Merge pull request #8671 from xuanxu/fix_irregular

Inflector irregular singularize rules

activesupport/lib/active_support/inflector/inflections.rb

@@ -132,6 +132,7 @@ def irregular(singular, plural)
           plural(Regexp.new("(#{singular[0,1]})#{singular[1..-1]}$", "i"), '\1' + plural[1..-1])
           plural(Regexp.new("(#{plural[0,1]})#{plural[1..-1]}$", "i"), '\1' + plural[1..-1])
           singular(Regexp.new("(#{plural[0,1]})#{plural[1..-1]}$", "i"), '\1' + singular[1..-1])
+          singular(Regexp.new("(#{singular[0,1]})#{singular[1..-1]}$", "i"), '\1' + singular[1..-1])
         else
           plural(Regexp.new("#{singular[0,1].upcase}(?i)#{singular[1..-1]}$"), plural[0,1].upcase + plural[1..-1])
           plural(Regexp.new("#{singular[0,1].downcase}(?i)#{singular[1..-1]}$"), plural[0,1].downcase + plural[1..-1])
@@ -139,6 +140,8 @@ def irregular(singular, plural)
           plural(Regexp.new("#{plural[0,1].downcase}(?i)#{plural[1..-1]}$"), plural[0,1].downcase + plural[1..-1])
           singular(Regexp.new("#{plural[0,1].upcase}(?i)#{plural[1..-1]}$"), singular[0,1].upcase + singular[1..-1])
           singular(Regexp.new("#{plural[0,1].downcase}(?i)#{plural[1..-1]}$"), singular[0,1].downcase + singular[1..-1])
+          singular(Regexp.new("#{singular[0,1].upcase}(?i)#{singular[1..-1]}$"), singular[0,1].upcase + singular[1..-1])
+          singular(Regexp.new("#{singular[0,1].downcase}(?i)#{singular[1..-1]}$"), singular[0,1].downcase + singular[1..-1])
         end
       end
 

activesupport/test/inflector_test_cases.rb

@@ -310,5 +310,6 @@ module InflectorTestCases
     'move'   => 'moves',
     'cow'    => 'kine',
     'zombie' => 'zombies',
+    'genus'  => 'genera'
   }
 end