Git commit message spell check hook (kind of a proof of concept, but still usable)

commit-msg

#!/usr/bin/env ruby

# 1. Install hunspell
# $ brew install hunspell

# 2. Download a dictionary and install it in a path listed by `hunspell -D`
# $ open http://wiki.services.openoffice.org/wiki/Dictionaries

# 3. Move this file into your repository
# $ mv commit-msg /path/to/repo/.git/hooks
# $ chmod +x /path/to/repo/.git/hooks/commit-msg

# 4. Get mad each time you try to commit
# $ git commit -m "Fix some spelling erorrs in the layout"

class GitSpellCheckeCommit
  def self.locale=(locale)
    @@locale = locale
  end

  def initialize(file)
    @file = file
  end

  def validate!
    @check = `cat #{@file} | LC_ALL=#{@@locale} hunspell`
  end

  def valid?
    validate! =~ /&/ ? false : true
  end

  def spelling_errors
    @check.split("\n").select{ |line| line =~ /^&/ }.map do |line|
      matches = line.match(/^&\s([^\s]+)\s\d+\s\d+:\s(.+)$/)
      "- You used “#{matches[1]}” and hunspell suggested instead “#{matches[2]}”"
    end
  end
end

GitSpellCheckeCommit.locale = :en_US
commit = GitSpellCheckeCommit.new(ARGV.first)

unless commit.valid?
  puts "---------------------------------------------------------------------"
  puts "It looks like you have spell checking errors in your commit message:"
  puts commit.spelling_errors.join("\n")
  puts "---------------------------------------------------------------------"
  exit 1 # comment this line if you only want the hook to list errors and keep on with the commit
end

exit 0