Bundler and Yarn update git hooks

README.md

Git hooks for Ruby on Rails

Tired of forgetting to run bundle after you pulled a branch?

Tired of getting Yarn's integrity error message because you forgot bin/yarn?

Just have Git run those for you after most Git operations that would change Gemfile.lock or package.json!

Install

• Put post-checkout, post-merge (no .rb extension) and utils/ inside .git/hooks
• chmod u+x .git/hooks/post-checkout .git/hooks/post-merge

Caveats

• You'll need a bit more time to get your prompt back, but chances are, you would run those commands anyway, right?
• There is no git hook that can run after a git reset operation.

post-checkout.rb

# .git/hooks/post-checkout

#!/usr/bin/env ruby

require_relative "utils/changed_files"
require_relative "utils/file_change_handler"

class PostCheckout
  def initialize(old_head, new_head, changing_branches)
    @old_head = old_head
    @new_head = new_head
    @changing_branches = changing_branches
  end

  def run
    FileChangeHandler.new(changed_files).run
  end

  private

    attr_reader :old_head, :new_head

    def changing_branches?
      @changing_branches == "1"
    end

    def changed_files
      @_changed_files ||= ChangedFiles.new(old_head, new_head)
    end
end

PostCheckout.new(*ARGV).run

post-merge.rb

# .git/hooks/post-merge

#!/usr/bin/env ruby

# Remove .rb extension (used for Git syntax highlighting) and chmod u+x

require_relative "utils/changed_files"
require_relative "utils/file_change_handler"

class PostMerge
  def initialize(squash_merge)
    @squash_merge = squash_merge
  end

  def run
    FileChangeHandler.new(changed_files).run
  end

  private

    def squash_merge?
      @squash_merge == "1"
    end

    def changed_files
      @_changed_files ||= ChangedFiles.new("ORIG_HEAD", "HEAD")
    end
end

PostMerge.new(*ARGV).run

utils__changed_files.rb

#.git/hooks/utils/changed_files.rb

require "open3"

class ChangedFiles < Array
  def initialize(old_head, new_head)
    @old_head = old_head
    @new_head = new_head
    super(changed_files)
  end

  private

    attr_reader :old_head, :new_head

    def changed_files
      command_output.lines.map(&:chomp)
    end

    def command_output
      Open3.capture2(*command).tap do |output, status|
        raise "There was an error" if status.exitstatus != 0
        return output
      end
    end

    def command
      %w(git diff-tree -r --name-only --no-commit-id) + [old_head, new_head]
    end
end

utils__file_change_handler.rb

# .git/hooks/utils/file_change_handler.rb

class FileChangeHandler
  def initialize(changed_files)
    @changed_files = changed_files
  end

  def run
    run_bundle
    run_yarn
  end

  private

    attr_reader :changed_files

    def run_bundle
      return unless changed_files.include?("Gemfile.lock")

      puts "Running Bundler after git changed Gemfile.lock..."
      system("bundle")
    end

    def run_yarn
      return unless changed_files.include?("package.json")

      puts "Running Yarn after git changed packages.json..."
      system("bin/yarn")
    end
end