A simple pre-commit hook to halt commits if Rubocop fails. Can be overridden if necessary.

pre-commit.sh

#!/usr/bin/env ruby

require 'english'
require 'rubocop'

ADDED_OR_MODIFIED = /A|AM|^M/.freeze

changed_files = `git status --porcelain`.split(/\n/).
    select { |file_name_with_status|
      file_name_with_status =~ ADDED_OR_MODIFIED
    }.
    map { |file_name_with_status|
      file_name_with_status.split(' ')[1]
    }.
    select { |file_name|
      File.extname(file_name) == '.rb'
    }.join(' ')

success = system(%(rubocop #{changed_files}))

STDIN.reopen('/dev/tty')

if success == false
  puts "Would you like to continue? Press any key or 'n/N' to halt commit."
  exit(1) if %w(N n).include?(gets.chomp)
end

~README.md

Pre-Commit Hook

Place pre-commit.sh into your project's root directory, then before making changes to your repository, copy pre-commit.sh to the repo .git/hooks folder using:

ln -s ../../pre-commit.sh .git/hooks/pre-commit

This hook halts your commit if there are any Rubocop errors. You can abort the commit with n/N or ignore warnings and commit anyway with any other key.

Best practice is to abort the commit and run rubocop -a to attempt to autocorrect any errors, and manually correct any remaining complaints. Then, re-add your files and commit again. For instance:

git add .
git commit -m "Commit message"