Custom Overcommit hook to replace the hook installed by git-lfs (which Overcommit removes)

git_lfs.rb

# .git_hooks/pre_push/git_lfs.rb

# Be sure to enable this hook in .overcommit.yml like this:
#
#  PrePush:
#    GitLfs:
#      enabled: true

module Overcommit::Hook::PrePush
  class GitLfs < Base
    # Overcommit expects you to override this method which will be called
    # everytime your pre-commit hook is run.
    def run
      # Create two arrays to hold our error and warning messages.
      error_lines = []
      warning_lines = []

      # Check if git-lfs executable exists
      path_to_git_lfs = `command -v git-lfs`.strip
      error_lines << "This repository is configured for Git LFS but 'git-lfs' was not found "\
                     "on your path. If you no longer wish to use Git LFS, disable GitLfs in "\
                     ".overcommit.yml." unless File.exist?(path_to_git_lfs)

      # Run the `git lfs pre-push` with supplied remote_name and remote_url accessors
      `git lfs pre-push #{remote_name} #{remote_url}`

      # Overcommit expects 1 of the 3 as return values, `:fail`, `:warn` or `:pass`.
      # If the hook returns `:fail`, the commit will be aborted with our message
      # containing the errors.
      return :fail, error_lines.join("\n") if error_lines.any?

      :pass
    end
  end
end