Return a sized Enumerator from Hash#{transform_values{!}|transform_keys{!}}

4 files changed, 12 insertions, 8 deletions

diff --git a/activesupport/lib/active_support/core_ext/hash/keys.rb b/activesupport/lib/active_support/core_ext/hash/keys.rb
index 05679f1dd0..963c6a8e67 100644
--- a/activesupport/lib/active_support/core_ext/hash/keys.rb
+++ b/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 @@ class Hash
   # 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
diff --git a/activesupport/lib/active_support/core_ext/hash/transform_values.rb b/activesupport/lib/active_support/core_ext/hash/transform_values.rb
index 9ddb838774..7d507ac998 100644
--- a/activesupport/lib/active_support/core_ext/hash/transform_values.rb
+++ b/activesupport/lib/active_support/core_ext/hash/transform_values.rb
@@ -9,7 +9,7 @@ class Hash
   #
   #   { a: 1, b: 2 }.transform_values.with_index { |v, i| [v, i].join.to_i } # => { a: 10, b: 21 }
   def transform_values
-    return enum_for(:transform_values) unless block_given?
+    return enum_for(:transform_values) { size } unless block_given?
     return {} if empty?
     result = self.class.new
     each do |key, value|
@@ -21,7 +21,7 @@ class Hash
   # Destructively converts all values using the +block+ operations.
   # Same as +transform_values+ but modifies +self+.
   def transform_values!
-    return enum_for(:transform_values!) unless block_given?
+    return enum_for(:transform_values!) { size } unless block_given?
     each do |key, value|
       self[key] = yield(value)
     end
diff --git a/activesupport/test/core_ext/hash/transform_keys_test.rb b/activesupport/test/core_ext/hash/transform_keys_test.rb
index 5a0b99e22c..99af274614 100644
--- a/activesupport/test/core_ext/hash/transform_keys_test.rb
+++ b/activesupport/test/core_ext/hash/transform_keys_test.rb
@@ -18,15 +18,17 @@ class TransformKeysTest < ActiveSupport::TestCase
     assert_same original, mapped
   end
 
-  test "transform_keys returns an Enumerator if no block is given" do
+  test "transform_keys returns a sized Enumerator if no block is given" do
     original = { a: 'a', b: 'b' }
     enumerator = original.transform_keys
+    assert_equal original.size, enumerator.size
     assert_equal Enumerator, enumerator.class
   end
 
-  test "transform_keys! returns an Enumerator if no block is given" do
+  test "transform_keys! returns a sized Enumerator if no block is given" do
     original = { a: 'a', b: 'b' }
     enumerator = original.transform_keys!
+    assert_equal original.size, enumerator.size
     assert_equal Enumerator, enumerator.class
   end
 
diff --git a/activesupport/test/core_ext/hash/transform_values_test.rb b/activesupport/test/core_ext/hash/transform_values_test.rb
index 7c33227dc0..114022fbaf 100644
--- a/activesupport/test/core_ext/hash/transform_values_test.rb
+++ b/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