1 files changed, 52 insertions, 26 deletions

diff --git a/activesupport/lib/active_support/core_ext/hash/keys.rb b/activesupport/lib/active_support/core_ext/hash/keys.rb
index 3d41aa8572..9297a59c46 100644
--- a/activesupport/lib/active_support/core_ext/hash/keys.rb
+++ b/activesupport/lib/active_support/core_ext/hash/keys.rb
@@ -6,7 +6,8 @@ class Hash
   #  hash.transform_keys{ |key| key.to_s.upcase }
   #  # => {"NAME"=>"Rob", "AGE"=>"28"}
   def transform_keys
-    result = {}
+    return enum_for(:transform_keys) unless block_given?
+    result = self.class.new
     each_key do |key|
       result[yield(key)] = self[key]
     end
@@ -16,6 +17,7 @@ class Hash
   # Destructively convert all keys using the block operations.
   # Same as transform_keys but modifies +self+.
   def transform_keys!
+    return enum_for(:transform_keys!) unless block_given?
     keys.each do |key|
       self[yield(key)] = delete(key)
     end
@@ -27,15 +29,15 @@ class Hash
   #   hash = { name: 'Rob', age: '28' }
   #
   #   hash.stringify_keys
-  #   # => { "name" => "Rob", "age" => "28" }
+  #   # => {"name"=>"Rob", "age"=>"28"}
   def stringify_keys
-    transform_keys{ |key| key.to_s }
+    transform_keys(&:to_s)
   end
 
   # Destructively convert all keys to strings. Same as
   # +stringify_keys+, but modifies +self+.
   def stringify_keys!
-    transform_keys!{ |key| key.to_s }
+    transform_keys!(&:to_s)
   end
 
   # Returns a new hash with all keys converted to symbols, as long as
@@ -44,7 +46,7 @@ class Hash
   #   hash = { 'name' => 'Rob', 'age' => '28' }
   #
   #   hash.symbolize_keys
-  #   # => { name: "Rob", age: "28" }
+  #   # => {:name=>"Rob", :age=>"28"}
   def symbolize_keys
     transform_keys{ |key| key.to_sym rescue key }
   end
@@ -57,9 +59,11 @@ class Hash
   end
   alias_method :to_options!, :symbolize_keys!
 
-  # Validate all keys in a hash match <tt>*valid_keys</tt>, raising ArgumentError
-  # on a mismatch. Note that keys are NOT treated indifferently, meaning if you
-  # use strings for keys but assert symbols as keys, this will fail.
+  # Validate all keys in a hash match <tt>*valid_keys</tt>, raising
+  # ArgumentError on a mismatch.
+  #
+  # Note that keys are treated differently than HashWithIndifferentAccess,
+  # meaning that string and symbol keys will not match.
   #
   #   { name: 'Rob', years: '28' }.assert_valid_keys(:name, :age) # => raises "ArgumentError: Unknown key: :years. Valid keys are: :name, :age"
   #   { name: 'Rob', age: '28' }.assert_valid_keys('name', 'age') # => raises "ArgumentError: Unknown key: :name. Valid keys are: 'name', 'age'"
@@ -75,53 +79,45 @@ class Hash
 
   # Returns a new hash with all keys converted by the block operation.
   # This includes the keys from the root hash and from all
-  # nested hashes.
+  # nested hashes and arrays.
   #
   #  hash = { person: { name: 'Rob', age: '28' } }
   #
   #  hash.deep_transform_keys{ |key| key.to_s.upcase }
   #  # => {"PERSON"=>{"NAME"=>"Rob", "AGE"=>"28"}}
   def deep_transform_keys(&block)
-    result = {}
-    each do |key, value|
-      result[yield(key)] = value.is_a?(Hash) ? value.deep_transform_keys(&block) : value
-    end
-    result
+    _deep_transform_keys_in_object(self, &block)
   end
 
   # Destructively convert all keys by using the block operation.
   # This includes the keys from the root hash and from all
-  # nested hashes.
+  # nested hashes and arrays.
   def deep_transform_keys!(&block)
-    keys.each do |key|
-      value = delete(key)
-      self[yield(key)] = value.is_a?(Hash) ? value.deep_transform_keys!(&block) : value
-    end
-    self
+    _deep_transform_keys_in_object!(self, &block)
   end
 
   # Returns a new hash with all keys converted to strings.
   # This includes the keys from the root hash and from all
-  # nested hashes.
+  # nested hashes and arrays.
   #
   #   hash = { person: { name: 'Rob', age: '28' } }
   #
   #   hash.deep_stringify_keys
   #   # => {"person"=>{"name"=>"Rob", "age"=>"28"}}
   def deep_stringify_keys
-    deep_transform_keys{ |key| key.to_s }
+    deep_transform_keys(&:to_s)
   end
 
   # Destructively convert all keys to strings.
   # This includes the keys from the root hash and from all
-  # nested hashes.
+  # nested hashes and arrays.
   def deep_stringify_keys!
-    deep_transform_keys!{ |key| key.to_s }
+    deep_transform_keys!(&:to_s)
   end
 
   # Returns a new hash with all keys converted to symbols, as long as
   # they respond to +to_sym+. This includes the keys from the root hash
-  # and from all nested hashes.
+  # and from all nested hashes and arrays.
   #
   #   hash = { 'person' => { 'name' => 'Rob', 'age' => '28' } }
   #
@@ -133,8 +129,38 @@ class Hash
 
   # Destructively convert all keys to symbols, as long as they respond
   # to +to_sym+. This includes the keys from the root hash and from all
-  # nested hashes.
+  # nested hashes and arrays.
   def deep_symbolize_keys!
     deep_transform_keys!{ |key| key.to_sym rescue key }
   end
+
+  private
+    # support methods for deep transforming nested hashes and arrays
+    def _deep_transform_keys_in_object(object, &block)
+      case object
+      when Hash
+        object.each_with_object({}) do |(key, value), result|
+          result[yield(key)] = _deep_transform_keys_in_object(value, &block)
+        end
+      when Array
+        object.map {|e| _deep_transform_keys_in_object(e, &block) }
+      else
+        object
+      end
+    end
+
+    def _deep_transform_keys_in_object!(object, &block)
+      case object
+      when Hash
+        object.keys.each do |key|
+          value = object.delete(key)
+          object[yield(key)] = _deep_transform_keys_in_object!(value, &block)
+        end
+        object
+      when Array
+        object.map! {|e| _deep_transform_keys_in_object!(e, &block)}
+      else
+        object
+      end
+    end
 end