Module: Jekyll::External

Defined in:
lib/jekyll/external.rb

Class Method Summary collapse

Class Method Details

.blessed_gemsObject

Gems that, if installed, should be loaded. Usually contain subcommands.


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# File 'lib/jekyll/external.rb', line 10

def blessed_gems
  %w(
    jekyll-compose
    jekyll-docs
    jekyll-import
  )
end

.require_if_present(names) ⇒ Object

Require a gem or file if it's present, otherwise silently fail.

names - a string gem name or array of gem names


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# File 'lib/jekyll/external.rb', line 23

def require_if_present(names)
  Array(names).each do |name|
    begin
      require name
    rescue LoadError
      Jekyll.logger.debug "Couldn't load #{name}. Skipping."
      yield(name, version_constraint(name)) if block_given?
      false
    end
  end
end

.require_with_graceful_fail(names) ⇒ Object

Require a gem or gems. If it's not present, show a very nice error message that explains everything and is much more helpful than the normal LoadError.

names - a string gem name or array of gem names


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# File 'lib/jekyll/external.rb', line 56

def require_with_graceful_fail(names)
  Array(names).each do |name|
    begin
      Jekyll.logger.debug "Requiring:", name.to_s
      require name
    rescue LoadError => e
      Jekyll.logger.error "Dependency Error:", <<~MSG
        Yikes! It looks like you don't have #{name} or one of its dependencies installed.
        In order to use Jekyll as currently configured, you'll need to install this gem.

        If you've run Jekyll with `bundle exec`, ensure that you have included the #{name}
        gem in your Gemfile as well.

        The full error message from Ruby is: '#{e.message}'

        If you run into trouble, you can find helpful resources at https://jekyllrb.com/help/!
      MSG
      raise Jekyll::Errors::MissingDependencyException, name
    end
  end
end

.version_constraint(gem_name) ⇒ Object

The version constraint required to activate a given gem. Usually the gem version requirement is “> 0,” because any version will do. In the case of jekyll-docs, however, we require the exact same version as Jekyll.

Returns a String version constraint in a parseable form for RubyGems.


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# File 'lib/jekyll/external.rb', line 43

def version_constraint(gem_name)
  return "= #{Jekyll::VERSION}" if gem_name.to_s.eql?("jekyll-docs")

  "> 0"
end