class Jekyll::GitHubMetadata::MetadataDrop

def build_revision
  @build_revision ||= begin
    ENV["JEKYLL_BUILD_REVISION"] || `git rev-parse HEAD`.strip
  end
end

def content_methods
  super - %w(to_s to_str)
end

def fallback_data
  @fallback_data ||= {}
end

def key?(key)
  return false if key.nil?
  return true if self.class.mutable? && mutations.key?(key)
  respond_to?(key) || fallback_data.key?(key)
end

def keys
  super.sort
end

def mutations
  @mutations ||= {}
end

def to_s
  require "json"
  JSON.pretty_generate to_h
end

def versions
  return @versions if defined?(@versions)
  begin
    require "github-pages"
    @versions = GitHubPages.versions
  rescue LoadError
    @versions = {}
  end
end