bin/erb: change template file encoding to UTF-8

Unlike Ruby source file encoding (script encoding) whose default is
changed to UTF-8 in Ruby 2.0 (Feature #6679), template's file encoding
given to erb(1) has been ASCII-8BIT since ERB supports m17n at r21170.

Like Ruby source file encoding, erb template file encoding should be
UTF-8 in Ruby 2.

[Bug #14095] [ruby-core:83708]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@60739 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

NEWS

@@ -143,6 +143,8 @@ with all sufficient information, see the ChangeLog file or Redmine
 * ERB
   * Add ERB#result_with_hash to render a template with local variables passed
     with a Hash object. [Feature #8631]
+  * Default template file encoding is changed from ASCII-8BIT to UTF-8 in erb
+    command. [Bug #14095]
 
   * Carriage returns are changed to be trimmed properly if trim_mode is specified
     and used. Duplicated newlines will be removed on Windows. [Bug #5339] [Bug #11464]

bin/erb

@@ -122,7 +122,7 @@ EOU
         exit 1
       end
 
-      $<.set_encoding(Encoding::ASCII_8BIT, nil)
+      $<.set_encoding(Encoding::UTF_8, nil)
       src = $<.read
       filename = $FILENAME
       exit 2 unless src

test/erb/test_erb_command.rb

@@ -9,4 +9,10 @@ class TestErbCommand < Test::Unit::TestCase
                        "var=hoge"],
                       "<%=var%>", ["hoge"])
   end
+
+  def test_template_file_encoding
+    assert_in_out_err(["-w",
+                       File.expand_path("../../../bin/erb", __FILE__)],
+                      "<%=''.encoding.to_s%>", ["UTF-8"])
+  end
 end