Return a sized Enumerator from Hash#transform_values{!}

But transform_keys{!} can't settlement own size.

activesupport/lib/active_support/core_ext/hash/keys.rb

@@ -10,7 +10,7 @@ class Hash
   #
   #  hash.transform_keys.with_index { |k, i| [k, i].join } # => {"name0"=>"Rob", "age1"=>"28"}
   def transform_keys
-    return enum_for(:transform_keys) unless block_given?
+    return enum_for(:transform_keys) { size } unless block_given?
     result = self.class.new
     each_key do |key|
       result[yield(key)] = self[key]
@@ -21,7 +21,7 @@ def transform_keys
   # Destructively converts all keys using the +block+ operations.
   # Same as +transform_keys+ but modifies +self+.
   def transform_keys!
-    return enum_for(:transform_keys!) unless block_given?
+    return enum_for(:transform_keys!) { size } unless block_given?
     keys.each do |key|
       self[yield(key)] = delete(key)
     end

activesupport/test/core_ext/hash/transform_keys_test.rb

@@ -21,12 +21,14 @@ class TransformKeysTest < ActiveSupport::TestCase
   test "transform_keys returns an Enumerator if no block is given" do
     original = { a: 'a', b: 'b' }
     enumerator = original.transform_keys
+    assert_nil enumerator.size
     assert_equal Enumerator, enumerator.class
   end
 
   test "transform_keys! returns an Enumerator if no block is given" do
     original = { a: 'a', b: 'b' }
     enumerator = original.transform_keys!
+    assert_nil enumerator.size
     assert_equal Enumerator, enumerator.class
   end
 

activesupport/test/core_ext/hash/transform_values_test.rb

@@ -47,15 +47,17 @@ class TransformValuesTest < ActiveSupport::TestCase
     assert_nil mapped[:b]
   end
 
-  test "transform_values returns an Enumerator if no block is given" do
+  test "transform_values returns a sized Enumerator if no block is given" do
     original = { a: 'a', b: 'b' }
     enumerator = original.transform_values
+    assert_equal original.size, enumerator.size
     assert_equal Enumerator, enumerator.class
   end
 
-  test "transform_values! returns an Enumerator if no block is given" do
+  test "transform_values! returns a sized Enumerator if no block is given" do
     original = { a: 'a', b: 'b' }
     enumerator = original.transform_values!
+    assert_equal original.size, enumerator.size
     assert_equal Enumerator, enumerator.class
   end