5 files changed, 10 insertions, 8 deletions
diff --git a/activesupport/lib/active_support/cache/mem_cache_store.rb b/activesupport/lib/active_support/cache/mem_cache_store.rb
index 530839b24d..e38a8387b4 100644
--- a/activesupport/lib/active_support/cache/mem_cache_store.rb
+++ b/activesupport/lib/active_support/cache/mem_cache_store.rb
@@ -165,7 +165,7 @@ module ActiveSupport
         # characters properly.
         def escape_key(key)
           key = key.to_s.dup
-          key = key.force_encoding("BINARY") if key.encoding_aware?
+          key = key.force_encoding("BINARY")
           key = key.gsub(ESCAPE_KEY_CHARS){ |match| "%#{match.getbyte(0).to_s(16).upcase}" }
           key = "#{key[0, 213]}:md5:#{Digest::MD5.hexdigest(key)}" if key.size > 250
           key
diff --git a/activesupport/lib/active_support/core_ext/string/encoding.rb b/activesupport/lib/active_support/core_ext/string/encoding.rb
index 236f72e933..dc635ed6a5 100644
--- a/activesupport/lib/active_support/core_ext/string/encoding.rb
+++ b/activesupport/lib/active_support/core_ext/string/encoding.rb
@@ -1,5 +1,8 @@
+require 'active_support/deprecation'
+
 class String
   def encoding_aware?
+    ActiveSupport::Deprecation.warn 'String#encoding_aware? is deprecated', caller
     true
   end
-end
-\ No newline at end of file
+end
diff --git a/activesupport/lib/active_support/gzip.rb b/activesupport/lib/active_support/gzip.rb
index 9651f02c73..f7036315d6 100644
--- a/activesupport/lib/active_support/gzip.rb
+++ b/activesupport/lib/active_support/gzip.rb
@@ -8,7 +8,7 @@ module ActiveSupport
     class Stream < StringIO
       def initialize(*)
         super
-        set_encoding "BINARY" if "".encoding_aware?
+        set_encoding "BINARY"
       end
       def close; rewind; end
     end
diff --git a/activesupport/test/core_ext/string_ext_test.rb b/activesupport/test/core_ext/string_ext_test.rb
index aeae2579b4..2e44cbe247 100644
--- a/activesupport/test/core_ext/string_ext_test.rb
+++ b/activesupport/test/core_ext/string_ext_test.rb
@@ -445,7 +445,9 @@ class OutputSafetyTest < ActiveSupport::TestCase
   end
 
   test 'knows whether it is encoding aware' do
-    assert 'ruby'.encoding_aware?
+    assert_deprecated do
+      assert 'ruby'.encoding_aware?
+    end
   end
 
   test "call to_param returns a normal string" do
diff --git a/activesupport/test/gzip_test.rb b/activesupport/test/gzip_test.rb
index f564e63f29..626981dc9d 100644
--- a/activesupport/test/gzip_test.rb
+++ b/activesupport/test/gzip_test.rb
@@ -9,10 +9,7 @@ class GzipTest < Test::Unit::TestCase
   def test_compress_should_return_a_binary_string
     compressed = ActiveSupport::Gzip.compress('')
 
-    if "".encoding_aware?
-      assert_equal Encoding.find('binary'), compressed.encoding
-    end
-
+    assert_equal Encoding.find('binary'), compressed.encoding
     assert !compressed.blank?, "a compressed blank string should not be blank"
   end
 end