Use LC_MESSAGES env for Locale.locale

Locale.charset keep using LC_CTYPE.

This change is backward imcompatible change. But the current behavior
is a bug. So this change is reasonable.

GitHub: fix #2

Debian Bug: #690572

Reported by Stefano Zacchiroli. Thanks!!!
Reported by Hleb Valoshka. Thanks!!!

lib/locale/driver/env.rb

@@ -34,19 +34,19 @@ module Driver
     module Env
       module_function
 
-      # Gets the locale from environment variable. (LC_ALL > LC_CTYPE > LANG)
+      # Gets the locale from environment variable. (LC_ALL > LC_MESSAGES > LANG)
       # Returns: the locale as Locale::Tag::Posix.
       def locale
         # At least one environment valiables should be set on *nix system.
-        [ENV["LC_ALL"], ENV["LC_CTYPE"], ENV["LANG"]].each do |loc|
+        [ENV["LC_ALL"], ENV["LC_MESSAGES"], ENV["LANG"]].each do |loc|
           if loc != nil and loc.size > 0
             return Locale::Tag::Posix.parse(loc)
           end
         end
         nil
       end
 
-      # Gets the locales from environment variables. (LANGUAGE > LC_ALL > LC_CTYPE > LANG)
+      # Gets the locales from environment variables. (LANGUAGE > LC_ALL > LC_MESSAGES > LANG)
       # * Returns: an Array of the locale as Locale::Tag::Posix or nil.
       def locales
         locales = ENV["LANGUAGE"]
@@ -61,14 +61,16 @@ def locales
         nil
       end
 
-      # Gets the charset from environment variable or return nil.
+      # Gets the charset from environment variables
+      # (LC_ALL > LC_CTYPE > LANG) or return nil.
       # * Returns: the system charset.
       def charset  # :nodoc:
-        if loc = locale
-          loc.charset
-        else
-          nil
+        [ENV["LC_ALL"], ENV["LC_CTYPE"], ENV["LANG"]].each do |env|
+          next if env.nil?
+          next if env.empty?
+          return Locale::Tag::Posix.parse(env).charset
         end
+        nil
       end
     end
 

lib/locale/driver/posix.rb

@@ -30,7 +30,7 @@ module Posix
       $stderr.puts self.name + " is loaded." if $DEBUG
 
       module_function
-      # Gets the locales from environment variables. (LANGUAGE > LC_ALL > LC_CTYPE > LANG)
+      # Gets the locales from environment variables. (LANGUAGE > LC_ALL > LC_MESSAGES > LANG)
       # Only LANGUAGE accept plural languages such as "nl_BE;
       # * Returns: an Array of the locale as Locale::Tag::Posix or nil.
       def locales

test/test_detect_general.rb

@@ -29,13 +29,14 @@ def setup
     Locale.clear_all
     ENV["LC_ALL"] = nil
     ENV["LC_CTYPE"] = nil
+    ENV["LC_MESSAGES"] = nil
     ENV["LANG"] = nil
     ENV["LANGUAGE"] = nil
   end
 
   def test_lc_all
     ENV["LC_ALL"] = "ja_JP.eucJP"
-    ENV["LC_CTYPE"] = "zh_CN.UTF-8"  #Ignored.
+    ENV["LC_MESSAGES"] = "zh_CN.UTF-8"  #Ignored.
     ENV["LANG"] = "ko_KR.UTF-8"  #Ignored.
     ENV["LANGUAGE"] = nil
 
@@ -49,9 +50,9 @@ def test_lc_all
     assert_equal "eucJP", Locale.charset
   end
 
-  def test_lc_ctype
+  def test_lc_messages
     ENV["LC_ALL"] = nil
-    ENV["LC_CTYPE"] = "ja_JP.eucJP"
+    ENV["LC_MESSAGES"] = "ja_JP.eucJP"
     ENV["LANG"] = "ko_KR.UTF-8"  #Ignored.
     ENV["LANGUAGE"] = nil
 
@@ -62,12 +63,12 @@ def test_lc_ctype
     assert_equal "eucJP", lang.charset
     assert_equal Locale::Tag::Posix.new("ja", "JP", "eucJP"), lang
 
-    assert_equal "eucJP", Locale.charset
+    assert_equal "UTF-8", Locale.charset
   end
 
   def test_lang
     ENV["LC_ALL"] = nil
-    ENV["LC_CTYPE"] = nil
+    ENV["LC_MESSAGES"] = nil
     ENV["LANG"] = "ja_JP.eucJP"
     ENV["LANGUAGE"] = nil
 
@@ -83,7 +84,7 @@ def test_lang
 
   def test_lang_complex
     ENV["LC_ALL"] = "zh_CN.UTF-8"  # Ignored.
-    ENV["LC_CTYPE"] = "ko_KR.UTF-8" #Ingored.
+    ENV["LC_MESSAGES"] = "ko_KR.UTF-8" #Ingored.
     ENV["LANG"] = "en_US.UTF-8"  # Ignored.
     ENV["LANGUAGE"] ="ja_JP.eucJP:zh_CN.UTF-8"
 
@@ -232,6 +233,40 @@ def test_clear
 
   end
 
+  class TestCharset < self
+    def test_lc_all
+      ENV["LC_ALL"] = "ja_JP.eucJP"
+      ENV["LC_CTYPE"] = "ko_KR.eucKR" # Ignored.
+      ENV["LANG"] = "fr_FR.ISO-8859-1" # Ignored.
+
+      assert_equal("eucJP", Locale.charset)
+    end
+
+    def test_lc_ctype
+      ENV["LC_ALL"] = nil
+      ENV["LC_CTYPE"] = "ko_KR.eucKR"
+      ENV["LANG"] = "fr_FR.ISO-8859-1" # Ignored.
+
+      assert_equal("eucKR", Locale.charset)
+    end
+
+    def test_lc_messages
+      ENV["LC_ALL"] = nil
+      ENV["LC_MESSAGES"] = "ko_KR.eucKR" # Ignored.
+      ENV["LANG"] = "fr_FR.ISO-8859-1"
+
+      assert_equal("ISO-8859-1", Locale.charset)
+    end
+
+    def test_lang
+      ENV["LC_ALL"] = nil
+      ENV["LC_CTYPE"] = nil
+      ENV["LANG"] = "fr_FR.ISO-8859-1"
+
+      assert_equal("ISO-8859-1", Locale.charset)
+    end
+  end
+
   private
   def jruby?
     RUBY_PLATFORM == "java"