pre-commit

#!/usr/bin/env ruby
# encoding: utf-8
#
# A hook script to verify that only syntactically valid ruby code is commited.
# Called by git-commit with no arguments.  The hook should
# exit with non-zero status after issuing an appropriate message if
# it wants to stop the commit.
#
# Put this code into a file called "pre-commit" inside your .git/hooks
# directory, and make sure it is executable ("chmod +x .git/hooks/pre-commit")

# Ruby 2 or higher required
if RUBY_VERSION.to_f < 2.0
  $stderr.puts "Ruby version 2.0 or higher required!"
  exit 1
end

require 'shellwords'
require 'open3'
include Open3

# Set this to true if you want warnings to stop your commit
stop_on_warnings = (%x(git config --bool hooks.stop-on-warnings).chomp != "false")

# Set this to true if you'd like to skip checking erb files
skip_erb_files = (%x(git config --bool hooks.skip-erb-files).chomp == "true")

# Set this if you'd like to use a specific ruby executable to for syntax checking
ruby_compiler = %x(git config hooks.ruby-compiler).chomp
if ruby_compiler.empty?
  compiler_ruby = %x(which ruby).chomp
end

if compiler_ruby.nil? or compiler_ruby == ""
  $stderr.puts "Couldn't find `rbx` or `ruby` executable!"
  exit 1
end

changed_ruby_files = `git diff-index --name-only --cached HEAD`.split("\n").inject([]) do |files, line|
  files << line.chomp if line =~ /(.+\.(e?rb|task|rake|thor)|[Rr]akefile|[Tt]horfile)/
  files
end

warnings_and_errors = []

changed_ruby_files.each do |file|
  next if not File.readable?(file)

  if file =~ /\.erb\z/
    next if skip_erb_files

    # use actual rails ERB renderer
    cmd = "#{compiler_ruby} -e 'require \"action_view\"; puts ActionView::Template::Handlers::Erubis.new(File.read(\"#{file}\")).src' | #{compiler_ruby} -wc"
  else
    cmd = [compiler_ruby, "-wc", file].shelljoin
  end

  errors = []
  popen3(cmd) do |stdin, stdout, stderr|
    errors = stderr.read.split("\n")
  end

  errors.reject!{ |line| line =~ /[0-9]+:\s+warning:/ } unless stop_on_warnings

  if errors.any?
    errors.map!{ |line| line.sub(/#{file}:/, '') }
    warnings_and_errors << "#{file}:\n#{errors.join("\n")}"
  end
end

if warnings_and_errors.any?
  $stderr.puts warnings_and_errors.join("\n\n")
  exit 1
else
  # All is well
  exit 0
end