A Language should know about it's language_id

lib/linguist/language.rb

@@ -289,6 +289,9 @@ module Linguist
       # Set legacy search term
       @search_term = attributes[:search_term] || default_alias_name
 
+      # Set the language_id 
+      @language_id = attributes[:language_id]
+
       # Set extensions or default to [].
       @extensions = attributes[:extensions] || []
       @interpreters = attributes[:interpreters]   || []
@@ -351,6 +354,17 @@ module Linguist
     # Returns the name String
     attr_reader :search_term
 
+    # Public: Get language_id (used in GitHub search)
+    #
+    # Examples
+    #
+    #   # => "1"
+    #   # => "2"
+    #   # => "3"
+    #
+    # Returns the integer language_id
+    attr_reader :language_id
+
     # Public: Get the name of a TextMate-compatible scope
     #
     # Returns the scope
@@ -547,6 +561,7 @@ module Linguist
       :group_name        => options['group'],
       :searchable        => options.fetch('searchable', true),
       :search_term       => options['search_term'],
+      :language_id       => options['language_id'],
       :extensions        => Array(options['extensions']),
       :interpreters      => options['interpreters'].sort,
       :filenames         => options['filenames'],

test/test_language.rb

@@ -386,6 +386,14 @@ class TestLanguage < Minitest::Test
     assert missing.empty?, message
   end
 
+  def test_all_languages_have_a_language_id_set
+    missing = Language.all.select { |language| language.language_id.nil? }
+
+    message = "The following languages do not have a language_id listed in languages.yml. Please add language_id fields for all new languages.\n"
+    missing.each { |language| message << "#{language.name}\n" }
+    assert missing.empty?, message
+  end
+
   def test_all_languages_have_a_valid_ace_mode
     ace_fixture_path = File.join('test', 'fixtures', 'ace_modes.json')
     skip("No ace_modes.json file") unless File.exist?(ace_fixture_path)