existing git pre-commit hook')
  fs.writeFileSync(precommit + '.old', fs.readFileSync(precommit))
  console.log('pre-commit: Old pre-commit hook backuped to pre-commit.old')
  console.log('pre-commit:')
}

//
// We cannot create a symlink over an existing file so make sure it's gone and
// finish the installation process.
//
try { fs.unlinkSync(precommit) } catch {}

// Create generic precommit hook that launches this modules hook (as well
// as stashing - unstashing the unstaged changes)
// TODO: we could keep launching the old pre-commit scripts
let hookRelativeUnixPath = hook.replace(root, '.')

if (os.platform() === 'win32') {
  hookRelativeUnixPath = hookRelativeUnixPath.replace(/[\\/]+/g, '/')
}

const precommitContent = '#!/usr/bin/env bash' + os.EOL +
  'if git diff --cached --quiet; then' + os.EOL +
  '  echo "No staged changes detected, skipping pre-commit hook."' + os.EOL +
  '  exit 0' + os.EOL +
  'fi' + os.EOL +
  hookRelativeUnixPath + os.EOL +
  'RESULT=$?' + os.EOL +
  '[ $RESULT -ne 0 ] && exit 1' + os.EOL +
  'exit 0' + os.EOL

//
// It could be that we do not have rights to this folder which could cause the
// installation of this module to completely fail. We should just output the
// error instead destroying the whole npm install process.
//
try { fs.writeFileSync(precommit, precommitContent) } catch (e) {
  console.error('pre-commit:')
  console.error('pre-commit: Failed to create the hook file in your .git/hooks folder because:')
  console.error('pre-commit: ' + e.message)
  console.error('pre-commit: The hook was not installed.')
  console.error('pre-commit:')
}

try { fs.chmodSync(precommit, '777') } catch (e) {
  console.error('pre-commit:')
  console.error('pre-commit: chmod 0777 the pre-commit file in your .git/hooks folder because:')
  console.error('pre-commit: ' + e.message)
  console.error('pre-commit:')
}